Genetic and heterosis analysis for important agronomic traits of Chinese vegetable mustard (Brassica juncea) in different environments.

Genetic effects and genotype by environment (GE) interaction effects for some important agronomic traits of Chinese vegetable mustard were analyzed by using a genetic model including additive, dominance, additive x additive effects and their interaction effects with the environment. Four variations of Chinese vegetable mustard as parental lines and their F(1s), F(2s) were evaluated in two locations. It was revealed that the agronomic traits of Chinese vegetable mustard were mainly controlled by genetic effects except plant weight (PW) and leaf weight (LW) were observed to be more affected by GE interaction effects. Among the genetic effects, additive effects took the main proportion for tiller number (TN), leaf number (LN), leaf breadth (LB) and LW; dominance effects were the main components of PW, leaf length (LL), root weight (RW) and plant height (PH); additive x additive effects were the main components of plant breadth (PB). Among the GE interaction effects, additive x environment interaction effects mainly affected LB, LW and RW, while PW, LL, PH and PB were mainly controlled by dominance x environment interaction effects. Besides, additive x additive x environment interaction was the main factor, which controlled TN and LN of Chinese vegetable mustard. For heterosis analyses, TN, LN, LB and LW of Chinese vegetable mustard showed positive H(PM) and negative H(PB). The other traits showed positive H(PM) and H(PB). Heterosis arising from GE interaction was found to varying degree for different environments. It was shown that genetic heterosis and GE interaction effects were important factors for agronomic traits in Chinese vegetable mustard.