Development and molecular confirmation of interspecific hybrids between Gossypium hirsutum and Gossypium arboreum

Crosses were attempted between accessions belonging to G. hirsutum and G. arboreum to develop interspecific hybrids through in-ovulo embryo culture. A mixture of growth regulators (GA₃ @ 50 ppm + NAA @ 100 ppm) was applied at the base of pedicel of crossed buds for three successive days starting from day of pollination. The ovules were excised and cultured three days after pollination on various tissue culture media. Of the 26,300 ovules cultured, 33 germinated with germination percentage of 0.12. Germination was observed in seven crosses namely, LH 2108 x LD 327 (0.57%), F 2164 x LD 949 (0.33%), F 2164 x FDK 124 (0.30%), PIL 43 x LD 949 (0.083%), LH 2108 x LD 949 (0.066%), LH 2108 x FDK 124 (0.044%) and LH 1556 x LD 491 (0.083%). Two media namely MS4 (MS + Gamborg's B5 vitamins + 1.9 g/l KNO₃) and MS5 (MS + 1.0 mg/l IAA + 0.2 mg/l Kin) were found to promote more embryo germination. Hybridity of the interspecific hybrid between LH 2108 x LD 327 was confirmed using microsatellite markers.