Genetic and cytological studies of a male-sterile, female-fertile soybean mutant

Abstract

Genetic studies of a new male-sterile, female-fertile mutation In Glycine max (soybean) demonstrated that male sterility Is controlled by a single recessive allele nonallelic to previously reported male-sterile mutations. The mutant has been assigned the gene symbol ms2, and the heterozygous form (T259H) has been added to the Soybean Genetic Type Collection. Linkage studies showed that ms2 is not linked to trisomics A, B, or C, nor was linkage detected between the ms2 locus and the breakpoint of a chromosomal inter-change from PI 101,404B (G. soja). Cytological evidence demonstrated that male sterility was due to an abortion of tetrads. Callose dissolution and initiation of microspore walls did not occur. Abnormalities in the tapetal layer were discovered in sterile anthers. Tapetal cells formed abnormally large vacuoles during prophase I of meiocyte meiosis. Sterile anthers were found to be completely empty at maturity and were morphologically distinct from fertile anthers.