Production of interspecific hybrids in sesame through embryo rescue

Investigations were carried out using cultivated and wild species of sesame viz Sesamum indicum cv DS-1 and E-8, S. radiatum and S. occidentale to standardize protocol for rescue of abortive hybrid embryos. Upon field pollination maximum capsule set was observed in the cross S. radiatum × S. indicum cv DS-1. The seeds however were shriveled and failed to germinate due to aborted embryos. To standardize the protocol for rescue of embryo both ovary and ovule culture was attempted. Both the cultivated species cv DS-1 and the wild S. radiatum showed best response (17.5% and 20.0% ovule germination respectively) when the ovules were cultured at 11 DAP. The ovule germination per cent still improved when the seed coat of ovules was removed before culture. The cv DS-1 had maximum ovules germinated (87.5%) at 12 DAP, whereas for S. radiatum, it was highest (50%) at 14 DAP. Out of the four interspecific crosses carried out, the cross S. radiatum × S. indicum cv DS-1 gave 40.0% plantlets followed by 38.4% from the cross S. radiatum × S. indicum cv E-8. The results of ovule culture at different days after pollination indicated that culturing of ovules at 11 DAP produce maximum number of plantlets when compared to culturing at later stages.