Pollen pistil interaction in the interspecific cross of Sesamum indicum and Sesamum radiatum

Abstract

The study deals with the pollen morphology, in vivo pollen germination and pollen pistil interaction in two species of Sesame viz., S. indicum (CO 1, VRI 3, TMV 7) and S. radiatum. As wild species are potential sources of biotic and abiotic stress-resistant genes, strong crossability with cultivated varieties is critical for gene transfer through traditional breeding programmes. The pollen morphology studied under a Scanning electron microscope revealed both species to be stephanocolpate and possessed the shape of prolate. The number of colpi counted assisted in differentiating the pollen of S. indicum from S. radiatum and represented the evolution of the former. The pollen pistil interaction by aniline blue technique between direct and reciprocal crosses of two species of Sesamum reported the pollen germination per cent of S. radiatum × S. indicum (CO1) (85.00) at one hour after pollination, S. indicum (CO1) × S. radiatum (80.00) at one hour after pollination and S. radiatum × S. indicum (VRI 3) (80.35) at two hours after pollination were on par with each other and expressed higher pollen germination per cent, while S. indicum (CO1) × S. radiatum (22.70), S. indicum (VRI 3) × S. radiatum (20.30) and S. indicum (TMV 7) × S. radiatum (20.15) at eight hours after pollination indicated lower pollen germination per cent. In both the direct and reciprocal crosses, the pollen tubes did not reach the ovary even after eight hours of pollination depicting the presence of pre fertilization barrier and hence capsules were not developed.