F1 Interspecific hybridity confirmation in cotton through morphological, cytological and molecular analysis

Abstract

Interspecific triploid hybrid was developed between tetraploid cultivated species Gossypium hirsutum cv. MCU 5 and CO 14 and diploid wild species Gossypium armourianum. The F1 hybridity was confirmed by morphological, cytological and molecular approaches. The ploidy level of interspecific F1 hybrid was triploid and male sterile. Female parents MCU 5 and CO 14 had erect growth habit, cream petals, palmate leaves, green stem, thick and prominent leaf veins, embedded stigma, hairy stem and leaves but MCU5 was with dense yellow anthers while CO 14 dense creamy anthers, whereas male parent Gossypium armourianum has spreading growth habit, yellow petals, cordate leaves, reddish green stem, medium dense yellow anthers, thin leaf veins, protruded stigma and glabrous plant body. The growth habit, petal colour, leaf shape and size of interspecific F1 hybrids were intermediate. Plant stem colour and hairiness, leaf pubescence, stigma protrusion and anther colour of Gossypium armourianum were observed to be dominant as hybrid fully resembled Gossypium armourianum for these characters. Petal spot was observed in Gossypium armourianum and in F1 hybrids while petal spot was not observed in MCU 5 and CO 14. Variable expression of petal spot, anther colour and filament colour was observed in the F1 hybrids. Gossypium hirsutum cv. MCU 5 and CO 14 had 52 chromosomes, Gossypium armourianum had 26 chromosomes and the interspecific F1 was with 39 chromosomes. Significant differences were observed between pollen size, pollen fertility of parents and their hybrids. The F1 interspecific hybrids having more than 97 percent of sterile pollen grains. Out of 11 SSR markers polymorphic between parents, 5 markers unambiguously confirmed the hybrid status of interspecific hybrid. These hybrids may serve as useful genetic resource for the transfer of jassid resistance gene to hirsutum cotton.