Genetic analysis of abiotic stress tolerance in tropical maize hybrids
1999
Betran, F.J. | Beck, D.L. | Edmeades, G.O. | Ribaut, J.M. | Banziger, M. | Sánchez, C. (Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Mexico, DF (Mexico))
Drought and low soil nitrogen (N) are limiting factors in farmer's fields throughout the world. Developing maize genotypes with better drought and low soil N tolerance has been a priority of breeders and physiologists at CIMMYT. This study examines: a) the genetic control and modes of gene action for drought and low N tolerance, b) dosage rate for drought and low N tolerance in hybrids, and c) combining ability for a group of promising lines under stress and non-stress conditions. Seventeen parental lines and their diallel were evaluated separately in trials planted side-by-side under drought stress, low N stress, and optimal conditions. Results show that as drought stress increased so did the importance of GCA and additive genetic effects. Non-additive effects were more important under low N stress and a significant number of cross-overs were observed between the GCA of lines under low and high N. Dosage effects were important under drought but not under low N, suggesting the need for including drought tolerant parents on both sides of a hybrid to achieve acceptable drought tolerance. CML339 had the highest GCA under drought and across environments. Hybrids including the lines CML341, CML344, and CML254 had good performance under low N.
显示更多 [+] 显示较少 [-]