‘Gin AGRIHJLTIJRAL EXPERIMENT smum AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS WV. B. BIZZELL, President LLETIN NO. 333 August,‘ 1925 DIVISION OF AGRONOMY ERITABLE CHLOROPHYLL DEFICIENCIES A IN SEEDLING COTTON B. YOUNGBLOOD, DIRECTOR COLLEGE STATION, BRAZOS COUNTY, TEXAS ‘M STAFF (As of August 1, 1925) ADMINISTRATION B. YOUNGBLOOD, M. S., Ph. D., Director A. B. CONNER, M. S., Vice-Director A. H. LEIDIGH, M. S., Asst. Director CHAS. A. FELKER, Chief Clerk A. S. WARE, Secretary ‘M. P. HOLLEMAN, JR., Asst. Chief Clerk J. M. SCHAEDEL, Executive Assistant C. B. NEBLETTE, Technical Assistant VETERINARY SCIENCE *M. FRANCIS, D. V. M., Chief H. SCHMIDT, D. V. M., Acting for Chief V. J. BRAUNER, D. V. M., Veterinarian CHEMISTRY G. S. FRAPS, Ph. D., Chief of Division; State Chemist _ S. E. ASBURY, M. S., Asst. Chemist WALDO H. WALKER, Asst. Chemist J. K. BLUM, B. S., Asst. Chemist J. E. TEAGUE, B. S., Asst. Chemist VELMA GRAHAM, Asst. Chemist K. KITSUTA, M. S., Asst. Chemist ADAH E. PROCTOR, B. S., Asst. Chemist N. J. VOLK, M. S., Asst. Chemist HORTICULTURE: A. T. POTTS,M. S., M. S. C., Chief of Division; Citriculturist H. NESS, M. S., Berry Breeder RANGE ANIMAL I-IUSBANDRY J. M. JONES, A. M.,Chief of Division; Sheep and Goats JAY L. LUSH, Ph. D., Animal Breeder (Genetics) FRANK GRAYSON, Wool Grader ENTOMOLOGY F. L. THOMAS, Ph. D., Chief State Entomologist H. J. REINHARD, B. S., Entomologist E. HOBBS, B. S., Asst. Entomologist of Division ; C. S. RUDE, B. S., Chief Foulbrood Inspector S. E. McGREGOR, JR., Apiary Inspector AGRONOMY E. B. REYNOLDS, M. S., Chief A. B. CONNER. M. S., Agronomist, Grain Sorghum Research A. H. LEIDIGH, M. S., Agronomist, Small Grain Research G. N. STROMAN, Ph. D., Agronomist, Cotton Breeding C. H. MAHONEY, B. S., Asst. in Cotton Breeding R. H. STANSEL, B. S., Asst. in Crops PLANT PATHOLOGY AND PHYSIOLOGY J. J. TAUBENHAUS, Ph. D.,Chief FARM AND RANCH ECONOMICS L. P. GABBARD, M. S., Chief B. YOUNGBLOOD, M. S., Ph. D., Farm and Ranch Economics V. L. CORY, M. S., Grazing Research Botanist (Sonora) **T. L. GASTON, JR., B. S., Assistant, Farm Records and Accounts "J. N. TATE, B. S., Asst. Ranch Records and Accounts **B. P. HARRISON, B. S., Collaborator SOIL SURVEY **W. T. CARTER, B. S., Chief H. W. HAWKER, Soil Surveyor E. H. TEMPLIN, B. S., Soil Surveyor BOTANY H. NESS, M. S., Chief PUBLICATIONS A. D. JACKSON, Chief SWINE HUSBANDRY FRED HALE, M. S., Swine Husbandman DAIRY I-IUSBANDRY —————,Chief POULTRY HUSBANDRY R. M. SHERWOOD, M. S., Chief MAIN STATION FARM D. T. KILLOUGH, M. S. Superintendent STATE APICULTURAL RESEARCH LAB- ORATORY (San Antonio) H. B. PARKS, B. S., Apiculturist in Charge A. H. ALEX, B. S., Queen Breeder FEED CONTROL SERVICE F. D. FULLER, M. S., Chief S. D. PEARCE, Secretary J. H. ROGERS, Feed Inspector W. H. WOOD, Feed Inspector G. M. MORRIS, B. S., Feed Inspector W. C. GAINEY, B. S., Feed Inspector K. L. KIRKLAND, B. S., Feed Inspector W. D. NORTHCUTT, JR., B. S., Feed Inspector SUBSTATIONS No. 1, Beeville, Bee County R. A. HALL, B. S., Superintendent No. 2, Troup, Smith County W. S. HOTCHKISS, Superintendent No. 3, Angleton, Brazoria County V. E. HAFNER, B. S., Superintendent No. 4, Beaumont, Jefferson County R. H. WYCHE, B. S., Superintendent No. 5, Temple, Bell County A. B. CRON, B. S., Superintendent No. 6, Denton, Denton County P. B. DUNKLE, B. S., Superintendent No. 7, Spur, Dickens County R. E. DICKSON, B. S., Superintendent No. 8. Lubbock, Lubbock County R. E. KARPER, B. S., Superintendent FRANK GAINES,Irrigationist and Forest Nurseryman No. 9, Balmorhea, Reeves County J. J. BAYLES, B. S., Superintendent MEMBERS OF TEACHING STAFF IN THE SCHOOL OF AGRICULTURE CARRYING No. 10, College Station, Brazos County, (Feeding and Breeding Station) R. M. SHERWOOD, M. S., Animal Hus- bandman in Charge of Farm L. J. McCALL, Farm Superintendent No. 11, Nacogdoches, Nacogdoches County G. T. McNESS, Superintendent **No. 12, Chillicothe, Hardeman County D. L. JONES, Superintendent "J. R. QUINBY, B. S., Scientific Assistant No. 14, Sonora, Sutton-Edwards Counties E. M. PETERS, B. S., Superintendent D. H. BENNETT, D. V. M., Veterinarian V. L. CORY, M. S., Grazing Research Botanist “O. G. BABCOCK, B. S., Collaborating Entomologist O. L. CARPENTER, Shepherd No. 15, Weslaco-Mercedes, I-Iidalgo County W. H. FRIEND, B. S., Superintendent A. T. POTTS, M. S., M. S. C., Citriculturist No. 16, Iowa Park, Wichita County E. J. WILSON, B. S., Superintendent COOPERATIVE PROJECTS G. W. ADRIANCE, M. S., Associate Profes- sor of Horticulture S. W. BILSING, Ph. D., Professor of Ento- mology F. A. BUECHEL, Ph. D., Professor of Agri- cultural Economics H. V. GEIB, B. S., Assistant Professor of Agronomy G. P. GROUT, M. S., Professor of Dairy Husbandry V. P. LEE, Ph. D., Professor of Agricul- tural Economics E. O. POLLOCK, A. M., Assistant Pro- fessor of Agronomy W. L. STANGEL, M. S., Professor of Animal Husbandry (Swine) R. C. WHITE, of Rural Sociology ‘Dean, School of Veterinary Medicine. “In cooperation with United States Department of Agriculture. M. A., Associate Professor SYNOPSIS _ 'I'~he purpose of this Bulletin is to report the heredi- tary behavior of two deficiencies in green coloring matter in seedling cotton. These two characters, one of which is yellow seed leaves instead of the usual green, and the other the lack of green color in certain portions of the seed leaves, are important defects not only because of their fundamental scientific interest but also because the pres- ence of these characters in a field of cotton lessens the stand and vigor of the plants. The two characters mentioned are shown to be in-‘ herited and the relations of the genetic factors concerned have been discovered. These factors thus form a true basis for future genetic work in cotton. The work presented herein is preliminary to and is only a small part of the genetic study of cotton which is being conducted at this Station. (3) CONTENTS W i, Introductory . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " Effects of the Amount of Cross-Fertilization in the Field upon the Val- 1. idity of the Data . . . . . . . . . . . . . . . ._. . . . . . . . . . . . . . . . . . . . . . . . . . . .. Nature of Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ~ - h Study of the Yellow Seedling Character . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 1, Segregation in a Sea Island by Burnett Cross . . . . . . . . . . . . . . . .. ‘Li’ Table 2, Segregation in an Egyptian by Mebane Cross, Family 218. . . . . Table 3, Segregation in an Egyptian by Mebane Cross, Family 22-221. . Table 4, Segregation in an Egyptian by Mebane Cross, Family 223.. ... "I Study of the Pattern Seedling Character . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 1, Chlorophyll Pattern in Cotton Seedlings . . . . . . . . . . . . . . . . . . .. Figure 2, Different Degrees of Expression for Pattern Characters . . . . .. i Figure 3, Showing Light Pattern Deficiencies . . . . . . . . . . . . . . . . . . . . . . . .. Inheritance of Pattern Seedlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. A Table 5, Segregation Summary of Family M6 . . . . . . . . . . . . . . . . . . . . . . Table 6, Genotypic Progeny Test for Family M6 . . . . . . . . . . . . . . . . . . . . . . . Table 7, Summary of Heterozygous Nature of Families M1 and M7. . . . . Table 8, Progeny Test for M1 and M7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 9, Families M1 and M7 Fitted to a Linkage Ratio . . . . . . . . . . . . . .. Table 10, Genotypic Progeny Test for Families M1 and M7 . . . . . . . . . . . .. 5 Table 11, Summary of Progeny Segregation in Family M10 . . . . . . . . . . .. Table 12, Genotypic Progeny Test for Family M10 . . . . . . . . . . . . . . . . . . . ff Table 13, Progeny Segregation of Family M15 . . . . . . . . . . . . . . . . . . . . . . .. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 14, Genotypic Progeny Test for Family M15 . . . . . . . . . . . . . . . . . . . .. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Appendix, Tables 15-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. (4) _ letin N0. 333 August, 1925 HERITABLE CHLOROPHYLL DEFICIENCIES IN SEEDLING COTTON G. N. Stroman and C. H. Mahoney * Chlorophyll deficiencies have been found in certain individuals of all _,}= plants which have been even partially genetically analyzed, and have fn observed in many others. Chlorophyll characters in maize occupy a ‘ther prominent place in genetic literature (Lindstrom, 1918, 1921; Em- on, 1923; Demeric, 1921; Stroman, 1924a, 1924b). _i Cotton has been studied genetically rather extensively but until now, '- one has reported deficiencies in the chlorophyll apparatus. The char- ters studied in cotton have been those of the adult plant and of the seed. work of Balls (1918) in Egypt; Fyson (1918); Leake (1920; Kottur 71921); and Prasas (1922) in India; and McLendon (1912), and Kearney 1923) in America show some interesting genetic behavior of the adult tton plant. l“ The object of this Bulletin is to report the presence of certain heritable lorophyll deficiencies in seedling cotton, and to give their genetic behavior Ix far as the results will justify at this time. » _ Elfects of the Amount of Cross Fertilization in the Field Upon the Validity of the Data Owing to the fact that the detailed data here presented on the genetic havior of these chlorophyll characters were obtained from plants that Q51- d been open-pollinated, it is necessary to estimate the amount of cross- llination occurring in the field at this Station during the season of 1924. Cotton pollen is sticky and therefore is not readily transported by the 'nd. As a result, cross-fertilization in cotton largely depends upon in- sects, especially bees (Allard, 1910). In the field in 1924 the writers ob- - very few bees, and these were bumble bees. Allard (1921) stated l if’ _at cross-fertilization in cotton was directly proportional to the number bees present. Parks (1921) found, however, that bees seldom visit the "tton bloom for pollen, and when collecting nectar, barely come in contact 'th the stamens and pistils. a The per cent of cross-fertilization in cotton has been estimated by sev- fral workers. Allard (1910), working in Georgia, gives figures showing .13 3 to'31 per cent of crossing between adjacent rows. He states that on an verage, 20 per cent of the bolls were affected by foreign pollen. His data, owever, fail to show the per cent of cross-fertilized ovules. Kearney 1923) notes that where insects are abundant, the amount of cross-fertili- ’ tion in cotton seldom exceeds 20 per cent. He also states that the av- 1 ge percentage of cross-fertilized ovules, under optimum conditions of oss-fertilization, was 12 per cent in Pima (Egyptian), and 28 per cent (5) 6-‘ ' i » BULLETIN NO. 333, TEXAS AGRICULTURAL EXPERIMENT STATION in Acala (upland). Kottur (1921) states that there is about 6 per cent of cross-fertilization in India cottons at Dwarwar, India. Balls (1918) in Egypt, as an average of a number of years, gives 13.5 per cent of cross- fertilization in cotton between adjacent rows. These observations of other workers are interesting, especially when compared with those made at this Station. In 1924, one row of material which was segregating for red and non-red or light-red plants was grown. Red plants have intensely red leaves and stems. The non-red or light-red types found in commercial varieties of up- land cotton have only faint traces of red at the base of the stem, on the branches, or on the petioles. In the greenhouse, seedlings of these latter types are totally devoid of red color; but the color appears in later stages. Seedlings of red plants, when grown 1n the greenhouse, have distinct red stems. From records of tests of these characters in the greenhouse, we can estimate the amount of cross-fertilization that occurred in 1924 at our Station. Family 241, (Egyptian), pure for non-red or light-red color, was grown in 3-foot rows alongside the red-stem plants above mentioned. Eighteen iprogenies from this family were tested in the greenhouse and over 50 seed- lings were grown from each progeny. Out of this total of about 2,000 seed- lings, not _a single red stem was observed. Families 247, 248, and 249 in the field, were segregating for red and non-red plants. In each family, we selected one non-red individual growing between two red-stem plants. The seeds from these non-red plants were grown in the greenhouse and the following counts made: Red. Stem Non-Red Stem 247(1) 1 65 248(3) 0 23 249(6) 1 77 Total 2 165 Per cent red stems : 1.17 Since the plants which furnished the pollen carrying the factor for red stems were heterozygous, it is necessary to double the observed per cent of red-stem seedlings thus giving 2.34 per cent of natural crossing in _ f these particular plants. (The color of red- and non-red-stem plants has been shown to be inherited in a simple monohybrid condition (Balls, 1918). Our data on this anthocyanin character, which will bepresented in a later bulletin, shows that here in these families there is one basic genetic factor for red- and non-red-stems present. This basic factor is designated herein as the Aa factor pair y A Further evidence of crossing in the field in 1924 is found in the progeny of two plants pure for non-red-stem seedlings. These two plants, 249(12) and 249(13), grew side by side and 3 feet apart in the row. Now, on the west side of 249(12) was 249(11), which was heterozygous for the Aa factor pair, and on the east side of 249(13) grew 249(14), also heterozygous for the HERITABLE CHLOROPHYLL DEFICIENCIES IN SEEDLING COTTON 7 VA factor. Seedlings grown from 249(12) and 249(13) totaled 366, of which "- nly 3 were red stems. This is 0.82 per cent of observed crossing under con- itions as stated above. We could actually observe only the crossing which _ sulted from the A male gamete. There were only one-fourth as many male {Fgametes of the A type as there were of the a type. Therefore, the theoret- e I ical amount of natural crossing was four times 0.82 per cent of 3.28 per cent. Another plant pure for non-red-stem seedlings, 250(1), throws some 1 urther light on the amount of crossing in the field during the season of 924. On one side of this grew a plant that was pure for red-stem seed- glmgs and on_ the other, one heterozygous for the A factor. Hence three- {fourths of the adjacent male gametes were of the A type and one-fourth of lithe a type. Here three-fourths of the crossing could be observed. One hundred and fifty-one seedlings from 250(1) were grown, of which 2 had cred stems. This is 1.32 per cent, or a theoretical adjacent natural crossing of 1.76 per cent. f“ Averaging the theoretical per cents of natural cross-fertilization shown igabove, 2.34, 3.28, and 1.76 per cents we have 2.46 per cent of cross-fertili- Y zation taking place between adjacent plants in the same row in the season v- of 1924 at College Station. i From these observations it is our opinion that the amount of cross~ f fertilization in 1924, though somewhat variable, was, in general, not large ; enough to affect seriously the value of the genetic data obtained from open pollinated seed. Nature of Material v In the fall of 1923, when this work began, seven hybrid rows of cotton were growing in the genetic garden, and from these the material for the p study of yellow seedlings was taken. The majority of these hybrids were Egyptian-upland crosses. Yellow seedlings were found in the F. from these _ crosses. The pattern character was found to be present not only in the descendants of these seven rows but also in nearly all other material tested 17in the greenhouse during the winter of 1923-24. Study of the Yellow Seedling Character A, This character is present in the seedling stage only, and such seedlings die as soon as the stored food of the seed has been used up. It appears as a very light greenish yellow in the young cotyledons as they push i through the surface of the soil. The small amount of green pigment soon disappears and the color of the cotyledons becomes a distinct yellow. In gsome families a portion of the yellow has been observed to disappear from tthe base of the leaf, thus leaving pure whitish areas. The cotyledons turn iii-entirely white toward the end of the life of the seedling, which is about ;_twelve days when grown in pure sand. A _ From a cross of Sea Island with Burnett made in 1922 by Dr. Geo. F. Freeman at this Station, the progeny of one F1 plant growing in the field in 51923 was found to be segregating for yellow seedlings in a proportion of jf‘,'63 green seedlings to 4 yellow. This is close to a 15:1 ratio. The seed from 8 BULLETIN NO. 333, TEXAS AGRICULTURAL EXPERIMENTSTATION thirteen of these green plants were planted in the greenhouse in the win- ter of 1924-1925. The counts of the progenies are found_ in Table 1. TABLE 1 Segregation of non-yellow and yellow seedlings in F, pro-l genies of a Sea Island by Burnett (upland) cross Family 216 and Family 217 Non-Yellow I Yellow I Appfzjfifate Plant No. 216(1) 13 0 pure (2) 23 0 pure (4) 20 3 15:1 (6) 16 0 pure (7) 20 0 pure (8) 116 ' 43 3:1 (12) 335 0 _ pure (13) 7 0 pure (14) 199 0 pure (17) 43 4 15:1 217(1) 16 1 15:1 (2) 95 3 15:1 (4) 140 0 pure Only one 3:1 ratio was observed (216-8) with 116 non-yellows to 43 yellows. Four progenies showing 15:1 ratios were found (216-4, 21647, 217-1 and 217-2) with a total of 174 non-yellows to 11 yellows. This is almost perfect for a 15:1 ratio. There were 8 progenies not segregating for yellow seedling. If the original parent of these progenies was heterozygous for two factors and if the double recessive condition only permits the expression of the yellow seedlings, we would expect seven progenies giving only-non- yellows, four giving 3:1 ratios, and four giving 15:1 ratios of non-yellow to yellow seedlings. ment with the expected p = 0.32. . Further evidence that yellow seedlings are determined by the double re- A cessive condition of two factors comes from three separate crosses studied among numerous crosses of Egyptian with Mebane. A field count of the progeny of an F, plant from one of these crosses gave 76 non-yellows to 4 yellows. This approximates a 15:1 ratio. The seed of nine of these non-yellow plants were grown in the greenhouse and counts made as to character of seedling. The counts are found in Table 2. One progeny, 218-10, gave a 3:1 ratio or a total of 87 non-yellows to 22 yellows, with a deviation only 1.42 times the probable error from the calculated ratio. This indicates a fair probability that the deviation is due to random sampling. Three progenies segregating into 15:1 ratios, with a total of 221 non-yellows and 9 yellows are also shown. The deviation from’ -- - a 15:1 ratio is 5, the probable error is 2.48, and the deviation divided by the probable error is 2.02. This is only a fair agreement between observed and expected ratios. l We obtained eight non-yellow progenies to one progeny giving a 3:1 ratio to four progenies giving a 15:1 ratio. This is a fair agree- \_ Wwpww. : _ ‘M! a. ~30.‘ "F fiwyngd» i: 1pm: t ,3 t I. HERITABLE CHLOROPHYLL DEFICIENCIES IN SEEDLING COTTON 9 TABLE 2 Segregation of non-yellow and yellow seedlings in F3 pro- genies of an Egyptian by Mebane (Upland) cross Family 218 P1 l. Approximate ant No. Non-Yellow ‘ Yellow Ratio 218(2) 48 1 0 pure (3) 19 t 1 15:1 (10) 87 Z2 3:1 (11) 173 1 6 15 =1 (13) 25 0 pure (15) 29 2 15:1 (16) 96 - 0 pure (19) 14 0 pure (20) 83 x 0 pure Only nine progenies are shown in Table 2 but the observed ratio of gen- otypes is close to the expected ratio. If the parent plant was heterozygous for two factors as was indicated, we should expect a ratio of seven pro- genies pure for non-yellow, four progenies giving 3:1 ratios, and four pro- genies giving 15:1 ratios. We observed five progenies pure for non-yel- low, one progeny giving a 3:1 ratio, and three giving 15:1 ratios, which ap- proxirnates the expectation. v The second representative of the Egyptian with Mebane crosses (19-2 selfed seed) gave 86 non-yellow and 6 yellow seedlings in the F2 genera- tion. This is a 15:1 ratio of non-yellow to yellow seedlings. The counts of sixteen progenies from this plant are found in Table 3. TABLE 3 Segregation of non-yellow and yellow seedlings in F3 pro- genies of an Egyptian by Mebane (Upland) cross Family 220 and Family 221 Plant No. Non-Yellow Yellow Applrggilirglate 220(2) 45 0 pure (3) 3 0 pure (4) pure (6) 15 1 15:1 (8) 12 1 15 :1 (11) 78 1 15:1 (19) 14 0 pure (21) 26 3 15:1 (24) 10 0 pure (28) 38 1 15:1 (29) 43 0 pure (30) 13 0 pure (32) 57 0 pure 221(3) 33 0 pure (4) 70 2 15:1 (2) 43 0 pure 1Q BULLETIN NO. 333, TEXAS AGRICULTURAL EXPERIMENT STATION The data are similar to those presented in Table 2 with the exception that no 3:1 ratios are found. The total for those progenies segregating gives 239 non-yellow to 9 yellow seedlings. The deviation for this ratio is six and this divided by the P. E. is 2.33. Ten progenies not segregating and six segregating are given. No 3:1 ratios were obtained. The number of progenies is too small to justify any estimate as to whether the non-ap- pearance of 3:1 ratios among them is significant. The deviations from a 15:1 ratio, shown in Table 3, may be accidental. The third representative of the Egyptian by Mebane crosses is the fam- ily of 19-25, selfed seed. This plant gave, in the field F; counts of 57 non- yellows and two yellows. The seed from seventeen of these non-yellow plants were planted in the greenhouse and the data are found in Table 4. TABLE 4 Segregation of non-yellow and yellow seedlings in F3 pro- genies of an Egyptian by Mebane (Upland) cross Family 223 ‘ Approximate Plant N0. Non-Yellow l Yellow Ratio l 223(1) l 36 1 15:1 (3) l 24 0 pure (4) l 21 0 pure (5) 49 l 8 15:1 (6) 43 O pure (7) 19 l 1 15:1 (s) l 43 i 1 , 15=1 (9) l l1 l 0 pure (l0) l 2:} l 0 pure <12) l 47 l a 15=1 (13) l 29 l O pure (14) 65 2 15:1 (1~' ) 103 l 0 l pure (17) l 24 l 2 15:1 (18) l 24 3 l 15:1 (l9) l 12 l 0 pure (20) l 2t) l 0 l pure l l Again, no 3:1 ratios of non-yellow to yellow seedlings were observed. The total of these progenies segregating gives 307 non-yellow to 21 yel- low seedlings. This is a 15:1 ratio. ‘There are nine progenies pure for non- yellow and eight progenies segregating. The absence of 3:1 ratios in this family, as well as in the preceding family may possibly be significant, but the present data are insufficient to establish this fact. It is clear, however, that there are two factor pairs in- volved in the production of yellow seedlings, which will be designated in later writings as Y1 y1 Y2 y: Study of the Pattern Seedling Character This type of chlorophyll deficiency is shown by certain areas devoid of green color on the young cotyledons, surrounded by normal green pigment. These areas are not of any uniform shape, but extend usually from the ex- HERITABLE CHLOROPHYLL DEFICIENCIES IN SEEDLING COTTON 11 treme edge half way across the leaf (Fig. 1). The pattern seems to start at the edge of the leaf and in some cases occurs only at this point (Fig. 2). In some families the deficient areas are a rich yellow, and in other families they are white. The light pattern is so called because the young leaves contain areas of light greenish color instead of a yellow or white color (Fig. 3). These light paterns also vary in their area of ex- pression. In some, the areas are as large as the true patterns; but where there is a trace of chlorophyll present in the deficient area, the seedling is classed as a light pattern. There are others that appear more or less mottled, and that have light greenish to greenish yellow areas throughout the green pigment of the leaf. These are called light patterns also. Figure 1. The chlorophyll pattern character in cotton seedlings. From actual observations, and from the data presented, it seems that these pattern types of cotyledons never mature but observations are con- fined to field tests in the spring of 1924, which was very unfavorable for the growth of young seedlings in the field. This may account for the fact that there are no light pattern or pure pattern seedlings that developed to produce seed. Most of the patterns are of a defective nature, and while they are not f totally without chlorophyll, it may be that there is such a decrease in the number of chloroplasts that the seedling must depend mostly upon the food stored up in the seed. ' 121 BULLETIN NO. 333, TEXAS AGRICULTURAL EXPERIMENTSTATION u Figure 2. Showing different degrees of expression of pattern character, pure pattern on right, light pattern in center, and normal green leaf on left. Figure 3. Seedlings showing the light pattern deficiency. Note absence of dark green color. HERTTABLE CHLOROPHYLL DEFICIENCIES IN SEEDLING COTTON 13 Inheritance of Pattern Seedling p, The families that are presented to show the genetic behavior of this acter are selections of 1923, made in the course of the plant-breeding , “i of the Station. They were observed in the greenhouse during the 'ter of 1923-1924 to be segregating for patterns. These strains were ‘ted in the field in 1924 and progeny tests made in the greenhouse the j er of 1924-1925. The first evidence that will be presented is from family M6. The de- "-- data for this family are shown in Table 15 (appendix) and the sum- l - of results in Table 5. ‘ TABLE 5 » Summary of family M6 -‘_ ogenies segregating for two factors i l Dark Light Light ; greens greens patterns Patterns I Total 1 r ‘observed . . . . . . . . 16s I 64 ( 54 19 | 30a i ted 913:3 :1 . . . . . 170 | 5'7 57 19 I 303 I 4 ‘ 7 i 3 0 _ enies segregating for one factor l , g Greens Light greens or light patterns I observed . . . . . . . . .. 188 58 247 '-- ted 3:1 . . . . . . . . .. I 62 247 ere are two kinds of ratios obtained in this family. When all four ‘i: dark greens, light greens, light patterns, and patterns, appeared same progeny the classes could be separated easily enough, but when f» defiicient character was present in one progeny the distinction _i n the light green and the light pattern was impossible so that light and light patterns have been grouped together in one class in the part of table 5. r the progenies giving 9:3:3:1: ratio, the observed numbers agree ex- well with the expected numbers, the probability being 0.78; and _e progenies giving a 3:1 ratio of greens to patterns the agreement is i d, the Dev. being 0.65. ' results of the genotypic progeny test of this family is given in hand agree well with the expectation. The factors responsible for in this family have been designated as C1 and C2. 14 BULLETIN NO. 333, TEXAS AGRICULTURAL EXPERIMENTSTATION TABLE 6 Genotypic progeny test for family M6 segregating for normal and chlorophyll pattern seedlings Ratio Genotypes l Observed Calculated l Deviation l l l l 1 l C1C1C2C2 l l l 1 .2 l . 2 l l I 2 ClClCgcL, 5 4 8 .2 2 ClclCaCfl ' l ' 1 l 4 ClclCzcg 5 4 . 8 . 2 l _ _ _ _"_‘i_i‘____i___i_‘__j_g""f;t'f_ {__ ‘T ii- x” : 0.6 Further evidence that the pattern character is caused by two recessive factors is found in families M1 and M7. The detailed data for these fam- ilies are given in Tables 16 and 17. The results of the progeny test are given in Table 8. A summary of the two families is given in Table 7. TABLE 7 Summary of two families, M1 and M7 1. Progenies heterozygous for one factor __€______ -—— Pmgeny numbers M1-1, 5, e, 10, 14, 2o, and ‘MT-ll, e, 10, 11, 14 l Greens l Patterns l Total I Total Observed . . . . . . . . . . . . . . . .. 436 l 162 598 Calculated 3 :1 . . . . . . . . . . . . . . . . .. 448 150 598 Deviation . . . . . . . . . . . . . . . . . . . . . . -—-12 l 12 l Dev. I 1 . '7 P.E. 2. Progenies heterozygous for two factors Total observed . . . . . . . . . . . . . . . . . . 442 285 727 Calculated 9 :7 . . . . . . . .‘ . . . . . . . . .. 409 318 , 727 Deviation 33 I -—33 Dev. I 3.7 P.E. The observed ratios agreed fairly well with the expected, i. e., those progenies segregating for one factor agreed fairly well with a calculated 3:1 ratio of greens to patterns, while those progenies which apparently seg- regated for two factors do not agree very closely with a 9:7 ratio of greens to patterns. It is possible that this deviation may be due to a small amount of crossing in the field, which would affect those progenies segregating for two factors more so than those segregating for only one factor. The de- Efiimsamtmmnl _ , HERITABLE CHLOROPHYLL DEFICIENCIES IN SEEDLING COTTON 15 TABLE 8 Progeny test for families M1 and M7 ' tio ‘ Genotypes Observed [ Calculated Deviation I 0101020, 1 ( 3 l 2 I . I 0,0102% 12 1 1 1 01010202 I | 01c102c, 12 11 || 1 _ I I 1.52 .48 O n may also be due to linkage, and for the purpose of comparison the are fitted to a 33 per cent crossing-over ratio as is given in Tables 9 710. _ ‘ TABLE 9 a, Summary of families M1 and M7 fitted to a linkage ratio vlnies M1-2, 4, 12, 1s, 19, and M 7-1, s, 5, 9, 15, 16, 1'1 I a ! Greens ; Patterns Total iobserved . . . . . . . . . . . . . . . . . . 442 i 22s 727 ted 22:14 ratio 33% C. O. . ..] 444 \ 283 727 j ‘n . . . . . . . . . . . . . . . . . . . . . .| -_2 2 4- I l y‘ v. 2 T I ——-——- I 0.22 .E. 8 9 TABLE 10 Genotypic progeny test for families M1 and M7 based on 33% 0. O. tio Genotypes Observed Calculated V Deviation clclczc, 1 a 4. 4 a . 4 c,c,c,¢, 12 8 . 8 3 . 2 CICICQCZ . | | 01c102c2 12 1 1.0 1.0 I . V oI1s _ "e results of the progeny tests, on the assumption of factor inde- lce, are given in Table 8, and show fair agreement between observed and f d ratios with p : 0.48. The agreement, however, between observed 16 BULLETIN NO. 333, TEXAS AGRICULTURAL EXPERIMENT STATION and expected ratios based upon linkage is poor; e. g., Table 10 shows only a p —_— 0.15. This leaves it doubtful whether or not linkage really exists be- tween these two factors. If it does exist, at least one of the factors in families M1 and M7 must be different from either of those acting in M6. Other evidence showing that the pattern seedling character is dependent upon two genetic factors is found in family M10. The summary of this family is given in Table 11. The detailed data are given in Table 18. TABLE 11 Summary of family M10 1. Showing segregation of progenies M 104, 5, 10, 11, 13, 19’ and 20 a Greens l Patterns i1 Total I l I I I Total observed . . . . . . . . . . . . . . . 266 l 72 I 338 Calculated 3:1 ratio . . . . . . . . . . . .. 254 | 84 I 338 Deviation . . . . . . . . . . . . . . . . . . . . . 12 I ~——12 Dev. 12 -—— I i I Z . Z P.E. 5 . 4 2. Showing segregation of progenies M 104, 6, 9, 12, 13, 14, and 16 . l ) Total observed . . . . . . . . . . . . . . . . .. 224 I 122 346 Calculated 9 . 7 ratio . . . _ . . . . . . . . . 195 | 151 I 346 Deviation . . . . . . . . . . . . . . . . . . . . . . 29 ] ~29 g l Dev. 29 ——- : ———— I 4 . 7 Hgzrs- 6-2 The observed ratios agree with the expected ratios only fairly well in the case of the 3:1 ratios of greens to patterns and poorly in the case of the 9:7 ratios of greens to patterns. If some of the progenies classified as giving a 9:7 ratio should have been classified as giving a 3:1 ratio (for ex- ample family M10-16) then the actual data fit the hypothesis better than these figures would indicate. TABLE 12 Segregating for normal and chlorophyll pattern seedlings Ratio Genotypes l Observed Calculated O-C r l 1 _ 01010202 1 0 1 . 56 1.56 I 2 0101C2c2 7 6 . 24 0 76 2 C1c1C2C2 I 4 C1c1C2c2 g 7 6 . 24 0 . 7 6 X2 : 1.7452 : 0.4286 HERITABLE CHLOROPHYLL DEFICIENCIES IN SEEDLING COTTON 17 H The progeny tests (Table 12) give no pure green progenies, which may sibly be due to the small number of progenies. There were seven pro- “es that gave 3 greens to 1 pattern, and seven progenies that gave 9 ns to 7 patterns.’ There were no progenies that gave pure patterns. The rved numbers agree fairly well with the expected with a P = 0.43. The inheritance of the pattern character in another family M15 is some- f»: different from any that have yet been presented. The parent of this _i1y came from a field of Mebane cotton but acts somewhat differently in the way families M1 and M7 act. The summary data of this family presented in Table 13, the detailed data in Table 19, and the progeny in Table 14. “ TABLE 1s KhOWiHE segregation of progenies M 154’ 2, 3, 6, and 19 l Greens Patterns i Total i i _ observed . . . . . . . . . . . . . . . . . . 326 88 414 ted 3:1 ratio . . . . . . . . . . . . . -311 103 I 414 , ‘tion . . . . . . . . . . . . . . . . . . . . .. 15 -15 | » l I I ‘Dev. 15 3y I i I 2 . 5 ;_P.E. 5 . 9 fig?» owing segregation Of progenies M15_8, 10’ 11, 12, 13’ 14’ 17, and 18 I l I _ observed . . . . . . . . . . . . . . . . . .| 498 326 824 ted 9 :7 ratio . . . . . . . . . . . . . . 464 360 824 _' tion . . . . . . . . . . . . . . . . . . . . . . 34 ~—34 I _ev. s4 , I -—-— I 3 . 5 .E. 9 . 6 owing segregation of progenies M15, 9, 15’ and 16 | 1 7observed . . . . . . . . . . . . . . . . . . 146 183 329 " ted 27:37 ratio . . . . . . . . . . .. 139 190 329 ’ ion . . . . . . . . . . . . . . . . . . . . . . 7 —7 ». 1 ' may be seen in the above family that there is, in addition to the C2 factors for pattern seedlings which have been discussed, a third I that, when recessive, produces pattern seedlings. This factor, when t with both c1 and c2, is shown above to produce 27:37 ratios. ACKNOWLEDGEMENT R writers acknowledge their gratitude to Dr. J. L. Lush of this Sta- “_ d to Dr. O. M. Ball, Head of the Biology Department of the College,' ir valuable criticisms and helpful suggestions. 18 BULLETIN NO. 333, TEXAS AGRICULTURAL EXPERIMENT STATION TABLE 14 Genotypic progeny test for family M15 Segregating for normal and chlorophyll pattern seedlings Ratio I Genotypes I Observed Calculated Deviation 1 C C C.,C C C 0 . 63 . 63 1 1 .. 2 3 3 I ._____._ -___|. <__ __ _ __ > ___ r_l _1_ __ 2 | C1C1C2C2C3c3 2 | Iqclczc. 03c, s 3 . 7 s 1 .22 2 [I clclczcjcsc, I m?” T LT“ § d Va 7 W n 4 | C1C1C2c2C3c3 4 I C1c1C2C2C3c3 8 7 .56 . 4 4 4 I ClclCzcgCaCs I I I I I I I 8 I ClclCzczCacs | 4 I 5. 04 I 1.04 I I I I X" = 1.2650 J. P —_— 0.740s ,- SUMMARY 1. An estimation of the amount of cross-fertilization in cotton in field in the season of 1924 is given to be 2.46 per cent. However, the amoh} of this cross-fertilization varied in different plants. 2. A type of seedling which is yellow in color and contains onl small amount of chlorophyll is reported. The presence of two reces genetic factors Y2 and y; is shown to be necessary for the expression of 1f character. . 3. The “pattern”, which is another chlorophyll deficient seedl'l ranges from a seedling with distinct areas devoid of chlorophyll to 3 which has a small amount of chlorophyll throughout the leaf. The exp sion of this character is shown to be responsible to one, two, and possi three different genetic factors, i. e., 3:1, 9:7, and 27:37 ratios were f =3 present in different and in the same families. Also there is a slight p0 bility that two of these factors are linked. HERITABLE CHLOROPHYLL DEFICIENCIES IN SEEDLING COTTON 19 LITERATURE CITED Allard, H. A. 1910 Preliminary observations concerning natural crossing in cotton. Am. Breed. Mag. 1:24—261. 1918 The cotton plant in Egypt. Macmillan and C0., pp. 1923 Inheritance of white seedlings in maize. Genetics merson R. A. 1923 Inheritance of blotched leaf in maize. Cornell Agr. ' Exp. Sta. Memoir 70:1——16. Fyson, P. F." 1908 Some experiments in hybridizing of Indian cottons. I Mem. Dept. Agric. India, Bot. Series II-No. 6. arney, T. H. 1923 Self-fertilization and cross-fertilization in Pima cot- ton. U. S. D. A. Dept. Bull. 1134. _ ottur, G. L. 1921 Cross-fertilization and sterility in cotton. Agric. J our. ‘ India, 16: Part I. - ake, H. M. 1920 Report on the maintenance and improvement of the %uality of Egyptian cotton and the increase of its yield. Min. of Agric. E gypt. iindstrom, E. W. 1918 Chlorophyll inheritance in maize. Cornell Univ. ‘ Agric. Exp. Sta. Memoir 13: 1——68. 1921 Concerning the inheritance of green and yellow pigments in maize seedlings. "Genetics 6: 91—110. arkJs, H. B. 1921 The cotton plant as a source of nectar. Am. Bee. a our. 51. 1‘ asas, Ram. 1922 Note on the probability of an inter-relation between ‘ the length of the stigma and that of the fiber in some forms of the p genus Gossypium. Agric. Res. Inst. Pusa Bull. 137. roman, G. N. 1924a Genetic relation of chlorophyll and anthocyanin ' seedling characters in maize. Genetics 9: 91-123. 1924b The inheritance of certain chlorophyll characters in maize. Genetics 9:493—~512. » 2Q BULLETIN N0. 333, TEXAS AGRICULTURAL EXPERIMENT STATION APPENDIX TABLES 15 TO 19 TABLE 15 Segregation of progenies for pattern and green seedlings 1. Those progenies segregating for two factors Data for family M6 Pedigree Dark Light l Light Approximate number greens greens patterns ~ Patterns / ratio (1) 43 19 16 8 9:3:3:1 (3 ) 17 8 8 4 9 :3 :3 :1 (4) all green —- —- -- p re (5) 3 1 13 8 2 9 :3 :3 :1 (6) 40 11 10 3 9:3:3:1 (7) 35 13 12 2 9:3:3:1 2. Those progenies segregating for one factor Dark I Light greens or greens light patterns g Approximate ratios I (8) . 34 1 3 8 :1 ( 1 0) 37 6 3 :1 ( 14) 24 1 1 3 . 1 ( 19 ) 42 33 9 :7 (2 0) 5 1 g 6 1 5 :1 TABLE 1 6 Segregation of progenies for pattern and green seedlings Data for family M1 Plant Nmmal Patterns fgptlicf ofiigitfs Number Greens to Patterns (1) 33 11 3:1 (2) 44 26 9:7 (4) 14 10 9:7 (5) 29 8 3:1 (6) 56 18 3 1 (10) 13 3 3:1 (12) 45 25 9:7 (13) 35 23 9'7 (14) 25 8 3 1 (17) 47 14 8:1 (19) 56 30 9:7 (20) 6 2 3:1 HERTTABLE CHLOROPHYLL DEFICIENCIES IN SEEDLING COTTON 21 TABLE 17 Segregation of progenies for pattern and green seedlings Data for family M7 Plant Normal Approximate Number Greens Patterns atio l (1) 30 17 ( 9:7 (3) 45 27 9:7 (4) 47 25 3:1 (5) 32 24 9:7 (6) 57 31 3:1 (9) 54 31 9:7 (10) 43 17 3:1 (11) 48 14 3:1 (13) all green — (14) 32 11 3:1 (15) 42 25 9:7 (16) 20 26 9:7 (17) 25 21 9:7 TABLE 18 Segregation of progenies for pattern and green seedlings Data for family M10 Plant Normal Approximate Number Greens Patterns Ratio (1) 39 11 3:1 (4) 28 14 9:7 (5) 45 12 3:1 (6) 53 24 9:7 (9) 27 23 9:7 (10) 31 8 - 3:1 (11) 55 9 3:1 (12) 31 14 9:7 (13) 38 26 9:7 (19) 44 12 3:1 (14) 29 13 9:7 (16) 18 8 9:7 (18) 26 10 3:1 (20) 26 10 3:1 22 BULLETIN NO. 333, TEXAS AGRICULTURAL EXPERIMENT ‘(STATION _ TABLE 19 Segregation of progenies for pattern and green seedlings Data for family M15 I Plant Normal Approximate Number r Greens Patterns l Ratio I I <1) 67 12 | 3:1 (2) 97 24 I 3:1 (3) 59 21 | 3:1 (4) 55 62 I 27:37 (6) 49 19 3:1 (8) 69 52 ( 9:7 (9) 32 37 27:37 (10) 43 29 9 :7 (11) 158 83 9:7 (12) 46 ‘ 38 9:7 (13) 36 30 9:7 (14) 43 36 9:7 (15) 26 43 27:37 (16) 33 41 27:37 (17) 49 2s | 9:7 (18) 54 30 I 9:7 (19) 64 12 l] 3 :1