Heterosis and combining ability studies in cauliflower

Abstract

Line X tester analysis involving six lines and six testers was carried out in early cauliflower (Brassica oleracea var. Botrytis) at IIHR, Hessaraghatta, Bangalore during 2000-2001. Thirty-six hybrids along with twelve parents and a check hybrid (NS-60) were evaluated in a randomized complete block design with three replications. The heterosis over mid parent was significant in majority of the F1 hybrids tested for days taken for 50% curd initiation, days taken for 50% curd maturity, stem weight, stem length and curd diameter indicating the pre-dominance of dominant type of gene action for these traits. Number of crosses showing significant heterosis over mid-parent was very less for number of leaves, leaf weight, leaf area, plant height, plant weight, curd weight and pronounced for the expression of these traits. Two hybrids viz., Katki x IIHR-263 (-3.50%) and First Early x IIHR-263 (-8.00%) exhibited lowest negative standard heterosis and the curd weight of these hybrids were on par with the curd weight of the standard check hybrid, NS-60. Significant GCA effects were observed in First Early, IIHR-217-1-4-6 and IIHR-263 for 50% of curd initiation whereas IIHR-Sel 3, IIHR-217-1-4-6, IIHR-302 and IIHR-305 for 50% curd maturity indicating that these were the best general combiners for earliness. Four hybrids, IIHRSel. 3 x IIHR-250-4-1-11, IIHR-73-24 x IIHR-302, IIHR-73-24 x IIHR-305 and Arka Kanti x IIHR-217-1-4-6 were good specific combiners for earliness. Four hybrids viz., IIHR-Sel. 3 x IIHR-302, Arka Kanti x IIHR-302, Early Kunwari x IIHR-250-4-1-11 and Early Kunwari x IIHR-217-1-4-6 were the best specific combiners for curd weight. The ratio of GCA and SCA variance reveals the dominant gene action to be predominant for all the characters. Thus, the present investigation revels that these characters can be improved by heterosis breeding. 99