Genetics and Cytology of a New Male-Sterile, Female-Fertile Soybean Mutant

Abstract

<p>Mutants affecting male sterility have potential applications in breeding methodology studies and for commercialization of hybrids. Male-sterile, female-fertile soybean [<em>Glycine max</em> (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, female-fertile mutant, and to conduct a detailed comparative microscopic study of microsporogenesis and microgametogenesis of fertile and sterile plants. The A94-JB-124 male-sterile, female-fertile mutant is a single recessive gene, allelic to <em>ms6</em>, and is linked to the <em>W1</em> (flower color locus) with 4.3 ± 0.3% recombination value based on 988 F₂ plants in the couplinglinkage phase. A comparative microscopic study of microsporogenesis and microgametogeucsis 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 <em>Ms6 ms6</em> (Ames 2) and Genetic Type Collection number T354H. The T295H <em>Ms6 ms6</em> mutant is now designated <em>Ms6 ms6</em> (Ames 1). T354H will be useful in the Coscgregation Method to produce hybrid soybean seed.</p>