General and specific combining ability in tropical winter cauliflower

Abstract

Few Brazilian cauliflower cultivars have shown to be adapted to tropical winter conditions. In addition, studies to obtain hybrids adapted to our winter conditions, from breeding lines originating from tropical regions, are scarce. The objective of this work was to estimate the combining ability of cauliflower breeding lines. The experiment comprised 38 genotypes, 36 hybrids from a partial diallel cross obtained by crosses between two groups of cauliflower lines: Group I (3 parents) and Group II (12 parents) and 2 commercial controls. We evaluated plant cycle, resistance to diseases, average curd mass, curd color, hollow stalk incidence, and overall evaluation. Additive genetic effects were more important than non-additive effects in the expression of these traits. No single parental line showed simultaneously the most favorable GCA values for all traits. The most promising hybrids were the combinations BR1 x TE6, BR1 x TE8, BR1 x TE12, BR2 x TE11, BR3 x TE6 and BR3 x TE7. The results of the choice of hybrids made by the method of independent culling levels reflect what it could be predicted by estimating GCA for cycle and average mass of the curd, reaffirming the importance of additive effects in the expression of these traits.