Genetic characterizations of three male-steriles in wheat, Triticum aestivum L. by Duane Lee Johnson A thesis submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Crop and Soil Science Montana State University © Copyright by Duane Lee Johnson (1978) Abstract: Male-sterility provides a quick and easy way to formulate genetic recombination in wheat. The inheritance and chromosome involvement of two spontaneous male-sterile mutants in 'Siete Cerros' spring wheat and a single gene male-sterile in 'Chancellor' winter wheat were studied. Chi square analyses of homogeneous F2, F3, F4, and F5 families were made for various expected ratios for the three male-sterile sources using spring and winter grown populations. Selections made from the 41 original sibcrossed families of the Siete Cerros mutants were evaluated as spring grown F3, F4 and F5 headrows. F2 and F3 plantrows of Chancellor male-sterile x various winter wheats were evaluated as winter wheats. An abnormal 7:1 segregation predominated in most Siete Cerros families with an unexpected high number of nonsegregating headrows. One family of the original 41 segregated for male-sterility as a single recessive allele. The influence of background genotype on the Chancellor male sterility was attributed to a superior gene(s) in the parental cultivars. Monosomic analyses of the three male sterile sources suggested complex inheritance. The male-sterile expression in Siete Cerros may be due to aneuploidy or gamete lethality. The major factor controlling male-sterility in Chancellor confirmed the results of Driscoll (10) as being associated with chromosome 4A. Five additional chromosomes may also be involved. i DEDICATION This thesis is dedicated to the memory of C. A. Suneson, pioneer of genetic male sterility in small grains. GENETIC CHARACTERIZATIONS OF THREE MALE-STERILES IN WHEAT, Triticum aestivum L. by DUANE LEE JOHNSON A thesis submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Crop and Soil Science Approved: MONTANA STATE UNIVERSITY Bozeman, Montana June, 1978 iv ACKNOWLEDGMENTS The author wishes to extend his deepest gratitude to Dr. G. Allan .Taylor for his advice, guidance and support in the course of this study 'and the preparation of this manuscript. The writer also expresses his appreciation to Professor Robert E . Eslick for his interest and support during the course of this study. The author also wishes to thank the other members of his examining committee, Drs. Raymond L. Ditterline, Harry McNeal, and Don E . Mathre, x. for their help and tolerance. Thanks are expressed to Mr* Duane E . Falk. His ideas and assis- ■ tance were invaluable in the pursuance of this investigation. The author would also like to thank Mr. G. Hollis Spitler and the wheat crew for their assistance in the field and greenhouse research, the excellent typing of Mrs. Homer (Jean) Julian,, and the Montana Wheat Research and Marketing Committee without whose assistantship the pur­ suit of this degree would have been impossible. Special gratitude is extended to my wife, Janet, and to my parents for their patience, encouragement and support in the completion of this degree. TABLE OF CONTENTS Page DEDICATION .......................'................... . V I T A .................................. . . . . ' . .......... i iii ACKNOWLEDGMENT.................... '........... iv TABLE OF CONTENTS .............'........................ LIST OF TABLES . ...........................' ........ .. . . v vii LIST OF FIGURES . .'.................... l . .......... . ABSTRACT ......... INTRODUCTION x xi . ............................................. I LITERATURE REVIEW .......................................... 3 Male S t e r i l i t y .......................................... History .............................................. Cytoplasmic Male-Sterility................ . Genetic Male-Sterility ................................ Genetic Male Sterility in Wheat ................ .. . Types and Patterns of GMS in W h e a t .................... 3 3 4 5 6. 7 Monosomic A n a l y s i s ...................................... . Aneuploidy - A.Genetic and Plant Breeding Tool . . . . . Monosomies - Cytological Problems ..................... 9 9 11 Study I. The Inheritance of Genetic Male-Sterility in Siete Cerros and Chancellor ........ . . . . . MATERIALS AND METHODS . . .............^......... ' ........ .. Genetic Materials.......................... Siete Cerros .....................* ............. .Chancellor............ ;■ Cytologic and Genetic P r o c e d u r e s ......... 13 14 14 14 14 15 Greenhouse Procedures............................ . . . .. . 17. Field P r o c e d u r e s .................... 18. vi Page RESULTS AND DISCUSSION. . . . . . . The Siete Cerros Male-Steriles ........................ ................ 21 Chancellor Male-Sterile .................................. 33 Allelism Tests Among Selected Families of the ■.Three Male-Steriles . ............................ .. . . . 38 Study II. ...... 21 Monosomic Analyses.......................... 42 MATERIALS AND M E T H O D S .................. Genetic Stocks 43 .......................................... 43 Field and Greenhouse Procedures.......................... 43 RESULTS AND DISCUSSION .................................... 44 Siete C e r r o s .............. 44 C h a n c e l l o r .......................... 46 GENERAL DISCUSSION ........................................ 48 The Inheritance of Genetic Male-Sterility in Siete Cerros and Chancellor............ ............. .. . Siete Cerros ................ Chancellor . . . . . . .................... REFERENCES .......................... APPENDIX ............................ ......... ' . . . . . V 48 48 49 51 ■ 59 vii ■ LIST OF TABLES Table I- 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. . Page Allelism tests between meiotically normal Siete Cerros A and B .......................... . 21 Siete Cerros A family fertile and male-sterile segregation and associated probability values for genetic ratios ............... 23 Siete Cerros B F^- family:fertile and male-sterile segregation and associated probability values for three genetic ratios . . . ........................... 24 Siete Cerros A F^ family:fertile and male-sterile segregation and associated probability values for four genetic r a t i o s ............................ 25 Siete Cerros B F^ family:fertile and male-sterile segregation and associated probability values for four genetic r a t i o s ................................ 26 Number of Siete Cerros A F^ headrows best fitting five genetic r a t i o s .................. 27 Number of Siete Cerros B F^ headrows best fitting five genetic ratios . . . . ; ................ 28 Siete Cerros A F^ family:fertile and male-sterile segregation and associated probability values for four genetic r a t i o s ................................ 29 Siete Cerros B F^ family fertile and male-sterile segregation and associated probability values for four genetic r a t i o s ............................ 30 Field grown F^ headrow distributions within families of Siete Cerros A for four genetic ratios of fertile: malersterile . ....................................... 31 Field grown F^ headrow distributions within families of Siete Cerros B for four genetic ratios of fertile: male-sterile................................ 32 viii Table . Page headrow distributions of greenhouse-grown Siete Cerros A and B families for four genetic ratios of fertile:male-sterile .............................. 34 F,_ headrow distribution of greenhouse-grown Siete Cerros A and B families for various genetic ratios of fertile:male-sterile . . ...................... 35 Siete Cerros spring wheat ms A and ms B x HRWW grown as F^ spring and winter wheats . . ........ 36 Probability of fit for ms C/Centurk F progeny using chi square tests of heterogeneity and goodness of f i t .................. ............... 37 Chi square test for heterogeneity for F populations of ms C x HRWW and ms C x HRSW .................... 38 Probability, values for six genetic ratios in ms C/ winter wheat F families using chi square tests of goodness of fit ................................ 39 Probability values for six genetic ratios in ms C/ spring wheat F 's.using chi square tests of goodness of fit . . . ....................................... 40 Allelism tests between Siete Cerros male-sterile A-1, A-3, B-20 and Chancellor male-sterile .' . . 41 20. Chromosome location of Siete Cerros ms A-I . . . 45 12 . 13. 14. 15. 16. 17. 18. 19. 21. Chromosome.location pf Siete Cerros male-sterile A-3 .............................. .. 45 22. Chromosome location of Siete Cerros ms B-20 .46 23. 47 Chromosome location of ms C ix Appendix Tables 1. 2. 3. 4. 5. Page Allelism tests of Chancellor male-sterile and other male-sterile sources...................... 60 Fertile and male-sterile progeny of heterozygous Siete Cerros ms A-I x monosomies ........ . . . . . . 61 Fertile and male-sterile progeny of heterozygous Siete CerrOs ms x Rescue monosomies . . . . . . . . . 61 Fertile and male-sterile progeny of heterozygous Siete Cerros ms B-20 x m o n o s o m i e s ........ '......... 62 Fertile and male-sterile progeny of heterozygous Chancellor male-sterile x monosomies ................... 63 X LIST OF FIGURES Figure I. Page Generation procedures for Siete Cerros A and B . . . . 16 xi ABSTRACT MaIe-sterility provides a quick and easy way to formulate genetic recombination in wheat. The inheritance and chromosome involvement of two spontaneous male-sterile mutants in 'Siete Cerros * spring wheat and a single gene male-sterile in 'Chancellor' winter wheat were studied. Chi square analyses of homogeneous F^, F3, F4 , and F families were made for various expected ratios for the three male-sterile sources using spring and winter grown populations. Selections made from the 41 original sibcrossed families of the Siete Cerros mutants were evaluated as spring grown F 3, F4 and F^ headrows. F3 and F 3 plantrows of Chancellor male-sterile x various winter wheats were evaluated as winter wheats. An abnormal 7:1 segregation predominated in most Siete Cerros families with an unexpected high number of nonsegregating headrows. One family of the original 41 segregated for male-sterility as a single recessive allele. The influence of background genotype on the Chancellor male ste­ rility was attributed to a superior gene (s) in the parental cultivars. Monosomic analyses of the three male sterile sources suggested complex inheritance. The male-sterile expression in Siete Cerros may be due to aneuploidy or gamete lethality. The major factor controlling male-sterility in Chancellor confirmed the results of Driscoll (10) as being associated with chromosome 4A. Five additional chromosomes may also be involved. INTRODUCTION The goal of plant breeding for yield has not changed over time but knowledge and control of the environment have changed the methodology used to attain that goal. Many present day plant breeding programs emphasize developing high yielding cultivars adapted to a specific en­ vironment with high quality standards and insect and disease resistance that must be met. As a result of these requirements, the technology for determining these factors is improving but the breeder is still manipulating the same pollination systems used by his prehistoric ancestors. Using genetics, modern man is learning to circumvent the limita­ tions of natural pollination mechanisms. Corn (Zea mays), normally a cross-pollinated crop species, can now be treated as a self-pollinated species. Barley (Hordeum vulgare), a ■self-pollinated species, can likewise be manipulated as a cross-pollinated crop. Genetic male-sterility in a self-pollinating species provides the plant breeder with a combination of factors which reduce the costs and increases the number of potential crosses substantially. The major advantage of genetic male-sterility in a self-pollinated crop, however, in the ability to shift from self-pollination to cross-pollination and back to self-pollination at the desire of the researcher. The occurrence of two spontaneous male sterile mutants in the spring wheat (Tricitum aestivum L.) cultivar 'Siete Cerros1 led to the initiation of this study. A winter wheat cultivar, 'Chancellor', which 2 contained a simply-inherited genetic male-sterile was included as a standard by which progress within the selection of Siete Cerros could be measured. The objectives of this research were to: I. Examine the inheritance of male-sterility within two spontan­ eous male sterile mutants of Siete Cerros spring wheat and a single gene male-sterile isolate of Chancellor winter wheat. 2. Locate as to chromosome the factor(s) causing male sterility. LITERATURE REVIEW Male Sterility ■History Wheat (Triticum aestivum, L.), a self-pollinated species, has very low levels of cross-pollination. Natural outcrossing in .wheat varies between 0.16 and 8% (19,22,24,74) and can be affected by environmental conditions (3,26,27,66). The low, natural levels of cross-pollination are insufficient and too unreliable to be used effectively for genetic recombination in wheat. The importance of controlled crossing has been recognized by wheat breeders since the latter part of the 18th century (46). The popular- ■ ity of producing hybrid populations for selection in the production of new cultivars increased and spread from Great Britain to Europe and the United States. By the end of the 19th century, wheat breeders through­ out the western world recognized the importance of obtaining new genetic recombinants for varietal improvement (46). Since, that time, breeders of self-pollinated crop species have attempted to accelerate their breeding programs through controlled genetic recombination. Most of these efforts have been involved with rendering the male gametes inviable in selected plants. This phenom­ enon, termed male-sterility, can be attained by emasculation (common in self-pollinated crops) or othrough genetically controlled manipu­ lation of factors affecting fertility. 4 Genetically controlled male-sterility is particularly useful in wheat breeding. This phenomenon relieves the wheat worker of the tedi­ ous task of.hand emasculation and allows opportunity for the manipu­ lation of wheat as a cross-pollinated species. methods of creating male-sterility in wheat: There are two common (I) cytoplasmic male sterility (CMS), and (2) genetic male-sterility (GMS). Cytoplasmic Male-Sterility •During the 1930's, CMS was discovered in corn (12). The use of CMS in the development of corn hybrids resulted in. improved corn yields at a reduced cost and caused breeders to examine the potential of male sterility in other crops (13). CMS in rye (Secale montanum Guss.)(41), barley. (56) and wheat (32,49,82,83) involve the use of alien cytoplasms. In rye, only one of the parent cytoplasms was effective in evoking male-sterility (40). Currently, wheat hybrids derive their cytoplasmic male sterility from Tricitum timopheevi, first reported by Wilson and Ross (84). In wheat, Aegilopis caudata cytoplasm commonly gave a high incidence of pistilloidy and .consequently partial or complete female sterility (6., 49). Other cytoplasmic sources, such as Aegilops ovata, tended to pro­ duce late flowering female wheat lines with decreased.seed set in crosses with hexaploid wheat pollen parents (49). CMS has been developed in hexaploid wheat specifically for hybrid wheat production. CMS is therefore limited in its poential 5 uses. The problems of uneconomical yield increases (21), incomplete restoration and the necessity of multigenic restorers at northern latitudes (83) limit the use of cytoplasmic male-sterility in Montana. Genetic Male-Sterility GMS offers a flexibility unattainable in the CMS system (29,30). GMS-derived hybrids can potentially be used as commercial hybrids, in recurrent selection populations and for conventional varietal improvement (16., 29,30,70,77) . GMS also offers wheat breeders the ability to shift easily from a program of conventional breeding to recurrent selection to hybrids (30). The first isolation of GMS in small grains was made by C. A. Suneson (73). In 1936, Suneson discovered a single male-sterile barley plant which phenotypically resembled some male-sterile wheat he had previously studied. In the earlier study, freezing temperatures had caused complete male-sterility in some wheat tillers (66). How­ ever, the male-sterility observed in the barley plots proved to be a simply-inherited single gene male-sterile (68) In 1945, Suneson (67) suggested the use of a simply-inherited, recessive, male-sterile in composite cross populations of barley to allow continued recombination coincident with plant competition favor­ ing the most vigorous plants. In 1951 (69)> he suggested the use of GMS in a program of male-sterile facilitated synthetic hybrid barley. Suneson later termed this male-sterile accelerated recurrent 6 recombination (72). Eslick suggested a similar program termed male- sterile facilitated recurrent selection (14). With the discovery of GMS in barley, an interest grew in the possibility of producing commercial F hybrids. Several systems have been proposed involving chemically-induced lethals (80), aneuploidy (51,53)., balanced genetic lethals and male-steriles (13,23), and others. Since the breeding systems of barley and wheat do not differ greatly, the potential exists for similar developments in wheat. Since the identification of the first genetic male-sterile in barley in 1940 (67,68) twenty-seven additional genes for male sterility have been reported (22). Genetic Male Sterility in Wheat In 1922, Sax (55) reported an increased proportion of sterility in wheat in conjunction with an increased proportion of univalents from interspecific crosses. The observed male and female-sterility was attributed to aneuploidy. In 1938, partially sterile F^ plants were noted in the cross 'Pathology'4592' x 'Nebawa1 (65). The partial male-sterility was attributed to chromosomal aberrations. Pugsley and Oram (50) found what appeared to be a genetic malesterile in an F _ family of 1Kenya Farmer1 x 1Javelin 48'. 3 The inher- itance of this male-sterility was unclear (50,71). ■This male-sterile, was used in■conjunction with induced male-sterile mutants in the first 7 wheat composite cross population (73,76). Suneson's investigations of the inheritance of this particular male-sterile were not conclusive. Suneson hypothesized the male-sterility, in this instance, could be due to a single recessive gene which was environmentally sensitive (71). Cytological studies by Wanige (79) and Zeven et al. (85) were also inconclusive concerning this male-sterile mutant. The chromosome number varied irregularly (79,82,85) and no apparent relationship between aneuploidy and the male-sterile character was noted. From Pugsley and Oram's original male-sterile germplasm, Briggle (5), through backcrossing, isolated and transferred a single gene for male-sterility to the cultivar 1Chancellor'. The gene behaved irradi- cally when placed in different parental combinations. Other genetic backgrounds differentially influenced the expression of male-sterility. •Briggle (5) hypothesized that modifiers from other cultivars or a gamete competition might be responsible for this difference in reac­ tion. Types and Patterns of GMS in Wheat Two types of GMS appear to exist in wheat. The first involves multiple genes which act in a cumulative fashion to express malesterility (1,18,27). The multigenic male-steriles have common characteristics. All are reported to involve three recessive genes having cumulative effects and exhibit partial sterility (1,19,28). An ability to set 5% selfed 8 seed has been advocated for the maintenance of male-sterile lines in hybrid wheat production (1,19,28). ■ The second type of GMS involves single gene inheritance such as the spontaneous male-sterile mutant found by Kruysnov (34) in 1Saratovskaya-29' in 1964. Fourteen of twenty-two F^ families from the original mutant, segregated for the male-sterile character. Thirteen of the fourteen segregated for a single, recessive malesterile gene. The fourteenth family segregated for a complimentary ■ two-gene recessive ratio (34). Plants grown under field conditions deviated more from the monofactorial ratio than did greenhouse grown material. Krupnov (34) proposed that decreased viability of the male- sterile phenotypes affected the ratio of fertile to sterile plants. Bozzini and Scarascia-Mugnossa (4) found a spontaneous mutant in the tetraploid wheat cross 1Yuma1 x 1Capeits1. The mutant allele acted as a single recessive gene for male-sterility. Bingham (2) reported a spontaneous male-sterile mutant in the hexaploid cultivar 'Maris Widgeon'. ically normal. This single gene mutant was meiot- Pollen transmission of the character was reduced while female transmission of the gamete appeared to be normal. This finding corroborated■other studies involving monogenic male-steriles in wheat (11,17,34). Monogenic male-steriles have also been induced. Fossanti and Ingold (16) induced a single gene male-sterile in the cultivar 'Probus' 9 using x-ray. Driscoll (11 ) induced a similar male-sterile in the cultivar 1Pitic-62' using gamma radiation. The GMS isolated from the original material of Pugsley and Oram and transferred to 1Chancellor1 (5) is allelic with the Probus mutant and located on chromosome 4A (10). The 'Cornerstone' mutant gene, isolated from 'Pitic-62' by Driscoll (11), is also on chromosome 4A. The Cornerstone source of male-sterility appears to involve a terminal deletion of the alpha arm of that chromosome (11). Maan (41) found the alien substitution line involving the trans­ fer of a single chromosome of Aegilops longissima (20" Th aestivum . + I" A. longissima) to be completely fertile. Telosomic and isosomic analyses showed the single A. longissima chromosome to be homologous to that of chromosome 4A in wheat. self-fertile. The substitution line is completely All male gametes carrying the A. longissima chromosome are fertile and functional. Thus, chromosome 4A in wheat.appears to ■ perform a vital function in fertility expression. Monosomic Analysis Aneuploidy - A Genetic and Plant Breeding Tool Aneuploidy involves an imbalance of chromosome pairs or between chromosomal homologues. Initially, aneuploid types such as monosomies, nullisomics and trisomics were used only for the chromosomal location of specific characters. Morris (43). These characters have been summarized by More recently, nullisomics and monosomies have provided 10 wheat researchers with the opportunity, to transfer specific chromo­ somes from cultivar to cultivar (54,64,78) and from species to species (39,41). Monosomies involve the loss of one member of a homologous pair of chromosomes. Instead of the expected 21 pairs of chromosomes (21"), the monosomic has 20 chromosome bivalents and a single univalent (20". + I')(33). . Monosomic plants, when self-pollinated, produce disomic (21"), monosomic (20" +1') and nullisomic (20") progeny. The proportion of these progeny depend upon the frequency with which the 20-chromosome (n-1) gametes function in fertilization and upon the degree of via­ bility of the nullisomic progeny (35). Approximately 75 percent of the functional female gametes are n1, regardless of the chromosome involved (35,61). Functional male gamates are generally of the 21 chromosome type since certation favors the 21-chromosome pollen (35). The percentage of functional 20- chromosome pollen varies from approximately I to 10 percent depending. upon the chromosome concerned (61). The failure to transmit specific male gametes may be effective in plant breeding research. Recently, in conjunction with genetic male- sterility, proposals have.been made to use aneuploids for hybrid wheat and barley production (8,9,51,53). 11 Monosomies - Cytological Problems Monosomies are meiotically unstable. The absence of one dose of chromosome, IB, 4B, 2D or 4D can promote misdivision of the centromere (31) and other meiotic irregularities (47,57,58). Chromosomes IB, 4B and 6B appear to control regular bipolar segregation of homologous chromosomes and, in the hemizygous state of the monosomic, can produce elevated numbers of double monosomies (31). In the monosomic series of 'Cheyenne' and 'Wichita' wheat, plants which lacked bivalents for 6A, 6B or 6D showed some necrosis in the seedling stage (44). Appar­ ently, there was no suppression of leaf necrosis when one of these chromosomes was in the hemizygous state. of n-1 gametes is common. Reduced pollen transmission The failure to effect fertilization by n-1 gametes is remarkably consistent across observed polyploid species (20> 36,45,61). The actual number of viable n-1 gametes varies between monosomic lines within a species (39,61). More information concerning the theoretical aneuploid ratios is available from Kuspira and Unrau (.35). Univalent shift is another potential problem with the use of monosomies. Person (47) found univalent shift occurred frequently. Univalent shift involves the mispairing of a chromosome with a uni­ valent from one of its homologues. For example, a univalent of 4A could occasionally mispair with a univalent of 4B leaving the 4B homologue to become the new univalent. Since all wheat chromosomes 12 are essentially metacentric, it is difficult to discriminate when , univalent shift has occurred (47). asynapsis to occur. Person (41) also found partial New aneuploid types such as double monosomies could result. A final potential problem in using monosomies is non-expression of a character in the hemizygous state (61). As a result, evidence gathered from monosomic analyses may be inconclusive. Study I THE INHERITANCE OF GENETIC MALE-STERILITY IN Siete Cerros AND Chancellor MATERIALS AND METHODS Genetic Materials Siete Cerros Two spontaneous male-sterile mutants, found.in the spring wheat cultivar 'Siete Cerros1 (C.I. 14493) by University of Arizona Profes­ sor R. K. Thompson, were studied. Seeds from open-pollination with Siete Cerros were assigned the population-designation A and B for identification. this study. These identifying letters were maintained throughout Each seed was assigned an Arabic number as a family desig­ nation (A—I through A-21 and B-I through B-20). Chancellor A single recessive gene for male-sterility was transferred from the original male-sterile mutant population of Pugsley and Oram, com­ monly called Pugsley1s male-sterile, to the soft, red, winter wheat. cultivar, 'Chancellor' (C.I. 12333) by Dr. L. W. Briggle (5). found no logical segregation pattern in the Briggle of the original cross. Continued selection for a single, recessive male-sterile gene with four backcrosses to Chancellor was, however, successful. plants in the F Partially sterile and early backcross generations were discarded by Briggle. The Chancellor male-sterile (ms C) is cytologically normal (21") in both fertile and male-sterile phenotypes (5). Driscoll (10) 15 reported the male-sterile allele from ms C was on chromosome 4A and allelic to the 1Probus1 male-sterile. Cytologic and Genetic Procedures Figure I provides an outline of generation procedures for green­ house and field materials of Siete Cerros A and B populations. mother cells (PMC) from twenty A and twenty-one B Pollen plants, hetero­ zygous for the male-sterile allele(s), were examined cytologically. PMC analysis followed the techniques of Zeven et al. (85). Preliminary allelism tests were made between cytologically normal F^ families of A and B during the summer of 1975. Allelism test eval­ uations were based upon primary tiller phenotype. Additional allelism test crosses were made among elite F^ families of A, B and C furing the summer of 1977. Test cross offspring were evaluated for fertile to male-sterile segregations in 1978. Crosses were made between male-sterile individuals from F^ fami­ lies of Siete Cerros A and B with various hard red winter wheats (HRWW) to examine the influence of genotypic background. These F^ progeny were fall and spring planted for field observation in 1977. Crosses were made between male-sterile individuals of Chancellor (ms C) and the HRWW cultivar 1Centurk1 in the greenhouse during 19741975. The F^ analysis of the cross.was made during the summer of 1976. All field grown materials were evaluated for male-sterility at 16 Year Field 1974-1975 1975 1. crosses ms x HRWW 2. allelism crosses (AxB) 3. 20 fertile heads har­ vested for headrows within fami­ lies 1975-1976 1976 1. selection for 3:1 (fertile heads har­ vested for F jl 4 headrows) 1976-1977 1977 I. selection for 3:1 segregating headrows fertile heads to be grown as F 5 F headrows 5 .F ' fa H \ 2 planted F \ spring 2 planted 2. selected samples for greenhouse V I. allelism crosses 1977-1978 Figure I. Generation procedures for Siete Cerros A and B 17 the Plant and Soil Science Field Research Laboratory, Bozeman, Montana. 1Individual F^ progeny (ms C x Centurk) were harvested and classified as to awnless, awnletted or awned plant types. F 3 C families from indi­ vidual F2 plants.were planted in the fall of 1976 and classified for male-sterility in 1977. Greenhouse Procedures Materials derived from populations A and B and families of C were greenhouse grown in steam-pasteurized benches of a sandy-loam soil (2 parts sand:2 parts Amsterdam silt loam:I part peat) and were irrigated with a complete nutrient solution. Greenhouse temperatures were main­ tained at 60-75°F for spring and 4O-SO0F for the winter wheat with a gradual increase to 60-75°F. The original open-pollinated F^ progeny of Siete Cerros popula­ tions A and B were greenhouse grown from December, 1974 to April, 1975. Progeny resulting from field sib-crossing within Chancellor (ms C x C) were also grown at this time. F 4 and F 5 headrows were greenhouse grown during 1976 and 1977. Greenhouse grown selected fertile F 4 plants, segregating for single gene male-sterility, provided seed for F 3 headrows. 18 Field Procedures The F families obtained from selfing individual F plants of populations A and B were field planted in'April, 1975 to determine F^ segregation ratios for male-sterility. available, from twenty fertile F Twenty random spikes, when plants from each A and B F family were harvested to provide seed for F^ families. 3 Greenhouse sub-crossed material from Chancellor (ms C x C) and F^ progeny of ms C x Centurk were field grown during the summer of 1975. Male-sterile plants from sib-crosses were crossed with various hard red winter wheats. Determination of fertile and male-sterile individuals within seg­ regating families of A, B and C was based upon the phenotypic expres­ sion of the primary tiller and 0% seed set from bagged heads of sus­ pected male-steriles. F^ A and B family segregations were tested using chi square tests of goodness of fit to three Mendelian ratios. The tested ratios were: 1 . ' 3:1, a single gene, recessive male-sterile; 2. 15:1, a two gene, recessive male-sterile; 3. 63:1, a three gene, recessive male sterile. ■ Sample sizes for determining genetic ratios (p = .90) were based on the formula of Mather (42). Samples sizes exceeding 146 observa­ tions were considered definitive for all ratios tested at the family level. 19: Chi square analyses were used to determine goodness of fit within Chancellor for the following ratios: 1. 3:1, a single gene, recessive male sterile with complete gamete transmission of the male-sterile allele; 2. 4:1, a single gene recessive male-sterile resulting from an assumed 10% reduction in pollen transmission of the malesterile containing gamete; 3. 5:1, a single gene recessive male-sterile resulting from an assumed 15% reduction in pollen transmission of the malesterile containing gamete; 4. 7:1, a single gene recessive male-sterile resulting from an assumed 18% reduction in pollen transmission of the malesterile containing gamete; 5. 15:1, a two gene recessive male-sterile ratio with complete gamete transmission; 6. 13:3, an epistatic, two gene male-sterile ratio with com­ plete gamete transmission. In 1976, segregation ratios for male-sterility of mx C x Centurk F21S and spring planted F 3 headrows of A and B were determined. F3 and F^ A and B family analyses included the ratios: I. 7:1, an observed segregation ratio of unknown origin.similar to one found by Falk (15) 2. 1:0, a nonsegregating Homogeneity of (fertile:male-sterile) headrow ratio. and F 3 families of C and F 3 and F4 families of A and B were tested using heterogeneity chi square (42). Headrows with within each A and B F 3 family were analyzed using chi square tests of goodness of fit to the expected ratios. RESULTS AND DISCUSSION The Siete Cerros Male-Steriles . Allelic factors producing male-sterility were not evident in crosses between heterozygous, cytologically normal (2n = 21") indivi­ duals within families of A and B (Table I). Consequently, the two populations were maintained separately and considered two mutational events.. F2 family analyses of A and B were essential to the determination of inheritance in the Siete Cerros mutants (Tables 2 and 3). Proba­ bility values provided information concerning the actual segregation ratio. Since random pollen parents were used in crosses to the orig­ inal male-sterile mutants, individual families could segregate for different numbers of genes. Table I. Allelism tests between meiotically normal Siete Cerros .A. and B . .Parentage Frequency Male-Sterile Fertile X2 (1:1 expected) Probability Value ■ <.001 ms A-l/B-8 • 15 O 15.0 ms A-5/B-8 3 O 3.0 ms A—8/B—8 7 O 7.0 ms A-ll/B-8 3 O 3.0 17 O 17.0 5 O 5.0 ms A-6/B-6 ms B-8/A-15. .05-.10 <.01 .05-.10 <.001 <.01 22 PMC analysis showed chromosomal observations (telosomy and trans­ locations) and provided a determination of meiotically normal and aberrant percents of Siete Cerros A and B (Tables 2 and 3). Family A-19.(Table 2) does not fit any of the expected ratios. Family A-2 (Table 2) best fits a three gene model (p = .50 - .70). Other families of A best fit 3:1 or 15:1 fertile to male-sterile seg­ regation. Most F2 B families best fit 3:1 segregation ratios (Table 3). Families B-7, B-17 and B-18 best fit a 15:1 ratio. Families B-5, B-6> B-16, B-19 and B-21 did not fit any of the tested ratios. F families (Tables 4 and 5) of Siete Cerros A and B did not fit segregation patterns consistent with observed segregations within families. ; There wa.s an unusual, high number of nonsegregating F^ headrows in A and B (Tables 6 and 7). The reduced number of segregating classes may be due to a gametic failure, aneuploidy. or a factor conditioning gametic lethality such as pollen killer, Ki (62). F4 families generally fit a 7:1 ratio of fertile:male-sterile• (Tables 8 and 9). Falk (15) reported an 8:1 ratio which may'be asso­ ciated with gametic lethality. A-15 and B-20 were the only families which fit a desired 3:1 ratio. F^ and F4 data are similar for a number of non-segregating headrows (Tables 10 and 11). Greenhouse F4 and F^ headfow 23 Table 2. Family A-I§ Siete Cerros A family fertile and male-sterile segregation and associated probability values for three genetic ratios Frequency Fertile Male--Sterile Probability for tested ratios 3:1 15:1 63:1 55 6 A-2 . 37 I A-3 41 9 A-4 48 6 A-5§ 28 4 A-6§ 19 I A-7 46 12 .30-.50 A-8§ 16 2 .10-.20 .30-.50 — A-9 14 2 .20-.30 .30-.50 — A-Il 29 11 .70-.80 — A-12 44 15 >. 99 — A-13 9' .20-.30 — .20-.30 — .10-.20 — 2 .50-.70 A-14 20 7 .90-.95 A-15§ 37 14 .50-.70 A-16 51 2 A-17 60 4 A-18 36 6 A-19 63 10 — A-20 28 3 — — .10-.20 .30-.50 — — .50-.70 — .10-.20 — .10-.20 — .80-.90 — .10-.20 .20-.30 — — -— — ™— .30-.50 — .10-.20 >.99 -- — — — .- .30-.50 t Probability determined by chi square tests of goodness of fit 4= P < .05 are not given § Meiotically normal plants 24 Table 3. .Siete Cerros B family:fertile and male-sterile segregation and associated probability values for three genetic ratios 4* . Frequency Fertile Male-Sterile Probability for tested ratios 3:1 15:1 63:1 . — B-I 38 10 .50-.70 B-2 57 11 .05-.10 — — B-3 23 9 .50-.70 — — B-4 50 21 .30-.50 —— — B-5 71 13 — -- B—6 47 7 — — B-7 36 5 — W I CO Family 59 14 B-9 57 19 B-IO 8 I .30-.50 B-Il 3 2 .30-.50 — — B-13 44 9 .10-.20 — -- — — .20-.30 >.99 .10-.20 — .05-.10 ' 26 5 .20-.30 B-15 . 47 14 .70-.80 B-16 53 9 — B-17 25 ' 2 — .80-.90 B-18 44 2 —— .50-.70 B-19 . 58 9 — B-20 • 44 10 B-21 59 31 — — — B-14 .30-.50 — —— — — — — .10-.20 -- — — — — — + Probabilities determined by chi square test of goodness of fit + P < .05 are not reported § Meidtically normal F plants 25 Table 4.. Family + Siete Cerros A F 3 family:fertile and male-sterile segregation and associated probability values for four genetic ratios Frequency Fertile Male-Sterile Probability for ratios tested 7:1 3:1 15:1 63:1 — ■ A-I 156 17 A-2 ■ 72 15 A-3 112 16 ■"— A-4 130 20 — A-5 156 21 --- A—6 114 13 — .30-.50 .05-.10 — A-7 47 6 — .80-.90 .10-.20 — A-8 • 160 25 — .50-.70 A-9 165 29 — .10-.20 A-Il 10 2 A-12 . Ill 20 A-13 128 18 — A-14 95 12 — .50-.70 A-15 133 12 — .05-.10 A-16. 81 11 — .50-.70 A-17 161 18 — ..50-. 70 — A-18 109 18 — .50-.70 —— A-19 76 10 -. .80-.90 — A-20 173 26 — .80-.90 .05-.10 .50-.70 — t Missing families due to hail damage 4 P < .05 are not reported .20-.30 .10-.20 .05-.10 — — — — — .20-.30 — — .80-.90 — — >.99 .50-.70 .20-.30 >.99 — — — .10-.20 —— — — — — — — .30-.50 —— — — .—— —™ 26 Table' 5. Family •f* Siete Cerros B family:fertile and male-sterile segregation • and associated probability values for four genetic ratios * Probability for ratios tested 3:1 7:1 15:1 63:1 Frequency Fertile Male-Sterile .50-.70 — — .20-.30 — — — .80-.90 — — 31 — .80-.90 — — • 137 23 — .20-.30 — — B-6 101 .21 — .05-.10 — — B-7 72 8 -. .30-.50 B-8 9 6 B-9 50 7 B-IO 48 12 B-Il 118 17 B-13 47 8 B-14 145 25 —— B-15 178 29 — B-16 36 5 B-17 158 23 — .90-.98 B-18 66 6 — .50-.70 ■ .30-.50 B—19 218 . 38 — .30-.50 — B-20 173 26 — .80-.90 — B-21 166 17 — .10-.20 B-I 87 12 B-2 76 14 B-3 142 22 B-4 209 B-5 ' — .10-.20 ' ■.30-.50 — .05-.10 .05-.10 t Missing families due to hail damage t P < .05 are not reported -. .90-.98 .I0— .20 — .05-.10 — — — .05-.10 ■ — — .90-.98 — — ■.50-.70 — — '.30-.50 — -- .20-.30 — — .80-.90 .10-.20 — .05-.10 " —— 27 Table.6. Family Number of Siete Cerros A genetic ratios 3:1 headro'ws best fitting, five Number of headrows best fitting ratios 7:1 15:1 63:1 1:0 A-I 2 3 I 0 14 A-2 3 3 I 0 13 A-3 5 2 5 0 8 A-4 3 7 3 0 7 A-5 5 4 2 0 9 A-6 . 2 7 0 0 10 A-7 0 6 I 0 12 A—8 2 0 0 0 3 A-9 I 2 I 0 6 A-Il 3 3 3 0 10 A-12 2 7 3 0 7 A-13 2 0 3 0 5 A-14 4 5 2 0 9 A-15 3 '5 I 0 10 A-16 I 2 0 0 17 A-17 3 4 2 0 9 A-18 2 I 2 0 15 A-19 5 3 5 0 7 A-20 0 6 5 0 8 t Using chi square tests of goodness of fit • 28 Table 7. Family Number of Siete Cerros B genetic ratios 3:1 headrows best fitting five Number of headrows best fitting ratios 7:1 15:1 63:1 1:0 . B-I 3 I 6 0 10 B-2 4 I I 0 14 B-3 2 4 ■ 3 0 ■ 11 B-4 0 4 3 0 10 B-5 2 I 4 0 12 B-6 0 5 3 0 12 B-7 ■3 0 2 0 15 B-8 4 2 5 0 6 B-9 4 3 4 0 9 B-IO 0 I 0 0 3 B-Il I I 0 0 I • B-13 3 4 2 0 9 B-14 2 3 2 0 13 B-15 I 4 4 0 11 B—16 I 4 2 0 13 B-17 'I 5- 5 0 .9 B—18 3 4 2 .0' 11 B-19 'I 3 2 0 14 B-20 5 6 -3 .0 6 B-21 0 4 I • 0 15 t Using chi square tests of goodness of fit 29 Table 8 . Family Siete Cerros A family:fertile and male-sterile segregation and associated probability values for four genetic ratios Frequency Fertile Male-Sterile A-I 251 30 A-2 249 34 A- 3 ,' 85 A-4 '' ■j* Probability for ratios tested 3:1 7:1 15:1 63:1 >.99 --- — — >.99 — — 11 — >.99 — — 114 17 —— >.99 — — . 86 12 — >.99 — — A-6 139 14 — .90-.95 A-Il 151 28 —— .95-.98 A-12 234 35 — A-13 76 12 A-14 284 38 A-15 78 18 A-17 103 18 — A-19 455 76 -. A-5 • .80-.90 — — — >.99 — — — >.99 — — — >.99 — — .30-.50 — — .90-.99 . - — — — .70-.80 >.99 . t. Probability determined by chi square tests of goodness of fit + P < .05 are not given 30 Table 9. Fnmil-^ B-2 ■ Siete Cerros B F 'family fertile and male-sterile segregation and associated probability values for four genetic ratios Frequency Fertile Male-Sterile t Probability for ratios tested 3:1 7:1 15:1 63:1 >.99 —— . — >.99 — — — — 169 28 B-3 97 16 B-8 60 12 B-9 314 62 — B-13 59 9 — B-14 80 44. — — 1 “— — B-16 ■ 95 ■ 11 — .98 .30-.50 — . 14 — .98-.99 . .80-.90 — .90-.95 — B-18 131 . ' ■ B-19 15 2 B-20 102 23 — .30-.50 .20-.30 >.99 .70-.80 — >.99 — - — , — .30-.50 — t Probability determined by chi square tests of goodness of fit 4 P < .05 are not reported — -. 31 Table 10. Family Field grown F headrow distributions within families of Siete Cerros A for four genetic ratios of fertile!malesterile Parental headrow__________ Male-Sterile Fertile Number of headrows best. _______ fitting ratios^ 3:1 7:1 15:1 1:0 A-1—1 11 4 0 3 2 4 A-l-2 11 2 I 3 2 5 A- 2—1 .5 4 I I 2 5 5 2 0 2 3 A-2-2 5 ' A-2-3 9 2 I 2 2 2 A-3-1 10 3 0 2 2 4 A—4—I 7 2 0 4 2 2 A-6-1 11 4 0 4 2 6 A—11—I 11 4 I 4 4 3 A—12-1 12 3 I 3 4 5 A-12-2 10 3 I I 3 2 8 4 0 2 2 4 I 3 .2 7 A-13-1 . . A-14-1 ■ 14' 4 I 3 A-15-1 ■ 16 4 3 . o A-I7-1 9 3 2 A-19-1 7 7 2 . A-19-2 11 4 2 ' • 3 '■3 ' . 5 5 6 6 3' 3 I. t Classification based on highest probability values in chi square tests of goodness of fit 32 Table 11. Family Field grown F 4 headrow distributions within families of Siete Cerros B for four genetic ratios of fertile:malesterile Parental headrow Fertile Male-Sterlie Number of headrows best fitting ratios^ 3:1 7:1 15:1 1:0 B-2-1 6 2 0 2 I B-2-2 11 3 I '4 2 I B-3-1 7 2 .0 2 .I 5 B-3-2 10 4 I 2 I I ■ B-8-1 9 3 0 3 I 0 B—9—I 18 7 4 6 4 4 B-9-2 7 3 0 I 2 8 B—11—I 13 I 0 0 0 3 B-13-1 5 2 0 . 2 ■ I B—20—I 4 2 I 0 I 2 B-20-2 3 I I 0 I I ’ B-20-3 7 3 0 I 3 2 . 3 . ■ .I t Classification based on highest probability value in chi square tests of goodness of fit 33 segregation (Tables 12 and 13) are similar to field grown F4 headrtiws. Heterogeneity chi square failed to differentiate A- and B x HRWW■ F3S for male-sterility grown in spring and fall plantings (Table 14). Results suggest an environmental! and genotypically insensitive genetic male-sterile. With the exception of Siete- Cerros B-8, B-9 and B-20, all fami­ lies segregate in a 7:1 ratio in crosses with other genotypes. Reduced transmission of the male-sterile factor(s) in other studies (2,5,11,34,71) were not associated with high numbers of non­ segregating progeny. The genetic system causing male-sterility in Siete Cerros may differ from other reported male-sterile sources. The factor affecting the expression of. male-sterility in Siete Cerros may have been altered in advanced generations. Initially, B-20 segregated 7:1 and in later generations segregated 3:1 (Tables 5 and 9). In crosses with Cheyenne winter wheat, 3:1 progeny ratios were obtained. Testcross progeny derived from an F4 male-sterile of B-20 and a fertile, heterzygous sibling fit a single gene male-sterile segregation with a chi square value of 0.50 and a probability of fit of .30 to .50. Chancellor Male-Sterile The inheritance of the Chancellor male-sterile allele was deter­ mined in crosses with HRWW using F Z and F _ progeny. 6 Tests of the 34 Table 1 2 . headrow distributions of greenhouse-grown Siete Gerros A and B.families for four genetic ratios of fertile:malesterile Parental headrow Fertile Male-Sterile Family Number of headrows best fitting ratios’^ 3:1 7:1 15:1 1:0 A—1-1 11 4 0 3 2 I A-2-3 9 2 0 3 0 2 A-3-1 10 3 I 0 0 I A-12-1 12 3 I I I 3 A-I2-2 10 3 0 3 0 2 A-14-1 14 4 0 4 3 I A-15-1 16 4 0 I 0 4 B-2-2 11 3 4 0 0 I 10. 4 I 4 . 2 . '0 B-8-1 9 3 2 I. 0 2 B-9-1 18 7 I I 0 3 B-ll-1 3 I 0 •0 0 3 B-20-3 7 3 2 0 0 3 B-3-2 . ' t Classification based bn higest probability values from chi square • tests of goodness of fit 35 Table 13. Family headrow distributions of greenhouse-grown Siete Cerros A and B families for various genetic ratios of fertile: male-sterile Parental headrow Fertile Male-Sterile Number of headrows best fitting ratios^ 3:1 7:1 15:1 1:0 "NP 3 2 2 I 0 A—2—3—2" 20 3 2 2 0 3 A-3-1-1 16 5 I 2 2 6 B— 2— 2— 3 14 3 4 I I 3 B—8—1—I 19 3 I 3 2 3 B-20-3-1 15 5 I I 2 6 CN I CO I O CN I m CO I CN 20 17 6 I 3. I 5 t Classification based on highest probability values in chi square tests of goodness of fit 36 Table 14. ' Siete Cerros spring wheat ms A and ms B x HRWW grown as F spring and winter wheats 2 Parents ■ ^ Environments S Frequency Fertile MaleSterile Probability values for ratios ____________ .tested^ _______ 3:1 7:1 15:1 63:1 SW 708 93 — .30-.50 — — SW 462 56 T— .20-.30 — — ms A-3/Sheepers SW 174 26 —— .80-.90 — — 913 107 — .05-.10 — — SW 496 65 — .30-.50 -------- SW 306 36 — .20-.30 — — MS A-14/Trappen SW 109 15 —— .80-.90 — — ms A-17/ID 7457 SW 189 18 —— . .05-.10 ms B- 3/Cheyenne ■ SW 177 27 ms B-8/MT-6827 SW 323 31 1943 205 — ms B-18/Winalta W 114 13 — ms B-20/Cheyenne SW- 202 63 ms A-l/HRWW ms A-2/HRWW •ms A-4/HRWW § S ms A-ll/HRWW MS A-12/HRWW SW S § ■S ms B-9/HRWW SW .70-.80 .- .50-.70 — — .30-.50 — - .05-.10 — — —. — .05— ;10 — .05-.10 - — — —— — t Spring planted (S); fall planted (W); both plantings homogeneous (SW) f p < .05 are not given (using chi square tests of goodness of fit) §. More than one pollen parent used with no indicated difference deter­ mined by heterogeneity chi square 37 mx C x Centurk F^s showed two types of progeny or subfamilies (Table 15). Subfamily I segregated for two independent complimentary genes while subpopulation 2 best fit a single gene ratio. These results differ from those of Briggle (5) and Driscoll (10,11) in that they assumed the reduced number of male-steriles was due to pollen trans­ mission problems. A gene(s) in Centurk could have influenced the ex­ pression of the Chancellor male-sterile allele. Probability values for ratios tested^ 3:1 4:1 5:1 7:1 15:1 13:3 — >.99 — O — I I 294 — I I 1428 § CD 2 — A HO I I 1889 I I I 1 Frequency Fertile Male-Sterilet H Subfamily Probability of fit for ms C/Centurk F progeny using chi square tests of heterogeneity and goodness of fit. 0 Ul Table 15. t Homogeneous populations derived from heterogeneity chi square test (P > .05) + Probability values determined by chi square tests of goodness of fit § P < .05 are not given To further test this hypothesis, crosses were made between ms C and various HRWW and HRSW cultivars. The F s of ms C x HRWW and ms C *■ x HRSW were fall and spring planted, respectively. Winter and Spring habitat did not influence the expression of male-sterility (Table 16). Within fall and spring planted F^s differences were observed. cross ms C x MT 6827 resulted in 104 fertile F The plants (Table 17). r MT 6827 may possess a suppressor gene(s) for male-sterility. The F^s 38 Table 16. Chi square test for heterogeneity for F^ populations of ms C x HRWW and ms C x HRSW Frequency Fertile Male-Sterile Subclass .HRWW 1672 316 HRSW 225 55 1897 371 Total t y2 A P 10-.20 2. 52 t Homogeneous populations derived from heterogeneity chi square test (P > .05) . of ms C x Cheyenne and ms C x PI 094436 (Table 17) were the only winter wheat crosses with segregation ratios which had a greater than 99% probability of fitting a single gene male-sterile. The F^s of ms C x Bluebird, ms C x Tobari and ms C x Tobari 66 were the only winter x spring wheat crosses with F^ segregation ratios which had a greater than 99% probability of fitting a single gene male-sterile (Table 18). Allelism Tests Among Selected Families of the Three Male-Steriles Two testcrosses, ms A-I x B-20 and ms B-20 x ,ms C/Centurk fit a two gene testcross ratio. A third testcross, ms A-I x A-3, was of insufficient sample size to.be definitive for a two gene testcross ratio. ratio. None of the three allelism tests fit a single gene testcross Table 17. Probability values for six genetic ratios in ms C/winter wheat using chi square tests of goodness of fit Cross designation . ms ms ms ms ms ms ms ms ms ms ms ms C/Brinkle C/Centurk C/Cheyenne C/Crest C/Froid C/Lancer C/MT 6827 C/MT 7243 C/PI 094436 C/Sundance C/Winalta C/Winoka Ratios tested Ratio fertile/ male sterile^ 3:1 4:1 81:17 233:60 95:30 108:9 434:78 118:14 104:0 86:10 83:25 179:33 46:16 105:24 .50-.70 .80-.90 >.99 — — —T — —— .95-.98 — — .30-.50 .90-.95 >.99 .70-.80 .■— — —— .80-.90 .90-.95 — .98-.99 5:1 ■ >.99 .80-.90 — — >.99 .30-.50 ■— .30-.50 .30-.50 >.99 .20-.30 .95 families * 7:1 .70-.80 — ..30-.50 >.99 .90-.95 — .90-.95 — .95-.98 .70-.80 — 15:1 **— — — .90-.95 — — — .30-.50 — .50-.70 — t Ratios from homogeneous populations using heterogeneity chi square (P > .05). + Probability values where P < .05 are not given. 13:3 .70-.80 — .10-.20 — —— — — —— .20-.30 .20-.30 ->.99 Probability values for six genetic ratios in ms C/spring wheat F^'s using chi square .tests of goodness of fit Ratios tested 4:1 39:14 — .05-.10 —— . I ms C/Tobari 66 CO O 27:9 O ms C/Tobari .80-.90 .20-.30 ' 0 r- .10-,20 — — 1 39:7 . .10-.20 13:3 O ms C/Siete Cerros .80-.90 15:1 in .90-.95 O CO 43:13 7:1 .30-.50 O LO ms C/Bluebird 4 — m 77:12 O ms C/Anza 5:1 NJ 3:1 O Ratio fertile/ male sterile^ ? Cross designation H Table 18. W O .05-.10 —— — t Ratios from homogeneous populations using heterogeneity chi square (P > .05). + Probability values where P < .05 are not given. .30-.50 1 — 0 CM — O .10-.20 I— I .80-.90 .30-.50 to ? >.99 41 The phenotypic expression of male-steriles from ms B-20 x ms C/ .Centurk was different from either parent and may have been environ­ mentally influenced. Table 19. Allelism tests between Siete Cerros male-sterile A-l, A-3, B-20 and Chancellor male-sterile Female/male Frequency Fertile Sterile 2 2 X (1:1 expected) X value (3:1 expected) ••P ^ 8 0 8.00 — ms A-I/ B-20 (Msms) 20 8 5.14 — ms A-I/ /ms C/Centurk 22 0 22.00 — 7.33 ms A-3/ B-20 (Msms) 78 .0 78.00 — •26.00 ms A-3/ /ms C/Centurk 30 0 30.00 — 10. 00 —— ms B-20/ /ms C/Centurk 60 15 27.00 — 1.00 .20-.30 ms A-I/ . A-3 (Msms) O .19 , .05-.10 £ LO t P < .05 are not given 2.67 ■- — Study II MONOSOMIC ANALYSES MATERIALS AND METHODS Genetic Stocks Siete Cerros A-I, A-3 and B-20 and Chancellor were the malesterile sources used in the monosomic analyses. Three monosomic series were used in this study: I) 'Chinese Spring', from Dr. E. R. Sears (USDA-SEA, University of Missouri); 2) 'Rescue', from Dr. R. I. Larson (Canada Department of Agriculture, Lethbridge); and 3) 'Kharkof', from Dr. G. A. Taylor (Montana State University). Field and Greenhouse Procedures The Chinese Spring and Rescue monosomic series were field planted in May, 1975. Cytologically determined monosomies.(85) were emascu­ lated at spike emergence and pollinated by random plants from within families of A-I, A-3 and C. The use of fertile pollen parents re­ quired progeny testing using the techniques described by Driscoll (7). Primary tillers of greenhouse grown F s were examined for malesterility. Monosomic analyses were similar to that of other workers (10,36,37,38,48,62,63,81). Remaining crosses of Rescue and Kharkof monosomies with A-3, B-20 and C were made in 1976 and 1977. Examination for male-sterility was . made in the greenhouse for the crosses made in the respective years. RESULTS AND DISCUSSION .Siete Cerros Three Siete Cerros families, A-I, A-3 and B-20, were crossed with monosomies to determine chromosome location of male-sterile factors. Siete Cerros A-I appeared to involve chromosomes 1A, ID and 7A (Table 20). No partial sterility was observed. Telosomics and isosomics of IA increase fertility but do not pro­ vide complete fertility (61). The male-sterile observation in mono- somic IA may be due to univalent shift. In other studies the main effect of chromosome ID has been to increase fertility over nullisomic ID plants (61). Homeologous group 7 also affects fertility in wheat (61). Mono- isosomic studies of chromosome 7A increased fertility over nullisomic counterparts primarily by the suppression of pistilloidy and not fer­ tility restoration. The partial monosomic analysis of A-3 produced only for monosomic ID (Table 21). male-steriles No partial, sterility was observed in the monosomic analysis of ms A-3. Male-sterile expression in B-20 involves chromosome 3B and 7A (Table 22). Chromosome 3B is shown to produce irratic response to fertility although the cause has not been determined (39). 45 Table 20. Chromosome location of Siete Cerros ms A-I Monosomic Designation Frequency Sterile Fertile Semisterile .IA ' 12 I • 0 IB 10 O 0 ID ■ 8 2 0 2B 3 O 0 2D 5 O 3D 3 O 0 4D 7 O 0 SB I 0. 0 SD 5 0 0 7A 6 I 0 Chromosome location of Siete Cerros male-sterile A-3 'Frequency • 2A 4 2D 8 . ' » 9 4A 9 4B 2 4D ■ 4 5A 6 8 O 6 7 O 3B ' to .O 7 o ID. o 4. o IA Sterile O Fertile O -O O Monosomic ■ 50 SD 0' O Table 21. . 46 Table 22. Chromosome location of Siete Cerros ms B-20 Frequency Monosomic Fertile . Sterile IA 18 O IB 2 O 2B 3 O 2D 5 O 3A 8 O 3B 16 3D 3 0 4A 3 • O 4D 7 O SB 2 O 6A 7 O 6B 13 . 4 , O , 6D 5 ' O 7A 6 I Chancellor Monosomic analyses of Chancellor male-sterile involved crosses of Chinese Spring, Rescue and Kharkof monosomies x F heterzygotes of C. Monosomic chromosomes 4A, 4B and 5A segregated for maler-sterility (Table 23). The largest proportion of male-sterile progeny involved chromosome 4A. Similar results fdr the location of ms C on 4A were found by Driscoll (10). Chromosome 4B may be involved,as a modifier or may be a univalent shift. Chromosome 5A is known to affect 47 fertility (61) or may. be a univalent shift to SB. Partial sterility (semisterile) was observed in monosomic crosses ID, SB, 6A, and 6Bi All of these monosomies affect fertility (61) or may be suppressions from other genotypes (Study I). Partial sterility was not observed in the Siete Cerros monosomic analyses. The ms C factor may be environ­ mentally sensitive. Table 23. Chromosome location of ms C Monosomic IA IB ID 2A 2B ■ 2D 3A 3B 3D 4A 4B 4D SA SB SD . 6A 6D. ' 7B ' 7D Fertile 33 13 21 6 15 28 24 8 2 45 36 25 36 22 11 37 63 24 24 Frequency Sterile ■ O O 3 O O O O O O 11 •4 O I O O O O .0 0 Semisterile 0 0 3 0 0 0 0 0 0 •0 0 .0 0 2 0 2 2 '0 0 GENERAL DISCUSSION The Inheritance of. Genetic Male-Sterility in Siete Cerros and Chancellor Siete Cerros Within families of Siete Cerros A and B, potential aneuploidrelated male-sterlies were observed. The unselected E 3 families of A and B generally fit 7:1 fertile to male-sterile segregation with an unexpectedly high number of non-segregating headrows. Large samples sizes (from headrows to plantrows) may have allowed a simplified Mendelian explanation. Because of small sample sizes, data analyses were insufficient to test fertile to male-sterile segregation ratios greater than a two gene model. Since pollen parents involved in the original crossed, seed may have provided different numbers of factors, segregation ratios for families were expected to differ. The observed 7:1 (fertile:male-sterile) in the F , F , F , and F j 4 (A- and B x HRWW) generations is not currently explainable. 3 Z A similar ratio observed by Falk (15) was attributed to gametic lethality. Fac­ tors effecting gametic lethality in wheat are known (62). One family, B-20, was selected for further evaluation as a single gene male-sterile. F^ family data and F^ data of crosses to Cheyenne support a single gene model. 7:1 segregation, F^ greenhouse data show a reversion to a ms B-20 may have a very mutable locus (or loci) or is currently in an unstable state. 49 Other F2 progeny of male-steriles of A and B families in crosses to HRWW segregated 7:1 similar to the parent families of Siete Cerros. The factor(s) invoking male-sterility in Siete Cerros A and B therefore appear stable in a variety of background genotypes. Monosomic analyses implicate the involvement of several chromo­ somes in most.Siete Cerros families studied, suggesting multifactorial control of male-sterility in Siete Cerros A and B. The occurrence of male-sterile progeny in a multitude of monosomic testers could be due to: I) a dominant-recessive factor relationship; 2) a translocation or series of translocations; 3) a deletion or series of deletions which affect gametic transmission rates; 4) a gametic lethal.. Allelism test results fitting a two gene model lend further, support •to a multigenic cause for male-sterility in Siete Cerros. Further research is required to clarify the causal^response relationship of male-sterility in Siete Cerros. Chancellor The presence of a suppressor gene(s) was apparent in F2 families of ms C x HRWW. Frequency of male-sterility in C was influenced by the ' background genotype, ms C x Cheyenne F 2 fit a single gene recessive . model while ms C x MT 6827 did not segregate for the male-sterile character. MT 6827 has a parent, PI 178383, which is used extensively in the Pacific northwest wheat improvement programs. A test of ms C x 50 ' PI 178383 is necessary before widespread use of ms C is made in combi­ nation with other cultivars having PI 178383 in their, background. The stability of the Chancellor male-sterile is exemplified by test results involving crosses of heterozygous C plants crossed to a random male-sterile individual in Composite Cross I (76). Composite Cross I (C.C.I) has been grown as a spring wheat bulk for 10 years at Bozeman, Montana. and the five A test cross of ms C.C. I x C (heterozygote) was made progeny fit the expected 1:1 ratio (Appendix Table I)., implying that the same gene conditioning male-sterility in Chancellor is also functioning in the non-selected C.C. I population as a stable, male-sterile allele. Monosomic analyses of Chancellor implicated three and possibly .6 chromosomes in the segregation of ms C. The involvement of multiple chromosomes is different from other studies (5,10). The multifactorial (multichromosomal) effects may be related to expression of suppressor factors hypothesized in Study I. REFERENCES REFERENCES 1. Athwal, D.S., P.S. Phul and J.L. Menocha. 1967. sterility in wheat. Euphytica. 16:354-360. Genetic male 2. Bingham, J. 1967. Rep. PI. Breed. Inst. Cambridge, England, p. 67. As cited by Jan, C.C., 1974. 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Allelism tests of Chancellor male-sterile and other male- sterile sources Frequency Cross designation■ 2 X Fertile Male-sterile P + F (1:1 expected) C .C.I ms/ms C 3 2 ms B-6/ms C 2 0 2.0 .10-.20 ms A-2/ms C 7 0 7.0 — ms A-14/ms C 22 0 22.0 — ms A-20/ms C 6 0 6.0 — ms C/C.C. I.://ms B-14/Cnn . 15 0 15.0 — ms C/ms D/3/ms A-6/ MT 00906//MT 7015 . 3 2 .20 t Probability values less than '0.05 are not reported. .20 .50-.70 .50-.70 61 Appendix Table 2. Fertile and male-sterile, progeny of heterozygous Siete Cerros ms A-I x monosomies Female monosomies Male ■ sterile Fertile Chinese Spring IA IB . 6B 6D 7A 8 3 I 5 ■ 6 Kharkof ID 4D 7 I O O Rescue IA IB ID 2B 2D 3D ,40 4 7 3 3 5 3 6 I. O 2 O ■O O . O Appendix Table 3. IA . ID. 2A 2D 3A 3B 4A 4B 4D 5A 5D 6D O O O .O I Fertile and male-sterile progeny of heterozygous Siete Cerros ms x Rescue monosomies Fertile Rescue ' '; ' 4 . 7 . 4 8 9 6 9 2 4 6 8 . 7 Male sterile O I O O O 'O O O O O O O . 62 Appendix Table 4. Fertile and male-sterile progeny of heterozygous Siete Cerros ms B-20 x monosomies Female monosomies ■ Rescue Kharkof Fertile Male-sterile IA 18 O IB 2 Q 2B 3 O 3A 8 O 3B 16 4 4A 3 O SB 2 O 6A 7 O 6B 13 O 6D 5 0 7A 6 1 63 Appendix Table 5. Fertile and male-sterile progeny of heterozygous Chancellor male-sterile x monosomies Female monosomies Fertile Chinese Spring IA IB ID 2D 3D 4A 4B 5A SB 6A 6B GD 30 7 . I 21 2 7 12 20 22 25 8 30 Rescue Karkof IA 2A 2B .3B 4A ' . 4B 6B GD 7D IB ID 2B 2D 3A 4B 4D SA SD . • GA GB GD 7B TD Male sterile 0 0 . 3 0 0 0 0 I 0 0 0 0 3 6 5 8 38 14 8 I 4 0 0 0 0 11 4 0 0 0 6 20 10 8 24 10 25 16 11 12 21 32 24 20 0 0 .0 0 0 0 0 0 0 . 0 0 0 0 0 'A Semisterile 0 0 I . 0 0 0 0 0 2 . 2 I 2 . ■0 0 0. I 0 0 I 0 0 0 2 0 0 0 0 0 0 6 0 I 0 0 0 D378 J&31 coo. 2 DATE Johnson, Duane L Genetic characteriza­ tions of three p a l e ­ st eri Ies in wheat . . . ISSUED TO yseU&ME ?NTERL:8R Z WiUiMS 'T) f < 2 ,'