CYTOLOGY AND GENETICS OF A TISSUE CULTURE-DERIVED SOYBEAN GENIC MALE-STERILE, FEMALE-STERILE

A completely male-sterile, female-sterile mutant was derived from tiss ue culture of cv, Calland, The primary goal was to identify its inheri tance, allelism, and cytology, Calland sterile (TC) was nonallelic wit h st(2), st(3), st(4), and st(5) female-sterile and male-sterile mutan ts, In all crosses, except st(5), single-gene recessive inheritance wa s documented, Critical ratios, 15 fertile:1 sterile (for two loci) and 45 fertile:19 sterile (for three loci), were observed in the F-2 fami lies from the cross of heterozygous Calland TC and St(5)st(5). F-3 seg regation data confirmed the duplicate factor inheritance of Calland TC , Calland TC was designated St(6)st(6)st(7)st(7) and assigned the gene tic type collection number T331H, The mutant was studied for abnormali ties during microsporogenesis, The first abnormality was the occurrenc e of hollow-core nucleoli in sporogenous mass cells, During anaphase I and anaphase II of meiosis, lagging chromosomes and unequal chromosom e segregation were observed, resulting in numerically and genetically unbalanced microspore nuclei, This also resulted in four microspores, and in five to eight microspores held together by common callose walls , Dissolution of callose released microspores into locules, Most micro spores enlarged and were surrounded by microspore/pollen walls, After microspore mitosis, most young pollen grains degenerated, No viable po llen grains were evident, The sterility in Calland TC can be attribute d to desynapsis.