This work aimed to estimate genetic parameters in a lettuce diallel, according to the Jinks & Hayman's method. The experiment was carried out in a greenhouse, at the Universidade Federal de Viçosa, from October 20 to December 12, 1996. The experimental design used was a randomized complete blocks, with three replications. Pots with 4,5 dm³ of substrate and one plant/pot (plot) were used. Six lettuce cultivars and their respective F1 hybrids were evaluated. The following characters were evaluated: fresh matter of aerial part (FMAP); dry matter of aerial part (DMAP), leaves (DML) and roots (DMR); number of leaves/plant (NUL); and stem height (SH). Some evidences of epistasis were detected for DMAP, NUL and SH characters. In FMAP the variation of additive nature contributes predominantly to the genetic variability observed between parents and F1. The prevalence of dominance gene effects on the control ofDML and DMR characters were evident. The estimates of genotypic determination coefficient on wide sense (<img src="http:/img/fbpe/pab/v36n3/4792fr3.gif" ALIGN="absmiddle">) in FMAP, DML and DMR were 0.84, 0.85 and 0.90, and restricted sense (<img SRC="http:/img/fbpe/pab/v36n3/4792fr2.gif" ALIGN="absmiddle">) 0.66, 0.45 and 0.49.
Lactuca sativa; agronomic characters; genetic control; genetic parameters; breeding methods
