Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/1998
Publication Date: N/A
Citation: Interpretive Summary: Male-sterile, female-fertile plants are commonly found in natural and field, horticulture, forestry, and vegetable crops. In crops such as soybean, these unusual plants are useful for certain plant breeding methods. Sometimes, these unusual plants may be of commercial value. This newly identified soybean plant is similar, perhaps identical, to a previously identified soybean male-sterile, female-fertile plant. Both unusual plants arose independently of one another. Both unusual plants are very closely associated (genetically linked) to a seedling (and flower) color trait. This very close association of seedling (flower) color with male sterility/female fertility allows the soybean breeder to use a technique called the Cosegregation Method to produce large quantities of hybrid seed. Until now research on hybrid soybeans has been hampered because of the labor intensive techniques employed to produce seed. This Cosegregation Method forms the basis of a joint USDA-ARS/Iowa State University invention for which a patent has been filed.
Technical Abstract: Male-sterile, female-fertile soybean [Glycine max (L.) Merr.] plants were observed in an F2 entry. Our objectives were to determine the inheritance, linkage, and allelism of the A94-JB-124 male-sterile mutant to known male- sterile mutants. The A94-JB-124 male-sterile, female-fertile mutant is a single recessive gene, allelic to ms6, and is linked to the W1 (flower color locus) with 4.3 +/- 0.3 percent recombination value based upon 988 F plants in the coupling phase. A comparative microscopic study of microsporogenesis and microgametogenesis of fertile and sterile plants was conducted. The expression of the male-sterile gene is associated with rapid degenerative changes both in the tapetum and the parietal layer. These changes are initiated at the late sporogenous mass stage. The A94- JB-124 mutant was assigned gene symbol Ms6 ms6 (Ames 2) and Genetic Type Collection number T354H. The T295H Ms6 ms6 mutant is now designated Ms6 ms6 (Ames 1). T354H will be useful in the Cosegregation Method to produce hybrid soybean seed.