Isolation and evaluation of novel male sterile and self-incompatible mutant lines of mungbean (Vigna radiata L.)

Heterosis has long been harnessed in crop production, and while crop fertility lays the groundwork for leveraging heterosis, there remains a dearth of comprehensive data regarding genic male sterility in mungbean. Mungbean (Vigna radiata (L.) Wilczek), being a self-pollinating crop, exhibits significant hybrid vigour in F-1 hybrid seed yield, suggesting the potential for developing hybrid varieties to propel mungbean yield beyond existing plateaus. A new male sterile mutant was induced, isolated, stabilized and evaluated, via gamma irradiation at a rate of 600 Gy, identified in the M-3 generation of the GM 4 accession. A uniform male sterile line was crossbred with the wild-type parental plant to explore the inheritance pattern of male sterility. Pollen sterility was validated through the acetocarmine test, while stigma viability was ascertained using the hydrogen peroxide. While all F-1 plants displayed fertile flowers, the F-2 generation showed a clear 3:1 segregation ratio for fertile to male sterile plants, indicating the control of male sterility by a single recessive gene, mms. Also, a novel existence of a truncated stigma nestled within the anther column inhibits the effective reception of pollen during anthesis, offering potential in reducing emasculation time by a slight cut on the flower bud and enhancing cross pollination during hybrid seed production. The isolation of these two mutants is poised to significantly advance the global mungbean hybrid breeding programme.