Study of morpho-physiological, phenological and reproductive behaviour in protogynous lines of Indian mustard [Brassica juncea (L.)

Abstract

Understanding the relationship between floral and reproductive traits are critical to understand the evolution of plant species in brassica and need for selecting lines as parental lines in hybrid seed prodcution. The protogyny nature of Brassica species are characterized based on the variations in floral morphology, protogyny interval, stigma receptivity, pollen biology, compatibility and seeds set. The variation in stigma morphology features (stigma exsertion prior to anthesis) and protogyny interval (ranged from 8 to 10 days) formed phenotypically distinct. Studies on stigma receptivity and pollen viability revealed significant variability and found to be at its peak up to 3 days after anthesis and reduced drastically thereafter. Compatibility crosses and post pollination events such as pollen deposition on the surface of the stigma and culminating with the entry of the pollen tube into the embryo sac, was rapid and completed within 2 days after pollination, whereas in in-compatible cross not even single pollen was germinated on stigmatic surface and consequently no pollen tube growth even after sixth day of pollination. In compatible crosses average seed set ranged from 3 to 8 seeds per pod from cross pollination and no seed set in self. The investigation revealed that variation exists for protogyny interval, stigma receptivity and compatibility in the protogynous lines of Indian mustard and this can be exploited for the production of hybrids without emasculation.