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dissertation entitled

DROUGHT ADAPTATION IN COMMON BEAN (Phaseolus vulgaris L.)

 

presented by

Ahmed Omar Jama

has been accepted towards fulfillment
of the requirements for

Ph.D. . Crop and Soil Sciences
degree in

 

 

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Date August 27, 1999

 

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DROUGHT ADAPTATION IN COMMON BEAN (Phaseolus vulgaris L.)
By

Ahmed Omar Jama

A DISSERTATION
Submitted to
Michigan State University
in partial fulﬁlment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Crop and Soil Sciences

1999

 

ABSTRACT
Drought Adaptation in Common Bean (Phaseolus vulgaris L.)
BY
Ahmed Omar J ama
Increasing common bean (Phaseolus vulgaris L.) yields in drought prone environments
requires a screening tool to identify resistant genotypes other than yield diﬁ‘erences at
harvest time. Both carbon isotope discrimination (CID) and osmotic adjustment (0A)
have been suggested as screening criteria. However, the relationships of CID and 0A to
yield and its determinants (water use eﬁiciency (WUE), harvest index (HI), and water use)
under stress have not been elucidated. Two resistant and one susceptible genotypes were
subjected to a vegetative water stress from 5-leaf stage (V5) to ﬁrst ﬂower (R1) and to
reproductive water stress from R1 to harvest from 1991 to 1993. Seed yield varied from
28 to 352 g m‘z. Vegetative stress reduced yield by 15 to 30% while reproductive stress
reduced yield by 35 to 50 % with one of the resistant genotypes producing a signiﬁcantly
greater yield than the susceptible genotype under reproductive stress. Reproductive
stress signiﬁcantly reduced CID by 9%. The drought susceptible genotype had 8 to 9%
higher CID than the resistant genotypes under all water regimes. Similarly, the drought
susceptible genotype had a higher level of osmotic adjustment under the reproductive
stress. Relative reductions in biomass and water use efﬁciency strongly and positively
correlated with relative CID reductions in both stress treatments. CID strongly and
positively correlated with pod m’2 (r2 =O.81 p<0.01 n=9). In addition, osmotic adjustment
(r 2 =0.91 p<0.0l n=6) strongly and negatively correlated with yield as well as with yield

detemiinants under the reproductive stress. It is concluded that both carbon isotope

discrimination and osmotic adjustment could be USCﬁll screening criteria for selections in

drought resistance studies but need further veriﬁcation with more diverse genotypes.

ACKNOWLEDGEMENTS

I would like to express my gratitude to my major professor Dr. Eunice Foster for giving
me the opportunity to succeed in my academic life and for being patient with me for a
long time. A lot of thanks to my advisory committee Drs. Irvin Widders, Richard
Harwood, and Alvin Smucker. Other Professors in the Crop and Soil Sciences
Department helped me at times. Among them I must name Dr. G. Philip Robertson, Dr.
Joseph Ritchie, Dr. Jim Kelly, Dr. Bernard Knezek. Mr. Jim Bronson and Mr. Brian
Graﬂ‘ both contributed a lot of leadership and personal help with ﬁeld activities. Mr.
John Ferguson assisted with equipment at various times. Mrs. Gina Centeno helped me
at critical times recently. This work could not have been completed without a lot of help

from other students both graduate and undergraduate. Thanks to everyone who helped.

iv

TABLE OF CONTENTS

LIST OF TABLES ................................................... .vii
LIST OF FIGURES .................................................... x
INTRODUCTION .................................................... 1
REFERENCES ................................................. 3
CHAPTER 1. LITERATURE REVIEW .................................... 5
CONCEPTUAL MODELS ........................................ 8
REFERENCES ................................................ 1 1
CHAPTER 2. BEAN ADAPTATION TO DROUGHT: YIELD COMPONENTS AND
YIELD DETERMINANTS ....................................... 14
ABSTRACT .................................................. 14
INTRODUCTION .............................................. 14
MATERIALS AND METHODS .................................. 15
RESULTS AND DISCUSSIONS .................................. 20
CONCLUSIONS ......................................... 38
REFERENCES ................................................ 40
CHAPTER 3. CARBON ISOTOPE DISCRIMINATION AND COMMON BEAN
ADAPTATION TO DROUGHT .................................. 44
ABSTRACT .................................................. 44
INTRODUCTION .............................................. 45
MATERIALS AND METHODS ................................... 46
RESULTS AND DISCUSSIONS .................................. 51
CONCLUSION .......................................... 69
REFERENCES ................................................ 72
CHAPTER 4. OSMOTIC ADJUSTMENT IN COMMON BEAN SUBJECTED TO
WATER STRESS .............................................. 75
ABSTRACT .................................................. 75
INTRODUCTION .............................................. 75
MATERIALS AND METHODS ................................... 77
v

RESULTS AND DISCUSSIONS .................................. 84

CONCLUSIONS ........................................ 104
REFERENCES ............................................... 105
CHAPTER 5. SUMMARY AND CONCLUSIONS ......................... 110
SUMMARY ................................................. l 10
CONCLUSIONS .............................................. 1 12

LIST OF TABLES

CHAPTER 2. BEAN ADAPTATION TO DROUGHT: YIELD COMPONENTS
AND YIELD DETERMINANTS

Table l. Irrigation treatment and application for three common bean genotypes grown in a
rain shelter at Hickory Corners, Michigan 1991-1993 ........................................ 18

Table 2. Yield , water use eﬁciency (WUE), harvest index (HI), and seasonal water Use
of three common bean genotypes grown under well water conditions (W1),
intermittent vegetative water stress (W2), and terminal reproductive stress (W3) at
Hickory Corners, Michigan 1991-1993 ............................................................... 21

Table 3. Yield , water use emciency (WUE), harvest index (HI), and seasonal water Use
of three common bean genotypes grown under diﬁ‘erent water stress treatments at
Hickory Corners, Michigan 1991-1993 ............................................................... 23

Table 4. Yield , water use emciency (WUE), harvest index (HI), and seasonal water Use
of three common bean genotypes grown under diﬂ‘erent water stress treatments at
Hickory Comets, Michigan 1991-1993 ............................................................... 24

Table 5. Yield components of three common bean genotypes grown under well water
conditions (W1), intermittent vegetative water stress (W 2), and terminal
reproductive stress (W 3) at Hickory Corners, Michigan 1991-1993 .................... 26

Table 6. Yield components of three common bean genotypes grown under diﬁ‘erent
moisture stress treatments at Hickory Corners, Michigan 1991-1993 .................. 27

Table 7. Yield components of three common bean genotypes grown under diﬁ‘erent
moisture stress treatments at Hickory Corners, Michigan 1991-1993 .................. 28

Table 8. Biomass and its components of three common bean genotypes grown under well
watered conditions (W 1), intermittent vegetative water stress (W2), and terminal
reproductive stress (W 3) at Hickory Corners, Michigan 1991-1993 .................... 29

Table 9. The biomass components of three common bean genotypes grown under
diﬁ‘erent moisture stress treatments at Hickory Corners, Michigan 1991-1993 ..... 31

Table 10. The biomass components of three common bean genotypes grown under
diﬁ‘erent moisture stress treatments at Hickory Corners, Michigan 1991-1993 ..... 33

CHAPTER 3. CARBON ISOTOPE DISCRIMINATION AND COMMON BEAN
ADAPTATION TO DROUGHT

Table 1. Irrigation treatment and application for three common bean genotypes grown in a
rain shelter at Hickory Corners, Michigan 1991-1993 ........................................ 49

Table 2. Carbon Isotope Discrimination (CID) of three common bean genotypes grown
under well watered control (W 1 ), vegetative intermittent (W 2), and reproductive
terminal (W3) water stress regimes at Hickory Corners, MI in 1991-1993 ........... 52

Table 3. Carbon isotope discrimination as affected by Moisture stress at diﬁ‘erent growth
stages for three common bean genotypes grown in a rain shelter in Hickory
Corners Michigan in 1991-1993 .......................................................................... 53

Table 4. Relative reductions- (control-stress)/control- in CID, yield, WUE, HI and pod
numbers for three common bean genotypes subjected to an intermittent vegetative
(W2) and a terminal reproductive(W3) moisture stress in Hickory Comers,
Michigan (1991-1993) ...................................................................................... .56

Table 5. The relationships of relative CID reduction-(control-stress)/control- to relative
reductions in biomass, yield and yield determinants for three common bean
genotypes grown under an intermittent vegetative (W 2) and terminal reproductive
(W3) moisture stress at Hickory Comers, Michigan 1991-1993 .......................... 58

CHAPTER 4. OSMOTIC ADJUSTMENT IN COMMON BEAN SUBJECTED TO
WATER STRESS

Table 1. Irrigation treatment and application for three common bean genotypes grown in a
rain shelter at Hickory Comets, Michigan 1991-1993 ........................................ 81

Table 2. Osmotic Adjustment and other water relations variables of common bean grown
at Hickory Corners Michigan under diﬁ'erent moisture treatments, 1991-1993....85

Table 3. Osmotic Adjustment and other water relations variables of common bean grown
at Hickory Corners Michigan under intermittent water stress, 1991-1993 ............ 87

Table 4. Osmotic Adjustment and other water relations variables of common bean grown
at Hickory Corners Michigan under terminal water stress, 1991-1993 ................. 88

Table 5. Osmotic adjustment and leaf water relations of common bean genotypes grown
at Hickory Corners Michigan under intermittent moisture stress 1991-1993 ....... 93

Table 6. Osmotic adjustment and leaf water relations of common bean genotypes grown
at Hickory Comers Michigan under terminal moisture stress 1991-1993 ............. 94

LIST OF FIGURES

CHAPTER 2. BEAN ADAPTATION TO DROUGHT: YIELD COMPONENTS
AND YIELD DETERMINANTS

Figure 1. Maximum and minimum air temperatures for the growing season at experimental
site 1991-1993 ................................................................................................... 17

Figure 2. Different irrigation treatments for three common bean genotypes grown in a rain
shelter at Hickory Corners, Michigan 1991-1993 ................................................ 19

Figure 3. Water use efﬁciency (WUE), harvest index (HI), and seasonal water use and
their relationship with yield and biomass of common bean genotypes grown at
Hickory Corners, Michigan 1991-1993. Data are the pooled water by genotype
means ................................................................................................................. 35

Figure 4. The relationship of water use efﬁciency (WUE), harvest index (HI), and water
use to yield as affected by different moisture stress treatments of common bean
genotypes grown at Hickory Corners, Michigan 1991-1993. Data are ﬁ'om the
pooled year by genotype means ........................................................................... 36

Figure 5. The relationships of water use efﬁciency (WUE), harvest index (HI), and water
use with yield and biomass of three common bean genotypes grown under diﬁ‘erent
water stress treatments at Hickory Corners, M] 1991-1993. Data are the pooled
water by genotype means .................................................................................... 37

CHAPTER 3. CARBON ISOTOPE DISCRIMINATION AND COMMON BEAN
ADAPTATION TO DROUGHT

Figure 1. Maximum and minimum air temperatures for the growing season at experimental
site 1991-1993 ................................................................................................... 47

Figure 2. Different irrigation treatments for three common bean genotypes grown in a rain
shelter at Hickory Corners, Michigan 1991-1993 ................................................ 48

Figure 3. The relationships between carbon isotope discrimination (CID), yield, pod
number, and yield determinants averaged across treatments for common bean
grown at Hickory Corners Michigan in 1991-1993 ............................................. 59

Figure 4. The relationships between CID and yield or yield determinants for three moisture

deﬁcit treatments across three common bean genotypes at Hickory Corners,
Michigan l991-1993.(Data are the pooled genotype by year means) ................... 60

Figure 5. The relationships between CID and yield or yield determinants for three common
bean genotypes grown under different moisture treatments at Hickory Comets,
Michigan 1991-1993.The data are the pooled water by year means ..................... 61

Figure 6. Correlations between CID and yield components under three water deﬁcit
treatments across three common bean genotypes at Hickory Corners, Michigan
1991-1993.(Data are the pooled genotype by year means) .................................. 62

Figure 7. Correlations between CID and the yield components of three common bean
genotypes grown under three moisture treatments at Hickory Comets, Michigan
1991-1993.(Data are the pooled water by year means) ........................................ 64

Figure 8. Relationships between CID and biomass components of three common bean
genotypes grown as aﬁ‘ected by different moisture treatments at Hickory Corners,
Michigan 1991-1993. Data are the pooled genotype by year means ..................... 65

Figure 9. Correlations between CID and biomass components of three common bean
genotypes grown at Hickory Corners, Michigan 1991-1993. Data are the pooled
water by year means ........................................................................................... 68

CHAPTER 4. OSMOTIC ADJUSTMENT IN COMMON BEAN SUBJECTED TO
WATER STRESS

Figure 1. Maximum and minimum air temperatures for the growing season at experimental
site 1991-1993 ................................................................................................... 78

Figure 2. Different irrigation treatments for three common bean genotypes grown in a rain
shelter at Hickory Comers, Michigan 1991-1993 ................................................ 80

Figure 3. Osmotic adjustment and solute accumulation as related to water potential
components at two growth stages for three common bean genotypes grown under
diﬁ‘erential irrigation at Hickory Comets, Michigan 1991-1993 ........................... 89

Figure 4. Relative water content (RWC) as related to osmotic adjustment, solute
accumulation, and water potential components at two growth stages for three
common bean genotypes grown under differential irrigation at Hickory Corners,
1991-993 ............................................................................................................ 90

Figure 5. Seed yield as related to osmotic adjustment, solute accumulation, relative water

content, and water potential components at two growth stages for three common
bean genotypes grown under differential irrigation at Hickory Comets, 1991-
1993 ................................................................................................................... 92

Figure 6. Harvest index (HI) as related to osmotic adjustment, solute accumulation,
relative water content, and water potential components at two growth stages for
three common bean genotypes grown under differential irrigation at Hickory
Corners, 1991-1993 ............................................................................................ 97

Figure 7. Water use eﬁiciency (WUE) as related to osmotic adjustment, solute
accumulation, relative water content, and water potential components at two
growth stages for three common bean genotypes grown under differential
irrigation at Hickory Corners, 1991-1993 ............................................................ 98

Figure 8. Water use at duration of stress as related to osmotic adjustment, solute
accumulation, relative water content, and water potential components at two
growth stages for three common bean genotypes grown under diﬁ‘erential
irrigation at Hickory Corners, 1991-1993 ........................................................... 99

Figure 9. Rooting depth as related to osmotic adjustment, solute accumulation, relative
water content, and water potential components at two growth stages for three
common bean genotypes grown under diﬁ‘erential irrigation at Hickory Corners,
Michigan 1991-1993 ......................................................................................... 100

Figure 10. Carbon isotope discrimination (CID) as related to osmotic adjustment, solute
accumulation, relative water content, and water potential components at two
growth stages for three common bean genotypes grown under differential
irrigation at Hickory Corners, 1991-1993 .......................................................... 10]

xii

INTRODUCTION
Common bean (Phaseolus vulgaris L.) is an important protein source worldwide and its
consumption in the United States has been increasing recently (Holden and Haytowitz,
1998). Drought is the major constraint to bean production after diseases (White et al.,
1990; Laing et al., 1984; Acosta-Gallegos et al.,l998).

The development of drought tolerant genotypes has been hampered by the lack of
screening techniques that easily distinguish between tolerant and susceptible genotypes.
Breeding for drought resistance in drought prone environments requires the existence of
heritable genotypic variation as well as a screening trait that is visible to the breeder
(Clarke and Townley-Smith, 1984). Obviously, such a trait must be directly linked to
yield or to one of the yield determining factors. Yield determining factors such as water
use or water use emciency were reported (Doorenbos and Kassarn, 1979; Stanhill, 1986;
Menéndez and Hall, 1996; Barros and Hanks, 1993) and a multiplicative identity was
proposed (Passioura, 1994) for this relationship as follows:

Yield=water transpired x water-use efﬁciency x harvest index

Field measurements of these factors usually take a whole season are not ﬁnalized
before harvest. On the other hand, physiological or morphological traits can be observed
early in the season. Besides, any trait that could be directly linked to any of the yield
determinants could also be a useful screening tool for yield under drought. Such a
relationship has, indeed, been suggested for traits like carbon isotope discrimination (A)
and osmotic adjustment among others (Ludlow and Muchow, 1990; Ehleringer et al.,
1991).

Seemann and Critchley (1985) reported that common beans do follow the

1

theoretically expected relationship between A and intercellular carbon dioxide
concentration as proposed by Farquhar et al. (1982). In addition, genotypic differences
among common bean cultivars for A have been reported (White et al., 1990; Ehleringer et
al., 1991). However, results linking A to yield or to yield determinants under drought in
common bean were not conclusive (White et al., 1990).

Similarly, there is no consensus on the relationship of osmotic adjustment to yield
under drought (Morgan et al., 1991; Cortes and Sinclair, 1986; Li et al., 1993; Guei and
Wassom, 1993; Kumar and Singh, 1998', Blum, 1989; Rodriguez et al., 1992) with some
studies suggesting that osmotic adjustment may have a physiological cost to the plants and
may result in yield reduction (Munns, 1988; Li et al., 1993). Compared to other crops,
few studies reported osmotic adjustment for common bean (Parsons and Howe, 1984;
Wullschleger and Oosterhuis, 1991; Raggi, 1994), and all three studies were conducted in
a controlled environment. Osmotic adjustment of ﬁeld grown common bean is not
known.

This study investigated the effect of an intemrittent (vegetative) and a
terminal(reproductive) water stress on a drought susceptible (Seafarer) and two drought
resistant bean genotypes (BAT 477 and LEFZRB).

The objectives of the study were to examine if relationships of water use
efﬁciency, water use, and harvest index to yield in beans could be explained by the
multiplicative yield model. Other main objectives included examining if beans osmotically
adjust when ﬁeld grown and the elucidation of the relationships of osmotic adjustment and
carbon isotope discrimination to yield, root depth and to yield determinants such as water

use eﬁciency and harvest index.

REFERENCES

Acosta-Gallegos, J .A., E. Acosta-Diaz, S. Padilla-Rarnirez, E. Lopez-Salinas, RA.
Salinas-Perez, N. Mayek-Perez, and J .D. Kelly. 1998. Seed yield of dry bean
cultivars under drought stress. Bean Improvement Cooperative 41: 151-152.

Barros, L. C. G., and R. J. Hanks. 1993. Evapotranspiration and yield of beans as aﬁ'ected
by mulch and irrigation. Agron. J. 85:692-697

Blum, A. 1989. Osmotic adjustment and growth of genotypes under drought. Crop
Science 29:230-233.

Clarke, J. M., and T. F. Townley-Smith. 1984. Screening and selection techniques for
improving drought resistance. In; P. B. Vose and S. G. Blixt. Crop breeding: a
contemporary basis. Pergamon Press, New York.

Cortes, PM. and TR. Sinclair. 1986. Water relations of ﬁeld -grown soybean under
drought. Crop Science 26:993-998.

Doorenbos, land A. H. Kassam. 1979. Yield response to water. F AO
Irrigation and Drainage Paper no. 33, Rome.

Ehleringer, J. R., S. Klassen, C. Clayton, D. Sherrill, M. Fuller-Holbrook, Q. Fu, and T.
A. Cooper. 1991. Carbon isotope discrimination and transpiration efﬁciency in
common beans. Crop Sci. 31:1611-1615.

Farquhar, G. D., M. H. O’Leary, and J. A. Berry. 1982. On the relationship between
carbon isotope discrimination and the intercellular carbon dioxide concentration in
leaves. Aust. J. Plant Physiol 9: 121-137.

Guei, RG and CE. Wassom. 1993. Genetics of osmotic adjustment in breeding maize for
drought tolerance. Heredity 71(4):436-441.

Holden, J. and D. Haytowitz. 1998. The nutritional value of beans. Bean Improvement
Cooperative 41:41-44.

Kumar, A and DP. Singh. 1998. Use of physiological indices as a screening technique for
drought tolerance in oil seed brassica species. Ann. Bot. 81(3):413-420.

Laing, D. R., P. G. Jones, and J. H. C. Davis. 1984. Common Bean (Phaseolus vulgaris
L.). In; P. R. Goldsworthy and N. M. Fisher. The physiology of tropical ﬁeld
crops. John Wiley & Sons, New York.

Li, X., Y. Feng and L. Boersma. 1993. Comparison of osmotic adjustment responses to
water and temperature stresses in spring wheat and sudangrass. Ann. Bot.

3

71(4):303-310.

Ludlow, M. M., and R. C. Muchow. 1990. A critical evaluation of traits for improving
crop yields in water-limited environments. Adv. Agron. 43:107-153.

Menéndez, C., and A. E. Hall. 1996. Heritability of carbon-isotope discrimination and
correllations with harvest index in cowpea. Crop Sci. 36:233-238.

Morgan, J .M., B. Rodriguez-Maribona, and BI. Knights. 1991. Adaptation to water-
deﬁcit in chickpea breeding lines by osmoregulationzrelationship to grain-yields in
the ﬁeld. Field Crops Research 27:61-70.

Munns, R. 1988. Why measure osmotic adjustment?. Australian Journal Plant Physiology
1 5:7 17-726.

Parsons, L. R and T. K. Howe. 1984. Effects of water stress on the water relations of
Phaseolus vulgaris and the drought resistant Phaseolus acutrfolius. Physiologia
Plantarum 60: 197-202.

Passioura, JB. 1994. The yield of crops in relation to drought. In: K. J. Boote (ed).
Physiology and determination of crop yield. ASA-CSSA-SSSA, Madison,
Wisconsin.

Raggi, V. 1994. Changes in free amino acids and osmotic adjustment in leaves of water-
stressed bean. Physiologia Plantarum 91:427-434.

Rodriguez-Maribona, B., J .L. Tenorio, J .R. Conde and L. Ayerbe. 1992. Correlations
between yield and osmotic adjustment of peas (Pisum sativum L.) Under drought
stress. Field Crop Research 29: 15-22.

Seemann, J. R, and C. Critchley. 1985. Eﬁ‘ects of salt stress on the growth, ion content,
stomatal behavior and photosynthetic capacity of a salt-sensitive species,
Phaseolus vulgaris L. Planta 164: 151-62.

Stanhill, G. 1986. Water use eﬁciency. Adv. Agron. 39:53-83.

White, J. W., J. A. Castillo, and Ehleringer. 1990. Associations between productivity,
root growth and carbon isotope discrimination in Phaseolus vulgaris under water
deﬁcit. Aust. J. Plant Physiol. 17:189-198.

Wullschleger, S. D. and D. M. Oosterhuis. 1991. Osmotic adjustment and growth
response of seven vegetable crops following water-deﬁcit stress. HortScience
26(90:1210-1212.

CHAPTER 1
LITERATURE REVIEW
Bean Production and Its Importance

The highest population growth rates are found in Sub-Saharan Africa and Latin
America (World Bank, 1992), two major bean (Phaseolus vulgaris L.) growing areas.
The bean crop is important not only as a source of carbohydrate to this fast growing
population but may be the only protein supplier in the diet of subsistence farmers. In
addition, bean consumption in the developed countries is increasing (Holden and
Haytowwitz, 1998) as people switch to vegetable protein for health reasons.

Bean yields have been disappointingly low, averaging less than 1 ton ha" in
developing countries to 2 tons ha“l in developed countries (Laing et al., 1984; Adams,
1996 ). Yet yields of 2. 19 to 4.12 t ha'l are reported from experiment stations indicating
the enormous gap between the potential and actual production for this crop. The major
constraint to bean production after diseases and other pests is drought. This occurs
because almost all bean production is on dryland farming systems with frequent drought
stress aﬂ‘ecting more than 60 percent of the bean producing areas world-wide (White et
al., 1990; Laing et al., 1984). The detrimental eﬁ‘ect of drought stress on beans growing
in semi-arid agroecological zones is known but bean yields are also reduced by
intermittent drought stress in humid zones (Acosta-Gallegos et al., 1998).

The Challenge of Drought

This important problem of drought stress for food crops in general and for beans in
particular has been examined at diﬂ‘erent levels of organization from cellular to whole
plant. Agronomists usually try to change the environment while plant breeders focus on

5

adapting the plant to the particular (in this case water-limited) environment. Crop
physiologists, on the other hand, try to elucidate the mechanisms of interaction between
the plant and its environment, thus working with both.

The effect of drought stress on plant growth and survival has been measured and
documented since the beginning of this century (Briggs and Shantz, 1914). More
important for yield improvement, however, is the existence of an intraspeciﬁc variation in
water use efﬁciency (Standhill, 1986).

Drought and drought resistance

Quantifying the notion of stress and drought resistance in crop plants has not been
easy and is best considered as a relative rating of response compared to an optimally
potential response under the same soil, weather and management conditions (Rana, 1986).

Thus, drought resistance is deﬁned as the ability of a genotype to reduce loss of yield
resulting ﬁ'om a quantiﬁed level of moisture deﬁcit relative to the maximum yield when
there is no water deﬁcit (Sinha, 1986; Doorenbos and Kassam, 1979). Based on this
deﬁnition drought can then be quantiﬁed as relative reduction in evapotranspiration while
resistance to drought resistance can be estimated as the relative yield reduction by the
drought. However, since genotypes do not respond equally to the same quantity of
drought researchers classify genotypes as follows (Fernandez, 1993):

High yielding resistant, high yielding susceptible, low yielding resistant, and low yielding
susceptible.
Bean sensitivity to drought

There seems to be a consensus in the literature on the sensitivity of beans to water

deﬁcit (Laing et al., 1984; Halterlein, 1983; Ehleringer et al., 1991; Nielsen and Nelson,

6

1998). The available soil water content should not drop below 50 percent for optimum
growth of beans (Vittum, and Gibbs, 1961; Maurer et al., 1969; Stegrnan and Olsen, 197;
Miller and Burke, 1983). However, all growth stages are not equally aﬁ‘ected by moisture
deﬁcit.

There are conﬂicting reports about the eﬁ‘ect of water deﬁcit during the vegetative
period ( Robins and Domingo, 1956; MacKay and Eaves, 1962; Dubetz and Mahalle,
1969; Walker and Hatﬁeld, 1979; Acosta-Gallegos and Shibata, 1989; Castellanos et al.,
1996). Moisture deﬁcits at this growth stage seem to have only a small effect on yield
(Robins and Domingo, 1956; Dubetz and Mahalle, 1969; Walker and Hatﬁeld, 1979). In
contrast, moisture deﬁcits are always detrimental when they occur during the reproductive
growth stages (Stoker, 1974; Walton et al., 1977; Acosta-Gallegos and Shibata, 1989;
Castellanos et al.,l996; Nielsen and Nelson, 1998).

Breeding beans for drought resistance

It has not been easy to breed drought resistant genotypes for semi-arid
environments based solely on grain yields. Plant traits that confer drought resistance are
expressed from year to year because of the extreme variability in the rainfall pattern of
these environments. Moreover, the genotypic variance of grain yield is low in such
environments (Ludlow and Muchow, 1990). Breeders need both the existence of heritable
genotypic variation and a screening tool to select for the desirable traits (Clarke and
Townley-Smith, 1984). Considerable genotypic variation in drought resistance among
common bean is does exist (CIAT, 1979; Singh, 1995). Most resistance is available in the
small seeded black, cream, or coffee colored types. The lack of a suitable screening

criterion seems to be the missing part of the puzzle.

Physiological and Morphological Traits

Selections are based on theoretical concepts, or correlations that may not be
necessarily indicative of causal relationships (Ludlow and Muchow, 1990). In addition,
selections rely on experiments conducted in controlled environments rather than ﬁeld
conditions. These authors suggested that it is critical to know if and how a particular trait
contributes to yield.

Some of the traits proposed for crop improvement in drought prone environments
were reviewed in detail (Clarke and Townley-Smith, 1984; Turner, 1986; Schulze, 1986;
Ludlow and Muchow, 1990). Ludlow and Muchow (1990) in particular listed about
seventeen traits that were careﬁrlly selected from prior research and based on empirical
data. Each of these traits was then subjected to a set of criteria that included whether the
trait has any demonstrated contribution to yield.

These reviews indicated a number of gaps in our knowledge about drought stress
resistance in crop plants as well as opportunities for future progress based on existing
conceptual models. The role of thermodynamically based concepts such as plant water
potential to assess drought stress has been questioned (Sinclair and Ludlow, 1985;
Passioura, 1988; Kramer, 1988).

CONCEPTUAL MODELS
The Yield Determinants Model

The ﬁrst model for the yield component analysis was proposed by Passioura
(1977) and considers grain yield in drought prone areas to be the product of three factors:
the total water transpired (WU=total water use - evaporation), the Water Use Eﬂiciency

(WUE)=grain yield /water transpired), and the Harvest Index (Hl=grain yield/total above

8

ground biomass). A trait that increases any one of these factors will contribute to yield as
demanded by this multiplicative model. This model is applicable to determinate species
but its usefulness to indeterminate or semi-determinate crops like beans is not clear.
Mechanisms of drought Resistance

The second conceptual model used by Ludlow and Muchow (1990) is based on
Levitt (1980) and classiﬁes the response of plants to drought stress. There are many such
classiﬁcations that do not always agree (May and Milthorpe, 1962; Levitt, 1980; Turner,
1986). Generally, two plant responses are recognized.

Drought escape occurs when plants evade the drought period by having a short life
span that ends before a terminal drought that comes at the end of the season or having
developmental plasticity to hasten life cycle in the event of sensing a mid season drought.

Drought resistance occurs when the plants actually experience the drought but
respond to it such that it does not adversely aﬁ‘ect them. In this model (Levitt, 1980)
drought resistance can be divided into drought avoidance and drought tolerance.
Drought Avoiders

Drought avoidance occurs when plants maintain high tissue water status by either
saving water or by taking up more water to meet the evaporative demand. Water saving
avoiders may close their stomates or activate leaf rolling, movement, or leaf senescence.
Water spending avoiders, on the other hand, may grow more roots to absorb water from
deeper proﬁles in the soil.

Drought avoiders also change tissue characteristics to maintain turgor. This
happens through osmotic adjustment or by increasing tissue elasticity or by increasing the

bound water fraction (Radin, 1983).

Drought Tolerators

Drought tolerance exists when the plant can cope with drought without
maintaining high tissue water status. This can occur in such cases as plants having
protoplasmic tolerance.
Screening for drought resistance in beans
The research reported in the following sections is based on the above working models. An
attempt was made to study the most promising physiological and morphological traits

together in one experiment.

10

REFERENCES

Acosta-Gallegos, IA, and J. K. Shibata. 1989. Effect of water stress on growth and yield
of indeterminate dry-bean (Phaseolus vulgaris) cultivars. Field Crops Research
20:81-93.

Acosta-Gallegos, 1A., B. Acosta-Diaz, S. Padilla-Ramirez, E. Lopez-Salinas, RA.
Salinas-Perez, N. Mayek-Perez, and J .D. Kelly. 1998. Seed yield of dry bean
cultivars under drought stress. Bean Improvement Cooperative 41:151-152.

Adams, M. W. 1996. An historical perspective on signiﬁcant accomplishments in dry bean
research- the ﬁrst 100 years. Bean Improvement Cooperative 39:32-45.

Briggs, L. J ., and H. L. Shantz. 1914. Relative water requirement of plants. J. Agric.
Research 3: 1-63.

Castellanos, J. 2., J. J. Peﬁa-Cabriales, and J. A. Acosta-gallegos. 1996. l’N-determined
dinitrogen ﬁxation capacity of common bean (Phaseolus vulgaris) cultivars under
water stress. J. Agric. Sci. 126:327-333.

Clarke, J. M., and T. F. Townley-Smith. 1984. Screening and selection techniques for
improving drought resistance. In; P. B. Vose and S. G. Blixt. Crop breeding: a
contemporary basis. Pergamon Press, New York.

CIAT. 1979. Annual report. Bean program. pp. C13 - C16, CIAT, Cali, Colombia.

Doorenbos, J .and A. H. Kassam. 1979. Yield response to water. F A0
Irrigation and Drainage Paper no. 33, Rome.

Dubetz, S., and P. S. Mahalle. 1969. Effect of soil water stress on bush beans Phaseolus
m L. at three stages of growth. J. Am. Soc. Hort. Sci. 94:479-481.

Ehleringer, J. R., S. Klassen, C. Clayton, D. Sherrill, M. Fuller-Holbrook, Q. Fu, and T.
A Cooper. 1991. Carbon isotope discrimination and transpiration eﬁciency in
common beans. Crop Sci. 31:1611-1615.

Fernandez, G.C.J. 1993. Eﬁ‘ective selection criteria for assessing plant stress tolerance. In:
C. G. Kuo (ed.) Adaptation of food crops to temperature and water stress. Proc.
International Symposium, Taiwan 13-18 August 1992, AVRDC.

Halterlein, A. J. 1983. Bean. In; I. D. Teare and M. M. Peet. Crop-water relations. John
Wiley & sons, New York.

Holden, J. and D. Haytowitz. 1998. The nutritional value of beans. Bean Improvement
Cooperative 41 :41-44.

11

Kramer, P. J. 1988. Changing concepts regarding plant water relations. Plant, cell,
Environ. 11:565-568.

Laing, D. R, P. G. Jones, and J. H. C. Davis. 1984. Common Bean (Phaseolus vulgaris
L.). In; P. R. Goldsworthy and N. M. Fisher. The physiology of tropical ﬁeld
crops. John Wiley & Sons, New York.

Levitt, J. 1980. Responses of plants to environmental stresses. Vol. 11: water , radiation,
salt, and other stresses. Academic press, New York.

Ludlow, M. M., and R. C. Muchow. 1990. A critical evaluation of traits for improving
crop yields in water-limited environments. Adv. Agron. 43:107-153.

Mackay, D. C., and C. A. Eaves. 1962. The Inﬂuence of irrigation treatments on yields
and on fertilizer utilization by sweet corn and snap beans. Can. J. Plant Sci.
42:219-228.

Maurer, A. R. , D. P. Ormrod, and N. J. Scott. 1969. Eﬂ‘ect of ﬁve soil water
regimes on growth and composition of snap beans. Can. J . Plant Sci. 49:271-278.

May, L. H. and F. L. Milthorpe. 1962. Drought resistance of crop plants. Field Crop
Abstr. 15:171-179.

Miller, D. E., and D. W. Burke. 1983. Response of dry beans to daily deﬁcit sprinkler
irrigation. Agron. J. 75:775-778.

Passioura, J. B. 1977. Grain yield, harvest index, and water use of wheat. Aust. Inst.
Agric. Sci. 43:107-153.

Passioura, J. B. 1988. Response to Dr. P. J. Kramer’s article, 'Changing concepts
regarding plant water relations', volume 11, number 7, pp.565-568. Plant, Cell, and
Environ. 11:569-571.

Passioura, J .B. 1994. The yield of crops in relation to drought. In: K. J. Boote (ed).
Physiology and determination of crop yield. ASA-CSSA-SSSA, Madison,
Wisconsin.

Radin, J. W. 1983. Physiological consequences of cellular water deﬁcits: osmotic
Adjustment. In: HM. Taylor, W.R. Jordan, and TR. Sinclair (eds) Limitations to
eﬁcient water use in crop production. ASA, CSSA, SSSA, Madison, WI.

Rana, R. S. 1986. Breeding Crop varieties for salt-aﬁ‘ected soils. In; V. L. Chopra and R.

S. Paroda. Approaches for incorporating drought and salinity resistance in crop
plants. Oxford &1BH Pub. Co. New Delhi.

12

Robins, J. S., and C. E. Domingo. 1956. Moisture deﬁcits in relation to the growth and
development of dry beans. Agron. J. 48:67-70.

Schulze, E. D. 1986. Whole-plant responses to drought. Aust. J. Plant Physiol. 13:127.

Sinclair, T. R., and M. M. Ludlow. 1985. Who taught plants thermodynamics? the
unfulﬁlled potential of plant water potential. Aust. J. plant Physiol. 12:213-217.

Sinha, S. K. 1986. Drought resistance in crop plants: a physiological and biochemical
analysis. In; V. L. Chopra and RS. Paroda (Eds) Approaches for incorporating
drought and salinity resistance in crop plants. Oxford & IBH Publishing Co.,
New Delhi.

Singh, S. P. 1995. Selection for water-stress tolerance in interracial populations of
common bean. Crop Science 35:118- 124.

Stanhill, G. 1986. Water use efﬁciency. Adv. Agron. 39:53-83.

Stegrnan, E. C ., and H. M. Olson .1976. Water management relationships for irrigated
pinto beans. N. D. Res. Rep. No. 61.

Stoker, R. 1974. Effect on dwarf beans of water stress at diﬁ‘erent phases of growth. N.
Z. J. Expl. Agric., 2:13-15.

Turner, N. C. 1986. Adaptation to water deﬁcits: a changing perspective. Aust. J. Plant
Physiol. 13: 175-190.

Vittum, M. T., and G. H. Gibbs. 1961. Don't wait too long to irrigate snap beans. Farm
Res. 27:15.

Walker, G. K., and J. L. Hatﬁeld. 1979. Test stress-degree-day concept using multiple
planting dates of red kidney beans. Agron. J. 71 :967-971.

Walton, D. C., E. Galson, and M. A. Harris. 1977. The relationship between stomatal
resistance and abscisic acid levels in leaves of water-stressed bean plants. Planta
133:145-148.

White, J. W., J. A. Castillo, and Ehleringer. 1990. Associations between productivity,

root growth and carbon isotope discrimination in Phaseolus vulgaris under water
deﬁcit. Aust. J. Plant Physiol. 17:189-198.

World Bank. 1992. Development and the environment. World Development Report 1992.
Oxford University Press.

13

CHAPTER 2
BEAN ADAPTATION TO DROUGHT: YIELD COMPONENTS AND YIELD

DETERMINANTS

ABSTRACT
Increasing bean (Phaseolus vulgaris L.) yields in drought prone environments requires the
identiﬁcation of drought resistant genotypes. The objective of this study was to evaluate
the relationship of water use emciency, harvest index and water use for beans growing
under moisture deﬁcit by comparing genotypes of known drought resistance
characteristics. Two resistant genotypes BAT 477 and LEFZRB and a susceptible
Seafarer were grown in a rain shelter in Michigan ﬁ'om 1991 to 1993 under a well watered
conditions (control), a vegetative intermittent stress, and a reproductive terminal stress.
Seed yield varied from 28 to 352 g m‘z. Vegetative stress reduced yield by 15 to 30%
while reproductive stress reduced yield by 3 5 to 50%. Genotypic diﬂ‘erences in yield were
observed only under the reproductive stress. Water use and water use eﬂiciency
correlated positively with yield and biomass specially when examined under speciﬁc water
treatment or by genotype but harvest index did not correlate with yield or biomass. It is
concluded that beans follow a simpler model relating water use and water use eﬁiciency to

yield with harvest index being generally higher and more stable than those of other crops.

INTRODUCTION
Drought is the major constraint to bean production after diseases. Almost all bean

production is on dryland farming systems with ﬁ'equent drought stress aﬂ‘ecting more than

14

60 percent of the bean producing areas world-wide (White et al., 1990; Laing et al., 1984;
Acosta-Gallegos et al., 1998).

It has also been proposed that yield under stressful environments is best
characterized by a multiplicative model (Passioura, 1994) as follows:
Yield=water transpired x water-use efﬁciency x harvest index

Field measurement of the water transpired can be approximated by the
evapotranspiration if similar evaporation is assumed for plots at the same site (Doorenbos
and Kassam, 1979; Barros and Hanks, 1993). This model was used in cereal crops
(Passioura, 1977) but its applicability to determinate genotypes of common bean has not
been reported. It is critical to evaluate such a model for beans because research on yield
determinants such as water use efﬁciency and harvest index would contribute to yield
directly. Similarly, any trait that can be directly linked to any of the yield determinants
can indirectly be a useful screening tool for yield under drought. Such a relationship has
indeed been suggested for traits like carbon isotope discrimination and osmotic adjustment
among others (Ludlow and Muchow, 1990; Ehleringer et al., 1991).

The objective of this study was to examine the relationships of water use, water
use eﬁciency, and harvest index with yield and biomass in common bean genotypes that
have contrasting drought resistance characteristics.

MATERIALS AND METHODS
Beans were planted on a Kalamazoo soil (Fine-loamy, mixed, mesic Typic Hapludalfs)
under a rain shelter (Martin et al.,1988)at the Michigan State University’s Kellog
Biological Station at Hickory Corners, Michigan on 18 June 1991, 14 June 1992, and 4

June 1993. Based on soil tests about 98 kg ha" of urea 46% N was applied as a starter

15

fertilizer each year together with soil rhizobium to avoid any existing non-uniforrnity of
rhizobium in the soil. The automatic rain shelter is set to close as soon as it starts raining.
Maximum and minimum temperatures for the three seasons are shown in Figure 1.

The experimental design was a split plot with water as the main plot, genotypes as
the subplot, and three (1991) or four (1992 and 1993) replications. Main plot was 6 m by
3.5 m which was sub divided into 3 sub-plots each 2 m long. The three genotypes in this
experiment were two resistant checks: BAT 477 (Sponchiado et al., 1989) and LEFZRB
(Schneider et al., 1997) and a susceptible control: Seafarer (Adams, 1996). The three
water treatments were a well-watered control, no moisture ﬁ'om V5 to R1 (vegetative
intermittent stress), and no moisture ﬁ'om R1 to harvest (reproductive terminal stress).
The irrigation amounts and times are presented in Table 1 and in Figure 2.

Water stress treatments were matched with phenological growth stages to
elucidate the differential effect of moisture deﬁcit on physiological and morphological
traits. The phenological stages were measured by counting leaf number during vegetative
growth. The ﬁrst ﬂower was considered as R1 and the details of other growth stages
were based on those proposed by Nuland and schwartz (1989).

Water use was calculated from neutron probe readings before and alter the water
treatment. The access tube for each plot was placed on one of the two center rows of
each plot. The count ratios of the neutron probe were calibrated with gravimetrically

measured soil moisture for each depth.

16

Temperature (0°)

Temperature (C)

1991 1992

 

 

 

 

 

 

 

 

 

 

 

4o 40
35 - 35 -
30 - 30 -
25 - 25 -
20 - . , .. . 20 -
15 - “-j 15 -
1o - i 10 -
5 - 5 -
0 a 0 a
-5 - -5 -
-10 , , , , 1 ~10 . I t u u
150 130 zoo 220 240 250 160 180 200 220 240 260
Day of Year Day of Year

1993

 

 

— Maximum
------ Minimum

 

 

 

 

 

 

-10 I I I T I
160 180 200 220 240 260

 

Day of Year

Figure 1. Maximum and minimum air temperatures for the growing season
at experimental site 1991-1993.

17

Table 1. Irrigation treatment and application for three common bean genotypes grown in

a rain shelter at Hickory Corners, Michigan 1991-1993.

 

 

 

Grth Stages

Year Irrigation Planting 5-1eaf R1 to Sum % of

Treatment to 5-leaf to Rl'l' Harvest Control
mm

1991 Control (W 1) 114 102 89 305 100
Stress (W2) 114 0 89 203 67
Stress (W3) 114 102 O 216 71

1992 Control (W 1) 152 51 90 294 100
Stress (W2) 152 0 90 242 83
Stress (W3) 152 51 0 203 69

1993 Control (W 1) 114 51 85 250 100
Stress (WZ) 114 0 85 199 80
Stress (W3) 114 51 O 165 66

 

‘l'R1=First open ﬂower in any node.

18

Irrigation (mm)

  

.83 down 80m

0033. 0038. 0036.

 

5843.183 583.33 .363...sz

 

 

 

Wm , E:

8 . 423.3.

 

 

Ans-3.3m.

433:5.

 

 

 

 

29.3 N 0.383 362.6: ”82333. «o- .3-8 8330: com: 030363 995 .2 m 8.: «30:2
m. 1.0.82 00329 3.96m: 33.68.

19

Grain yield, yield components and the above ground dry weight (Biomass)
data were recorded from the harvested samples of 1.5 m of the two center rows. Growth
stage biomass yield was also measured from 5 randomly selected plants per plot through
out the growing season. At any sampling date, the number of pods and seeds per plot
were obtained by counting. Water use efﬁciency (WUE) was measured from the ratio of
biomass yield and Seasonal cumulative water use.

The data were analyzed by the SAS General Linear Model (GLM) (SAS Institute,
1993). Correlation analysis was also done to examine any associations among
parameters. A combined analysis over all the years was done whenever there were no
interactions with years in addition to individual yearly analysis to show the general trend.
Years are considered random variables and represent environments as the plots rotated
each year around the shelter and a new randomization was done for each site. Thus, years
were confounded with sites. Means ﬁ'om diﬁ'erent treatments were compared by using
Fisher's ANOVA protected Least Signiﬁcant Difference (LSD).

RESULTS AND DISCUSSION
Yield determinants

Both vegetative and reproductive stress reduced bean yields. The highest yield of
352.16 g rn'2 was attained in 1991 under well watered conditions by LEFZRB. The
lowest yield of 28.35 grn'2 was also attained by the same genotype under the reproductive
terminal stress in 1993. Intermittent vegetative stress reduced yield by 15% in 1991 and
by 30% in 1992 (Table 2). Similar reductions for vegetative stress have been reported
(Acosta-Gallegos and Shibata, 1989). There are conﬂicting reports about the effect of
water deﬁcit during the vegetative period for beans (Robins and Domingo, 1956; MacKay

20

Table 2. Yield , water use eﬁiciency (WUE), harvest index (HI), and seasonal water Use
of three common bean genotypes grown under well water conditions (W 1 ), intermittent
vegetative water stress (W 2), and terminal reproductive stress (W 3) at Hickory Corners,
Michigan 1991-1993.

 

 

Year Treatment Yield WUE HI Water Use
(g ml) (3 Kg") (mm
1991 Control-W1 270.46 0.74 0.57 638.60
Stress-W2 190.63 0.87 0.56 406.06
Stress-W3 160.03 0.63 0.52 483.92
LSD(0.05) 55.82 NS+ NS 58.89
1992 Control-W1 254.99 0.88 0.50 583.74
Stress-W2 217.48 0.89 0.51 485.11
Stress-W3 166.85 0.79 0.47 444.01
LSD(0.05) 31.32 NS NS 19.65
1993 Control-W1 181.27 0.62 0.58 498.21
Stress-W2 119.32 0.57 0.54 387.44
Stress-W3 90.36 0.46 0.52 368.03
LSD(0.05) 64.72 NS 0.04 24.37

 

+signiﬁcant at the p<0.10 level.

21

and Eaves, 1962). Moisture deﬁcits at this growth stage seem to have only a small effect
on yield (Robins and Domingo, 1956; Dubetz and Mahalle, 1969; Walker and Hatﬁeld,
1979; Castellanos et al., 1996).

Reproductive terminal stress reduced yields greatly every year with reductions
ranging ﬁ'om 35% in 1992 to 50% in 1993. These results are comparable to those of
Acosta-Gallegos and shibata (1989). Generally, moisture deﬁcits are always detrimental
when they occur during the reproductive growth stages (Stoker, 1974; Walton et al.,
1977;Acosta-Gallegos and Shibata, 1989; Castellanos et al.,l996). The two stress
treatments did not signiﬁcantly diﬁ‘er from each other except in 1992 (Table 2).
Moderately stressed beans grown under plastic covers yielded similarly as those under
well watered control (Raeini-Sarjaz and Barthakur, 1997).

Across water treatment, there was no signiﬁcant genotypic yield diﬁ‘erences at any
year but Seafarer ranked lowest every year (Table 3). It was under the reproductive
terminal stress that the resistant BAT 47 7 could be clearly distinguished from the
susceptible Seafarer both in yield as well as in some of the yield determinants. Under this
stress, Seafarer had 24% lower yield than BAT 477 in part due to more reductions in
water use eﬁciency and water use (Table 4).

There was no signiﬁcant diﬂ‘erences between water treatments in water use
eﬁciency (WUE) in any year at the p<0.05 level across genotypes. Seafarer had lower
WUE than the other two genotypes in 1992. In mung beans, three irrigations increased
water use eﬁciency over four irrigations but harvest index increased in the treatment with
two irrigations only (Pannu et al.,l993).

Harvest index (HI) was signiﬁcantly reduced by both stress treatments only in

22

Table 3. Yield , water use eﬁiciency (WUE), harvest index (HI), and seasonal water Use
of three common bean genotypes grown under different water stress treatments at Hickory

Corners, Michigan 1991-1993.

 

 

Year Genotypes Yield WUE HI Water Use
(8 mi) (3 Kg") (nun)
1991 Seafarer 190.66 0.68 0.56 497.00
LEF2RB 198.94 0.69 0.55 522.31
BAT 477 231.51 0.87 0.55 509.26
LSD(0.05) NS NS NS NS
1992 Seafarer 200.76 0.76 0.52 500.69
LEF2RB 226.94 0.91 0.50 506.29
BAT 477 211.62 0.90 0.47 505.88
LSD(0.05) NS 0.10 0.03 NS
1993 Seafarer 120.44 0.52 0.55 410.12
LEFZRB 136.73 0.57 0.55 417.30
BAT 477 133.79 0.55 0.55 426.26
LSD(0.05) NS NS NS 1 1.30

 

23

Table 4. Yield , water use eﬁiciency (WUE), harvest index (HI), and seasonal water Use
of three common bean genotypes grown under different water stress treatments at Hickory
Corners, Michigan 1991-1993.

 

 

Treatment Genotypes Yield WUE HI Water Use
(a m'z) (3 Kg") (mm)
Control-W1 Seafarer 221.32 0.70 0.56 558.13
LEF2RB 254.95 0.82 0.55 571.79
BAT 477 220.93 0.72 0.54 572.87
LSD(0.05) NS NS NS NS+
Stress-W2 Seafarer 165.14 0.67 0.58 423.67
LEFZRB 169.91 0.76 0.52 430.33
BAT 477 188.34 0.88 0.51 430.09
LSD(0.05) NS 0.16 0.04 NS
Stress-W3 Seafarer 119.93 0.57 0.48 418.45
LEF2RB 134.63 0.60 0.52 432.76
BAT 477 156.96 0.71 0.51 430.58
LSD(0.05) 27.29 0.12 NS 10.41

 

+Signiﬁcant at the p< 0.10 level only.

24

1993 (Table 2). Harvest index ranged from 0.34 to 0.61 across the years and that range
agrees with prior research (Scully and wallace, 1990; Pilbearn, 1996). BAT 47 7 scored
lowest in HI in 1992 than both of the genotypes but had higher water use than Seafarer
(table 3). Seafarer had higher harvest index under the vegetative stress treatment (Table
4). Bush forms like Seafarer produce less due to shorter remobilization period
(Fernandez, 1981). De costa et a1. (1997) reported the post ﬂowering stress increased
harvest index in faba beans.

Seasonal water use was reduced by the vegetative by 17% in 1992 to 36% in
1991. Reproductive stress reduced seasonal water use by an average of 25% every year
(Table 2).

Genotype by treatment interactions were found for yield and yield determinants
except water use when the data was pooled over the years. Similar interactions were
reported in beans (Samper, 1984) indicating the existing potential in selecting for drought
resistant genotypes. In this study, there was no genotypic differences under well watered
conditions indicating a measure of similarity in yield potential (Table 4).
Yield Components

Vegetative stress reduced pod m'2 by 16% in 1991 and by 22% in 1993. Similarly,
pods plant'1 were reduced by 15 to 28% for the same years, respectively. This stress did
not affect seed weight or seeds per pod (Table 5). Reproductive terminal stress reduced
pods m’2 in all three years. In addition, this stress was detrimental to seed weight relative
to the control (Table 5). Seeds pod" were not reduced by any stress at any year contrary
to the ﬁndings of Nielsen and Nelson (1998). These results agree with those of Sarnper

(1984) for both seed weight and seed number.

25

Table 5. Yield components of three common bean genotypes grown under well water
conditions (W 1), intermittent vegetative water stress (W 2), and terminal reproductive

stress (W3) at Hickory Corners, Michigan 1991-1993.

 

 

Year Treatment Pods Pods Seeds Seed wt
in2 Plant" pod" (mg Seed")
1991 Control-W1 344.74 13.75 4.50 187.45
Stress-W2 288.89 11.70 3.59 188.12
Stress-W3 251.26 10.37 6.62 169.79
LSD(0.05) 47.43 1.78 NS NS
1992 Control-W1 343.78 12.53 5.05 153.77
Stress-W2 329.39 11.76 4.55 152.79
Stress-W3 269.39 10.55 4.51 141.56
LSD(0.05) 57.77 NS NS 6.69
1993 Control-W1 237.94 10.28 3.88 201.65
Stress-W2 184.50 7.37 3.38 185.80
Stress-W3 166.00 7.31 3.24 166.48
LSD(0.05) 51.10 2.13 NS 22.82

 

26

Table 6. Yield components of three common bean genotypes grown under diﬁ‘erent

moisture stress treatments at Hickory Corners, Michigan 1991-1993.

 

 

Year Genotypes Pods Pods Seeds Seed wt
1n‘2 Plant" pod" (mg Seed")
1991 Seafarer 347.93 14.98 3.39 155.74
LEF2RB 271.11 10.73 3.31 214.46
BAT 477 265.85 10.10 5.02 175.16
LSD (0.05) 48.26 1.95 0.72 14.46
1992 Seafarer 374.11 13.78 4.54 117.47
LEF2RB 299.28 11.03 3.95 190.81
BAT 477 269.17 10.04 5.62 139.84
LSD (0.05) 39.19 1.39 0.47 9.30
1993 Seafarer 244.39 12.14 2.91 162.59
LEF2RB 184.89 7.46 3.18 212.10
BAT 477 159.17 5.35 4.41 179.24
LSD (0.05) 25.06 0.84 0.36 13.24

 

27

Table 7. Yield components of three common bean genotypes grown under different
moisture stress treatments at Hickory Corners, Michigan 1991-1993.

 

 

Treatment Genotypes Pods Pods Seeds Seed wt
rn’2 Plant" pod" (mg Seed")
Control-W1 Seafarer 378.12 16.32 4.05 151.26
LEF2RB 297.82 11.12 4.00 217.29
BAT 477 240.73 8.69 5.38 172.54
LSD (0.05) 49.07 1.79 0.60 9.83
Stress-W2 Seafarer 315.88 12.47 3 .74 142.26
LEF2RB 243.52 9.54 3.16 211.02
BAT 477 237.58 8.43 4.69 170.01
LSD (0.05) 29.25 1.16 0.49 11.78
Stress-W3 Seafarer 265.39 1 1.7 3. 12 139.42
LEF2RB 208.67 8.28 3.32 186.69
BAT 477 206.49 7.94 4.97 148.85
LSD (0.05) 28.18 0.96 0.37 14.60

 

28

Table 8. Biomass and its components of three common bean genotypes grown under well
water conditions (W 1), intermittent vegetative water stress (W2), and terminal

reproductive stress (W 3) at Hickory Comets, Michigan 1991-1993.

 

 

 

Year Treatment Biomass Pods‘l’ Straw Stover
(g m”) (g m") (g m") (s m")
1991 Control-W1 473.38 81.89 121.03 202.92
Stress-W2 352.37 63 .76 97.98 161.74
Stress-W3 300.35 56.95 83.36 140.31
LSD(0.05) 56.14 10.82 23 .08 20.35
1992 Control-W1 514.80 98.91 160.90 259.82
Stress-W2 430.42 84.81 128.13 212.94
Stress-W3 350.06 64.56 118.65 183.21
LSD(0.05) 67.14 13.99 NS 54.82
1993 Control-W1 309.22 63.86 50.59 114.45
Stress-W2 216.89 43.88 43.86 87.74
Stress-W3 169.52 35.90 35.72 71.62
LSD(0.05) 108.15 19.23 NS NS+
‘l'Empty pods + Signiﬁcant at the p<0.10 level only.

29

The three genotypes in this study had each one yield component over which it excelled
over the two genotypes no matter what water stress treatment they were in. Seafarer
excelled in pod numbers, BAT 477 in seeds pod", and LEF2RB in seed weight. This was
consistent in all the years (Table 6). Moreover, BAT 477 consistently scored over
Seafarer in seed weight while LEF2RB had higher pod numbers than BAT 477 in 1993
only.

Yield component adjustment per genotype did not seem to have occurred based on
the above but genotype by water interactions did take place. For example, BAT 477 had
lower pod numbers than both Seafarer and LEF2RB under the well watered conditions but
was similar to LEF2RB under stress (Table 7). In addition, LEFZRB was more sensitive
to vegetative stress regarding seeds pod" than Seafarer. Correlation analysis did not
indicate any negative cross correlations for seed yield components when the treatment
means were used for any year (data not presented). Seed weight negatively but weakly
correlated with seeds per pod (r=-0.62 p<0. 10 n=9) and with pods rn'2 ( r=-0.62 p<0.10
n=9) under the vegetative stress if the year by genotype means were used. Seafarer was
the only genotype that indicated any negative correlations between seeds pod" and seed
weight (r=-0.69 p<0.05 n=9)and only when the year by water means were used in the
analysis. Similar results were found in faba beans (De costa et al., 1997).

Biomass Components

Biomass was reduced by the intermittent vegetative stress in two of the three years

(Table 8). These reductions varied from 16% (1992) to 26% (1991). Further more,

empty pod weights were severely lowered by this stress treatment in all the years as well

30

Table 9. The biomass components of three common bean genotypes grown under
diﬂ‘erent moisture stress treatments at Hickory Corners, Michigan 1991-1993.

 

 

 

Year Genotypes Biomass Pods? Straw Stover
(g m") (g m") (g m") (s m‘z)
1991 Seafarer 334.53 62.84 81.03 143.87
LEF2RB 365.34 59.31 107.10 166.40
BAT 477 426.22 80.45 114.26 194.71
LSD(0.05) NS 16.20 NS NS
1992 Seafarer 379.56 82.28 96.52 178.80
LEF2RB 461.43 76.46 158.02 234.49
BAT 477 454.29 89.54 153.14 242.68
LSD(0.05) 53.03 NS+ 21.33 26.53
1993 Seafarer 216.92 47.08 39.48 86.56
LEF2RB 240.79 47.18 45.96 93.14
BAT 477 237.92 49.38 44.74 94.12
LSD(0.05) NS NS NS NS
‘l'Empty pods. + Signiﬁcant at the p<0.10 level.

31

but straw weights were not (table 8). In contrast, reproductive stress reduced biomass
and all of its components except straw weights in all the years. Biomass reductions varied
from 32% in 1992 to 45% in 1993. In other studies biomass reductions reached up to
50% for some genotypes (Samper, 1984). Straw weights were adversely affected by the
terminal reproductive stress only in 1991 (Table 8).

Seafarer had signiﬁcantly lower biomass, straw weight and stover weight than both
BAT 477 and LEF2RB in 1992. On the other hand, BAT 477 had signiﬁcantly higher
empty pod weight than the other two genotypes in 1991. The diﬂ‘erences in empty pod
weight between Seafarer and BAT 477 in 1992 were signiﬁcant at the p<0.10 level only
(Table 9). The Samper (1984) study examined twenty two genotypes and described
LEF2RB as on of two genotypes that increased their biomass under stress which is one of
the reasons why LEF2RB was thought of as a drought resistant genotype.

The susceptible Seafarer had lower straw and stover weights than LEF2RB even
under well watered conditions (Table 10). In addition, BAT 477 was not different than
Seafarer and was in fact lower in straw weight than LEF2RB under the control. In
contrast, BAT 477 was similar to LEF2RB but signiﬁcantly higher yielding in biomass and
straw weight than Seafarer under the intermittent vegetative stress (Table 10). Moreover,
BAT 477 had higher pod and stover weights than both Seafarer and LEF2RB under the
vegetative stress. Similarly, BAT 47 7 had signiﬁcantly higher biomass yield than Seafarer
under the terminal reproductive stress. Under this stress, LEF2RB produced lower stover

and pod weights than BAT 477 (Table 10).

32

Table 10. The biomass components of three common bean genotypes grown under
different moisture stress treatments at Hickory Corners, Michigan 1991-1993.

 

 

 

Treatment Genotypes Biomass Pods‘l’ Straw Stover
(s m") (g m") (g m") (s m'2)
Control-W1 Seafarer 396. 82 81.50 89.00 170.50
LEF2RB 474.80 79.14 135.56 214.70
BAT 477 414.62 83.93 105.19 189.12
LSD(0.05) NS+ NS 17.97 28.40
Stress-W2 Seafarer 285.01 59.94 56.74 116.67
LEF2RB 329.49 59.62 95.89 155.51
BAT 477 379.95 73.00 115.16 188.16
LSD(0.05) 63.67 10.22 29.30 37.26
Stress-W3 Seafarer 242.59 51 . 10 68.93 120.02
LEF2RB 260.67 44.65 78.69 123.34
BAT 477 309.29 60.45 89.00 149.44
LSD(0.05) 49.07 8.14 NS 23.99
‘l'Empty pods + Signiﬁcant at the p<0.10 level.

33

Yield determinants relationships with yield

Across treatments and genotypes, water use efﬁciency modestly and positively
correlated with yield (Figure 3-a,d). The relationship between yield and WUE was
stronger when the data was organized under water treatment or genotypes.

In contrast, harvest index did not correlate with yield or biomass (Figure 3-b, e).
In other studies, harvest index correlated weekly (Fernandez, 1981) or strongly (Acosta-
Gallegos and Adams, 1991)with yield .

Seasonal water use, on the contrary, strongly correlated with yield and biomass
(Figure 3-c, f). Because the data for water use were ﬁ'om plots that were either well
watered or stressed there are two clusters of data with no points in between them (Figure
3-c,f). Generally, assuming a linear relationship in such types of data may seem
questionable but in the case of well watered versus stressed plots this spread of the data is
common (Mahalakshmi et al., 1990)and the assumption of a linear relationship is justiﬁed
based on results from other methods (Barros and Hanks, 1993; Miller and Burke, 1983).

The relationship between yield and WUE was stronger when the data was
organized under water treatments and specially so under the stress treatments (Figure 4-
a). Again, harvest index did not correlate with yield under any water treatment (Figure 4-
b). In contrast to WUE, seasonal water use correlated more strongly with yield under the
control treatment (Figure 4-c). These results indicate that of the three yield determinants
only water use eﬁciency may predict yield under stress. This is in line with the concept
that WUE acts like the link between drought response and drought stress (Stanhill, 1986).

All three genotypes had signiﬁcant positive associations between water use

34

 

 

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35

Yield (9 m")

 

 

 

 

 

 

 

 

 

 

 

 

  
   

350
a
300 - O .
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250 4 3 . O ’O/// o WW1
200 - g o A /' O 0 5mm
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350
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200 -
150 r
100 ; W22r: =o.sa-
W32r =O.54‘
50 I ﬁr I I

 

 

 

300 350 400 450 500 550 600 650 700

Seasonal water use (mm)

Figure 4. The relationship of water use efﬁciency (WUE), harvest index (HI).
and water use to yield as affected by different moisture stress treatments of
common bean genotypes grown at Hickory Corners, Michigan 1991-1993. Data are

from the pooled year by genotype means.

36

 

Yield

 

 

 

 

200-

150-

Yield (9 m '2)

100-

 

50

 

Biomass (g m '2)

 

 

0.44 0.48 0.52 0.56 0.60

I I

 

 

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63: 3,05-

 

 

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m3504m450500550600650700

Water Use (mm)

 

 

 

 

 

 

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0 Q//’
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Water use (mm)

Home 5. Therelatlonshipe otvsdettseeﬂidencyMUE), havest index (HI). andwdet
usewlthyleldandblonmsofthreecormlonbean

W
stress treatmentsatl-lickoryComets. M1991-1993. Ddaarethepooledvdetby
yearrneans

37

murdetdliletentwatet

eﬁiciency (WUE) and yield or biomass (Figure 5-a,d). This relationship was least strong
for the resistant BAT 47 7 and strongest for LEF2RB. No signiﬁcant correlations were
found for any of the three genotypes between harvest index and yield or biomass (Figure
5-b,e).

On the other hand all genotypes had positive associations between water use and yield or
biomass ( Figure 5-c,f). Similar relationships were reported for water use and yield
(Barros and Hanks, 1993).

Correlation analysis using the treatment means as well as any other second degree
interactions did not indicate any negative cross correlations among the yield determinants
(data not presented). Musick et a1. (1994) analyzed 178 crop-year data for wheat and
concluded a linear relationship between evapotranspiration and yield but a curvilinear
relationship between yield and water use efﬁciency with no cross correlations found.
Strong positive correlations were also reported in faba beans (Vicia faba L.)between seed
yield and post anthesis water use (Mwanamwenge et al.,l998; Loss et al., 1997).

Since diﬂ‘erent genotypes do not respond equally to the same quantity of drought
some researchers classify them as follows (Fernandez, 1993): high yielding resistant, high
yielding susceptible, low yielding resistant, and low yielding susceptible. In this study,
Seafarer was susceptible and BAT 477 resistant under the terminal reproductive moisture
stress (Table 4) but they yielded equally well under control. LEF2RB, on the other hand,
seems to be high yielding susceptible as it reduced its yield more than Seafarer but still

yielded similarly to the resistant BAT 47 7 under the terminal reproductive stress.

38

CONCLUSIONS

The yield determinants of the three genotypes in this study behaved similarly. It is
concluded that the yield determinants model as proposed for cereal crops seems to be
applicable to beans but that the harvest index is more stable and higher in beans (Table 1 ;
Figure 3-b, e; Pilbearn, 1996; Fernandez, 1981 ). Harvest index was the one factor that
did not strongly correlate with yield but it is an important research objective for many
breeders. This study does not encourage the use of harvest index as screening tool for
yield improvement in beans and conﬁrms similar ﬁndings by Pilbearn (1996) and
Fernandez (1981). On the other hand, the other yield determining factors such as water
use and water use eﬁiciency seem to be more drought stress responsive and better
predictors of yield under stress for beans. It follows that any screening trait that can be

linked to these yield determinants may improve yield.

39

REFERENCES

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beans (Phaseolus vulgaris) cultivars under stress. J. Agric. Sci. 117:213-219.

Acosta-Gallegos, J .A., and J. K. Shibata. 1989. Effect of water stress on growth and yield
of indeterminate dry-bean (Phaseolus vulgaris) cultivars. Field Crops Research
20:81-93.

Acosta-Gallegos, J .A., E. Acosta-Diaz, S. Padilla-Ramirez, E. Lopez-Salinas, RA.
Salinas-Perez, N. Mayek-Perez, and JD. Kelly. 1998. Seed yield of dry bean
cultivars under drought stress. Bean Improvement Cooperative 41:151-152.

Adams, M. W. 1996. An historical perspective on signiﬁcant accomplishments in dry bean
research- the ﬁrst 100 years. Bean Improvement Cooperative 39232-45.

Barros, L. C. G., and R. J. Hanks. 1993. Evapotranspiration and yield of beans as affected
by mulch and irrigation. Agron. J. 852692-697.

Castellanos, J. Z., J. J. Peﬁa-Cabriales, and J. A. Acosta-gallegos. 1996. 1’N-deterrnined
dinitrogen ﬁxation capacity of common bean (Phaseolus vulgaris) cultivars under
water stress. J. Agric. Sci. 126:327-333.

Clarke, J. M., and T. F. Townley-Smith. 1984. Screening and selection techniques for
improving drought resistance. In; P.B. Vose and S. G. Blixt. Crop breeding: a
contemporary basis. Pergamon Press, New York.

De Costa, W. A. J. M., M. D. Dennett, U. Ratnaweera, K. Nyalemegbe. 1997. Eﬂ‘ects of
diﬂ‘erent water regimes on ﬁeld-grown determinate and indeterminate faba bean
(Viciafaba L.). 11. Yield, yield components and harvest index. Field Crops
Research 52: 169-178.

Doorenbos, J., and A. H. Kassam. 1979. Yield response to water. F AO Irrigation and
Drainage Paper no. 33, Rome.

Dubetz, S., and P. S. Mahalle. 1969. Effect of soil water stress on bush beans Bhaseglns
mm: L. at three stages of growth. J. Am. Soc. Hort. Sci. 94:479-481.

Ehleringer, J. R., S. Klassen, C. Clayton, D. Sherrill, M. Fuller-Holbrook, Q. Fu, and T.
A. Cooper. 1991. Carbon isotope discrimination and transpiration eﬁciency in
common beans. Crop Sci. 31:1611-1615.

Fernandez, G.C.J. 1993. Effective selection criteria for assessing plant stress tolerance. In:

C. G. Kuo (ed) Adaptation of food crops to temperature and water stress. Proc.
International Symposium, Taiwan 13-18 August 1992, AVRDC.

4O

Fen

lo

Fernandez, J.A.I. 1981. The eﬂ‘ect of accumulation and remobilization of carbon assimilate
and nitrogen on abscission, seed development, and yield of common bean
(Phaseolus vulgaris L.) With different artichectural forms. Ph.D. diss. Michigan
State University, East Lansing.

Laing, D. R, P. G. Jones, and J. H. C. Davis. 1984. Common Bean (Phaseolus vulgaris
L.). In; P. R. Goldsworthy and N. M. Fisher. The physiology of tropical ﬁeld
crops. John Wiley & Sons, New York.

Loss, S.P., K.H.M. Siddique, and D. Tennant. 1997. Adaptation of faba bean (Viciafaba
L.)to dryland mdeiterranean-type environments. 111. Water use and water-use
eﬁcieency. Field Crops Research 54:153-162.

Ludlow, M. M., and R. C. Muchow. 1990. A critical evaluation of traits for improving
crop yields in water-limited environments. Adv. Agron. 43 : 107-1 53.

Mackay, D. C ., and C. A. Eaves. 1962. The Inﬂuence of irrigation treatments on yields
and on fertilizer utilization by sweet corn and snap beans. Can. J. Plant Sci.
42:219-228.

Mahalakshmi, V., F .R. Bidinger, and GDP. Rao. 1990. Line-source vs.
hrigated/nonirrigated treatments for evaluation of genotype drought response.
Agron. J. 82:841-844.

Martin, E. C., J. T. Ritchie, S. M. Reese, T. L. Loudon, and B. Knezek. 1988. A large-
area, light-weight rainshelter with programmable control. Trans. ASAE 31:1440-
1444.

Menéndez, C., and A. E. Hall. 1996. Heritability of carbon-isotope discrimination and
correllations with harvest index in cowpea. Crop Sci. 36:233-238.

Miller, D. E., and D. W. Burke. 1983. Response of dry beans to daily deﬁcit sprinkler
irrigation. Agron. J. 75:775-778.

Musick, J.T., O.R. Jones, B.A. Stewart, and DA Dusek. 1994. Water-yield relations for
irrigated and dryland wheat in the US. southern plains. Agron. J. 86:980-986.

Mwanamwenge, J ., S. P. Loss, K.H.M. Siddique, and PS. Cooks. 1998. Growth, seed
yield and water use of faba beans (Viciafaba L.) In a short -season mediterranean-
type environment. Aust. J. Exp. Agric. 38:171-180.

Nuland, D.S., and H. F. Schwartz. 1989. A visual description of the common bean plant:
Four major groth periods. Bean Improvement cooperative 32:16-17.

Pannu, R.K., and DP. Singh. 1993. Eﬁ‘ect of Irrigation on water use, water-use eﬁciency,

41

grth and yield of mungbean. Field Crops Research 31287-100.

Passioura, J. B. 1977. Grain yield, harvest index, and water use of wheat. Aust. Inst.
Agric. Sci. 43:107-153.

Passioura, J .B. 1994. The yield of crops in relation to drought. In: K. J. Boote (ed).
Physiology and determination of crop yield. ASA-CSSA-SSSA, Madison,
Wisconsin.

Pilbeam, C. J. 1996. Variation in harvest index of maize (Zea mays) and common bean
(Phaseolus vulgaris)grown in a marginal rainfall area of Kenya. J. of Agric.
Science 12621-6.

Raeini-Sarjaz, M., and N. N. Barthakur. 1997. Water use eﬂiciency and totaldry matter
production of bush bean under plastic covers. Agric. and Forest Meteor. 87:75-
84.

Robins, J. S., and C. E. Domingo. 1956. Moisture deﬁcits in relation to the growth and
development of dry beans. Agron. J. 48:67-70.

Samper, C. 1984. Effect of water stress imposed at mid-pod ﬁlling upon yield and dry
matter partitioning in dry beans (Phaseolus vulgaris L.). MS. Thesis. Michigan
State University. East Lansing.

SAS Institute. 1993. SAS/STAT guide for personal computer, version 6, 4" ed. SAS
Inst, Cary, NC.

Schneider, K. A., R. Rosales-Sema, F. Ibarra-Perez, B. Cazares-Enriquez, J. A. Acosta-
Gallegos, P. Ramirez-Vallejo, N. Wassirni, and J. D. Kelly. 1997. Improving
common bean performance under drought stress. Crop Sci. 37:43-50.

Scully, B. T., and D. H. Wallace. 1990. Variation in relationship of biomass, growth rate,

harvest index, and phenology to yield of common bean. J. Amer. Hort. Sci.
115(2):218—225.

Singh, S. P. 1995. Selection for water-stress tolerance in interracial populations of
common bean. Crop Science 35: 1 18-124.

Sponchiado, B. N., J. W. White, J. A. Castillo, and PG. Jones. 1989. Root growth of four
common bean cultivars in relation to drought tolerance in environments with

contrasting soil types. Expl. Agric. 25:249-257.

Stanhill, G. 1986. Water use efﬁciency. Adv. Agron. 39:53-83.

42

Stegrnan, E. C., and H. M. Olson .1976. Water management relationships for irrigated
pinto beans. N. D. Res. Rep. No. 61.

Stoker, R. 1974. Effect on dwarf beans of water stress at different phases of growth. N. Z.
J. Exp]. Agric., 2:13-15.

Walker G. K., and J. L. Hatﬁeld. 1979. Test of the stress-degree -day concept using
multiple planting dates of red kidney beans. Agron. J 71:967-971.

Walton, D. C., E. Galson, and M. A. Harris. 1977. The relationship between stomatal
resistance and absicic acid levels in leaves of water-stressed bean plants. Planta
133: 145-148.

White, J. W., J. A. Castillo, and Ehleringer. 1990. Associations between productivity,

root growth and carbon isotope discrimination in Phaseolus vulgaris under water
deﬁcit. Aust. J. Plant Physiol. 17:189-198.

43

CHAPTER 3
CARBON ISOTOPE DISCRMINATION AND COMMON BEAN ADAPTATION

TO DROUGHT

ABSTRACT
Carbon Isotope Discrimination (CID) has been suggested as a screening tool for drought
resistance, but its relationship with common bean (Phaseolus vulgaris L.) productivity
under moisture stress is not clear. This study was conducted to assess the eﬂ‘ect of
moisture deﬁcit on CID and on the relationship of CID to yield, water use, water use
eﬁciency (WUE) and harvest index (HI). Two drought resistant (BAT 47 7 and LEF2RB)
and one drought susceptible (Seafarer) genotypes were grown under well watered
conditions and under vegetative (intermittent) and reproductive (terminal) moisture stress
from 1991 to 1993 in a rain shelter at the Kellogg Biological Station in Hickory Comers,
MI. Reproductive moisture stress signiﬁcantly reduced CID by 9% in comparison to the
5% reduction that occurred under intermittent stress. Seafarer had a signiﬁcantly higher
CID than both BAT 477 and LEF2RB. Positive correlations were found between CID
and yield, WUE, and water use for each genotype or water treatment but not across
genotypes or water treatments except for water use and pods per m". Relative biomass
and WUE reductions strongly and positively correlated with relative CID reduction. It is
concluded that CID can be a useﬁil screening tool for drought resistant genotypes but

needs further testing with additional genotypes.

INTRODUCTION

Breeding for drought resistance in drought prone environments requires the existence of
a heritable genotypic variation as well as a screening trait that is visible to the breeder
(Clarke and Townley-Smith, 1984). Carbon isotope discrimination (CID or A) has been
proposed as one such screening trait (Ludlow and Muchow, 1990), since a strong
correlation was found between A and water use efficiency (WUE) in many crops,
including legumes like peanuts (Hubick, 1990; Condon et al., 1987). Water use efﬁciency
is considered to be the link between the drought factor and drought resistance (Stanhill,
1986)

Among the models that relate A to photosynthesis and water use efﬁciency, that
of F arquhar et a1. (1982) is considered to be the most developed and tested (Ehleringer et
al., 1991). Seemann and Critchley (1985) reported that common beans, like other C3
plants, followed the theoretically expected relationship between A and intercellular carbon
dioxide concentration as proposed by Farquhar et a1. (1982).

Genotypic diﬁ‘erences among common bean cultivars for A have been reported
(White et al., 1990; Ehleringer et al., 1991). However, results linking A to yield under
drought or to any other drought adaptation trait by common bean were not conclusive
(White et al., 1990). Carbon isotope discrimination (A) may be a useﬁil screening tool if
it can be related to long term water use eﬁ'iciency or to other determinants of yield in a dry
environment such as water use and harvest index. This should be true also if CID could
separate known drought resistant and susceptible genotypes. This study investigated the

eﬁ‘ect of an intermittent and a terminal water stress on a drought susceptible (Seafarer)

45

and two drought resistant bean genotypes (BAT 47 7 and LEF2RB). The objective was to
assess if A is associated with yield and yield determinants and whether A can be used as a
predictor of drought resistance in common bean.
MATERIALS AND METHODS

Three common bean (Phaseolus vulgaris L.) Genotypes were planted on a
Kalamazoo soil (F inc-loamy, mixed, mesic Typic Hapludalfs) under a rain shelter (Martin
et al., 1988) at the Michigan State University Kellogg Biological Station at Hickory
Corners, Michigan on 18 June 1991, 14 June 1992, and 4 June 1993. BAT 477 was
reported in the literature as a drought resistant genotype based upon extensive germplasm
evaluations in CIAT where it was developed (Singh, 1995). LEF2RB was evaluated in
previous studies on the basis of yielding ability under drought (Schneider et al., 1997) and
Seafarer is a commercial check widely grown and developed in Michigan (Adams, 1996).
Based on soil tests about 98 kg ha" of urea (46% N) was applied as a starter fertilizer
each year, together with soil rhizobium to avoid any existing non-uniforrnity of rhizobium
in the soil. The automatic rain shelter was set to close as soon as it started raining. The
maximum and minimum temperatures for each year are shown in Figure 1.

The experimental design was a split plot with water as the main plot, genotypes as
the sub-plot, and three (1991) or four (1992 and 1993) replications. The main plot was 6
m by 3 .5 m which was subdivided into 3 sub-plots each 2 m long. The three water
treatments were a well-watered control, vegetative or intermittent stress: no irrigation
from V5 (ﬁve leaf stage) to R1 (ﬁrst open ﬂower), and a reproductive terminal stress: no

moisture ﬁom R1 to harvest. The amounts and times of irrigation are presented in Table 1

46

Temperature (0°)

Temperature (0")

1991 1992

 

 

   

 

 

 

 

 

 

40 40
35 - 35 4
3° ‘ 30 4
25 - 25 _
20.1 20..
15 i 15 4
10 - 10 - j".
5 - 5 .
0 - 0 - 5
-5 - -5 _
-1o 1 1 . . , -1o . . . . a
160 180 200 220 240 250 160 180 200 220 240 260
Day of Year Day of Year
40 1993

 

 

— Maximum
------ Minimum

 

 

 

 

 

 

 

'10 I j I I I
160 180 200 220 240 260

Day of Year

Figure 1. Maximum and minimum air temperatures for the growing season
at experimental site 1991-1993.

47

Irrigation (mm)

80..

02:3.

 

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.m... :E E:

 

 

 

 

 

 

8 - 403.5%
N:
a -
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£1.0on 00303.. 3.963 .63 L www.

48

Table 1. Irrigation treatment and application for three common bean genotypes grown in a
rain shelter at Hickory Corners, Michigan 1991-1993.

 

 

 

 

Grth Stages

Year Irrigation Planting 5-leaf R1 to Sum % of

Treatment to 5-leaf to R1 1' Harvest Control
mm

1991 Control (W 1) 114 102 89 305 100
Stress (W2) 114 0 89 203 67
Stress (W3) 114 102 0 216 71

1992 Control (W 1) 152 51 90 294 100
Stress (W2) 152 O 90 242 83
Stress (W3) 152 51 0 203 69

1993 Control (W1) 114 51 85 250 100
Stress (W2) 114 0 85 199 80
Stress (W3) 114 51 0 165 66

 

‘I'R1=First open ﬂower in any node.

49

and in Figure 2.
Phenology

Water stress treatments were matched with phenological growth stages to
elucidate the differential effect of moisture deﬁcit on physiological and morphological
traits. Phenological stages were measured by counting leaf number during vegetative
growth. The ﬁrst ﬂower was considered as R1 and the details of other growth stages
were based on the procedure of Nuland and Schwartz (1989).

CID, Water use, and WUE

Carbon isotope discrimination was measured by sampling 5 fully open, expanding
trifoliates per plot at mid-pod ﬁlling time (R7). These were then bulked per plot, dried in
the oven for 48 hours at 70 °C and ground before sending for 13C/ 12C analysis. Leaf
samples were analyzed by mass spectrometry at the University of Utah (1991) or by
Isotope Services Inc., Los Alarnos (1992, 1993). Laboratory results are usually expressed
in negative values representing isotopic compositions of MC since plant materials have
usually lower 13C than the standard Pee Dee Belemnite (PDB). These negative 6‘3C
values are converted to C11) or A as follows:

CID(A )=( 0‘3C_-,-0‘3Cp_)/(1+0‘3Cﬂ_,) (Farquhar et al., 1989).

Water use was calculated from neutron probe readings before and after the water
treatment. The access tube for each plot was placed on one of the two center rows of
each plot. The count ratios of the neutron probe were calibrated with gravimetrically
measured soil moisture for each depth. Water use eﬁciency (WUE) was measured from

the ratio of biomass yield and seasonal cumulative water use.

50

Grain Yield, Yield Components, and Relative Biomass

Grain yield, yield components and the above ground dry weight (biomass) data
were recorded from the harvested samples of 1.5 m of the two center rows. Relative
water use is deﬁned as (control-stress)/control. It was determined by using a neutron
probe to assess water extraction ﬁom a 1.20 in depth. Drought resistance is deﬁned as
relative yield reduction in response to drought: (control-stress)/control (Sinha, 1986;
Doorenbos and Kassam, 1979).

The data were analyzed by the SAS General Linear Models (GLM) including the
analysis of variance (ANOVA) and regression (SAS Institute, 1993). Further analysis of
the diﬂ‘erences between genotypes under speciﬁc water treatments was done by analyzing
the data as a randomized complete block design when there was no water by genotype
interaction. Correlation analysis was done to examine any associations among
parameters. A combined analysis over all the years was done whenever the single year
results were similar or in addition to individual yearly analysis to show the general trend.
Means ﬁ'om different treatments were compared by using Fisher's AN OVA protected
Least Signiﬁcant Diﬂ‘erence (LSD).

RESULTS AND DISCUSSION
CID and Water Stress

Intermittent vegetative water stress reduced CID in 1991 while terminal
reproductive stress reduced CID relative to the control in 1992 and 1993 (Table 2).
Across water treatments, Seafarer had a signiﬁcantly higher CID than both BAT 477 and

LEFZRB in 1992 and 1993. The latter two genotypes were not signiﬁcantly diﬂ‘erent

51

Table 2. Carbon Isotope Discrimination (CID) of three common bean genotypes grown
under well watered control (W1 ), vegetative intermittent (W 2), and reproductive terminal

(W3) water stress regimes at Hickory Corners, MI in 1991-1993.

 

Treatment
Control (W1)
Stress (W2)
Stress (W3)
LSD (0.05)
LSD (0.10)

Genotype
Seafarer

LEF2RB
BAT 477
LSD (0.05)

 

1991 1992 1993 3-years
A x 10'3
19.60 20.44 18.07 19.34
18.58 19.73 17.90 18.75
19.24 18.63 16.51 18.03
NS 1.15 0.88 0.67
0.74 0.91 0.70
19.14 20.53 18.60 19.95
19.05 19.05 16.80 18.23
19.23 19.22 17.07 18.44
NS 0 . 52 o . 61 o . 67

 

 

52

Table 3. Carbon isotope discrimination as affected by Moisture stress at different growth
stages for three common bean genotypes grown in a rain Shelter in Hickory Corners

Michigan in 1991-1993.

 

Year

1991

1 992

1993

3-yrs

Genotype

Seafarer
LEF2RB
BAT 477
LSD (0.05)
Seafarer
LEF2RB
BAT 477
LSD (0.05)
Seafarer
LEF2RB
BAT 477
LSD (0.05)
Seafarer
LEF2RB
BAT 477
LSD (0.05)

 

MW
Control Stress
(W 1) (W2)
A x 10'3

19.39 18.96
19.77 18.01
19.63 18.78

NS NS
21.36 20.52
20.04 18.84
19.91 19.82

NS 1.06
19.08 18.93
17.65 17.02
17.47 17.73

NS 1.22
19.99 19.52
19.10 17.95
18.94 18.78
0.66 0.59

Stress

(W3)

 

19.06
19.38
19.28
NS
19.72
18.26
17.92
0.72
17.79
15.74
15.99
0.90
18.84
17.65
17.59
0.63

LSD
(0.05)

NS
0.76
NS

0.56
NS
1.56

0.42
1.31
NS

0.41
0.77
0.86

 

53

(Table 2). No interactions between water treatments and genotypes were found at any
year. The lack of genotype by water interaction suggested that the genotypes were
similar in their reduction of CID values due to water stress. A similar lack of such
interactions in the presence of treatment and genotypic differences were reported for cool
season grasses (Johnson and Bassett, 1991).

For any given year, there was no Signiﬁcant difference in C11) among the
genotypes when they were grown under, well watered conditions (Table 3), although BAT
477 had a signiﬁcantly lower CID than Seafarer when data were combined across years.
Thus, no confounding eﬂ‘ects from preexisting varietal differences in C11) potential was
noted, which if found, could aﬂ‘ect subsequent genotypic evaluations.

Intermittent stress signiﬁcantly reduced CID for LEF2RB (1991) and Seafarer
(1992) and the same was true for Seafarer when the data for the intermittent stress
treatment were combined across years (Table 3). Under the intermittent water stress,
Seafarer had a signiﬁcantly higher CID than LEFZRB (1992 and 1993). There was no
signiﬁcant difference between BAT 47 7 and the other two genotypes in any year under the
intermittent water stress treatment (Table 3). The ranking of the three genotypes was
consistent for all three years under this treatment, unlike the variable rankings under the
terminal stress treatment.

Terminal water stress reduced CID relative to the control for all genotypes when
the data were combined across years (Tables 2). This was true for Seafarer (1992,
1993), LEF2RB (1991,1993) and BAT 477 (1992)(Tab1e 3) . Terminal stress reduced

CID relative to the intermittent stress only for Seafarer (1992 and 1993) and for Seafarer

54

and BAT 477 when data were pooled across years. This may be an indication that the
susceptible genotype was discriminating against the heavier isotope more than the resistant
genotypes under this stress. Since there was no signiﬁcant diﬁ‘erence between Seafarer
and BAT 477 under the intermittent stress within each year (Table 3), their differences
under the terminal stress may be due to differential response to drought at later grth
stages. The eﬂ‘ect of growth stage on CID determination in common bean was studied
by Ehleringer (1990) who concluded that the ranking of the genotypes did not change
when CID was sampled at different grth stages within a season. Carbon isotope
discrimination was sampled only at the pod ﬁlling period (R7) in this study, so results
cannot be compared to those of Ehleringer (1990). On the other hand, the ranking of the
genotypes across water treatments appeared stable for 1992-93 (Table 2). In contrast, the
genotypic ranking varied among water treatments (Table 3).

All three genotypes had positive correlations (Seafarer:r=0.92 p< 0.001 n=11;
LEF2RB: r=0.82" p<0.01 n=11; BAT 477:r=0.53+ p<0. 10 n=11) when the control
treatments were compared to the vegetative stress treatments. Similar positive
correlations were found between the control and reproductive stress treatments (r=0.76* *
p<0.01 n=11 for Seafarer; r=0.64* p<0.05 n=11 for LEF2RB; and r=0.63* p<0.05 n=11
for BAT 477 ). Ehleringer et al. (1991) found differences among cultivars based on the
geographic location for which the common beans were developed when they compared
irrigated and stressed treatments.

The diﬁ‘erential reduction in CID by the genotypes due to the terminal stress might

indicate that the resistant check BAT 47 7 was more stable than the others since it reduced

55

Table 4. Relative reductions- (control-stress)/control- in CID, yield, WUE, HI and pod
numbers for three common bean genotypes subjected to an intermittent vegetative (W 2)
and a terminal reproductive(W 3) moisture stress in Hickory Corners, Michigan (1991-
1993).

 

Relative Reductions= (Control-Stress)/ Stress

 

Stress DS‘I’ Genotype CII) Yield WUE HI Pod s Pods

 

Treatment Plant" m“2
Stress 0.82 Seafarer 0.02ab 0.22 0.003 -0.03 0.20a 0. 12ab
(W2) 0.79 LEF2RB 0.06a 0.34 0.09 0.05 0.14ab 0.19a

0.79 BAT477 0.0056 0.09 -029 0.05 0.035 0.01b
LSD(0.1) 0.04 NS NS NS 0.13 0.15

Stress Seafarer 0.060 0.45a 0.18ab 0.13a 0.26a 0.27a

(W3) 0.82 LEF2RB 0.08 0.48a 0.29a 0.04b 0.26a 0.30a
0.80 BAT 477 0.07 0.29b 0.002b 0.05b 0.08b 0.14b
0.77 LSD (0.1) NS 0.15 0.19 0.07 0.12 0.10

 

iDrought Stress (DS)= (control-stress)/control) in water use during treatment period.

56

its CID in only one year compared to the others. This stability in C11) reduction from
stress could be a useful indicator of drought resistance if it could be correlated to similar
stability in yield reduction under drought.

CID and Drought Resistance

Drought resistance has been deﬁned in this study as the reduction in yield or its
determinants in response to soil moisture deﬁcit relative to the well watered treatment.
The resistant genotype BAT 477 had a signiﬁcantly smaller relative CID reduction than
LEF2RB under intermittent water stress (Table 4). In addition, BAT 477 had smaller
relative reductions in pods plant" and pods m’2 than Seafarer and LEF2RB, respectively.
There were no signiﬁcant differences in relative reduction among the genotypes in yield ,
WUE, or HI under the intermittent stress (Table 4). Across genotypes, relative CD)
reduction correlated positively with relative reductions in biomass, yield, and WUE but
did not correlate with reductions in HI or water use (Table 5).

The three genotypes did not diﬁ‘er signiﬁcantly in their relative reductions for CID
under terminal moisture stress (Table 4). This could indicate a similarity in their response
to CID reductions at this growth stage. As expected BAT 477 was more drought
resistant than Seafarer under the terminal stress with lower relative reductions in yield, HI
and pod number. Surprisingly, LEF2RB was as drought susceptible as Seafarer except
for HI (Table 4). Similar to the intermittent stress, relative reductions in CID positively
correlated with relative reductions in biomass and WUE. Carbon isotope discrimination
positively correlated with water use but not with yield under this stress. White et a1.

(1990) found similar results when they compared biomass and seed yield to reductions in

57

Table 5. The relationships of relative CID reduction-(control-stress)/control- to relative
reductions in biomass, yield and yield determinants for three common bean genotypes
grown under an intermittent vegetative (W 2) and terminal reproductive (W 3) moisture
stress at Hickory Corners, Michigan 1991-1993.

 

 

Stress Relative Reduction in W

Treatment 1991 1992 1993 pooled

Stress Biomass 0.53 0.75" 092*" 076“"

(W2) Yield 068" 050+ 0.60"" 074*"
Water Use Efficiency 062+ 0.71" 091*" 072*"
Harvest Index 0.22 -0.30 0.45 0.09
Water Use -0.22 0.02 0.47 0.02

Stress Biomass 0.49 0.58“ 0.17 0.35"

(W3) Yield 0.59+ 0.31 0.13 0.25
Water Use Emciency 060+ 057+ 0.16 038"
Harvest Index 0.43 -0.37 -0.37 -0.16
Water Use 0.41 0.58‘ 0.21 0.48"

 

58

Seed Yield (9 m '2)

Pods Plant"

Pods m"

 

 

 

 

 

 

 

 

 

b

16 -

14 -

12 " g
10 - .

s _ a.

8:057"
6 r 1
17 10 19 20 21

 

 

 

 

 

HI

0.60

 

0.58 ~
0.56 -
0.54 a
0.52 -
0.50 4

 

 

 

WUE
O
5‘

 

 

 

Seasonal Water Use (mm)

 

 

 

 

 

Figure 3. Relationship of carbon isotope discrimination (CID) to yield, pod

number, and yield determinants when averaged across treatments
for common been grown at Hickory Corners. Michigan 1991-1993.

59

 

Yield (9 m '2)

VWE

 

0.62

 

100-1 g

 

 

0.50 -
0.58 -
0.56 -
0.54 -
0.52 -
0.50 -
0.4a -
0.46 1

 

 

 

 

 

I T 0.44 I f I 7 I I

 

50 r r r

15161718192021z151617181920212

CID

CID

 

O Control-VIII

OStrees-WZ

A Stress-W3

 

 

 

 

 

1.2

1.0 -1 111012-02":

0.8 4

0.6 r

0.4 -

 

 

 

 

 

 

 

0.2 T I I I

1516171819202122 15151713

CID

I

 

I

CID

Flm 4. The relationships between CID and yield or yield deteminans for three moisture
delidttteetmentsacroesthreeconmon beengenotypeeatl-ickory Comets, Meligen
1991-1993. (Data arethe pooled genotype by year means).

60

350

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

300-
9.7" 250-
E
9 200-
i 150‘
100- _
m I I I I I I a 0.44 _I T I i T I
1516171819202122 1516171819202122
CID CID
O mar-GI
o Lamp-62
A ”477-G3
1.2
I
Gizr2=0.70" a / .
1.01 G2t2=0.41+ 43/ -°
G3zr2=0.51' 9 /-'/ ‘
05- ”‘6’ -

0.6 -

0.4 4

 

 

0.2

1516171819202122

 

C_

T r I I I I

CID

Met Use (nm)

§§§§§§§§§

l

J

l

l

 

—_

T T I I I I

 

 

1516171819202122
CID

Flanammaﬁmslipsbetmdomdyidduyidddeleminmtsietmeem
gremmderdﬂetentnnisuedeﬁcittmatments attidroryComets,M
1991-1993. Theddaaelhepooledmterbyyearmeans

bear

61

 

 

Pods Plant "
Pods m"

 

 

 

 

 

 

 

 

4 /I I I I I I 1m I l T 7 I I
15 16 17 18 19 20 21 22 15 16 17 18 19 20 21 22
CID CID
0 MW

 

 

 

 

 

 

 

 

 

 

 

 

Wl:t=-0.63+
VIEW-0.87“
260 Mr=-0.27ns
\ d
240‘ \ .
220- O '
1 °\
200- \ 0
A 00‘\ 4..
150-\ AR.
150- \\\\ 0A
A A 59.31
140- 9.. \
A \
o
.l .
120 A o\.
2 /.l I i I I I 1m I I I I I I\
1516171819202122 1516171319202122

FigueB. CortelationsbaweenClDandyieldconm mdetthreeumertteamenls
acroeetlvewonrnon bear genotypes a HckotyComets. Mch‘gan1991-1993. (Data
arethepooledgenoypebyyeermeene).

62

CID from control to stress.

The results presented for relative reductions indicate that these three genotypes
reacted diﬁ‘erently when subjected to similar amounts of drought stress (D8) of around
80% soil moisture depletion (Table 4). Seafarer reduced its harvest index (HI) while
LEFZRB reduced its WUE more (Data not presented). Both of these genotypes reduced
their pod numbers compared to the resistant genotype.

CID and Yield

There was no signiﬁcant linear correlation between CID and seed yield across
genotypes, water treatments, and years (Figure 3-a). There was a weak association
between CID and yield under diﬁ'erent water treatments when the data were pooled
across genotypes and years (Figure 3-a). Seed yield correlated weakly with CID under the
well watered and vegetative stress treatments, but not under the reproductive moisture
stress treatment (Figure 4-a).

There was a strong positive correlation between seed yield and CID for each of the
three genotypes when data were combined across water treatments and years (Figure S-a).
BAT 477, the resistant genotype, had a stronger association between its C11) and yield
than the other two genotypes. White et a1. (1990) reported a lack of correlation
between CID and yield in common bean and reports from other crops were inconsistent
(Menendez and Hall, 1996; Matus et al., 1997; Matus et al., 1995; Condon et al., 1987).
CID and WUE

There was no signiﬁcant linear correlation between CID and WUE when the data

were combined across water treatments, genotypes, and years (Figure 3-e). These results

63

 

 

GI: r=0.40ns 0

PodsPlant "

 

 

 

 

 

 

 

100 I I It I I I

 

1516171819202122

 

 

 

 

15 16 17 18 19 20 21 22
0 01-501!!!
0 can-Lam
A Gena-1477 G1:r=-0.69‘
—' GZ:r=-0.01ns
G3:r=-0.13ns

 

 

 

 

 

 

 

 

 

T I I I I I

1516171819202122 1516171819202122

CID CID

1:19:57. Correldionbetween Cledtheyieldconponentsoftlreecommn bear
genotypesgown mderttreemoishretreMatl—ickotyComs,
Md'igm1991-1993. (Dds aethe pooled wderbyyea name)

64

 

110

 

 

 

 

 

 

 

 

 

WI "073' Win-0.83" /
V12 "0.501s 1m- Mzt-OJZ' O
”A We , 90 “On-0.” C, ./
e ' /O
9 30‘
3 70 A A70
>- 4 A//
E 604 O, /
m 50‘ G
40 - 43 0“
1m I # I H T 1 w I I I I I I
15 16 17 18 19 20 21 22 15 16 17 18 19 20 21 22
CID CID
. WI Gourd
0 human»

 

 

 

 

 

 

 

 

 

 

 

 

 

1515171519202122
CID

1516171819202122
CID

1719198. RddionstipbetweenCledbiomessconpormtsotmeemnmbem
gantypesasaﬂededbydﬁeteramdsuebeatmntsatﬁdrayCamts,Mdigm
1991-1993. Daaaethepooledgenotypebyyeamems.

65

disagree with those of Saranga et a1. (1998) in cotton. There was a signiﬁcant association
between CID and WUE under the well watered treatment (Figure 4-c). In contrast, CID
did not correlate with WUE under any stress treatment (Figure 4-c).

CID correlated positively with WUE for all three genotypes (Figure S-c) .
However, Seafarer and BAT 47 7 had stronger relationship between CID and WUE than
LEFZRB (Figure 5-c). Ehleringer et al., (1991) found differences in the slopes of the
WUE and CID correlations based on the geographical area for which genotypes were
developed (North/South American). We did not ﬁnd any such diﬁ‘erence between
Seafarer (North American) and BAT 477 (South American) using Chi square (p<0.05
n=1 1). Positive correlations between CID and WUE were reported for wheat (F arquhar
and Richards, 1984), but negative correlations were found between CID and WUE in
peanuts (Craufurd et al., 1999) and in coffee (Meinzer et al., 1990).

CID and III

There was a weak linear correlation between CID and HI (Figure 3—d) when the
data were combined across water treatments, genotypes, and years. This weak
association was lost when data were separated by water treatment (Figure 4-b). Similarly,
there was no signiﬁcant linear association between CID and H] for any of the three
genotypes (Figure 5-b). This diﬁ'ers from the low to moderate correlation between CID
and HI that Menendez and Hall (1996) reported in cowpea, and the signiﬁcant and

positive correlation that Matus et a1. (1995) reported in lentil.

66

CID and Water Use

There was no signiﬁcant linear correlation between C11) and water use (Figure 3-
0 when the data were combined across water treatments, genotypes, and years. There
was a positive linear association between CID and water use under speciﬁc water
treatments. This association was weakest under the well watered conditions and
strongest under the terminal moisture stress treatment (Figure 4-d). Carbon Isotope
Discrimination correlated positively with water use for all three genotypes but LEF2RB
had a stronger correlation than the other genotypes (Figure S-d).

C11) and Yield Components

There was a highly signiﬁcant positive correlation between CID and pods plant‘1 or
pods m‘2 (Figure 3-b and c). CID did not correlate with other yield components like
seeds per pod and seed weight across treatments (Data not presented). Similar results
were found for biomass components other than seed yield except that empty pod weights
correlated weakly with CID (r’=0.37, p<O. 10, n=11).

Seed yield components indicated contrasting relationships with CID under different
water treatments. Under well-watered conditions, CID strongly and positively correlated
with pods m'z, and weakly but negatively with seed weight (Figure 6-b,d). Under
vegetative moisture stress, C1D correlated positively with pods plant", pods m’z, and seeds
pod " but had a strong negative correlation with seed weight (Figure 6-a,b,c,d).
Additionally, the correlations with pod number were much stronger than the correlations
with seed number. Under the reproductive moisture stress treatment, CID strongly and

positively associated with pods plant"and pods m“2 but did not correlate with the other

67

 

 

Empty MS (9 m '2)

 

 

 

 

 

 

 

 

 

1m 1 1 r I T I 30 r ' r ' ' I
1516171819202122 1516171319202122
010 CID
.61“
062mm
(scan-1m

 

 

 

 

 

 

 

 

 

 

I

 

 

 

CID

1516171819202122 1516171819

I

202122
CID

ﬁmamwmmcmmdbimmofmmbem
WmatﬁcloryCanus. Mdigm1991-1993. Danube

pododwaarb/yeamems

68

seed yield components (Figure 6).

CID did not correlate signiﬁcantly with pods plant‘1 for Seafarer but strongly did
so for the other genotypes (Figure 7-a), yet CID strongly correlated with pods m'2 for all
three genotypes (Figure 7-b). Seafarer had the strongest correlation between CID and
seeds pod’l (ﬁgure 7-c), and only Seafarer had a strong negative correlation with seed
‘ weight (Figure 7-d). This contrasting relationship of CID with seed yield components
due to genotype or water treatment may have masked the overall relationship between
CID and seed yield across genotypes and water treatments (Figure 3-a).

CID, Biomass and Biomass Components

There was a strong positive correlation between CID and biomass under the well
watered conditions (Figure 8-a ). In contrast, there was no signiﬁcant correlation
between CID and biomass under the vegetative moisture stress (Figure 8-a). Positive
correlations between CID and biomass were reported in wheat (Condon et al., 1987) while
negative correlations were found in cool season grasses (Johnson and Bassett, 1991). In
common bean, White et al., (1990) reported positive CID and biomass correlations in one
of three sites but no negative relationship was noted.

CID strongly and positively correlated with biomass in each of the genotypes
(Figure 9-a). The susceptible genotype (Seafarer) could be identiﬁed ﬁom the resistant
genotypes by its lower line indicating that it had a higher CID per biomass.

There was a positive linear relationship between CID and empty pod weight
under all water treatments (Figure 8-b). This relationship was stronger under the control

and vegetative stress treatments and was weaker under the terminal reproductive stress

69

(Figure 8-b). A strong and positive correlation was found between CID and empty pod
weight for all three genotypes (Figure 9-b).

Similarly, there was a strong positive correlation between CID and stover yield
under the well watered conditions (Figure 8c). But this relationship was either non
existent or weaker under the stress treatments (Figure 8-c). CID strongly and positively
correlated with stover yield for all three genotypes (Figure 9-c).

Straw yield correlated with CID only under the intermittent water stress treatment
(8-d). Across water and years, however, a strong and positive correlation was found
between CID and straw yield for all three genotypes (Figure 9-d).

CONCLUSION

It has been proposed that, in drought prone environments, yield is the product of
water use eﬁciency (WUE), harvest index (HI), and water used by the plants (Passioura,
1977 ; Menendez and Hall 1996). Carbon isotope discrimination could potentially serve
as useful screening tool for yield or its determinants in drought prone environments. The
theoretical models relating CID to assimilation rate and hence productivity also predict a
negative relationship with water use eﬁciency (F arquhar et al., 1982; Farquhar et al.,
1989; Ehleringer et al., 1991).

Contrasting correlations for CID with water use eﬁiciency, water use, and
productivity have been reported for diﬂ‘erent crops. These include reports about the
relationships between CID and biomass (Johnson and Bassett, 1991; Condon et al., 1987),
CID and yield (White et al., 1990; Matus et al., 1997), and CID and WUE (Johnson and

Bassett, 1991; Saranga et al., 1998; Meinzer et al., 1990; Craufurd et al., 1999).

70

Our results generally conﬁrm those of other bean researchers who reported
positive associations between CID and productivity (White et al., 1990; Ehleringer, 1990;
Ehleringer et al., 1991) and other crops (Saranga et al.,l998; Matus et al.,l995). In
contrast, we did not ﬁnd negative correlations for CID and WUE or water use as
reported for beans (Ehleringer et al., 1991), cowpeas (Ismail and Hall, 1992), peanuts
(Brown and Byrd, 1996; Hubick, 1990), barley (Hubick and Farquhar, 1989) and
tomatoes (Martin and Thorstenson, 1988). Departures from theory for CID specially in
ﬁeld grown crops had been discussed before (F arquhar et al.,l989; Matus et al., 1997) and
might have contributed to the positive relationship between CID and water use eﬁciency
in our study.

In conclusion, our results directly relate relative CID reductions to genotypic
drought resistance deﬁned as relative reduction in productivity due to moisture deﬁcit and
to relative reductions in water use and water use eﬁciency as well (Tables 4 and S). No
such relationships were found for harvest index (HI). Our results need further
veriﬁcation with larger number of genotypes and environments but do clearly indicate that

CID can be used as screening tool when selecting for drought resistant genotypes.

71

REFERENCES

Adams, M. W. 1996. An historical perspective on signiﬁcant accomplishments in dry bean
research- the ﬁrst 100 years. Bean Improvement Cooperative Annual Report
39232-45.

Brown, RH, and G. T. Byrd. 1996. Transpiration eﬁciency, speciﬁc leaf weight, and
mineral concentration in peanut and pearl millet. Crop Science 36:457-480

Clarke, J. M., and T. F. Townley-Smith. 1984. Screening and selection techniques for
improving drought resistance. In P. B. Vose and S. G. Blixt. Crop breeding: a
contemporary basis. Pergamon Press, New York.

Condon, A G., R. A. Richards, and G. D. F arquhar. 1987. Carbon isotope discrimination
is positively correlated with grain yield and dry matter production in ﬁeld-grown
wheat. Crop Science 27:996-1001.

Craufurd, P. Q., T. R. Wheeler, R.H. Ellis, R. J. Summerﬁeld, and J. H. Williams. 1999.
Eﬂ‘ect of temperature and water deﬁcit on water-use eﬂiciency, carbon isotope
discrimination, and speciﬁc leaf area in peanut. Crop Sci. 39: 136-142.

Doorenbos, J. and A. H. Kassam. 1979. Yield response to water. FAO Irrigation and
Drainage Paper no. 33, Rome.

Ehleringer, J. R. 1990. Correlations between carbon isotope discrimination and leaf water
conductance to water vapor in common beans. Plant Physiol. 93: 1422-1425. -

Ehleringer, J. R, S. Klassen, C. Clayton, D. Sherrill, M. Fuller-Holbrook, Q. Fu, and T.
A. Cooper. 1991. Carbon isotope discrimination and transpiration eﬁciency in
common beans. Crop Sci. 31:16] 1-1615.

Farquhar, G. D., J. R. Ehleringer, and K. T. Hubick. 1989. Carbon isotope discrimination
and photosynthesis. Annu. Rev. Plant Physiol. Plant Mol. Biol. 40:503-537.

Farquhar, G. D., M. H. O’Leary, and J. A. Berry. 1982. On the relationship between
carbon isotope discrimination and the intercellular carbon dioxide concentration in
leaves. Aust. J. Plant Physiol 9:121-137.

Hubick, K. T. 1990. Eﬁ‘ects of nitrogen source and water limitation on growth,
transpiration eﬁiciency and carbon-isotope discrimination in peanut cultivars. Aust.
J. Plant. Physiol. 17:413-430.

Hubick, K. T. and G. D. Farquhar. 1989. Carbon isotope discrimination and the ratio of
carbon gained to water lost in barley cultivars. Plant, Cell and Environment

72

12:795-804.

Ismail, A. M. and A. E. Hall. 1992. Correlation between water- use emciency and carbon
isotope discrimination in diverse cowpea genotypes and isogenic lines. Crop Sci.
3227-12.

Johnson, R. C., and L. M. Bassett. 1991. Carbon isotope discrimination and water use
emciency in four cool-season grasses. Crop Sci. 31:157-162.

Ludlow, M. M., and R. C. Muchow. 1990. A critical evaluation of traits for improving
crop yields in water-limited environments. Adv. Agron. 43:107-153.

Martin, B. and Y. R. Thorstenson. 1988. Stable carbon isotope discrimination, water use
eﬁciency, and biomass productivity of Lycopersicon esculentum, Lycopersicon
penelli, and the F1 hybrid. Plant Physiol. 88:213-217.

Martin, E. C., J. T. Ritchie, S. M. Reese, T. L. Loudon, and B. Knezek. 1988. A large-
area, light-weight rainshelter with programmable control. Trans. ASAE 31 : 1440-
1444.

Matus, A, A E. Slinkard, and C. van Kessel. 1995. Carbon isotope discrimination and
indirect selection for seed yield in lentil. Crop Sci. 35:679-684.

Matus, A, A. E. Slinkard, and C. van Kessel. 1997. Genotype x Environment interaction
for carbon isotope discrimination in spring wheat. Crop Sci. 37:97-102.

Menendez, C., and A. E. Hall. 1996. Heritability of carbon-isotope discrimination and
correlations with harvest index in cowpea. Crop Sci. 36:233-238.

Meinzer, F. C ., G. Goldstein, and D. A. Grantz. 1990. Carbon Isotope discrimination in
coﬁ‘ee genotypes grown under limited water supply. Plant Physiol. 92:130-135.

Nuland, D.S., and H. F. Schwartz. 1989. A visual description of the common bean plant:
F our major grth periods. Bean Improvement cooperative 32:16-17.

Passioura, J. B. 1977 . Grain yield, harvest index, and water use of wheat. J. Aust. Inst.
Agric. Sci. 43:117-121.

Saranga, Y., 1. Flash, and D. Yakir. 1998. Variation in water-use efﬁciency and its relation
to carbon isotope ratio in cotton. Crop Sci. 38:782-787.

SAS Institute. 1993. SAS/STAT guide for personal computer, version 6, 4m ed. SAS
Inst, Cary, NC.

73

Schneider, K. A, R. Rosales-Sema, F. Ibarra-Perez, B. Cazares-Enriquez, J. A. Acosta-
Gallegos, P. Ramirez-Vallejo, N. Wassimi, and J. D. Kelly. 1997. Improving
common bean performance under drought stress. Crop Sci. 37243-50.

Seemann, J. R., and C. Critchley. 1985. Eﬂ‘ects of salt stress on the growth, ion content,

stomatal behavior and photosynthetic capacity of a salt-sensitive species,
Phaseolus vulgaris L. Planta 164: 151-62.

Singh, S. P. 1995. Selection for water-stress tolerance in interracial populations of
common bean. Crop Science 35:118-124.

Sinha, S. K. 1986. Drought resistance in crop plants: a physiological and biochemical
analysis. In V. L. Chopra and R. S. Paroda (eds) Approaches for incorporating
drought and salinity resistance in crop plants. Oxford & IBH Publishing Co., New
Delhi.

Stanhill, G. 1986. Water use efﬁciency. Adv. Agron. 39:53-83.
White, J. W., J. A. Castillo, and Ehleringer. 1990. Associations between productivity,

root grth and carbon isotope discrimination in Phaseolus vulgaris under water
deﬁcit. Aust. J. Plant Physiol. 172189-198.

74

CHAPTER 4
OSMOTIC ADJUSTMENT IN COMMON BEAN SUBJECTED TO WATER

STRESS

ABSTRACT
The role of osmotic adjustment due to moisture stress and its contribution to yield or yield
determinants in common bean (Phaseolus vulgaris L.) have not been well documented.
This study was conducted to assess genotypic diﬁ‘erences in osmotic adjustment and its
relationship to yield, harvest index, water use efﬁciency, rooting depth and carbon isotope
discrimination. Three common bean genotypes with similar yield potential but diﬁ‘ering in
drought resistance were grown in a rain shelter at Hickory Corners, MI in 1991 - 1993 in
a split plot design. Treatments were a control, intermittent vegetative stress, and a
terminal reproductive stress. Water potential and osmotic potential were signiﬁcantly
reduced (15 to 59%) while solute accumulation increased (21 to 34%) under the stress
treatments. Genotypic differences in osmotic adjustment were found only under terminal
moisture stress. Osmotic adjustment (r= -O.9l p s 0.05 n=6) and solute accumulation (r =
-0.91 p s 0.05 n=6) both strongly and negatively correlated with yield. Similarly,
signiﬁcant negative correlations of osmotic adjustment with water use efﬁciency, harvest
index and water use were found across water treatments at the reproductive growth
stage. Solute accumulation or osmotic adjustment may be indicative of susceptibility to

moisture deﬁcit rather than resistance in common bean.

75

INTRODUCTION

Common bean (Phaseolus vulgaris L.) is an important protein source in
subsistence agriculture worldwide, and common bean consumption in the United States
has been increasing (Holden and Haytowitz, 1998). Terminal moisture stress which
occurs aﬁer ﬂowering and intermittent moisture stress which occurs before ﬂowering both
have been shown to reduce yield in common bean (Acosta-Gallegos et al., 1998). The
development of drought resistant genotypes has been hampered by the lack of screening
techniques that easily distinguish between resistant and susceptible genotypes.

Osmotic adjustment, the ability of plants to actively accumulate solutes to maintain
cell turgor and volume (Radin, 1983; Guei and Wassom, 1993 ), has been suggested as a
criterion for selection of drought resistant genotypes (Ludlow and Muchow, 1990;
Morgan, 1983; Sloane et al., 1990; Rodriguez et al., 1992; Kumar and Singh, 1998) and
has, in some cases, been shown to be controlled by a single gene (Morgan, 1991).
Compared to other crops, few studies have reported osmotic adjustment or water relations
for common bean (Parsons and Howe, 1984; Wullschleger and Oosterhuis, 1991; Raggi,
1994), and all three studies were conducted in a controlled environment.

The transferability of ﬁndings from a controlled environment to a ﬁeld situation has
not been consistent (Morgan et al., 1991; Oosterhuis and Wullschleger, 1987; Turner et
al., 1987). Similarly, there has been no consensus on the beneﬁts of osmotic adjustment to
yield under drought (Morgan et al., 1991; Cortes and Sinclair, 1986;Li et al., 1993; Guei
and Wassom, 1993; Kumar and Singh, 1998;B1um, 1989; Rodriguez et al., 1992). It is

critical to obtain this information since any selection criterion that has no direct

76

relationship with yield or its determinants may not be useﬁrl in drought-prone
environments (Passioura, 1994; Menendez and Hall, 1996; Passioura, 1977).

This study investigated the relationship of osmotic adjustment, relative water
content (RWC), and water potential components to yield, harvest index, and water use
eﬁciency in three common bean genotypes that differed in yielding ability under drought
but which were similar in yield potential. The objectives were (1) to assess osmotic
adjustment in common bean grown in a ﬁeld environment, (2) to assess genotypic
differences in osmotic adjustment or water relations, and (3) to determine the relationship
of osmotic adjustment and other water relations variables to yield, harvest index, water
use eﬁciency, rooting depth, and carbon isotope discrimination.

MATERIALS AND METHODS

Three common bean genotypes were planted on a Kalamazoo soil (Fine-loamy,
mixed, mesic Typic Hapludalfs) under a rain shelter (Martin et al. , 1988) at the Michigan
State University Kellogg Biological Station at Hickory Corners, Michigan on 18 June
1991, 14 June 1992, and 4 June 1993 and harvested in September each year. Based on
soil test results, approximately 98 kg ha'1 of urea (46% N) was applied as a starter
fertilizer each year together with Rhizobr'um phaseoli to avoid any existing non-uniformity
of rhizobium in the soil. Agronomic practices were similar each year and reﬂected those
recommended for commercially grown crops. The automatic rain shelter was set to close
as soon as it accumulated 15 mm of rainfall. Maximum and minimum temperatures are
presented in Figure 1 for the three seasons.

The experimental design was a split plot with water as the main plot, genotype as

77

1991 1992

 

 

 

   

 

 

 

 

 

 

 

 

 

 

 

 

4o 40
35 - 35 A
30 - 30.,
{; 25-+ 25-
s 20 - 20 -
g 15- 15-
3. 1o - 10 -
§ 5
r- 5"
o - 0'4
-5 - -5 .
'10 m I I I I '10 I 1 r I T
160 180 zoo 220 240 260 160 180 200 220 240 260
Day of Year Day of Year
1993
35 -
30 -
i;' 25-
93 20 -
3 :' -— Maximum
g 15 ' 5 51,5 f ------ Minimum
Ii 10- 5 E if if
a: _ i t 3:
r- 5 c
o -
-5 -
'10 j T l I f

 

 

 

160 180 200 220 240 260
Day of Year

Figure 1. Maximum and minimum air temperatures for the growing season
at experimental site 1991-1993.

78

the subplot, and three (1991) or four (1992 and 1993) replications. The main plot was 6
m by 3.5 m and was sub-divided into 3 sub-plots, each 2 m long. The three genotypes in
this experiment were a drought susceptible Seafarer (G1)(Adams, 1996) and two drought
resistant LEF2RB (G2) (Schneider et al., 1997) and BAT 477 (G3) (Singh, 1995)
genotypes. The three water treatments were a well-watered control (W 1); intermittent
vegetative stress (W 2)with no irrigation from 5-leaf stage (V5) to ﬁrst open ﬂower (R1);
and terminal reproductive stress (W 3) with no moisture ﬁ'om R1 to harvest. Water stress

treatments were closely matched with phenological growth stages using the method
described by Nuland and Schwartz ( 1989). The amounts and times of irrigations are
presented in Table l and in Figure 2.

Osmotic Adjustment and Leaf Water Relations

Water potential and its components were measured using end-window
thermocouple psychrometers (Merrill Specialty Equipment, 84-series, Logan, Utah). Both
the calibration and equilibration methods closely followed those described by Oosterhuis
and Wullschleger (1987). Each Psychrometer, representing one plot was calibrated with
NaCl solutions of known water potential (Lang, 1967). A close ﬁt was found between
actual psychrometer output and those predicted by Brown and Bartos (1982) for the 15
second cool time at 25 °C temperature such that one equation was developed by linear
regression ﬁ'om the predictive data published by Brown and Bartos (1982) to convert
microvolts of ﬁeld data to water potential in megapascal.

Osmotic adjustment (CA) was calculated as follows:

OA=1tP-1t. where Itp=(1t1 x RWC,)/RWC2 (Note: negative values mean np<1t,).

79

 

Irrigation (mm)

.30..

0038.

 

 

Mm;
not
.51
31

m1

uc

58.3303

 

 

Nut
no-
amt
3-

m1

 

40:550.

 

 

 

30M Room

003:5: 003:0—

55-3303 503.502

4.03.50. 40.350.

 

Inc-0 N 9.4083 36020: #305020 *0- 3-00 00330: 000: 00002000 032: 5 m 3.: «30:2
0. 1.0.62 00303. 30:60: .60.. L 08.

80

Table 1. Irrigation treatment and application for three common bean genotypes grown in a
rain shelter at Hickory Corners, Michigan 1991-1993.

 

 

 

 

Growth Stages

Year Irrigation Planting 5-leaf R1 to Sum % of

Treatment to 5-leaf to Rl‘I' Harvest Control
mm

1991 Control (WI) 114 102 89 305 100
Stress (WZ) 114 O 89 203 67
Stress (W3) 114 102 O 216 71

1992 Control (W 1) 152 51 90 294 100
Stress (W2) 152 0 90 242 83
Stress (W3) 152 51 O 203 69

1993 Control (WI) 114 51 85 250 100
Stress (WZ) 114 O 85 199 80
Stress (W3) 114 51 0 165 66

 

‘I‘R1=First open ﬂower in any node.

81

np=Predicted Osmotic potential (Salisbury and Ross, 1985).

n,=Actual osmotic potential measured at end of stress

rtl=Osmotic potential before stress

RWC1=Relative water content before stress

RWC2=Relative Water Content after stress

Solute accumulation (n)was calculated from the equation of Morgan (1991)with
some modiﬁcation as follows:

n=-(It*RWC)/RT

n=Number of solute molecules

R=The gas constant

T=absolute temperature (leaf temperature taken at sampling time)

n=Osmotic potential

RWC=Relative Water Content
Relative Water Content

Relative water content was measured from 3 cm by 0.9 cm leaf strips cut from one
side of the midrib of the same trifoliate that was used for water potential measurements.
The strips were immediately sealed in glass vials and placed in a cooler with ice to reduce
photosynthesis. Each strip was weighed for fresh weight within 1 hour and returned to the
vial, ﬁlled with deionized water and capped. To minimize respiration, the vials were kept
in a dark room for 24 hours at 4 ° C to ensure ﬁill turgidity (Pardossi et al., 1992; Lecoeur
et al., 1992; Rodriguez-Maribona et al., 1992), dried with paper towel, and their turgid

weight taken. Each leaf strip was then returned to its vial and oven dried at 70 ° C for 48

82

hours. Relative water content was calculated as per Turner (1981). The 24 hour time for
turgidity in this study diﬁ‘ers from the 4 hours usually reported by other authors because it
is species or genotype dependent (Turner, 1981; Yabba and Foster, 1996) and because
preliminary tests found that all the leaves were not ﬁrlly saturated at shorter periods for
Seafarer.
Water Use and WUE

Water use was monitored using neutron probe measurements that were calibrated

against soil moisture using gravimetric measurements. The water holding capacity of this

 

soil type was found to be about 100 cm per 1.20 m proﬁle which was the maximum depth
sampled. Water use was calculated ﬁ'om the difference of neutron probe readings upon
initiation and conclusion of the water treatment. The access tube for each plot was placed
on one of the two center rows of each plot. The count ratios of the neutron probe were
calibrated with gravimetrically measured soil moisture for each depth. Water use
eﬁciency (WUE) was measured ﬁ'om the ratio of biomass yield and seasonal cumulative
water use.
Seed Yield

Seed yield was recorded from the harvested plants of 1.5 m of the two center
rows. The seed was oven dried and is reported on a 0% moisture basis.
Carbon Isotope Discrimination

Carbon isotope discrimination was measured by sampling 5 fully open, expanding
leaves (trifoliates) per plot at mid pod ﬁlling time (R7). These were then bulked per plot,

dried in the oven for 48 hours at 70 °C and ground before sending for analysis. Leaf

83

samples were analyzed by mass spectrometry at University of Utah (1991) or by Isotope
Services Inc, Los Alamos (1992, 1993).
Rooting Depth

Minirhizotron tubes were placed at a 45° angle in one of the two center rows of
each plot to record root grth by a video camera. Root depth was recorded by visually
monitoring the depth of common bean roots in each plot through each minirhizotron tube
before and after each treatment.

The data were analyzed by the SAS General Linear Model (GLM) including the
analysis of variance (ANOVA) and regression (SAS Institute, 1993). Correlation analysis
was done to examine associations among parameters. After checking for compliance with
the assumptions for equal variance and normality, a combined analysis over all years was
done whenever the single year results were similar or as an addition to yearly analysis to
show the general trend. Means from diﬂ'erent treatments were compared by using F isher's
ANOVA protected least signiﬁcant difference (LSD).

RESULTS AND DISCUSSIONS
Osmotic Adjustment

Intermittent water stress did not affect osmotic adjustment across genotypes
(Table 2). In contrast, there were signiﬁcant diﬂ‘erences in osmotic adjustment between
the control and terminal water stress treatments (Table 2). The few studies reporting
osmotic adjustment in common bean did not include the reproductive growth stages .

This ﬁnding conﬁrms that common bean is capable of osmotic adjustment but diﬂ‘ers from

earlier reports that found osmotic adjustment at the vegetative stage (Wullschleger and

84

Table 2. Osmotic Adjustment and other water relations variables of common bean grown
at Hickory Corners Michigan under different moisture treatments, 1991-1993.

 

Treatment Variable Units Control Stress LSD
WW
Intermittent Osmotic MPa -0.01 0.3 3 NS
Sm Adjustmentﬂ
Solute Accumulation Moles Kg"H,O 27_ 72b 3 3 .443 *
Water potential Mpa -1 .22a -1 .5 lb *
Osmotic Potential MPa -1 .45a -l.67b 1'
Turgor Potential Mpa 0.23 0. 16 NS
RWC % 47.76 50.04 NS
WM
Terminal Osmotic Adjustment MPa -0.04b 0.32a * "‘ *
Stress
Solute Accumulation Moles Kg"H,O 27. 3 lb 36. 54a * "‘ "'
Water potential Mpa -0. 86a -1 .37b * * *
Osmotic Potential MPa -l.15a -1.53b "'**
Turgor Potential Mpa 0.29a 0. 16b *
RWC % 59.18 59.86 NS

 

 

Note: +=p-va1ue < 0.10 *=p-value < 0.05 "=p-value < 0.01 NS=Not Signiﬁcant

Note: Same letters in a row indicate no signiﬁcant diﬁ‘erences between means.
fdataforthatrowareﬁomtwoyears 1991-1992 only. Therestofthe dataarefromall 3years.
thgative osmotic adjustment means predicted osmotic potential is less than the actual.

85

Oosterhuis , 1991; Raggi, 1994). The diﬁ‘erent results at the vegetative stage may be due
to the diﬁ‘erences in the methods. Both of the above studies were conducted in a
controlled environment and both rewatered the plants, to more than 88% of the relative
water content (RWC) in the case of Wullschleger and Oosterhuis (1991), before sampling
for osmotic adjustment. In this study the plants were ﬁeld grown and were not rewatered
similar to other ﬁeld studies (Bolar‘ios and Edmeades,l99l).

The three genotypes responded differently to the intermittent vegetative stress but
similarly to terminal reproductive stress. Both Seafarer and BAT 477 osmotically
adjusted under the vegetative stress but LEF2RB did not (Table 3). In contrast, all three
genotypes had osmotic adjustment under the reproductive stress (Table 4). Genotypic
differences in osmotic adjustment were found only under terminal moisture stress where
Seafarer had a higher osmotic adjustment than BAT 477 and LEF2RB and comparisons
across water treatment indicated that Seafarer had a higher osmotic adjustment than the
other genotypes (Tables 5 and 6).

Osmotic adjustment had a signiﬁcant negative correlation with water potential and
osmotic potential only at the reproductive stage sampling (Figure 3-a and b) but did not
correlate with turgor potential at any growth stage sampled (Figures 3-c).

Solute Accumulation

There was a signiﬁcant diﬁ‘erence in solute accumulation between the control and
stress treatments across genotypes in both grth stages (Table 2). Other studies have
also reported increases in solute accumulation due to stress (Raggi, 1994; Zhang and

Archbold, 1993; Dingkuhn et al., 1991). The speciﬁc solutes that accumulate appear to

86

 

Table 3. Osmotic Adjustment and other water relations variables of common bean grown
at Hickory Comers Michigan under intermittent water stress, 1991-1993.

 

 

Genotype Variable Units Control Stress LSD
Seafarer Osmotic Adjustment MPa 0.08b 0.39a 0.29‘
Solute Accumulation M015 Kg"H,O 29. 59b 36.338 6.51 "'
Water potential Nine -1 .25a -1 .72b 04]"
Osmotic Potential MPa -1.53a -l.8lb 0.22"
Turgor Potential Mpa 0.28 0.09 NS
RWC % 48.44 50.36 NS
LEF2RB 051110110 Adjustment MP8 0.19 0.17 NS
Solute Accumulation Moles Kg"H,O 27.64b 33.75a 5.38“
Water We!!!“ Mpa -1 .22a -1.48b 0.14“"I
Osmotic Potential MPa -1.43a -l .671) 019+
Turgor Potential Mpa 0.21 0.19 NS
RWC % 48.23b 50.61a 221+
BAT 477 Osmotic WWI“: MP3 -0.30b 0.43a 065+
Solute Accumulation Moles Kg"H,O 2592 3023 NS
Watcrpotcntial Mpa -1.18 -1.32 NS
Osmotic Potential MPa -l.39 -l.53 NS
Turgor Potential Mpa 0.21 0.21 NS
RWC % 46.61 49.14 NS
Note: +=p-value < 0.10 ’=p-value < 0.05 "=p-value < 0.01 NS=Not Signiﬁcant

Note: Samelettersinamwindicatenosigniﬁcantdiﬁ‘erencesbetweenmeans. Datasampledatﬁrst

ﬂower (R1).

:Negative osmotic adjustment means predicted osmotic potential is less than the actual.

87

Table 4. Osmotic Adjustment and other water relations variables of common bean grown
at Hickory Corners Michigan under terminal water stress, 1991-1993.

 

 

 

Genotype Variable Units Control Stress LSD
Seafarer Osmctic Adjustment MP3 0.04b 0.53a 0.29”
Solute Accumulation Mole Kg"H20 30.79b 41.03a 4.04m
Water potential M98 -0.86a -1 .42b 0.24"I * "'
Osmotic Potential MPa -1.25a -1.65b 018""
Turgor Potential Mpa 0.39 0.22 NS
RWC % 60.94 62.39 NS
LEF2RB Osmctic Adjt-IStmcnt 1 MPa -0.06b 0.27a 0.24“
Solute Accumulation Mclcs K8"H20 26.15b 35.81a 8.54“
Water potential Mpa -0.84a -1 .41b 0.26"
Osmotic Potential MPa -1.10a -1.50b 0.33"
Turgor Potential Mpa 0.26a 0.09b 0.18*
RWC % 60.08 60.31 NS
BAT 477 Osmotic Adjustment MPa -0.09b 0.16a 0.24“
Solute Accumulation Moles K8"H20 24.97b 32.7% 6.71 *
Water potential Mpa -0.89a -1.27b 0.27 "
Osmotic Potential MPa -1.09a -1.45b 0.25‘
Turgor Potential Mpa 0.20 0. l 7 NS
RWC % 56.53 $6.87 NS
Note: +=p-value < 0.10 *=p-value < 0.05 "=p-value < 0.01 NS=Not Signiﬁcant

Note: Sameleuersmamwmdicatemsigniﬁcantdiﬁemncesbetweenmeans. Datasampledatmidpod
(R8). INcgative osmotic adjustmentmeanspredicted osmotic potential islessthantheactual.

88

Osmotic Adjustment (MPa)

 

0.6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

§\ 0 ._
\ e
0.4 - \\ O
o \ '—
0'2 ‘ 0\9\\ 11:079.
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.0-4 I I I I I
-1.8 4 .6 4.4 .42 4 .0 0.8 -0.6 6 '1 3 '1-3 *1-4 '1-2 '1-0 418 '0-6
Water Potential (W8) 1" 42 water Potential (MPa)
b \3 g 40 r \\
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.20 -13 _1_6 4.4 -12 4.0 3 -20 -1.8 -1.6 4.4 4.2 4.0
Osmotic Potential (MPa) 05m Potential (We)

 

 

 

 

 

 

 

Turgor Potential (M38)

 

f

 

 

0.1
Turgor Potential (M’a)

0.3

Fiona. mmwmmum tow-ﬁrm
Wattwogowhmforttnembmmmmder
dﬁerenh’alirﬁmﬁorutﬂdorymmn 1914993.

89

 

. e
a/Ofosst/

 

 

 

I I 7 I

-0.4 -0.2 0.0 0.2 0.4 0.6

Relative Water Content (RWC)

04
62 ‘_ ° r’=0.07ns

so - ""r-0 ...... ‘0
58 ~
56 J
54 .1
52 -«
50 ~ '
4a 4
46 ~ =0.70”
44

2888392818832

Osmotic Adjustment (M Pa)

 

0 o

 

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~
‘
~—

9 c

 

 

I I I I

Water Potential (MPa)

-1.8 -1.6 4.4 ~12 -1.0 -0.8 -O.6

 

    

 

 

0.0 0.1 0.2 0.3 0.4
Turgor Potential (MPa)

4 r2=0.08ns o

.l O _______Q.-—-“'"o’”
try"- 0 O

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.J

.4

* r2=0.27ns

 

0.5

64
62 - r’=0.37ns 0,,

60- o #2,,I-o"
58 4”“.I-
56- 0 O
54.
52-
50...
43‘ r’=088”
46- ' b
44 I I I I I I T I

24262830323436384042

 

 

 

 

Solute Accumulation(MoIes Kg'IHZO)

 

62 - r2=0.20ne o
60 J o ,Ba—O'”" .-

’

 
 

82.0.80“
44 I 1 I I 7
-1.8 -1.6 4.4 4.2 4.0 -0.8 -0.6

Osmotic Potential (MPa)

  

 

 

 

 

O Vegetative

O Reproductlve

 

 

 

Figure 4. Relative water content (RWC) as related to osmotic adjustment. solute
accumulation, and water potential components at two growth stages for three common
been genotypes grown under dﬁerential irrigation at Hickory Corners, Michigan 1991-1993.

90

differ among crop species. Raggi (1994) found free amino acids like proline in common
bean. Proline was found in rice (Oryza sativa)(Dingkuhn et al.,l991) but not in Fragarr‘a
spp which accumulated glucose, fructose and non-proline amino acids instead.
Furthermore, organic acids were found in chickpea (Lecoeur et al., 1992). It is possible
that speciﬁc accumulated solutes may have differing effects on source-sink relationships,
translocation, and yield.

Across years within genotypes, both Seafarer and LEF2RB increased their solute
accumulation under intermittent stress (P s 0.05) while Bat 477 did not (Table 3). In
addition, terminal stress increased solute accumulation in all genotypes (Table 4). Among
genotypes, BAT 47 7 had a lower solute accumulation than Seafarer under both moisture
stress treatments (Tables 5 and 6 ). Across water treatments, Seafarer had signiﬁcantly a
higher solute accumulation than LEF2RB under the reproductive grth stage (Table 6).

Solute accumulation strongly but negatively correlated with water and osmotic
potentials at both growth stages, but there was no association with turgor potential
(Figure 3-d, e, 1)).

Relative Water Content

Although, there were no signiﬁcant diﬁ‘erences between stress and control
treatments for RWC across genotypes at either grth stage (Table 2), there was a
tendency for RWC to increase numerically under stress treatment. In fact, under
intermittent stress, RWC increased in LEFZRB (Table 3). While signiﬁcant only at the
10% probability level, the LEF2RB response indicates this tendency and agrees with

Raggi (1994) who found signiﬁcantly higher RWC in stressed plants but disagrees with

91

Seed Yield (9 n‘?)

 

 

 

 

 

 

 

 

280

 

 

260 -
240 A
220 J
200 -
180 -
160 -l
140 4
120 -
100

 

 

 

 

-1.8

-1.8 -1.4 -1.2

Water Potential (M Pa)

-1.0 -0.8 -0.8

 

 

  

8:037:13

O r2=0.36ns

 

 

 

IIIIIIIIIIIIIMIIIII

0.1 0.2 0.3 0.4
Turgor Potential (MPa)

280
260 4
240 -
220 d
200 -
180 -
180 a
140 J
120 4
100

 

 

 

 

 

I I I I T I I

26 28 30 32 34

f

24 38 38 40 42

Solute Accumulation(MoIes Kg“H,O)
280

 

    

 

 

/
,9, r‘

=0.92“

100 r I
-1.8 -1.8 -1.2

Osmotic Potential (MPa)

 

-1 .4 -1.0

 

230
260 -
240 -
220 - e
200 -
180 -
160 - 0 \4
14° 4 B=0.50+ 0

120 -
100

\ - r
\.L r2-0.07ns

 

 

 

I l I I I I I I I

44 48 48 50 52 54 58 58 80 82 84
RWC

Figure 5. Seed yield as related to osmotic adjustment, solute accumulation. relative water
content, and water potential components at two growth stages for three common bean
genotypes grown under differential irrigation at Hickory Corners, Michigan 1991-1993.

92

Table 5. Osmotic adjustment and leaf water relations of common bean genotypes grown
at Hickory Corners Michigan under intermittent moisture stress 1991-1993.

 

 

Treatment Genotype Osmotictx Solute Water Osmotic Turgor RWC
Adjustment Accumulation potential Potential Potential
(th8) (Moles Kg’ (MPa) (MPa) (MPa) (%)
lH20)
Control Seafarer 0.08 29.59 -l.25 -l.53 0.28 48.44
LEF2RB 0.19 27.64 -l.22 -1.43 0.21 48.23
BAT 477 -0.30 25.92 -1. 18 -l .39 0.21 46.61
LSD NS NS NS NS NS NS
Stress Seafarer 0.39 36.33a -l.72b -l.8lb 0.09 50.36
LEF2RB 0.17 33.75ab -l.48ab -l.67ab 0.19 50.61
BAT 477 0.43 30.23b -l.32a -1.53a 0.21 49.14
LSD NS 4. 16+ 027+ 0. 19* NS NS
Pooled Seafarer 0.24 32.96a -1.48b -1 .67b 0.18 49.40
LEF2RB 0.18 30.69ab -l .35ab -l .55ab 0.20 49.42
BAT 477 0.06 28.08b 4.258 -1.46a 0.21 47.88
LSD NS 3.34“ 0. 15+ 014* NS NS

 

Note: diﬂ'erent letters in a column indicate signiﬁcant differences.

Note: + = p-value <0.10 *= p-value <0.05 ” = p-value <0.01 NS=Not Signiﬁcant.

tData for this column is from 2 years only (1991-1992) while the rest include 1993 as well.
tNegative osmotic adjustment means predicted osmotic potential is less than the actual.

93

Table 6. Osmotic adjustment and leaf water relations of common bean genotypes grown
at Hickory Corners Michigan under terminal moisture stress 1991-1993.

 

 

Treatment Genotype Osmotic I Solute Water Osmotic Turgor RWC
Adjustment Accumulation potential Potential Potential
(MPa) (Moles Kg ’ (MPa) (MPa) (MPa) (%)
l1-120)
Control Seafarer 0.04 30.793 -O.86 -1.25 0.393 60.943
LEF2RB -0.06 26.15b -0.84 -1.10 0.263b 60.083b
BAT 477 -0.09 24.97b -0.89 -l.09 0.20b 56.53b
LSD NS 3.67+ NS NS 013+ 367+
Stress Seafarer 0.533 41.033 -1.42b -1.65 0.22 62.393
LEF2RB 0.27b 35.813b -l.4lb -1.50 0.09 60.313
BAT 477 0. 16b 32.79b -l.27a -l.45 0.17 56.87b
LSD 0.19" 607* 012+ NS NS 3.32”
Pooled Seafarer 0.293 35.913 -l.14 -1.45b 0.31 61.663
LEF2RB 0.10b 30.981) -1. 12 -l.303 0.18 60.193
BAT 477 0.041) 28.88!) -1.08 -1.273 0.19 56.70b
LSD 0.16“ 3.62” NS 0.14" NS 2.67""

 

Note: diﬁ‘crent letters in 3 column indicate signiﬁcant differences.
Note: + = p-value <0.10 *= p-value <0.05 " = p-value <0.01 NS=Not Signiﬁcant.
INegative osmotic adjustment means predicted osmotic potential is less than the actual.

94

Parsons and Howe (1984) who reported higher RWC in stressed plants. In this study,
RWC was maintained by all genotypes under the terminal stress (Table 4). Genotypes did
not diﬁ‘er in RWC at the initiation of ﬂowering under any water treatment (Table 5).
However, BAT 47 7 had a signiﬁcantly lower RWC than the other two genotypes under
stress and across water treatments at the R7 growth stage (Table 5). Relative water
content correlated weakly with osmotic adjustment at the vegetative stage (Figure 4-a).
On other hand, relative water content strongly and positively correlated with solute
accumulation and negatively correlated with water and osmotic potential at the vegetative
stage (Figure 4-b, c, d). RWC did not correlate with turgor potential at any growth stage
(Figure 4-e). No correlations were signiﬁcant between RWC and the other water
relations parameters at the reproductive stage. These results may indicate that relative
water content was maintained at reproductive stage when osmotic adjustment occurred.
Water Potential and Its Components

Water and osmotic potential were reduced by water stress at both growth stages,
while turgor potential was reduced by the terminal water stress (Table 2). Similar results
were reported by other researchers for common bean (Parsons and Howe, 1984;
Wullschleger and Oosterhuis,1991; Raggi, 1994) and for other crops (Premachandra et
al., 1992; Li et al., 1993; Sloane et 31,1990; Oosterhuis and Wullschleger, 1987).

Intermittent water stress reduced water and osmotic potential for Seafarer and
LEF2RB but not BAT 47 7 (Table 3). This stress did not reduce turgor potential relative
to control for any genotype (Table 3). In contrast, reproductive terminal stress
signiﬁcantly reduced water and osmotic potential for all genotypes, while turgor potential

95

was reduced for LEF2RB only (Table 4). No genotypic differences were found for any of
the water relations variables under well watered conditions during the vegetative growth
stage but BAT 47 7 had signiﬁcantly higher (less negative) water and osmotic potentials
than Seafarer under the stress treatment (Table 5). On the other hand, BAT 477 had a
lower turgor potential than Seafarer under well watered conditions at R7 stage (Table 6).
This difference was only signiﬁcant at the 10 % level but may indicate that the resistant
genotype may have lower thresholds for moisture deﬁcit than the susceptible genotype. In
addition, BAT 477 maintained a higher water potential than the other two genotypes
under terminal stress measurd at the R7 stage (Table 6). Across water treatments at R7,
Seafarer had a lower (more negative ) osmotic potential than the other two genotypes, but
there were no signiﬁcant diﬁ‘erences in water and turgor potential among the genotypes
(Table 6).
Seed Yield and Water Relations

Osmotic adjustment correlated strongly and negatively with seed yield (Figure 5-3)
under terminal stress when the data was pooled across years. Wullschleger and
Oosterhuis (1991), while not reporting yield data, did not ﬁnd any association between
osmotic adjustment and leaf growth in common bean. Moreover, grth was reduced in
grape even as turgor was maintained (Schultz and Mathews, 1993). Similarly, Guei and
Wassom (1993) found non signiﬁcant correlations between osmotic adjustment and yield
in maize (Zea mays). Blum (1989) found a non-linear negative correlation between
osmotic adjustment and percent reduction in barley (Hordeum vulgare) yield. Kumar and
Singh (1998) reported a positive correlation between osmotic adjustment and seed yield in

96

0.60 0.60

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Harvest Index (HI)

 

 

 

 

   

 

 

 

 

 

 

 

 

 

 

 

 

a _ b
0.53 ,\\\ e 0.58 - '2‘°-°‘"‘ e
0.56 T \\ oe r2=°-002n8 0.56 -\ e o
‘0‘ e mg
0.54 -_e U \\ 0.54 ~ 0 \\
\
0.52 q }\o 0.52 - ‘O‘\o
O \ O . O \\
0.50 " . V” \\ 0.50 " \\\
__ \ N
a 0 ""' r2: 77* 0.48 ~ 0
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046 I ‘ I I 0.46 I I I I I I I I
-o.4 -o.2 0.0 0.2 0.4 0.6 24 26 28 3° 32 34 36 38 4° 42
- -1
Osmotic Adjustment (Mp3) Solute Accumulation(MoIes Kg H20)
0.60
0.60 007
c = . ns d
0'58 . r2=0.08ns // 0'58 1 .
0.56 «
0.54 -
0.52 «
0.50 ..
0.4a ~
0.46
-1.8 -1.6 -1.4 -1.2 -1.o -o.a cs -2.0 4.8 -1.e -1.4 -1.2 -1.o
Water Potential (MPa) Osmotic Potential (MP3)
0.60
=0.004ns f
0.58 - e
\\
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e \\\ o
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e o
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0.46 I I r T 0.46 i I l I l I T r I
0.1 0.2 0.3 0.4 44 4s 48 so 52 54 56 58 so 62 64
Turgor Potential (M Pa) vac

Figure 6. Harvest index (Hi) as related to osmotic adjustment, solute accumulation, relative
water content, and water potential components at two growth stages for three common bean
genotypes grown under differential irrigation at Hickory Corners, Michigan 1991-1993.

97

0.90

 

0.35 -\

 

\

0.80 - \\
0.75 e \
0.70 - Be.

12:0.12ns

\ O O

 

 

 

 

   

 

 

 

 

 

 

 

 

   

r2=0.12ns

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

O
\
0.65 - \\ ' .
0.60 ‘ O \\\ 0'65 " \\
4 ‘Q 0.60 « o \
0'55 8:0.76' \ =0.77* \
0.50 T I I l 0.55 —I I T I I I I I
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Osmotic Adjustment (MPa) Solute Accumulation(MoIes Kg’1H20)
A 0.90
m . c 0.90 ,2- . d
g 0.85 . r2=0.17ns 035 . —0.18ns
a 0.80 - 0.30 _
C
.3 0.75 - 0.75 -
lE . /
m 0.70 « Q / 0.70 -
0 0 / o
to I _. /
3 0.05 // 0.05 //
5
§ 0'60 J / O 8:070" 0'6“ 6’ O r2=0.75*
3 0.55 4 . . . . 0.55 5 / . . .
-1.a -10 -1.4 -1.2 -1.0 .08 .00 -2.0 -1.8 -1.6 4.4 -1.2 -10
Water Potential (MPa) Osmotic Potential (MP3)
0.90 f \Q
0.85 - \ r2=0.003ns
0.80 a
0.75 -
0.70 .
0.65 ~
- r2=0.17ns
0.60 o O 0.60 _
=O.18ns o
0.55 0'1 or2 0'3 0'4 0.55 I I I I I I l I I
' ° ' ' Mwmmnammwmm
Turgor Potential (M Pa) RWC

Figure 7. Water Use Efﬁciency (WUE) as related to osmotic adjustment, solute accunmlation.
relative water content. and water potential components at two growth stages for three common
bean genotypes grown under differential irrigation at Hickory Comers, Michigan 1991-1993.

98

 

 

 

 

 

1401

 

404

 

 

 

 

 

 

 

.20 0 I 1 T I I I I I L
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Osmotic Aqustment (MPa) Solute Ammulaﬁonwoles Ken-I20)

 

 

 

 

 

 

 

 

 

 

 

 

    

 

 

 

 

 

 

 

E 200 200
E, 180 - 160 4
in 160 4 160 «
g 140 q 140 ~
0) 120 ~ 120 ~
g 100 4 100i
8 60 - 00 -
a 60 - 60 4
3 40 - 40 -
g 20 - c 20 -
0 0
-1.8 4.6 4.4 4.2 4.0 -0.8 -0.6 -2.0 -1.8 -1.6 -1.4 4.2 -1-0
Water Potential (MPa) Osmotic Potential (MP3)
200 / 200
180 4 / o 160 «
140 ‘1 140 d
120 ~ 120 .
100 - 100 4
80 go ..
60 4 50 .
40 - ,9 4o .
20 J r2=0.41ns e 20 ‘
0 I I l I O I F I I T T j I *II
04 m 03 m «mmmmummwmm
Turgor Potential (MPa) ch

Figure 8. Water use a duration of stress as related to osmotic adjustment. solute
accumulation, relative water content, and waer potential cements a two growth
stages for three common been genotypes grown under differentid inigaion at Hickory
Corners, Michigan 1991-1993.

99

 

 

 

 

 

 

 

 

 

 

 

 

 

68 68
55 ‘ o a 66 J r=0.01ns O b
64 _ r=0.01ns . 64 d .
62 - 32 .. O O
60 . 601--—e“"6""_-0”——
56 - 56 « 0 .
54 4 54 .-
C

q C
52 r=0.28ns 52 1 ' r=0.02ns
50 ﬂ f j I 50 Iﬁ I I T I j I

-0.4 -O.2 0.0 0.2 0.4 0.6 24 26 28 30 32 34 36 38 40 42

 

 

 

 

 

 

 

 

 

Osmotic Adjustment (MPa) Solute Accumulation(MoIes Kg"HZO)
66 66
66 4 O r=0.06ns c 66 _ do
___ e
If} 60 ‘ 8 e “"—o-- 60 -
Q 58 4// 58 ..
+- . o
3 56 . 56 4
m 54 1 54 "i
e . J
52 - r=0.01ns 52
50 I I I f I 50
-1.8 4.6 4.4 4.2 4.0 -0.6 -0.6 .2 -1 0 1 2

Water Potential (MPa)

 

 

 

 

 

O
r=0.16ns

I I T I I I T I I

OJ M 03 M ummmaammwmm

 

 

 

50 I I I I 50

 

Turgor Potential (MPa) RWC

Figure 9. Rooting depth as related to osnacﬁc adjustment, solute accumulation. relative
water content. and water potential cormonents at two growth stages for three common
bean genotype grown under diﬂerential irrigation at Hickory Corners. Michigan 1991-1993.

100

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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101

different brassica spp. They calculated osmotic adjustment as the reciprocal of the slope
of the linear regression of log transformed relative water content on osmotic potential.
Likewise, Rodriguez et al. (1992) reported positive osmotic adjustment associations with
yield in chickpea (Cicer arietinum) when osmotic adjustment was expressed as the relative
water content at -1.5 MPa osmotic potential. Our ﬁndings support other work suggesting
that osmotic adjustment has a physiological cost to the plant (Munns, 1988; Li et al.,
1993) and may actually reduce yield under drought (Grumet et al., 1987).

Solute accumulation strongly and negatively correlated with seed yield at both
growth stages (Figure 5-b)when the data is pooled across years. In contrast, genotypic
differences in osrnoregulation measured in a controlled environment were consistent with
yield in the ﬁeld for wheat (Triticum aestivum) and chickpea (Morgan, 1983; Morgan et
al. , 1991).

Water and osmotic potential positively correlated with seed yield at both growth
stages while turgor potential did not (Figure S-c, d, e). In addition, relative water content
at the initial ﬂower stage weakly and negatively correlated with yield (Figure 5-1).
Harvest index

Osmotic adjustment correlated strongly and negatively with harvest index (Figure
6-a) at mid podﬁll stage when the data was pooled across years but solute accumulation
correlated weakly with harvest index (Figures 6-b) at the same growth stage. Further
more, water and osmotic potentials both correlated positively and strongly with harvest
index at the reproductive grth stage only (Figures 6-c,d). There was no correlation
between turgor potential and relative water content with harvest index at either of the two

102

growth stages (Figure 6-e,t).
Water use and Water use efficiency

Osmotic adjustment and solute accumulation correlated negatively and strongly
with water use efﬁciency during reproductive stage across water treatments (Figure 7-a,
b). Similar results were found for the amount of water used during the stress period
(Figure 8-a, b).

Water and osmotic potentials positively correlated with WUE at mid-podﬁll (R7)
but not at ﬂowering(Rl) but turgor potential did (Figures 7-c,d,e). In addition, there was
positive relationship between water and osmotic potentials and water use but the
relationship was stronger at R7 growth stage (Table 8—c, d). In contrast, turgor did not
correlate with water use at any growth stage (Figure 8-e).

Relative Water Content did not correlate with WUE at either of the two growth
stages but did correlate negatively with the water used during the intermittent stress
period (establishment up to R1 growth stage) (Figures 7-f, and 8-t).

Rooting Depth

Osmotic adjustment did not correlate with rooting depth at any growth stage
(Figure 9—a), contrary to Wullschleger and Oosterhuis’s (1991) report of osmotic
adjustment in common bean roots. Across years and genotypes, solute accumulation did
not correlate with rooting depth at either of the two growth stages (Figure 9-b). None of
the water potential components correlated with rooting depth across treatments (Figure 9-
c, d, 6). However, when data was analyzed as water by year, only LEF2RB had a
signiﬁcant positive correlation between turgor potential and rooting depth at R8 grth

103

stage ( r = 0.88 p s 0.01 n=9). Similarly, relative water content did not correlate with
rooting depth at any growth stage across treatments (Figure 9-t). Water stress reduced
root osmotic potentials in a study reported by Wullschleger and Oosterhuis (1991).
Carbon Isotope Discrimination

Osmotic adjustment and solute accumulation did not correlate with CID at either
growth stage (Figure lO-a, b). Across water treatment and over years, BAT 477 ( r = -
0.57 ps 0.01 n=33) and LEF2RB (r = -0.30 ps 0.10 n=33) showed a negative
correlation of solute accumulation with CID at R7 sampling. The literature gives no
indication of other studies that compared osmotic adjustment with carbon isotope
discrimination in common bean or other crops.

Among the water potential components, only turgor strongly and positively
correlated with CID and only at mid pod-ﬁll (Figure 10-c,d,e). Likewise, relative water
content did not correlate with CID at either of the two growth stages (Figure 10-t).
Again, relative water content correlated negatively with CID only for BAT 47 7 when the
data was analyzed across water treatments and years (r=-0.43 ps 0.05 n=33).

CONCLUSIONS

Osmotic adjustment was proposed as a screening tool for yield under stress or for
yield determinants such as water use eﬁciency (Morgan, 1991; Ludlow and Muchow,
1990) even though in theory it could come as a cost to the plant (Munns, 1988). The few
studies reporting osmotic adjustment in beans were conducted in controlled environments
and did not relate it to yield or its determinants. In this study, osmotic adjustment was
documented for ﬁeld-grown common bean. Genotypic diﬂ‘erences in osmotic adjustment,

104

solute accumulation and leaf water relations paralleled their differences in yield
determinants. Terminal moisture stress increased osmotic adjustment across and within
genotypes. The drought resistant line, BAT 477, had a lower osmotic adjustment as well
as lower relative water content than the more drought susceptible Seafarer. These results
support the theory that osmotic adjustment appears to have a physiological cost to the
plants that may result in yield reduction (Munns, 1988; Li et al., 1993).

It is concluded that solute accumulation (osmoregulation) does not appear to be
beneﬁcial to yield or its determinants such as water use, water use eﬁiciency, and harvest
index in common bean. This study suggests that yield reduction may be predicted by
solute accurmrlation. Genotypes with low solute accumulation may have other response
mechanisms that impart drought resistance traits such as intrinsically lower relative water
content, deep rooting or the ability to maintain higher water potential (Tables 5 and 6).
Thus assessment of solute accumulation may be applicable for screening genotypes for

drought resistance by direct selection or through the use molecular markers.

105

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Adams, M. W. 1996. An historical perspective on signiﬁcant accomplishments in dry bean
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CHAPTER 5
SUMMARY AND CONCLUSIONS

SUMMARY

One strategy to increase yield of common bean in drought aﬁ‘ected areas is to
grow drought resistant genotypes. Breeding for drought resistance in drought-prone
environments requires the existence of heritable genotypic variation as well as a visible
screening trait that can be related to yield. Obviously, such a screening trait must be easier
to obtain than yield in order to be useful. The existence of genotypic variation for drought
resistance in common bean has been reported for small seeded black or cream colored
types. But the search for a useﬁil screening tool for drought resistance has remained
elusive.

The current conceptual model for yield determination in moisture deﬁcit
environments was originally developed for determinate cereal crops and considers yield
under stress as the product of water-use eﬁiciency (WUE), harvest index (HI), and water
use but its applicability to semi-determinate crops like common bean has not been veriﬁed.
In addition, a number of physiological traits such as carbon isotope discrimination (CID),
deeper rooting, relative water content, osmotic adjustment, and water potential
components were proposed as screening tools for drought resistance but the role of some
of the thermodynamically based water relations traits have been questioned. This study
was conducted to evaluate the relationship of water use eﬂiciency, harvest index and
water use with yield for common been growing under moisture deﬁcit and to assess
genotypic diﬁ‘erences in osmotic adjustment and carbon isotope discrimination and their

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relationship to yield, harvest index, water use efﬁciency, and rooting depth.

Three common bean genotypes with similar yield potential but with known
diﬁ‘erence in drought tolerance characteristics were grown in a rain shelter at Hickory
Comers, MI in 1991 - 1993. Irrigation treatments included a well watered control,
intermittent vegetative stress from V5 to R1, and a terminal reproductive stress from R1
to harvest. The three genotypes in this study were BAT 477 and LEF2RB two drought
resistant genotypes, and Seafarer a commercial but drought susceptible genotype.

Vegetative stress reduced yield by 15 to 30% while reproductive stress reduced
yield by 35 to 50%. Reproductive moisture stress signiﬁcantly reduced CD) by 9% in
comparison to the 5% reduction that occurred under intermittent stress. Similarly, water
potential and osmotic potential were signiﬁcantly reduced (15 to 59%) while solute
accumulation increased (21 to 34%) under intermittent vegetative and terminal
reproductive moisture stress. Seafarer had a signiﬁcantly higher CID than both BAT 477
and LEF2RB. Genotypic differences in yield and osmotic adjustment were found only
under terminal moisture stress where Seafarer had a signiﬁcantly lower yield and a
signiﬁcantly higher osmotic adjustment than BAT 477. Water use and water use
eﬁiciency correlated positively with yield and biomass and C1D had positive correlations
with yield, WUE, and water use for each genotype or water treatment but not across
genotypes or water treatments. Relative biomass and WUE reductions strongly and
positively correlated with relative CID reduction. Osmotic adjustment (r = -0.91 p s
0.05 n=6) and solute accumulation (r= -0.91 p s 0.05 n=6) both strongly and negatively
correlated with yield. Similarly, osmotic adjustment and solute accumulation had

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signiﬁcant negative correlations with water use efﬁciency, harvest index and water use
were found across water treatments.
CONCLUSIONS

Common beans seem to follow a simpler model relating water use and water use
eﬁciency to yield in that harvest index is generally higher and more stable in common
bean than in other crops. Harvest index was the one factor that did not strongly correlate
with yield and this raises the question of whether or not breeders should use harvest index
as a selection criterion for yield in common bean.

Carbon isotope discrimination (CID) appears to be a useful screening tool for
drought resistant genotypes but ﬁrrther testing of CID response to drought is needed with
additional genotypes and environments. In this study CID correlated positively with water
use eﬂiciency, a ﬁnding that conﬂicts with the ﬁndings of other common bean researchers
and with theory.

Water and osmotic potential correlated strongly and positively with yield and with
yield determinants at the reproductive growth stage. These ﬁndings support the continued
use of these traits for drought stress research. Solute accumulation or osmotic
adjustment may be indicative of susceptibility to moisture deﬁcit rather than resistance in
common bean. Genotypes with low osmotic adjustment should be selected for drought
resistance rather than those with higher adjustment. The larger issue of why osmotic
adjustment through solute accumulation correlates differently with yield in diﬂ‘erent craps

needs to be addressed by further research.

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