Development of Interspecific Hybrids (Abelmoschus Esculentus × A. Tetraphyllus) in Okra Using Embryo Rescue Approach

Abstract

Undomesticated related species are the rich stock of genes providing resistance to various diseases, pests and unfavourable environmental conditions. The sexual incompatibilities are bottleneck in introgression of such genes from wild species to popular varieties. The present study was executed to standardize a protocol of embryo rescue so to obtain the hybrids of Abelmoschus esculentus × A. tetraphyllus IC141017. Crosses were made between four (Arka Anamika, Pusa Makhmali, Parbhani Kranti, Jammu Okra-05) cultivated varieties of okra (A. esculentus) and a wild species (A. tetraphyllus IC141017) in reciprocal manner. Out of the four popular cultivars used in crossing, fruit set was recorded in Arka Anamika, Pusa Makhmali, Parbhani Kranti only when A. tetraphyallus IC141017 was used as a male parent. Fruit showed distal cracking after 25 d of pollination. The seeds appeared healthy for up to 15 d after pollination and later shrivelled and became pale yellow. Cross combinations, viz., Parbhani Kranti × A. tetraphyllus IC141017, Arka Anamika × A. tetraphyllus IC141017 and Pusa Makhmali × A. tetraphyllus IC 141017 showed the highest shoot regeneration on MS media containing 0.5 mg l-1 NAA + 1.0 mg l-1 IBA. Greatest number of shoots per explant (0.92±0.12) as well as the highest frequency of shoot regeneration (86±0.12%) was reported in Parbhani Kranti × A. tetraphyllus IC141017. Arka Anamika × A. tetraphyllus IC 141017 (86±0.12%) and Pusa Makhmali × A. tetraphyllus IC 141017 (82±0.13%) resulted in high frequency of shoot regeneration on MS media containing 0.5 mg l-1 NAA + 1.0 mg l-1 IBA. It can be inferred that MS media containing on 0.5 mg l-1 NAA + 1.0 mg l-1 IBA showed positive results in regeneration of interspecific hybrids of okra.