Hernandez Mateo V, Crossa Jose, Singh Pawan K, Bains Navtej S, Singh Kuldeep, Sharma Indu
International Maize and Wheat Improvement Center, CIMMYT, Mexico Distrito Federal, Mexico.
PLoS One. 2012;7(6):e38008. doi: 10.1371/journal.pone.0038008. Epub 2012 Jun 5.
Stripe rust, leaf rust, tan spot, and Karnal bunt are economically significant diseases impacting wheat production. The objectives of this study were to identify quantitative trait loci for resistance to these diseases in a recombinant inbred line (RIL) from a cross HD29/WH542, and to evaluate the evidence for the presence loci on chromosome region conferring multiple disease resistance.
METHODOLOGY/PRINCIPAL FINDINGS: The RIL population was evaluated for four diseases and genotyped with DNA markers. Multi-trait (MT) analysis revealed thirteen QTLs on nine chromosomes, significantly associated with resistance. Phenotypic variation explained by all significant QTLs for KB, TS, Yr, Lr diseases were 57%, 55%, 38% and 22%, respectively. Marginal trait analysis identified the most significant QTLs for resistance to KB on chromosomes 1BS, 2DS, 3BS, 4BL, 5BL, and 5DL. Chromosomes 3AS and 4BL showed significant association with TS resistance. Significant QTLs for Yr resistance were identified on chromosomes 2AS, 4BL and 5BL, while Lr was significant on 6DS. MT analysis revealed that all the QTLs except 3BL significantly reduce KB and was contributed from parent HD29 while all resistant QTLs for TS except on chromosomes 2DS.1, 2DS.2 and 3BL came from WH542. Five resistant QTLs for Yr and six for Lr were contributed from parents WH542 and HD29 respectively. Chromosome region on 4BL showed significant association to KB, TS, and Yr in the population. The multi environment analysis for KB identified three putative QTLs of which two new QTLs, mapped on chromosomes 3BS and 5DL explained 10 and 20% of the phenotypic variation, respectively.
CONCLUSIONS/SIGNIFICANCE: This study revealed that MT analysis is an effective tool for detection of multi-trait QTLs for disease resistance. This approach is a more effective and practical than individual QTL mapping analyses. MT analysis identified RILs that combine resistance to multiple diseases from parents WH542 and/or HD29.
条锈病、叶锈病、黄斑病和印度腥黑穗病是影响小麦生产的重要经济病害。本研究的目的是在HD29/WH542杂交后代的重组自交系（RIL）中鉴定对这些病害的抗性数量性状位点，并评估染色体区域上存在赋予多种病害抗性位点的证据。
方法/主要发现：对RIL群体进行了四种病害的评估并用DNA标记进行基因分型。多性状（MT）分析在九条染色体上揭示了13个与抗性显著相关的QTL。所有显著的印度腥黑穗病、黄斑病、条锈病和叶锈病QTL解释的表型变异分别为57%、55%、38%和22%。边际性状分析确定了1BS、2DS、3BS、4BL、5BL和5DL染色体上对印度腥黑穗病抗性最显著的QTL。3AS和4BL染色体与黄斑病抗性显著相关。在2AS、4BL和5BL染色体上鉴定出了条锈病抗性的显著QTL，而叶锈病抗性在6DS染色体上显著。MT分析表明，除3BL外的所有QTL均显著降低印度腥黑穗病发病率，且来自亲本HD29，而除2DS.1、2DS.2和3BL染色体外的所有黄斑病抗性QTL均来自WH542。条锈病的五个抗性QTL和叶锈病的六个抗性QTL分别来自亲本WH542和HD29。4BL染色体区域在群体中与印度腥黑穗病、黄斑病和条锈病显著相关。对印度腥黑穗病的多环境分析确定了三个推定的QTL，其中两个新QTL分别位于3BS和5DL染色体上，解释了10%和20%的表型变异。
结论/意义：本研究表明，MT分析是检测抗病多性状QTL的有效工具。这种方法比单个QTL定位分析更有效、更实用。MT分析鉴定出了结合了亲本WH542和/或HD29对多种病害抗性的RIL。
