Drought stress and tropical maize: QTL-by-environment interactions and stability of QTLs across environments for yield components and secondary traits
Drought stress and tropical maize: QTL-by-environment interactions and stability of QTLs across environments for yield components and secondary traits
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DOI：
10.1007/s00122-009-1099-x
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发表时间：
2009-09-01
影响因子：
5.4
通讯作者：
Ribaut, Jean-Marcel
中科院分区：
文献类型：
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作者：
Messmer, Rainer;Fracheboud, Yvan;Ribaut, Jean-Marcel
在代表四种环境的七个田间实验中评估了重组自交系（RIL）群体：墨西哥和津巴布韦的开花水分胁迫（WS）和灌溉良好（WW）条件。在每个单独的实验（单实验分析）以及每个环境，每个水分制度跨地点和跨所有实验（联合分析）中确定每个性状的QTL。在4个逐步分析中，共检测到雄性开花、开花至吐丝间隔、产量、粒数、百粒鲜重和株高6个目标性状的QTL，分别为81、57、51和34个。尽管高值的遗传力，QTL解释的表型方差减少，表明上位性相互作用。在每种环境、每种水分状况和所有试验的联合分析中，约有80%、60%和6%的QTL没有表现出显著的QTL与环境的互作（QTL x E）。在同一地点和同一水分条件下，QTL的表达在不同年份和不同地点都比较稳定。然而，QTL的稳定性急剧下降时，数据组合在不同的水分制度，反映了不同的遗传基础的目标性状在干旱和良好的浇水试验。通过WW（第1和8染色体）和WS（第1、3和5染色体）处理以及不同水分条件（第1染色体）的联合分析，鉴定出了几个不同性状的QTL簇。这些地区是未来标记辅助育种的明确目标，我们的研究结果证实，耐旱育种的最佳方法包括在水分胁迫下进行选择。
A recombinant inbred line (RIL) population was evaluated in seven field experiments representing four environments: water stress at flowering (WS) and well-watered (WW) conditions in Mexico and Zimbabwe. The QTLs were identified for each trait in each individual experiment (single-experiment analysis) as well as per environment, per water regime across locations and across all experiments (joint analyses). For the six target traits (male flowering, anthesis-to-silking interval, grain yield, kernel number, 100-kernel fresh weight and plant height) 81, 57, 51 and 34 QTLs were identified in the four step-wise analyses, respectively. Despite high values of heritability, the phenotypic variance explained by QTLs was reduced, indicating epistatic interactions. About 80, 60 and 6% of the QTLs did not present significant QTL-by-environment interactions (QTL x E) in the joint analyses per environment, per water regime and across all experiments. The expression of QTLs was quite stable across years at a given location and across locations under the same water regime. However, the stability of QTLs decreased drastically when data were combined across water regimes, reflecting a different genetic basis of the target traits in the drought and well-watered trials. Several clusters of QTLs for different traits were identified by the joint analyses of the WW (chromosomes 1 and 8) and WS (chromosomes 1, 3 and 5) treatments and across water regimes (chromosome 1). Those regions are clear targets for future marker-assisted breeding, and our results confirm that the best approach to breeding for drought tolerance includes selection under water stress.