Interspecific Hybridization in Gossypium L.

II. Cytomorphological studies in hybrid G. hirsufum haploid (2n=2x=26, A_hD_h)×G. thurberi (2n=2x=26, D₁D₁)

Abstract

A new interspecific hybrid (2n=26) A_hD_hD₁/2 has been obtained by crossing G. hirsutum L. haploid (2n=2x=26, A_hD_h) with G. thurberi Tod. (2n=2x=26, D₁D₁). Observations on its morphological characters and cytology have been recorded. The hybrid was found to be highly vigorous and fairly fertile. The characters in F₁ like leaf shape, gossypol glands boll bearing and shape, rind thickness and earliness of G. thurberi which are associated with bollworm tolerance and other economic characters like plant habit, bract shape, flower colour and shape, anther arrangement, seed fuzz and presence of lint of G. hirsutum were found to be dominant. The F₁ being fairly fertile it is likely to get segregants with different character combinations both on glanded and glandless background. The possibility of incorporating insect resistance in glandless lines has been indicated.
From the chromosome analysis in this plant it was observed that D₁ chromosomes of G. thurberi show greater homology with A_hD_hchromosomes resulting in formation of on an average 8.8 bivalents per cell and thus high degree of fertility.