Yield heterosis and average fruit weight as a function of inbreeding in cucurbita moschata duch. Ex Poir.

In order to estimate the mean heterosis, mid parent heterosis and heterobeltiosis (HB), three diallel crossings of Cucúrbita moschata were evaluated, each formed by six parents with three levels of inbreeding (S0, S1, S2). A randomized complete block experimental design was used with four replicates, arranged in split plots. The variables yield per plant (YPP) and average fruit weight (AFW) were analyzed. The hybrids between S1 or S2 inbred lines presented heterotic superiority regarding to those between S0 parents for the variables YPP and AFW. Likewise, the hybrids between S2 inbred lines reported heterotic superiority in comparison to those among S1 inbred lines, for such variables. The hybrids between S2 inbred lines that reported the highest expression levels of HB for YPP were P1xP3, P2xP6 and P1xP2, with values ranging between 131.42 and 98.24%; while the hybrids among S1 inbred lines that recorded the highest values of HB, for this same variable, were P3xP5 and P1xP5 with values of 191.71 and 139.29%, respectively. Furthermore, the hybrids between S2 and S1 inbred lines that registered the highest level of HB for AFW were P1xP3 and P1xP5 with values of 108 and 83.7%, respectively.

Key words: butternut squash; selection; heterobeltiosis; diallel crossing; inbred lines; hybrids