Intraspecific heterosis in diploid and tetraploid cottons

Studies on heterosis were made in diploid (Gossypium arboreum L.) and tetraploid (G. hirsutum L.) cottons for seed cotton yield over three years. Heterosis overbetter parent and commercial heterosis ranged from 10.9–98.7% and 40.2–162.2% in diploid and from 7.3–246.2% and 6.9–107% in tetraploid cotton, respectively. In the latter species, heterosis over the popular hybrid ranged from 11–134.4%. The important heterotic aosses were LD 135 x Spotless (162.2%), LD 135 x Naked Seeded (155.7%), and Lohit x Spotless (136.9%) in diploid; and DCI 118c x F414 (107.7%), Tamcot Camde x MCU 10.(97.7%), and MCU 10 x H 777 (89.6%) in tetraploid cotton. A close relationship between the yield of parental lines andtheirhybrids was observed. The genetic base and geographical diversity of the parental lines were also associated with the manifestation of heterosis. Ample scope for evolving high yielding intra-hirsutum hybrids but limited scope for intra-arboreum hybrids was indicated.