COMBINING ABILITY ESTIMATES IN 5X5 DIALLEL INTRAHIRSUTUM CROSSES

A study was carried out to determine general and specific combining abilities of seed cotton yield, number of bells, sympodial branches, ginning outturn percent, seed and lint indices from 5x5 diallel intrahirsutum crosses. Qalandari was the best general combiner of the parents studied for seed cotton yield and number of bells followed by K-68-9. Parent Acala SJI which had the poorest general combining ability for yield and number of bells, was the top parent for ginning outturn percent and seed and lint indices. The parents that formed the best general combining ability did not always form best specific combining ability with every other parents, however, Qalandri with highest general combining ability estimate also ranked first in specific combination with NIAB-78. The regression of observed vs expected values suggested the importance of specific combining ability (control of dominant genes) for seed cotton yield and seed and lint indices, and general combining ability (control of additive genes) for number of bells, sympodial branches and ginning outturn percentage. The consistency in estimates of combining ability for bells and yield indicate that selection based on number of bells will result in simultaneous improvement in cotton yield.