Research Notes : United States : A new mutation at the ms1 locus

Volume 13 Article 32 4-1-1986 Research Notes : United States : A new mutation at the ms1 locus H. Skorupska Iowa State Unievrsity Reid G. Palmer United States Department of Agriculture Follow this and additional works at: http://lib.dr.iastate.edu/soybeangenetics Part of the Agriculture Commons, Agronomy and Crop Sciences Commons, and the Plant Breeding and Genetics Commons Recommended Citation Skorupska, H. and Palmer, Reid G. (1986) "Research Notes : United States : A new mutation at the ms1 locus," Soybean Genetics Newsletter: Vol. 13 , Article 32. Available at: http://lib.dr.iastate.edu/soybeangenetics/vol13/iss1/32 This Article is brought to you for free and open access by the Journals at Iowa State University Digital Repository. It has been accepted for inclusion in Soybean Genetics Newsletter by an authorized editor of Iowa State University Digital Repository. For more information, please contact . 140 IOWA STATE UNIVERSITY Department of Genetics, and Department of Agronomy Ames , IA 50011 1) A new mutation at the msl locus . Five different populations have been recognized as sources of msl al- leles . Genetic studies of male- sterile, female-fertile mutat ions conducted by Palmer et al. (1978) showed that msl-North Carolina (T260), msl- Urbana (T266), msl- Tonica (T267) , and msl-Ames (T268) are independent mutations at the msl locus . Yee and Jian (1983) reported another mutation at the msl lo- cus, designated Shennong Male- Sterile Soybean L- 78- 387 . The objective of our study is to determine if a spontaneous mutation that occurred within progeny developed from .AP6(Sl)Cl popula tion is associated with the msl locus. Materials and methods : One hundred s 1 seeds of AP6(Sl)Cl were planted in the spring of 1979 in Ron Secrist ' s plant nursery, and 55 single plants were Among s : hill plots, one hill plot segregated for 4 5 sterility. Figure 1 shows the origin of this hill . Twelve s : pro genies (8 5 6 of fertile, 4 of sterile plants ) were grown in Ames in 1985 . Class ification harvested that fall. fo r male sterility and fertility involved the stainability of po llen grains in I KI and pod set at maturity . Test crossing was conducted by using homozy2 gous recessive msl-Urbana plants as female parents and heterozygotes of the new mutant s as male parents. ism test. Thirty- one F Sixty-nine F seeds were obtained for the allel1 seeds were grown during fall/winter 1985 at the UPR/ 1 ISU Soybean Breeding Nursery in Isabela, Puerto Rico . They were class ified for mal e-sterility/fertility on the basis of pollen staining . Results: The new mutations arose in a population character ized by very compli cat ed nuclear genetic background. AP6(Sl)Cl population was derived by intermating and recurrent selection procedure from 40 strains of Group 0 to Group IV maturity (Fehr and Ortiz , 1975). It i s worth mentioning that in this same population a partially male-sterile mutant msp msp was found in 1974/7 5. Expression of msp msp genes influenced different flower size and morphology, anther and pollen appearance , and phenotype at maturity (Stelly and Palmer, 1980). Unknown sterile mutants showed similariti es to the pattern of abnormalities caused by the msl alleles . They exhibited prolonged vegetative growth 141 and produced large coenocytic pollen grains. ly 5.1 pods, with 5.9 seeds . Sterile plants had approximate- Sterile msl-Urbana plants had 7.1 pods, with 14.9 seeds . Among eight single-plant progenies observed in 1985, six progenies segregated for sterility, two did not . Within segregating progenies, 392 plants were fertile, 140 plants were sterile; that fit a ratio of 3:1, chi-square= 0.4912, P = 0.10-0.50 (Table 1). s5:6 progenies of four sterile plants gave the ratio of 23 fertile to 32 sterile plants . These results pointed out that this spontaneous new mut ation is inherited monogenically. Testcrosses between ms1-Urbana and Msl msl un- known mutants confirmed our cytological observations of sterile plants. Six- teen F 1 plants had normal pollen, 15 F coenocytic pollen grains. plants were characterized by large, 1 This population gave a good fit to the expected 1:1 ratio , chi- square= 0 . 032, P = 0 . 50-0 . 90 (Table 1). Seeds of these 15 F fertile plants will be planted in 1986 for further observations . 1 The results indicated that this mutation occurred independently and a single locus was conditioning male sterility . The gene responsible for male sterility is allelic to the msl locus . Acknowled gement: The authors thank Ron Secrist for all information and seed supply . 1979 100 s 1 seeus of AP6(Sl)Cl (single plant threshed) 1980 55 s 1 : 2 progenies (seeds of each row harvested separately) 1981 1 1 1983 100 s 4 seeds 1984 10 s4:5 progenies / 55 S progenies (single pods from 30 selected rows harvested and b ulked) l 1 (single plants threshed) One hill plot No. 709, AP- 6-63 , segregated for sterility (8 fertile : 4 sterile plants) Figure 1 . Origin of unknown sterile mu tant 142 Table 1. Segregation ratios for fertility/sterility in s : progenies and 5 6 F testcross population 1 Number of plants Parentage Observed Fertile Sterile Expected ratio x2 p 3: 1 0.4912 0 .10-0. 50 1: 1 0.032 0.50-0.90 s5 : 6 progenies of fertile plants 532 392 140 s5:6 progenies of sterile plants 55 23 32 Fl (msl msl -Urbana) x Msl msl unknown mutant 31 16 15 References Fehr, W. R. and L. B. Ortiz. 1975. Registration of a soybean germplasm population (Reg. No. GP 19). Crop Sci . 15 : 739. Palmer, R. G. , C. L. Winger and M. C. Albertsen. 1978 . Four independent mutations at the msl locus in soybeans . Crop Sci . 18 : 727-729 . Stelly, D. M. and R. G. Palmer. 1980. A partially male-sterile mutant line of soybeans , Glycine max (L . ) Merr.: Inheritance . Euphytica 29 : 295- 303 . Yee, C. C. and L. Jian. 1983. Allelism tests of Shennong male-sterile soybean L-78-387. Second Assembly Symp . Genet . Soc . China, Sec. 4 , No. 053: 241- 242 . H. Skorupska R. G. Palmer - USDA 14 3 2) Tes t for apomixis in ms4 male-sterile soybean . Soybean plants homozygous fo r the male-sterile mutation ms4 are capable of seed produc tio n in the a bsence of insect po llinators (Graybosch and Palmer , 1984). Cytological investigations have demonstrated the genesis of pollen g r a ins by male-sterile plants at a frequency of 3.3% (Graybosch and Palmer , 1985). Pollen f ormed is identical t o that of mal e-fertile plants , and will germina te when placed in an in vitro ge rmina ti on medium . A test using the genetic marker y ll was desi gned to determine whether seed production by males terile plants wa s a fun c tion of the activity of these pollen grain s , or a pomixis. The ms4 a nd msl mut a ti ons bo th influenc e th e pro cess of postmeiotic c ytokinesis during microspor ogenes is . effec t on female r epr od uction . The msl mutation also has a pleiotropic A hi gh f r eq (...truncated)