Construction of high-density linkage map and identification of QTLs for resistance to sorghum downy mildew in maize (Zea mays L.)

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• 作者：Nagabhushan ; H. C. Lohithaswa ; Anand S. Pandravada
• 关键词：Sorghum downy mildew ; SSRs ; SNPs ; Linkage map ; QTLs ; Marker ; assisted selection
• 刊名：Molecular Breeding
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：37
• 期：1
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Plant Sciences; Plant Genetics & Genomics; Plant Pathology; Plant Physiology; Biotechnology;
• 出版者：Springer Netherlands
• ISSN：1572-9788
• 卷排序：37

文摘

Sorghum downy mildew (SDM), caused by obligate biotrophic fungi Peronosclerospora sorghi, is an economically important disease of maize. The genetics of resistance was reported to be polygenic thereby necessitating identification of QTLs for resistance to SDM to initiate effective marker-assisted selection programs. During post-rainy and winter season of 2012, 645 F_2:3 progeny families from the cross CML153 (susceptible) × CML226 (resistant) were screened for their reaction to SDM. Characterization of QTLs affecting resistance to SDM was undertaken using the genetic linkage map with 319 polymorphic SSR and SNP marker loci and the phenotypic data of F_2:3 families. Three QTLs conferring resistance to SDM were consistently identified on chromosomes 2, 3 and 6 in both seasons. The resistant parent CML226 contributed all the QTL alleles conferring resistance to SDM. The major QTL located on chromosome 2 explained 38.68% of total phenotypic variation in the combined analysis with a LOD score of 9.12. All the three QTL showed partially dominant gene effects in combined analysis. The detection of more than one QTL supports the hypothesis that quantitative genes control resistance to P. sorghi. The generation was advanced to F₆ using markers linked to major QTLs on chromosomes 2 and 3 to derive 33 SDM resistant maize inbred lines.