Combining ability of waterlogging tolerance in barley

Waterlogging tolerance is one of the major objectives in barley (Hordeum vulgare L.) breeding programs. To make the selection more efficient, an understanding of the genetic behavior of waterlogging tolerance in barley is needed. For this purpose, a 6 by 6 half diallel analysis was conducted in barley from crosses of three waterlogging tolerant Chinese cultivars; and three susceptible Australian or Japanese cultivars. The waterlogging treatment was imposed starting from the three-leaf stage. The percentage of yellow leaf was recorded after waterlogging treatment. The diallel analysis was conducted according to Griffing. Three Chinese cultivars showed significantly higher general combining ability (GCA) for waterlogging tolerance while the variance of specific combining ability (SCA) was not significant, indicating that the tolerance was mainly controlled by additive effects. High heritability (h(B)(2)=h(N)(2)=0.73) of waterlogging tolerance indicated that selection in early generations could be very efficient. When selections are made in a segregating population, the most effective selection strategy is to discard the plants with severe leaf chlorosis.