Okra-leaf accessions of the upland cotton (Gossypium hirsutum L.): genetic variability in agronomic and fibre traits

Okra-leaf types of the upland cotton have the potential to be competitive to the normal-leaf types in yield and fibre quality, in addition to its potential resistance to insect pests and drought. Okra-leaf cotton accessions, collected at Cotton Research Institute, Faisalabad, Pakistan, were evaluated in respect of genetic variance and relative performance in half- and full-sib crosses (combining ability) for 2 years. Variation due to parents x years interaction was significant for lint percentage, seed weight and earliness index, resulting in moderately low but significant genetic variance across environments (years) for these traits. Interaction of environment with general combining ability was significant for seed yield, seed weight, and earliness index. General combining ability variation, contributed by females and males together, accounted for 71% of the total variation available for seed cotton yield, 60% of that for seed weight and height to node ratio each, and 75% of that for earliness index. Specific combining ability variation accounted for 85% and 51% of the total variation available for lint percentage and staple length, respectively. The contribution of female parents to general combining ability variation was higher than that of male parents for seed cotton yield, seed weight, height to node ratio, and earliness index. Okra-leaf accessions HR-VO-MS and HR107-NH were predicted to produce progenies having high yield, HR109-RT high lint percentage, while HR100-Okra, Gambo-Okra and HR-VO-1 were predicted to impart early crop maturity to their progenies by reason of their good general combining ability for these traits. The results also provided evidence that genes controlling high yield in HR-VO-MS and HR107-NH were different from those controlling high yield in HR109-RT. The set of genes controlling the high earliness index in HR100-Okra and that in HR-VO-MS also appeared to differ in expression.