i yd It ll iii 235 ill Dna me CMS MST Sa < ee THESIS FOR DEGREE OF M.S. PAUL KWONG FU, THESIS } ~ THESIS Y 4 ~ a ee rhesus ya . . Ok —'% * — -- > 4 ‘ . " va , ‘ a we 1 @ we _* » —_, ' f ‘ XN LA tee j \ ' “4 “ ' < INHERITANCE OF SIZE AND SHAPE IN BEANS. Thesis for Degree of M.S. Paul Kwong Fu. 1916. THES(< ACKNOWLEDGMENT. I wish to thank Mr. Frank A. Spragg, Expert in Plant 4 Breeding of the Experiment Station of the Michigan Agricul- tural College, under whose careful supervision the investiga- tion was carried on, for kindly advice and assistance during the course of the work. SOGEL CONTENTS. Introduction Previous Works On Beans Sources of Materials Method of Work Datas and Discussions Conclusions Page 16 28 INTRODUCTION. Many farmers like to grow small pea beans, but it has been their opinion that these pea beans tend to become larger and longer as years go by. It is said that many kinds of small pea beans of a decade ago have now become navies of larger types, and in many instances have lengthened into kidneys. There is no data to support these contentions, yet the opinion of men who for many years have handled beans should not be lightly laid aside. For this reason, Mr. F. A. Spragg saw the need of a fuller knowledge regarding the inheritance of size and shape, and suggested that I investigate the reason why beans have become longer and larger thru the years, if this be true. This paper is the result of observations and statistical studies on the inheritance of size and shape obtainable in one year (part of two season) from crosses between common commercial varieties possessed by the Station. The early work had been done in the Plant Breeding Division of this Station. Because of the great value of bean crop as food, it has great economic importance. Consummers of beans usually object to colors and certain size and shape in beans (not that they have any correlation with quality, but that it is a mere fashion demanded by them). Thus, colored beans and certain sizes and shapes do not generally find as ready a market nor @s good a price as white ones having the sizes and shapes con- ~2- sidered desirable. In order that the plant breeder may obviate such troubles and produce the varieties most gener ally desired by consumers, he needs a better knowledge of bean heredity. It is because of this fact that this work is attempted. PREVIOUS WORK ON BEANS. Professor E. A. Emerson did mich work on the inheritance of color in the seed coat of beans when he was connected with the Nebraska Experiment gtation. In his work with bean cross— es, he found that all the racial crosses of beans produced, show little variation in the first generation, but pronounced variation in the second and third generations. Under selec- tion, they appeared fairly well fixed in the fourth and fifth generations. The characters of the two parents (atavistic tendencies) were usually reproduced among the offspring of the second or third generation tho often the new tendencies were noticable. Characters different from the parent forms were usually blends in the crosses or united unchanged in mosaics of small or large pattern. In the study of size and shape in beans, he made numer ous crosses between Fillbasket Wax having long flat seeds, Longfellow having long slender seeds, and Snowfzake Navy having small round seeds. He then determined the mean, the coefficient of variability for each of their lengths, weights, breadths and thicknesses. He observed that in the first gen- -3~ eration, the mean and the coefficient of variability were not materially greater than for parents, but in the second genera- tion, individuals exhibited marked segregation of size and shape. From this, he concluded that "Shape may be definitely inherited. Qbservations of the second generation bean seeds where the parents differ in size but not in shape indicate that length and breadth are probably not inherited independent- ly of each other. Large round beans crossed with small roumd ones do not give any long slender beans in the second generation, but only large medium and small round ones. On the other hand, when the parents differ in shape as well as in size, intermediate and parental shape as well as inter mediate and parental dimensions ocour in the second generation’ Mr. J. Belling, Assistant Botanist of the Florida Experi- ment Station in an attempt to secure a hybrid that would com bine the thin unopening hull of the Velvet bean with the Lyon Beans' smooth pods which do not have the objectional irritating bristles, has also studied the standard deviation and coefficient of variability of the length, breadth, thick- ness and weight, also the correlation of length and breadth and thickness of the F, crosses between the Lyon and Velvet beans. He measured from 8 to 200 seeds of each of this 118 plants and found that they varied between 10.5 and 20.Q5 mm. in length, and from 8.3 to 12.55 mm. in breadth. In his study of theweights of these seeds, he found that they varied from .65 to 1.9 gm. He then concluded that, "The close agreement of the length and breadth of the hybrid seeds with those of ~4— the Lyon beans and of the thickness that of the Velvet may possibly be genetic or may be due to special conditions of growth". However, he did not investigate the size and shape of beans in general. W. Johannsen worked with the weights of beans and found his pure line theory. He weighed the seeds of a single variety of beans and planted them spparately. They arranged them selves in a normal curve round the weight of greatest frequency where the seeds from the individual plants were harvested separately. The crop from each individual again could be grouped according to their weights in normal curve around the most frequent weight characteristic of each individual. Thus, there was a rough correspondence between the modes for the individual plants and the weights of the individual seeds from which they sprang. The heavier strains on the whole come from the heavier seeds and the lighter from the lighter seeds. But when he selected the heavier and lighter seeds from a single strain and planted them separately, he found that the modal weights were approximately the same for the produce of both the heavier and the lighter seeds. This indicates that selection inside the strain raised from a single seed does not alter the modal weight, i. e., the product of the two selections are the same genetically. TO gum up, it may be said that none of these invéstiga- tors have told us what sizes are séparately inherited, nor the number of inherited factor involved. Johannsen has shown that there are such factors, because ~5- the progeny of homozygous beans belonging to slightly differ— ent sizes maintain separate means, and do not regress to the mean of all sizes of beans. Emerson has shown that length and width are not inher- ited separately, but togehter as inheritance of sizes of the same shape. Variations in the inheritanca of shape, he finds occur only when the parents differ in shape. It remains for me to lay some foundation in an investi- gation of the factors involved. "SOURCES OF MATERIALS. The Michigan Experiment Station had gathered varieties of beans from different sections of the state and country. These had been selected to eliminate impurities and then tested in variety series where the plats were long anil narrow strips side by side. Tous, these varieties had been brought close together in the variety series and exposed to general crossing if beans are so inclined. Beans are normally auto- gamous (close fertile) yet a very few natural crosses result- ed (perhaps not one in ten million). Altho 106 different lots of beans have been given accession numbers by the Mich- igan Experiment Station and only four of these (viz. s=Nos. 2,4, 36, and 40) have become the mothers of colored crosses, there seems to have been other natural crosses of which ac- cession numbers 61, 87, 88, and 89 have become mothers be- cause segregations are obtained. The following are all that have in any way entered in this investigation:- ~ 6 MATERIAL FROM WHICH THE MATERIAL FOR THE STUDY OF SIZE AND SHAPE ARE SELECTED. Accession Numbers. Accession xing °f beans. Where from. Year obtained. numbers. Medium red Kidney Michigan 1907 4 White kidney . ° 13 White navy " " 36 " " " 1910 40 " e e 61 " " " 1913 62 " " 8 " 65 Large white navy Portland,Oregon 1914. 67 Pink navy - " " 71 Navy Stockton, Calif. " 75 Large wiite navy " " " 76 ” ® e " " ® 78 " " " San Francisco,Cal. " 83 Red kidney , 8 8 87 Yellow Sweedish navy Idaho " 88 White pea Michigan " 89 White kidney " 91 Pea bean 1913. ~7- Natural Crosses. Ki:d of Crosses. Fl Fg a Na ~ White na Black and brown kidney White and colored icc. Fo Red kidney navy and kidney Na = white na Black kidney White and colored Acc. $4 ney navy and kidney Na - White na Black navy Colored navy cc. FO6 White navy Na - White na Black navy White and colored cc.#40 White navy navy. Out of the plats representing accession nymbers 2,4,36 and 40, the station had obtained some black and brown seeds. The result of crosses between these varieties and some navy bean that grew alongside. The source of pollen was slightly uncertain but must have come at least partly from white navy beans in every cross. The first generation of the crosses (¥,) (grown in 1913) gave in all cases either a deep purple (almost black) or brown offspring. ‘he crosses between navy and kidney forms were kidney beans in F,. The crosses between two navy beans have given navies in all cases. Unfortunately, the F, crop was threshed each plat as a whole, and for this reason, we do not know but what there may have been some purple kidney of Fy having a kidney sire producing all kidneys in crop. The beans grown in 1913 were sorted according to color and shape and the classes counted. Then each such lot was planted separately in 1914. Growing thus in rows with classes recorded, and stakes attached to each, I harvested the 1914 beans, gathering the ~8~ Beeds of each individual plant separately. The seed from each Plant was placed in an envelope and given a selection number in accordance with the system used by the Michigan Experiment Station. This system consists usually of five figures, the first of which stands for the year in which the crop is grown, the second and third of which stand for the muimber of plat in which the plant belongs, and the fourth and fifth, for the selection number, the only exception to this being, that when the plat number exceeds 99, an extra figure is inserted. When I took over the mterial, most of these crosses were in their second generation and were rich in color of various combinations and also sizes and shapes. After they were fully classified it was décided to make selections with a view of studying the size and shape in beans, as the inher- itance of color had been well covered by others. METHOD OF WORK. In selecting the material, preference was given to white beans because those are the types preferred by the market. I also saved an extra quantity of small white navy and pea beans that the Michigan Experiment Station might have material from which to develop the new varieties most desired by the farmers and the trade. All other sizes and shapes were included in so far as they could be found among the white beans. When a type of size and shape was not repre- gented among the whites, colored beans were selected to -~Q— represent that type. Also when the data indicated that certain lots were especially apt to furnish the segregations desired, these were included. From among the 1914 individual plant selections, about 200 were chosen to become mothers of individual progeny plats in 1915. TXese lots totalled 14280 seeds. Each of the plant s§lectiors was given a plat mumber and a record of this and pede gree numbers was written on a small card using waterproof ink. These cards were afterwards paraffined and tacked to small stakes located at the end of the row in field. Piant- ing was done on Jums 12 and 14. The plants from 50500 to 59500: were planted on sandy soil near the poultry plant, while the remainder were planted on loamy soil in field #9. The season was extremely unfavorablefor beans but most seeds rushed their cotyledons above ground within one week's time. The same kind of culture was given t all, and in one month's time, the stand was beginning to thicken. Te number of plants was then taken and found to total 10787 plants. The growth in leaves and stalks was very profuse in some plats and very little in others, and sonstimes there was great contrast among plants of the same progeny (1. e. from the same mother plant).