Genetic and Cytogenetic Aspects of Colchicine-induced Male Sterility in Sorghum

Genic-cytoplasmic male sterility is important in production of hybrid seed in sorghum. This report deals with a study of four male sterile sorghum plants which occurred in a segregating progeny-row of a mutant plant derived by colchicine treatment of the variety Experimental 3. The objectives of this study were: (1) to determine the nature of inheritance of the colchicine-induced male sterility and to compare this with the previously known male sterile lines, Martin and Reliance, (2) to evaluate seed set on selfed panicles and pollen staining as means of determining the amount and origin of abnormal pollen mother cells occurring in the male sterile material. Inheritance of male sterility in the colchicine-induced male sterile plants appeared to be the same, except for modifying factors, as that of male sterile Martin and Reliance. Restoration of fertility in the male sterile plants was found to require one dominant or two dominant, complementary genes depending on the parent plants used. Seed set after selfing was found to be more reliable as a criterion for determining pollen fertility in partially male sterile plants than the proportion of stained pollen unless the florets within a panicle were thoroughly sampled