W { I IN I | | I ( l WWI \ | 1m } | f UNI a 32% Ml THE EFFECT OF PELLETING ON THE GERMINATION OF VEGETAgLE Sf: EDS Thesis for the Degree of M. S. MTCHIGAN STATE COLLEGE W iniam Carl McGuffey 1949 THESIS This is to certitg that the thesis entitled - e ‘ 1 13 t A . L ‘t‘ V _ ' L ’»41 { t o t?” has been accepted towards fulfillment of the requirements for . —. y‘ul W n‘- ‘f ‘;‘,‘\"‘ 4 |, _ - degree in" I ' , v ./ ‘1’ " .1 . /) a! a, ' . it {—(b/ ‘.’_ llla—jm profesgnr Date :q — M-TQS _-H_.- - ----_ _...___..__.._‘- .. TrlE EFFECT OF PELLETING ON THE GEMEENATION OF VEGETABLE SEEDS By William Carl McGuffey A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MAS TER OF SCIENCE. Department of Horticulture Mar ch 194 9 'Vf-‘d ' . 5 . ACIiBIO‘flgEDGLENTS / The author wishes to express his most sincere apprecia- tion to Doctor R. L. Carolus for his direction and planning of the experimental work, and criticisms in the prepation of this manuscript; to the Ferry Morse Seed Company, Detroit, Michigan, for its contribution of seed used in this problem; and to Doctor P. Vogelsang, of the Processed Seeds Inc., Midland, Michigan, for the time and materials consumed in processing the seed. THE EFFECT OF PELLETING ON THE GERMINATION OF VEGETABLE SEEDS INTRODUCTION Due to the high cost of production, many new techniques and practices are being developed to increase the efficiency in agricultural operations. The pelleting of seed offers a possi- bility of aiding not only in the mechanization of the planting operation, but also in insuring a more uniform stand of many vegetable crOps. Precision planting of small seeds, which can eliminate the costly practice of thinning and blocking, is made possible by means of pelleting seed. The process of pelleting will be economically feasible if the Operation does not adversely affect germination. Observations to date have indicated that under certain conditions, the Pelleting of seed has had a detrimental effect upon germination. However, in many cases, especially with sugar beets(4), pelleting of seed has markedly improved stands, par- ticularly under unfavorable environmental conditions. Because of the possible aid to cr0p production that might result from this technique, a careful study of the various aspects of the problem appears to be warranted. 2 REVIEW OF LITERATURE The treatment of seed with chemicals to attain fungicidal protection has been practiced for some time, and occupies a use- ful place in our agricultural methods of today(6). There has (14) and been considerable work by Newhall(9), Nelson(8), walker many others to prove its worth. The trend has been from liquid to dust treatment of seed. Nelson(8) indicates that even though formaldehyde provides better control of onion smut, it is being replaced by fungicidal dusts because of their ease of handling. (13) suggests that the effectiveness of dust and liquid Vogelsang treatments can be improved by pelleting, because through this process it is possible to use fungicides at 10 to 50 times the concentrations that can be made to adhere to the seed by conven- tional methods. Linn and Newhall(7) dipped onion seed in a 5 per cent methocel solution which enabled them.to stick on a weight of fungicide equal to the weight of the seed. This treat- ment produced a coated seed that was both smaller and cheaper than the conventional pellet. Their experiments indicated that this treatment gave better smut control than pelleted seed. Nelson(8) experimented with Hewhall's type of pellet, but was inclined to favor the control method of sewing fungicidal dust in conjunction with the seed in a 1:4 ratio. However, he men- tioned the possibilities of disease control with pelleted seed, 3 and indicated that many growers were receptive to this new tech- nique because of its labor saving potentialities. The Farmers and manufacturers Beet Sugar Association of Saginaw have been pioneers in the practical development of pel- leted seed. A considerable acreage of pelleted sugar beet seed has been planted in the last two years with favorable results(4). Pelleting segmented sugar beet seed, in one test, resulted in a 20 per cent increase in germination under dry soil conditions, but 65 per cent increase in germination under wet soil condi- tions. It was suggested that soil organisms were more active in the wet soil, and as a result of pelleting, more effective con- trol was obtained. Kotowski(5) showed in his work that different kinds of vegetables have different temperatures for Optimum germination. He observed that cr0ps like cabbage, spinach, cauliflower, beet, carrot and parsley have a higher per cent germination at temper- atures below 50° F., while pepper, cucumber, beans and melons give higher per cent germination at 70° to 86° F. The other crops that he tested fell between these two extremes in the temr perature required for optimum germination. Furthermore, Kotowski showed that with most crops a high temperature is probably opti- mum for the speed of emergence, but not for the production of the largest number of seedlings. Aeration of the soil has an important effect on germina- 4 tion, and is related to soil texture, water relationships in the soil, aid the oxygen requirement for germination of the seeds of different kinds of plants. Shull(10) demonstrated that seeds of higher plants vary widely in the amount of oxygen required for germination. Some Species like Alisma Plantago-aquatica (water plantain), rice and others can germinate under water, where no free oxygen is available, while other plants like Xan- thium seeds need large amounts of free oxygen to germinate. He concludes that the majority of plants fall somewhere between these two extremes given in oxygen requirements for germination. Shull(10) also found that a rise in temperature lowers the oxy- gen minimum needed by Xanthium for germination, and suggests that it might be due to the increase of anaerobic respiration at higher temperatures. The Mechanics of Pelleting Pelleting* is the process by which a coat of inert pulver- ized chemicals is made to adhere to the seed by a water soluble plastic (methocellulose). These inert materials may be fly ash, feldspar, celite, bentonite clay, or vermiculite. Fungicides, slightly soluble fertilizers, and growth regulators can be added to the pellet to give protection and stimulation to the seed and *Information obtained from personal interviews with Dr. Phelps Vogelsang of the Processed Seeds Inc., Midland, Michigan 5 seedling. It is feasible, if desirable, to add a fungicide at 10 to 50 times the concentration that can be made to adhere to the seed with a dry dust treatment. The operation is performed in a rotary pan similar to those used in the manufacture of pills and candies. Pelleting may increase the volume of the seed from one to twenty times, and the weight from five to twenty-five times, depending upon the size of the seed. Small seed like onion can be processed to form a spherical pellet, while large seeds as corn are treated to form a coat of mater- ials that does not materially change their original shape. If large seeds were treated to form.a spherical pellet, their vol- ume and weight might be increased to a point where the process would be impractical. 6 STATEMENT OF THE PROBLEM Pelleting vegetable seeds to facilitate precision plant- ing will be an economically sound practice if the process does not have a detrimental influence on germination. This paper presents results of experiments conducted to determine the influence of the coating material on germination and rate of emergence under various conditions. The germination of pelleted and unpelleted seed of fifteen vegetable crops will be compared under varying environmental conditions. The influence of tem- perature, soil moisture, and soil type on the relative germina- tion and emergence of pelleted seed will be determined. This investigation should indicate some of the problems and difficulties that may be encountered in practical operations with coated seed. The conditions under which the process is least detrimental to germination, and the kind of seed that can be most successfully pelleted will be indicated. In addition, this work can serve as background for future study involving the incorporation of other chemicals with the coating materials. METHODS AND MATERIALS A factorial experiment was conducted in whidh the germin- ation and rates of emergence of 15 kinds of vegetable seeds, both pelleted and unpelleted, were determined. The seed was furnished by the Ferry Morse Seed Company of Detroit, and the seed was pelleted by the Processed Seeds, Inc., of Midland, Michigan. All germinations were conducted on two soil types, each at two mois- tures, and at four temperatures, representing 960 determinations. The seeds of the following crops were used: KIND Broccoli Cabbage Chinese Cabbage Carrot Cauliflower Dill Kale Mustard Onion Radish Rutabaga Spinach Parsnip Tomato Turnip VARIETY DeCicco Golden.Acre Michihli Chantenay Snowball X mammoth Dwarfed Blue Curled Southern Giant Curled Brigham Yellow Globe Scarlet Globe Amer. Purple Top Virginia Savoyed Hollow Crown Rutgers Purple Top White Globe The seed was germinated in wooden flats 15" x 21“ x 4" in size. The soil in the flats was firmed with a marking board, and 25 seeds planted in each of 10 rows Spaced at two inch intervals. The seed was then covered with a measured amount of soil and firmed again. Five vegetables were planted in each flat with the pelleted seed planted adjacent to the check seed. All plantings were replicated. The pelleting material was composed of 35 per cent fly ash and 65 per cent feldspar, with methooel used as a sticker to form the pellet. Probably a pellet consisting of these three inert materials does not have any chemical effect on the seed. The soils used were a sandy loam and a well decomposed muck. The optimum water content of the soil was found by exper- imentation to be approximately 87 per cent of field capacity. The weight of the water necessary to saturate a given weight of soil was calculated, and this quantity was added to a flat to obtain 100 per cent water holding capacity, and 70 per cent of that quantity was added to secure the optimum moisture content. The moisture relationships are shown by the data below. W MUCK SOIL MINERAL SOIL PERCENTAGE H20 DRY WT. 1497; 25% OPTIMUM HIGH OPTIMUM HIGH MOISTURE MOISTURE MOISTURE MOISTURE -====:“ Percentage H20 after watering 210.8% 257.2% 41.9% 49.3% Percentage of water holding capacity 88.9% 100.0% 85.0% 100.0% Wm _:- ‘, The seeds were germinated in four walk-in type regriger- ators, in which the temperatures were maintained at approximately 40°, 50°, 60° and 70° F. The flats were stacked in groups of 9 four, and the stacking sequence rotated from time to time. The flats were left in the constant temperature rooms for 14 days, and then they were removed to room temperature and com- pleted germination at approximately 70° F. Observations of the progress in the germination of each lot were made daily, and any seedling that had completely emerged was pinched off and counted. To obtain a weighted average of the number of days to emergence, the number of seedling that emerged each day was multiplied by the number of days to emer- gence, and the sum of these products was divided by the total number of seedlings that emerged. To determine the most suitable depth of planting and mois- ture content of the soil for optimum germination, a preliminary study was conducted on the influence of these factors on the ger- mination of five vegetables. Seed was planted in replicated flats containing muck and mineral soil at four moisture levels, and its germination was determined. To attain the effect of dif- ferent depths of planting, varying amounts of soil were used to cover the seed. The five vegetables used were Sweet Spanish onion, Rutgers tomato, Slo-bolt lettuce, Danish Ball Head cab- bage, and Nantes carrot. The data are reported in Tables I and II. The figures in Table I show that the highest average ger- mination obtained was at the 5/8" depth on muck, and at the 1/4" 10 TABLE I EFFECT OF PLANTING DEPTH ON PERCEHTAGE EMERGEHCE r" ' —fi v -\ r' ‘1’”! e. :7 ‘1 'wr'w'w I 0 OF PELLETED “ND Chh h VnueTaBLn SEED AT 70 F. v hoax SOIL MINERAL SOIL CPOP 1/8" 1/4" 3/8" I/2" I/8" 1/4" 5/8" I/2" .KVG. ONION (P) 92 . 94 88 72 72 78 68 84 81 ONION (c) 82 90 88 84 74 94 92 9o 86 CHATO (P) 86 100 88 92 96 92 9o 88 90 TOMATO (c) 88 78 84 8o 80 76 7C._4 Ti ..J§i_ LETTUCE (P) 64 58 60 48 54 76 44 50 57 LETTUCE (c) 68 80 84 64 60 76 52 56 67 CABBAGE (P) 84 82 82 84 76 94 84 72 82 CABBAGE (c) 94 86 82 9o 88 96 82 80 9o_ CARROT (P) 78 78 86 64 70 72 56 72 72 CARROT (c) 82 84 9o 72 80 J_m72 64 66 76 AVERAGE (P) 80 82 81 72 78 82 68 73 76 AVERAGE (c) 85 84_g__86 78 76 83 72 74 883 *Average of four observations 11 TABLE II EFFECT OF SOIL MOISTURE ON PERCENTAGE “A! 0F PELLETED AND CHECK VEGETABLE SEED.AT 70 F. PERCENTAGE OF FIELD CAPACITY CROP 70% F. C. 78% F. C. 87% F. c. 100% F. 6. AVERAGE ONION (P) 66* 86 82 84 80 ONION (C) 82 88 86 92 87 TOEATO (P) 70 80 100 84 84 TOEATO (C) 82 74 100 78 84 LETTUCE (P) 36 56 56 64 53 LETTUCE (C) 74 68 76 78 74 CABBAGE (P) 62 9o 94 72 8O CABBAGE (c) 76 82 100 96 89 CARROT (P) 58 64 80 80 71 CARROT (c) 66 82 86 9O 81 AVERAGE (P) 58 75 82 77 73 AVERAGE (C) 76 79 90 87 81 *Average of four observations 12 depth on mineral soil. The highest per cent germination was secured in the soil with a moisture content of 87 per cent of field capacity (Table II). The reduction in germination obtained at the two lower moisture levels differs between the pelleted and check seed. At the 70 per cent level, pelleting reduced germination 18 per cent, while at the 78 per cent level pelleting reduced germination only 4 per cent. The data in this test showed that at both low (70 per cent) or high (100 per cent) moisture levels, pelleting is relatively more harmful to germination than at the intermediate moisture contents. 13 EXPERIMENTAL RESULTS The information obtained with respect to the per cent ger- mination of each of the 960 lots was subjected to a statistical analysis<12). The significant effects of the various factors, and the first and second order interactions, are expressed in the analysis of variance summary. The third and fourth order interactions were placed in the error term. Due to the large number of degrees of freedom involved, the error is quite small, and consequently all of the main factors are highly significant, and many of the interactions are worth studying. The data on germination and rate of emergence are arranged in Tables III to VIII to portray the significant relationships. Based on an average of all crops and all factors, pel- leting reduced germination 15 per cent (Table III). Pelleting significantly reduced the germination of all creps except car- rot, cauliflower and turnip. The figures in Table IV show that on an average of all conditions, pelleting delayed emergence by 1.2 days. However, with cauliflower and turnip, pelleting did not significantly lower germination, nor materially prolong the rate of emergence. With pelleted kale, mustard, onion, parsnip and tomato seed, a reduction in the per cent germination can be related to a pronounced increase in the time to emergence as come pared to unpelleted seed. This relationship is easily Observed graphically in Fig. l. 14 PERCENT GERMINATION ANALYSIS OF VARIANCE SUMMARY SUMS OF MEAN SOURCE OF VARIANCE D.F. SQUARES SQUARE Replications l l 1.00 Crops (c) 14 8,201 585.78** Pellet Treatments (P) 1 3,264 3,264.00** Soils (S) 1 499 499.00** Moisture (M) 1 511 511.00** Temperature (T) 3 314 104.47** CxP 14 1,453 103.78** CxS 14 825 58.93** CxM 14 250 17.86* CxT 42 1,874 44.61** PxS 1 27 27.00 PxM 1 98 98.00** PxT 3 46”; 15.33 SxM l 10 10.00 SxT 3 80 26.67* MXT 3 64 21.33 CxPxS 14 219 15.64* CXPXM 14 213 15.21 CxPxT 42 823 19.604: PxSxM 1 4 4.00 PxSxT 3 13 4.33 SxmxT 3 47 15.67 CxSxM 14 228 16.28* CxSxT 42 344 8.19 CxMXT 42 515 12.26* PxMxT 3 70 23.33 Error 644 5,975 9.0 Total 959 25,968 1% Snedecor's t Value 2.586 Least Difference for Sig: Averages of 8 15.5 " " 16 10.9 " " 32 7.7 " " 64 5.5 " " 120 4.0 " " 240 2.8 " " 480 2.0 F VALUE 65.09 362.67 55.44 56.78 11.61 11.53 6.55 1.98 4.96 3.00 10.89 1.70 1.11 2.96 2.37 1.74 1.69 2.18 0.44 0.48 1.74 1.81 0.91 1.36 2.59 5% 1.960 1 15 The average effect of temperature on the per cent germin- ation and rate of emergence of pelleted seed is shown in Fig. 2 and Tables III and IV. The highest germination for both pellet and check seed was obtained at 500 F., and the most rapid rate of emergence was at 70° F. The relative (R/C) decrease in both germination and rate of emergence was more pronounced at the higher temperatures. Table V and Fig. 3 express the relative effects of teme perature on germination of pelleted and Check seed. Small rela- tive germination figures indicate seriouSEharmful effect from pelleting; however, a large relative rate of emergence figure indicates a pronounced detrimental effect from pelleting. Pel- leting had the effect of reducing relative germination and increasing the relative time to emergence at the high tempera- tures, while increasing the relative germination and reducing the relative time to emergence at low temperatures (Table V). Table V indicates that with spinaCh, rutabaga, kale, cab- bage and broccoli, the relative germination of pelleted seed decreased as the temperature increased; on the other hand, the relative germination of carrot, tomato and turnip increased with an increase in temperature. The relative rate of emergence of most creps, with the exception of Spinach, was reduced more at the high temperatures than at the low temperatures. Pelleting reduced the relative germination of spinach and kale about 16 2 mm .— $3.3.— c ONH : = ** mesae> 0 mo owepebd 4. 0.05 0.00 0.50 0.05 0.H0 0.00 0.55 5.00 0.05 H.05 0.H0 0.00 0.H5 0.00 **5.00 mm¢mm>< 0.00 0.00 0.50 0.00 0.00 0.00 0.a0 0.Hm 0.00 0.am 0.00 0.00 0.05 0.05 0.H0 magmas 0.H5 H.05 0.50 0.H0 0.05 0.00 0.00 0.05 0.00 0.05 0.55 0.H5 0.00 0.00 0.50 opmaoa 0.00 0.00 0.00 0.00 0.05 0.00 0.00 0.00 0.00 0.00 0.40 0.30 0.00 0.50 0.00 madmaem 0.H0 0.H0 H.0¢ 0.H0 0.00 0.00 0.00 0.00 0.H0 0.00 0.00 0.H0 0.00 0.00 0.0a zoenwam 0.00 0.50 0.05 0.00 0.00 0.05 0.H0 0.00 0.05 0.05 0.00 0.05 0.00 0.00 0.00 60020psm 0.00 0.00 0.05 0.00 0.00 0.05 0.00 0.50 0.00 0.00 0.00 0.05 0.00 0.00 0.00 nmwvex 0.05 0.00 0.00 0.05 0.H0 0.00 0.H0 0.50 0.05 0.00 0.am 0.00 0.05 0.00 0.00 newso 0.00 0.00 0.05 0.05 0.00 0.05 0.00 0.00 0.00 0.55 0.00 0.00 0.00 0.00 0.05 ondpwom 0.H0 0.H0 0.00 0.50 0.50 0.50 0.00 0.00 0.00 0.00 0.H5 0.He 0.00 0.00 0.00 maem «.H5 0.05 0.00 0.00 0.H5 0.00 0.05 0.05 0.05 0.05 0.H0 0.05 0.00 0.00 0.50 dawn 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.Hm 0.00 0.55 0.05 0.05 0.00 0.00 0.H0 .HMHHSEU 0.00 0.00 0.00 0.00 0.00 0.55 0.00 0.50 0.00 0.00 0.00 0.H0 0.00 0.00 0.00 poaaeo 0.55 0.00 0.¢0 0.Hm 0.00 0.00 0.55 0.00 0.00 0.05 0.50 0.00 0.50 0.00 0.00 = .00 5.00 0.05 H.00 0.05 0.05 0.50 0.05 0.00 0.H0 0.00 0.0090.¢w 0.00 0.00 0.00 0000980 0.00 0.00 ***H.55 0.00 0.50 0.40 0.00 0.00 0.05 0.00 0.00 0.00 0.55 0.00 *0.00 HHo000hm _ .00205 00¢ .0>« 00¢ 000 000 005 .0>< 0 m .0>< 0 m .0>< 0 m .0>< 0 m .0>< 0 m momo mmomo mqmdymwm> 0H mo ZOHB 0053440000 020 omamqqmm 00 momm0zflzm 05 0000 mo<0m>< >H 0400B #1 00.0H 05.HH 00.0H 00.0H 00.0H 00.0H 05.0H 00.0 00.0H 00.0 HH.0 0040054 00.0 00.0 00.0 H5.0H 00.0H 00.0 00.0 00.5 00.5 05.0 00.0 mflfihse 00.0H 50.0H 00.0H 00.00 00.00 00.0H 05.5H 05.0 H0.0H 00.0 a0.0 090805 00.0H 00.0H 00.0H 00.0H 00.0H 00.0a 00.HH 00.0 00.0 05.0 00.0 sodmflmm 50.0H 00.0 00.0H 00.5H 00.5H 00.0 00.0H 00.0 05.5 50.0 05.0 00000950 HH.0 00.5 05.0 0H.0H 00.0H 00.0 00.5 00.0 0H.0 0H.0 05.0 000000 00.00 00.0H 50.00 00.00 00.50 0H.H0 05.00 00.5H 00.H0 00.0H 00.0H mwsmhem 00.0H OH.0H 00.0H 00.00 00.00 00.0H 0H.0H 00.0H H0.0H 00.5 00.HH QOfiQO H0.0H 00.0H 00.0H H0.00 H0.00 00.5H 00.0H H0.0H 00.00 HH.0H 00.5H 0009050 05.0H 0H.0H 00.HH 05.5H 00.0H 00.HH 05.0H 0H.5 0H.0 H0.0 00.0 mama HH.0H 0H.0H 00.0H 00.H0 00.H0 00.5H 00.0H 00.HH 05.0H 05.0 05.0 HHwQ 00.0H 00.HH 00.0H 00.00 00.00 00.HH H0.0H 00.0 00.5 0H.0 00.5 .Hmfiaswo 00.0H 00.0H 00.0H 5H.00 00.00 00.0H 00.0H 05.0H 00.0a 00.0 00.0H p0hh00 00.5 a5.0 00.5 00.0H 00.0H 05.0 50.0 H0.0 00.0 H0.0 50.0 : .00 00.0 05.0 00.0 05.0H 00.0H 00.0 00.0H 00.0 00.5 50.0 00.0 0000900 00.5 00.5 05.5 00.0H 00.0H 00.0 00.5 00.0 00.0 00.0 00.0 Haooooam .0>< 0 m 0 m 0 m 0 m 0 m 0000 mMMDH<flHmfiMH AA< 00 00 00 05 O O O O 41 [5 IT ’— FIG. 1. m3 INFLUENCE OF PEILETING OI GERJIINAIION AID RATE OF “GEN EUGENE DIETZGEN CO. NO. 375 mi; 2. 15: names or Wm: my mum: m mm or mamas or mumsm 20 n.0HH m.moH w.HHH n.mHH 5.0»H m.Hm H.«w 5.mm m.Hm m.m5 0000050 0.00H «.00 H.00H m.mm n.0ma 0.5m m.Hm 0.000 0.0m m.moa mfiqpse 5.mHH ¢.mOH o.on m.mma N.mNH o.5w n.05 «.05 m.mm 0.00H opmaO5 0.0HH N.5oH m.mHH 0.000 0.00H m.©m ¢.Hm 0.00 m.0m 0.5m 00amuam 0.00 m.mm m.moH m.wm 0.50 w.mm 0.00 m.m5 ¢.mm 0.0m goanflmm ¢.mHH ¢.Hofi o.¢ma m.HHH m.mma «.00 N.Hm m.mm 0.00 H.05 awanapsm o.¢NH H.00H 0.0HH «.mma w.mwa 0.00 m.mw H.mm 0.00 m.05 gmfiuam m.5HH m.moH 5.00H o.mHH N.m¢H 5.55 H.ww m.mm 0.05 0.00 nOqu N.mofi o.¢oH 0.000 o.HHH H.HHH 9.00 m.¢m 0.90 w.m5 0.0m uuapwsz H.mHH w.moH n.0HH 0.0HH «.mwfl H.mm H.HoH 0.00 0.0m 0.50 oflwx H.mHH o.moH m.moa n.0ma m.m¢H 0.00 ¢.m5 m.mm 0.0m H.5m Haas «.NHH w.moH 5.5oH 5.0HH «.QHH 0.09 m.mm 5.0m 0.000 0.5m .HMfiHsdo m.mHH m.HoH ¢.moH 0.000 m.mma 0.0m 0.5m H.00H N.Hoa m.HoH poggmo N.5NH m.5oH m.NNH o.¢ma m.¢mH H.H5 $.00 o.mo H.05 0.0m a .nu 0.5HH m.HoH H.oNH 5.0HH m.5na 0.05 0.00 m.05 N.¢© 0.00 owanpgo 0.0HH m.ooH m.HHH o.mHH m.o¢~ H.5w 0.0m 0.00 0.0m 0.05 fiHOOOOMm .054 ‘p00 000 000 005 .Afll .¢>« 00¢ waQm ‘pom .005 momu o\w 002000000 mo 0900 0>He¢qum Amv ob 28320200 0350300 5553 3.:— 0flmafimmmmfia azmufimmHO 84 0030 00006 OH mmeamm 00 007.30 lmngm .00 0540 020 ZOHHESEHO 00.5. zmomnm 050.30 005 > 0.005.. 21 GEIU'JINATION AND RATE OF EMERGENCE OF PBLLETED SEED THE RELATIVE INFLUENCE OF TEMPERATURE ON FIG. 3. \.\ - .I \-\.. 04H ./ / 0 5\ // / 4.1.!“ \ .fl\ 1.\\ . / v / If F F F F Ema: 0 \ II x . 5 .. V /v o o o o \ .\ O 0 O 0 0.0000000 \ \\ \ \ 7 6 5 4. \ 5 / \ .\ _ \ . \ 0 x x \x _ n 0000 0 , v \ A\ . . cg \ \ fi 5////v/¢/ / I - - u. \\ \\ / ll! ./ II. .1: \v «N v 5. egos A/ A 0 \ i \\\ H K! I \\ \ Jada-Ill. _ /' HI I: l I I . I / I, I I ll. ' I _ x v , \ 000500 _ _ a 5 I I 00590 x V\ 0% y 5r\\.\\.\ . A. . 1. ll _ NV 00000001 \.\ \ A A. fluooooum 0400500 3 0032.6 0 .0. 0 0 0. 0“ 0. 0 0 0 0 0 .0“ 0 0. 0 00006400503000 mo 0003.90.20.30 213.330. 3005\pozom. .00 ooqomuofim mo 3.0m 0130030 III N- - -|.I.5.--!. ............... ..... _ . 5 _ ......... __ #5“ ...... ”0235.20.57... .gnjfi. 071.15.005.10--. 3:00.30.-j¥:50 ¢0T0Iirnflwwfi+w -5 r- -EfirfiL 0 iii 10-00%: ..... 0 , . . . . . 5 _ ........ 5 . . . . . . , A . . . . . 0 ........ . . . . . . . . . . . . _ 5 . .5 05 ........................ A A I . . ¢ 0 22 54 per cent more at 70° F. than at 40° F. The germination of parsnip was reduced by pelleting about 45 per cent at all tem- peratures, while the germination of cauliflower and turnip was reduced only 3 per cent based on the averages of all tempera- tures. Table VI (A) shows that the relative germination of all crops with the exception of onion, radish, spinach, tomato and turnip was lower on mineral than on muck soil. Relative to the check, the pelleting of cabbage, cauliflower, dill, mustard, broccoli, Chinese cabbage and parsnip resulted in a higher per cent germination on muck than on mineral soil. These relative correlations can be graphically interpreted in Fig. 4. However, only with cauliflower, mustard, onion, parsnip and turnip did the pelleting process result in a pronounced higher relative time to emergence on muck than on mineral soil (Table VII). Field capacity in this paper is considered synonymous with water holding capacity of a soil. Table VI (B) indicates that the highest per cent germination was obtained at the 87 per cent level, and.only with cauliflower, tomato and parsnip did the pellet give a higher germination at 100 per cent field cap- acity. However, the germination of check seed shows small dif- ferences due to temperature, soil and moisture content of the soil as compared to the pellet. Data in Table VIII shows that on an average of the 15 23 wodadb ma mo mowdao>< * 5.05 0.00 0.00 0.55 0.00 0.05 0.00 0.05 0.55 0.00 0.05 5.05 0.05 0.00 0000000 0.00 0.00 0.50 0.00 0.00 0.50 0.00 0.000 0.00 0.00 0.00 0.00 0.00 0.00 000000 0.05 0.05 0.50 0.05 0.05 0.00 0.00 5.00 0.00 0.05 0.00 0.05 0.05 0.05 000000 0.00 0.00 0.00 0.50 0.00 0.00 0.00 5.00 0.05 0.00 0.00 0.00 0.05 0.00 0000000 0.00 0.00 0.00 0.00 0.50 0.00 0.00 0.00 0.00 0.50 0.00 0.00 0.00 0.00 0000000 0.55 0.00 0.00 0.00 0.50 0.00 0.00 0.05 0.00 0.00 0.05 0.00 0.00 0.05 00000000 0.00 0.00 0.05 0.00 0.00 0.00 0.55 5.00 0.00 0.50 0.05 0.00 0.00 0.55 000000 0.05 0.00 0.00 0.00 0.00 0.05 0.05 0.00 0.00 0.00 0.00 0.05 0.00 0.00 00000 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.50 0.00 0.00 0.00 0.05 0.05 0.00 0000000 0.00 0.00 0.00 0.50 0.00 0.50 0.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0000 0.00 0.05 0.00 0.05 0.05 0.05 5.50 0.00 0.55 0.05 0.55 0.00 0.00 0.00 0000 0.00 0.00 0.50 0.00 0.00 0.00 0.000 0.00 0.00 0.00 0.00 0.00 0.00 0.55 .0000000 0.00 0.00 0.00 0.00 0.00 0.00 0.000 0.00 0.00 0.00 0.00 0.00 0.50 0.00 000000 0.05 0.00 0.50 0.00 0.00 0.05 0.05 0.00 0.00 0.00 0.05 0.05 0.00 0.00 a .00 0.00 0.05 0.50 0.00 0.05 0.00 5.05 0.00 0.05 0.00 0.00 0.00 0.50 0.00 0000000 0.05 0.00 0.00 0.50 0.00 .0.00 0.00 0.00 0.50 0.00 0.00 0.05 0.50 00.05 00000000 .030 0 .0 .03. 0 0 00000 0.0000 .030 0 .0 .030 0 .0 .0000 0000 050 0\0 00000 0000 0000200 00000000 0200000 0000; 00 0000200000 00v 0000 0000 000 00200000 00000000 0000 000 00 00v 000 .00000 0000 000 000 20 Qmmw mqmdamom> QMBMAAMfi mo ZOHH mqm¢H TABLE VII 24 THE EFFECT OF PELLETING AND SOIL ON THE AVERAGE DAYS TO EMERGENCE OF 15 VEGETABLES '__ __: :0. MINERAL MUCK RATIO P/C CROP P c P c MINERAL MUCK Broccoli 7.61 6.97 7.79 7.16 109.2 108.8 Cabbage rfi9.84 8.60 9.80 8.93 114.4 109.7 an. " “ 7.88 6.66 7.88 6.76 118.3 116.6 Carrot 14.94 13.68 £15.00 13.54 109.2 110.8 Caulifl. 13.21 12.43 12.73 11.52 106.3 110.5 5111 16.55 14.43 15.59 13.90 114.7 112.2 Kale 11.49 10.26 11.41 10.00 112.0 114.1 thtard 19.84 19.19fi 19.22 16.96 103.4 113.3 Onion 17.08 15.54 #16.84 14.65 109.9 115.0 Radish 8.71 7.54 8.69 7.49 115.5 116.0 Rutabaga 10.90 9.78 10.81 9.58 111.4 112.8 Spinach 10.62 10.45 11.00 11.24 101.6 97.9 Parsnip 23.08 20.27t 21.69 18.25 113.9 118.8 Tomato 15.12 13.20 15.84 13.75 114.5 115.2 Turnip 10.00 10.26 9.09 8.69 97.5 104.6 AVERAGE £16.12 12.00 12.82 10.89 110.1 111.8 FIG. 4. THE RELATIVE INFLUENCE OF SOIL TYPE ON GERMINATION 25 AND RATE OF EMERGENCE 0F FELLETED S- IUGENE DIETZGEN CO. NO. 375 26 TABLE VIII THE EFFECT OF TEKPERATURE AND SOILS UPON THE OVERALL AVERAGE PERCENTAGE GERHINATION OF 15 VEGETABLES o o o o TEMPERATURE 7O 60 50 40 AVERAGE Muck 75.5* 78.2 79.6 76.7 77.5 Mineral 67.5 70.1 76.2 73.1 71.7 Average 71.5 74.2 77.9 74.9 74.6 *.Average of 120 values 27 cr0ps the per cent germination on muck soil, at all temperatures, was higher than on mineral soil, and that the optimum tempera- ture for germination on both soils was at 500 F. 28 PRELIMINARY FIELD INVESTIGATIONS In order to obtain some observations on the influence of pelleting and coating on germination under field conditions, a small experiment was conducted in.uhy, 1948. The following kinds and varieties of seeds were used. CROP VARIETY TREATEENT Muskmelon Honey Rock Coated Cucumber Straight 8 " Green bean Giant stringless Gr. Pod " Wax bean Brittle wax " Lima bean Thorogreen " Onion Downings Yellow Globe Pelleted Carrot Red Cored Chantenay " Tomato Stokesdale " Sweet corn North Star Coated " " Golden Hybrid " " " Golden Security " Two lOO-seed lots of pelleted or coated seed, which had been treated with a fungicide, were compared with fungicide treated uncoated seed. The small seeded crops were processed to attain a spherical pellet, while the large seeded crOps were coated with chemicals without changing the shape of the seed. The pelleted or coated seed was processed with various fungicides, fertilizers and plant stimulants in the coating material, by Processed Seeds, Inc., hfidland, Michigan. The materials used were those that had shown the greatest benefit in previous tests conducted by that company. The effect of the 29 process on the per cent germination is expressed by the data in the following table: TABLE IX PER CENT GERHINATION GREEN LIMA BEAN BEAN ONION CARROT TOMATO MELON CUCUHBER BEAN 90 93 59 77 O 22 14 78 Pelleted 53 56 81 87 55 41 3 15 Unpelleted COATED WITH COATED WITH 1.5% SWEET CORN 2% CUPROCIDE ARASAN & 3% CHLORONIL UNCOATED I - A“ North Star 52 88 72 Golden Hybrid 42 60 55 Golden Security 72 79 48 W” 3.1:: Before these plantings had emerged a hard rain tended to crust the soil, which reduced the germination of the small seeded crOps. The germination of melon and cucumber was benefited notice- ably by coating the seed, while the germination of coated wax and green beans was only slightly better than that of the uncoated seed. However, onions were reduced in their germination as a result of pelleting. Coated lima beans failed to germinate, pos- sibly due to injury received during the coating process. 'With sweet corn, the Golden Security variety showed the greatest increase in germination from coating. 30 DISCUSSION In this experiment only one lot of each kind of seed was pelleted. Consequently, differences in the relative germination or emergence of the pelleted seed of the 15 different crOps may possibly be as much a reflection of variations in the pelleting technique as in the response of a crop to pelleting. The hard- ness of the pellet or the drying time may have influenced ger- mination. Pelleted cauliflower seed gave a relative germination of 99 per cent, while cabbage gave a relative germination of only 71 per cent (Table V). Perhaps this result is not due so much to the fact that these two cr0ps react differently to pel- leting, as to the fact that they were pelleted separately and probably with some slight differences in pelleting procedure. The data presented on Tables I, II and III indicate that the per cent germination of onion, tomato, cabbage and carrot varied markedly. Although different varieties of these cropS'were used in these treatments, the variation in pelleting technique may be the factor that caused the observed differences in germination. The difference between a relative germination of 99 per cent in carrot and 56 per cent in parsnip, two related crops, may also be due to variations in the pelleting process, and not inherent in the seed. Varieties of seed can also vary in viability, moisture 51 content and susceptibility to diseases. Consequently, future work conducted with different lots of seed and different pellet- ing procedures probably would produce results varying from those found in this experiment. However, the observations relating to the interaction between crop and pelleting under various ger- minating conditions with respect to soil, soil moisture and tem- perature should be valid. For example, at 700 F. the relative germination of pelleted cabbage seed was only 65 per cent, while at 40° F. it was 84 per cent of the check seed (Table V). This tendency for a better relative germination at the lower tempera- ture with some crops would probably occur under any condition of pelleting. The relative germination of pelleted tomato seed was 30 per cent better at 70° F. than at 40° F. (Table V). It is apparent then that temperature has a profound influence on the germination of pelleted seed, and shows great variations between crops. In Kotowski's(5) experiment, the highest germination of cabbage was at 46° F., while with tomato the highest germination was obtained at temperatures between 65° and 770 F. This study indicates that the necessity for germinating seeds at their opti- mum temperature is accentuated by pelleting. Also at tempera- tures unfavorable for germination, pelleting further lowers the per cent emergence. Considering all crops at all factors involved, pelleting delayed emergence 1.2 days, and lowered germination 15 per cent. 32 This detrimental effect might be caused by a decreased rate of water absorption or a reduced gaseous exchange, or both. Crocker(3) has stated that an accumulation of carbon dioxide or a deficiency of oxygen in the area around the seed caused decreased respiration, and a delay in germination. A delay in emergence of any crop caused by low soil temperature, high soil moisture, or the pelleting process would expose the germinating seed to infection by soil organisms for a longer time. This extended exposure to attack by soil pathogens could be the factor that reduced germination. In this work an inert pellet was used which contained no seed protectant, plant nutrient, or seed or plant stimulant. In a field experiment, where some of these materials were incorpor- ated into the pellet, germination was substantially better than that found with check seed. The germination of certain varieties of muskmelon, cucumber, wax bean, green bean, tomato and sweet corn seed was markedly benefited by the addition of fungicides and fertilizers to the pellet. Other tests have been conducted that substantiate these results(4)(13). Soil type had a significant effect on the germination of the crOps used in this work. Muck soil is better aerated than mineral soil, which might explain the increases in germination and rates of emergence on muck soil, that were noted in this test with some crops. Crocker<3)suggested that nitrates stimulate 33 the germination of some seeds, and nitrates are found in fairly large amounts in organic soils. Others have suggested that muck soils contain many growth regulating substances which might stim- ulate germination. On the average of all crOps the relative ger- mination of pelleted seed was 3.8 per cent better on muck than on mineral soil. This may be related to the fact that muck soils, due to their structure, are better aerated. This factor may help the germination of pelleted seed. Most crOps had a higher per cent germination in a soil with a moisture content of 87 per cent field capacity than in soils at 100 per cent field capacity. When the water was added to attain the high moisture content, probably much of the oxygen was forced out of the soil, and this excess water limited the diffusion of more oxygen from the atmosphere. A considerable amount of damping-off was noticed in this experiment. Whetzel<15) found that in saturated soils there was a greater infection from damping-off organisms. In this experiment no actual counts were made of the diseased seedlings at the two moisture levels, but it might be expected that infection was higher on the soil at 100 per cent field capacity. Carrot, cauliflower, onion, dill, parsnip, tomato and turnip showed no significant difference in germination as related to the moisture level of the soil. These crops may not require a high concen- tration of oxygen for germination, or may not be affected as much 34 by damping-off organisms. Considering all crops, pelleted seed germinated relatively poorer in soil held at the higher moisture level. Kotowski(5) has shown that seed vary in their temperature requirements for germination. This may be due to the fact that seeds differ in their physiological make up, and that temperature regulates the activity, solubilities and absorption of many chemr icals including water. Barton(l) has indicated that many seeds absorb varying amounts of water at different temperatures, and that seeds like onion, tomato, lettuce, flax, peanut and pine absorb more water at 50° F. than at any other temperature. This effect might be related to the high germination of seeds obtained at 50° F. in this experiment. Whetze1u5) stated that DeBary's Pythium.organism requires a temperature between 70° and 86° F. for optimum infection and development, which might suggest ano- ther possibility for the high per cent germination at 50° F. Most of the vegetables used in this experiment could be classed as cool season crOps, which might offer another explanation for the optimum per cent germination at 50° F. Crops are affected differently by soil organisms, which in turn are influenced by temperature. The higher rate of emer- gence at 70° F. is a result of a higher rate of metabolic activ- ity at higher temperatures. The optimum germination obtained at 500 F. might be a compromise between optimum germination temper- ature and the temperature at which soil organisms are least active. 55 CONCLUSIONS The pelleting of vegetable seeds altered their germina- tion and rate of emergence under various conditions. Pelleting affected the per cent germination and time to emergence rela- tive to the unpelleted seed differentially, with respect to crops, germination temperature, soil types, and soil moisture content. The variations in pelleting technique may also effect germination and rate of emergence. On the basis of 960 observations involving fifteen cr0ps, germinated at four temperatures, on two soil types, at two mois- ture levels, the following conclusions relative to the effect of pelleting on germination and rate of emergence appear warranted: l. Pelleting delayed emergence by 1.2 days, and reduced germination by 15 per cent. 2. The pelleting of seed apparently accentuates the necessity for its germination under optimum environmental conditions. 3. The highest per cent germination was obtained on soil with a moisture content of 87 per cent field capacity. 4. Better germinations of most crOps were attained on muck soils. 5. Considering all crops, the most rapid rate of 36 emergence was observed at 70° F., and the highest per cent germination was at 50° F. The pelleting of the smaller seeded vegetables is econ- omically sound from the standpoint of mechanical planting, if the process can be developed to the point where it does not materially reduce germination. On the bases of preliminary field tests, the possibilities of adding chemicals with the pel- leting materials that protect the seed from pathogens, and/or stimulate germination or seedling growth, offer a fertile field for future investigations. 1. 3. 4. 5. 6. 7. 8. 9. 10. 12. 13. 14. 15. 57 LITERATURE CITE Barton, Lela V., Relation of certain air temperatures and humidities to viability of seeds. Contrib. Boyce Thomp- son Inst. 12:85-102, 1943. Crocker,‘Wm., Growth of plants. Reinhold Publishing Corp., New York, N. Y., pp. 28-138, 1948. Farmers and Khnufacturers Beet Sugar Assoc., Saginaw, Mich- igan. Memo. Test of 1948 production pelleted seed. 1948. Kotowski, Felix. Temperature relations to germination of vegetable seed. Proc. Amer. Soc. Hort. Sci. pp. 176-184, 1926. Leukel, R. W., Recent developments in seed treatment. Bot. Rev. 14:235-269, 1948. Linn, M. B., and Newhall, A. 0., Comparison of two methods of pelleting onion seed in the control of smut. Phyto- path. 38:218-221, 1948. Nelson, B., Dust fungicides versus formaldehyde in the con- trol of onion smut. Mich. Agr. Exp. Sta., Quart. Bul. 28:226-247, 1946. Newhall, A. G., Pelleting onion seed with fungicides. Farm Research (Cornell Agr. Exp. Sta.) 11 (1): 18-20, 1945. Shull, C. A., The oxygen minimum and germination of Xanthium seeds. Bot. Gaz. 52:453-477, 1911. Snedecor, George W., Statistical Methods. Iowa State College Press, 4th Ed., 485 pp., 1946. Vogelsang, Phelps, Processed Seeds,Inc., Midland, Michigan. Private communications. 1948. walker, J. C., Vegetable seed treatment. Bot. Rev. 14:588- 601, 1948. Whetzel, H. H., Lecture text. DeBary's Pythium damping-off. Cornell Univ. Revision of January, 1942. hit 11 ’50 M24’ 1" "‘ g H: " Hf“. H- _. MAGIC .9 OCT 1 8 1993 ”'TITI'ITlflflafiflMI[[l'llilllffllelWflTlW