Interspecific Hybrids Involving Genetic Male Sterile Line of Gossypium arboreum and Gossypium stocksii

An interspecific hybrid between Gossypium arboreum x G. stocksii was obtained by pollinating previous day bagged flowers of G. arboreum genetic male sterile line MPKV GMS with pollen from wild G. stocksii. A single boll was obtained after 768 pollinations, containing 9 seeds out of which only two germinated and proved hybrid. The hybridity was conferred on the basis of cytomorphological observations made in the hybrid plants in comparison with their parents. The hybrid was intermediate in growth habit, height, leaf shape, petal colour, while anther colour was different from both the parents. The hybrid plant produced few flowers after 240 days, which were sterile. The chromosome behaviour during meiosis in both the parent was normal, however, in F₁ hybrid the average chromosome association were found to be unequal. The separation of chromosome and chromatid during anaphase-I and II respectively, leading to formation of 3 to 7 microspores pollen mother cell and pollen grains with high size variation and sterility was observed. Efforts are under way to induced chromosome doubling in this hybrid to restore fertility and exploit this cross combination for transferring drought resistance from G. stocksii to G. arboreum.