Genetic component analysis of waterlogging tolerance in cucumber.

摘要

Waterlogging is one of the most important environmental stresses that severely limits crop growth and productivity. Greenhouse studies were conducted to estimate the genetic variation of F3 families for waterlogging tolerance of cucumber by estimating the variance component, broad- and narrow-sense heritabilities of waterlogging traits and determine the phenotypic and genetic correlations between these traits in the F3 families. A set of 144 F3 families derived from a cross between a PW0801 (susceptible) and PW0832 (tolerant) cucumber breeding lines were assessed for three waterlogging traits, tolerance (TOL), adventitious root formation (ARF) and shoot dry weight (SDW). The results showed that F1 generation in the waterlogged treatment had substantial increase in mean value across all traits with values higher than mean of the 2 parents. The phenotypic and genetic correlations among waterlogged traits were significantly positive between TOL and ARF, TOL and SDW and ARF and SDW. The magnitude of the variance component estimates for variations among F3 family mean ( sigma 2F3) were generally higher than that of the mean variation of the F3 families ( sigma 2mF3). The estimates of the additive genetic variance ( sigma 2A) for all treatments were high and positive in magnitude while their dominance variance ( sigma 2D) estimates were negative and smaller. Finally, with the wide range of genetic variation among members of the F3 family means coupled with the high narrow-sense heritabilities, it was suggested that cucumber cultivars with high level of waterlogging tolerance could be developed through breeding programme with the parental lines selected in the present study.