Combining ability and gene action of four seed yield contributing characters in onion (Allium cepa L.)

For the improvement of onion seed yield mode gene action is essential to know. Significant D indicated additive variations were greater in magnitude except umbel diameter and significant H1 dominant variation for scape height diameter. F indicating presence genes only number umbel. H­2 component non-significant all characters height. Non-significant h2 suggested dominance effect over loci heterozygous phase was not important umbel, volume. Ratio [(4DH1) 1/2 + F] / – than one volume an excess parents. characters, ratio h2/H2 smaller involvement at least group genes. Parent P4 observed as good general combiner, F1 (P3 ´ P4, P1 P2, × P5 P3) reciprocal crosses (P2 P1, P3 P1) different traits recorded specific combiners. So, this parent, need special consideration yield.