HETEROSIS IN RELATION TO COMBINING-ABILITY EFFECT AND PHENOTYPIC STABILITY IN SUNFLOWER (HELIANTHUS-ANNUUS)

An experiment was conducted in monsoon, winter and summer seasons of 1990 to study the extent of heterosis, combining ability and stability of the parents and hybrids (4 female lines mated with 20 restorers in a Line x tester design) in sunflower (Helianthus annuus L.). The first 5 crosses showing high heterosis, high effects of specific combining ability (sca) and high adaptability for plant height, filled seed (%), 1 000-seed weight, harvest index, oil content and seed yield/plant were assessed along with the general combining ability (gca) of the parents. Most of the crosses showed high heterosis and sca effects and at least 1 parent proved a good general combiner. The crosses 'CMS 234 A' X 'RHA 273' for filled seed (%), 'CMS 338A' x 'CO 7-11' and 'CMS 338A' x 'KSP 1' for harvest index, 'CMS 338A' x 'CO 7-11' for oil content and 'CMS 338A' X 'KSP 1' for seed yield were found highly adaptable with high heterosis and high effects of specific combining ability.