Rahman H, Pekic S, Lazic-Jancic V, Quarrie S A, Shah S M A, Pervez A, Shah M M
John Innes Centre, Norwich Research Park, Colney, Norwich.
Genet Mol Res. 2011 May 17;10(2):889-901. doi: 10.4238/vol10-2gmr1139.
Drought tolerance is one of the most important but complex traits of crops. We looked for quantitative trait loci (QTLs) that affect drought tolerance in maize. Two maize inbreds and their advanced lines were evaluated for drought-related traits. A genetic linkage map developed using RFLP markers was used to identify QTLs associated with drought-related traits. Twenty-two QTLs were detected, with a minimum of one and a maximum of nine for drought-related traits. A single-QTL was detected for sugar concentration accounting for about 52.2% of the phenotypic variation on chromosome 6. A single-QTL was also identified for each of the traits root density, root dry weight, total biomass, relative water content, and leaf abscisic acid content, on chromosomes 1 and 7, contributing to 24, 0.2, 0.4, 7, and 19% of the phenotypic variance, respectively. Three QTLs were identified for grain yield on chromosomes 1, 5, and 9, explaining 75% of the observed phenotypic variability, whereas four QTLs were detected for osmotic potential on chromosomes 1, 3, and 9, together accounting for 50% of the phenotypic variance. Nine QTLs were detected for leaf surface area on chromosomes 3 and 9, with various degrees of phenotypic variance, ranging from 25.8 to 42.2%. Four major clusters of QTLs were identified on chromosomes 1, 3, 7, and 9. A QTL for yield on chromosome 1 was found co-locating with the QTLs for root traits, total biomass, and osmotic potential in a region of about 15 cM. A cluster of QTLs for leaf surface area were coincident with a QTL for osmotic potential on chromosome 3. The QTLs for leaf area also clustered on chromosome 9, whereas QTLs for leaf abscisic acid content and relative water content coincided on chromosome 7, 10 cM apart. Co-location of QTLs for different traits indicates potential pleiotropism or tight linkage, which may be useful for indirect selection in maize improvement for drought tolerance.
耐旱性是作物最重要但又复杂的性状之一。我们寻找了影响玉米耐旱性的数量性状位点（QTL）。对两个玉米自交系及其高世代品系进行了与干旱相关性状的评估。利用限制性片段长度多态性（RFLP）标记构建的遗传连锁图谱用于鉴定与干旱相关性状相关的QTL。共检测到22个QTL，与干旱相关性状相关的QTL最少1个，最多9个。在6号染色体上检测到一个与糖浓度相关的单QTL，占表型变异的约52.2%。在1号和7号染色体上还分别鉴定出一个与根密度、根干重、总生物量、相对含水量和叶片脱落酸含量等性状相关的单QTL，分别占表型变异的24%、0.2%、0.4%、7%和19%。在1号、5号和9号染色体上鉴定出3个与籽粒产量相关的QTL，解释了观察到的表型变异的75%；而在1号、3号和9号染色体上检测到4个与渗透势相关的QTL，共占表型变异的50%。在3号和9号染色体上检测到9个与叶面积相关的QTL，表型变异程度各异，范围为25.8%至42.2%。在1号、3号、7号和9号染色体上鉴定出4个主要的QTL簇。在1号染色体上发现一个与产量相关的QTL与根性状、总生物量和渗透势相关的QTL在约15厘摩的区域内共定位。一组与叶面积相关的QTL与3号染色体上的一个与渗透势相关的QTL重合。叶面积相关的QTL也在9号染色体上成簇，而叶片脱落酸含量和相对含水量相关的QTL在7号染色体上重合，相距10厘摩。不同性状相关QTL的共定位表明可能存在潜在的多效性或紧密连锁，这可能有助于在玉米耐旱性改良中进行间接选择。
