Inheritance of Protruded Stigma in Black Gram [Vigna mungo (L.) Hepper]

Inheritance of protruded stigma in black gram [Vigna mungo (L.) Hepper] was investigated in the F(1), F(2), and F(3) generations of four crosses and their reciprocals involving a natural flower mutant with its parent genotype (IPU 99-167) and three other genotypes (PLU 710, Type 9, and Barabanki local). The outcrossing in the mutant was due to a flower mutant with protruded stigma and crumpled petals, thus presenting a physical condition for functional male sterility. The mutant plants appeared in the parent population at an average frequency of 3.05%. The F(1) plants showed normal flowers with normal pod and seed set. The segregation analysis of F(2) and F(3) populations indicated a single recessive gene conditioning protruded stigma and crumpled petals with pleiotropic effect. The gene symbol stg1stg1 is proposed for this mutation. Under natural conditions in the crossing block, 100% of the seeds obtained from the mutant plants were the result of cross pollination despite 93.6% pollen viability. However, the number of seeds produced by the mutant was 92% less than normal plants. Although the mutant genotype provides a mechanism for outcrossing, unless the poor seed set can be improved (e.g., by delayed planting), its use in exploiting heterosis and population improvement will be limited.