Ação gênica associada à expressão da heterose em jiló (Solanum gilo Raddi)

Abstract

The objectives of this work were to assess heterosis and its components in a diallel cross among African eggplang (Solanum gilo) Raddi lines, and to obtain information about the types of gene action involved in its expression. A trial was carried out in Ijaci county, State of Minas Gerais, Brazil, from June 2008 through January 2009, in a randomized complete block design with four replications. Genotypes tested were 6 S. gilo lines and 15 hybrids obtained from all possible crosses among them (reciprocals excluded), comprising 21 treatments altogether. Traits studied were early and total yields, mean fruit mass, fruit length, and fruit length: diameter ratio. Epistasis was important in the expression of early yields, and was in great part responsible for the expression of heterosis for this trait. Epistasis was not detected in the expression of total yield, mean fruit mass, fruit length and fruit length:diameter ratio. For these latter traits, heterosis was associated with a degree of dominant gene action. Heterosis for total yield was associated with overdominant gene action, and higher yields were only weakly associated with higher proportion of dominant alleles. For mean fruit mass and for fruit length, heterosis was associated with incompletely dominant gene action, and higher values were associated with higher proportions of dominant alleles. In the fruit length: diameter ratio rounded fruit has higher proportions of dominant alleles, and gene action of incomplete dominance.