Stability of QTL Across Environments and QTL-by-Environment Interactions for Plant and Ear Height in Maize

摘要

Better understanding of genotype-by-environment interaction(GEI)is expected to provide a solid foundation for genetic improvement of crop productivity especially under drought-prone environments.To elucidate the genetic basis of the plant and ear height,2 F2:3 populations were derived from the crosses of Qi 319 × Huangzaosi(Q/H)and Ye 478 × Huangzaosi(Y/H)with 230 and 235 families,respectively,and their parents were evaluated under 3 diverse environments in Henan,Beijing,and Xinjiang,China during the year of 2007 and 2008,and all the lines were also evaluated under water stress environment.The mapping results showed that a total of 21 and 12 QTLs were identified for plant height in the Q/H and Y/H population,respectively,and 24 and 13 QTLs for ear height,respectively.About 56 and 73% of the QTLs for 2 traits did not present significant QTL-by-environment interaction(QEI)in the normal joint analyses for Q/H and Y/H population,respectively,and about 73% of the QTLs detected did not show significant QEI according to joint analyses for stress condition in Q/H.Most of the detected major QTLs exhibited high stability across different environments.Besides,several major QTLs were detected with large and consistent effect under normal condition(Chr.6 and 7 in Q/H;Chr.1,3 and 9 in Y/H),or across 2 water regimes(Chr.1,8 and 10 for in Q/H).There were several constitutive QTLs(3 for Q/H and 1 for Y/H)with no or minor QTL-by-environment for the 2 populations.Finally,we found several genomic regions(Chr.1,10,etc.)to be co-located across the populations,which could provide useful reference for genetic improvement of these traits in maize breeding programs.Comparative genomic analysis revealed that 3 genes/genetic segments associated with plant height in rice were orthologous to these 3 identified genomic regions carrying the major QTLs for plant and ear height on Chr.1,6,and 8,respectively.