Abstract

ESPITIA CAMACHO, Miguel Mariano; VALLEJO CABRERA, Franco Alirio  and  BAENA GARCIA, Diosdado. INBREEDING DEPRESSION AND HETEROSIS FOR YIELD AND ITS COMPONENTS IN PUMPKIN Cucurbita moschata Duch. Ex Poir. Rev. Fac. Nac. Agron. Medellín [online]. 2006, vol.59, n.1, pp.3089-3103. ISSN 0304-2847.

With the goal of estimating inbreeding depression (DE) and the four types of heterosis: general average (HP), mean (HM), heterobeltiosis (HB) and standard (HU), in two diallelic [one among five cross pollinated varieties (VAR) and the other among five self-pollinated lines S1(LS1), derived from these], for yield/plant (PFP), number of fruits/plant (NFP) and weight/fruit (PPF). The 30 genotypes were evaluated using a complete randomized design with five replicates in Candelaria (Valle del Cauca, Colombia ). Significant differences (p < 0,01) occurred between crosses (C) for the three characters in both dialleles; whereas the statistical significance for parents (P) and P vs C, was different in each diallele. On average the LS1 presented inbreeding depression of 15,4 % (PFP), -4,6 % (NFP) and 20,3 % (PPF). The HP was significant ( p< 0,01) only for PFP (17,8 %) and NFP (-1, 3 %) in diallele VAR; whereas in the diallele of LS1 HP was significant for PFP (65,6 %) and PPF (35,4 %) to 1 % of probability. The HM, HB and HU had greater significant expression (trans-heterosis) in the diallele of LS1(4,1 % to 65 %) than in the diallele VAR (-12 % to 17,5 %) for the three characters. The hybrids LSO x LA34, LBV x LA126, LBV x LA34, LSO x LA126 and LBV x A88, showed the greatest levels of HB (>40 %) and HU (>60 %) in PFP.

Keywords : Dialelic crossing; hybridization; heterosis; pumkin.

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