ESTIMATION OF GENETIC EFFECTS FOR STARCH CONTENT IN Cucurbita moschata PARENTS

Starch is of biological and commercial interest, it contributes to the taste and texture properties of squash fruit, it´s the main component of dry matter, a determining variable for agribusiness processes such as obtaining flour. In the collection of C. moschata from the vegetable program of the Universidad Nacional de Colombia, the genetic effects associated with starch content are unknown. The genetic effects of six selected parents were estimated 47-1, 17-2, 30-3, 56-4, 6-5 through the analysis of combining ability P(P-1)/2. Six parents and 15 direct hybrids were evaluated, in a randomized complete block design (RBC) with four repetitions and two semesters of contrasting evaluation 2016 and 2017. The average starch content (SC) in the parents evaluated was 0.67 and 1.21 kg of starch per plant in the A and B semesters, respectively, with better results in the B semester. The combined analysis of variance detected highly significant differences (p<0.001) for genotype interaction per semester (gxs). The analysis by semester showed highly significant differences (p<0.001) of general combining ability (gca) and specific combining ability (sca) in semester A, and highly significant differences (p<0.001) of sac in semester B, this suggests that genes with additive and dominant effects are involved in the expression of the starch content. The parents 47-1 and 6-5 expressed significant additive effects (gi) of 0.47 * and 0.40 * respectively, which increased the starch content. The hybrid combination (47-1 x 6-5) showed significant dominance (sij) effects of 0.9*, with of 2.6 kg of starch per plant. The contribution of the mean squares indicated that the additive gene action effects corresponded to 11% while the dominance effects are 43%. Parents 47-1 and 6-5 showed the best own behavior and have a good ability to transmit genes and increase starch content in squash.