Detection and integration of gene mapping of downy mildew resistance in maize inbred lines though linkage and association

• Published in: Euphytica Vol. 187; no. 3; pp. 369 - 379
• Main Authors: Phumichai, Chalermpol, Chunwongse, Julapark, Jampatong, Sansern, Grudloyma, Pichet, Pulam, Taweesak, Doungchan, Weerasak, Wongkaew, Arunee, Kongsiri, Nongluck
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2012; Springer; Springer Nature B.V
• Subjects: Agronomy. Soil science and plant productions; Airborne microorganisms; Association analysis; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Breeding; Classical and quantitative genetics. Population genetics. Molecular genetics; Corn; Crop science; Downy mildew; Fundamental and applied biological sciences. Psychology; Gene mapping; Generalities. Genetics. Plant material; Genes; Genetic diversity; Genetic linkage; Genetic markers; Genetic research; Genetics and breeding of economic plants; Germplasm; Heritability; Inbreeding; Integration; Life Sciences; Linkage disequilibrium; marker-assisted selection; Molecular genetics; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant resistance; Plant Sciences; Population structure; Subpopulations; Transgenic plants; Variance analysis; Varietal selection. Specialized plant breeding, plant breeding aims; Zea mays; Association mapping; Population structure; Maize inbred lines; SSR; Downy mildew; Genetic mapping; Cartography; Monocotyledones; Zea mays; Cereal crop; Resistance; Gramineae; Microsatellite DNA; Angiospermae; Genetic improvement; Spermatophyta; Pure line
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1007/s10681-012-0699-8

Association mapping relies on the variation and extent of linkage disequilibrium within a species to identify genes of interest; this is an alternative to linkage mapping in traditional biparental population, which exploits only the variation in the two parents of the mapping population. This study was designed to identify association between 48 SSR markers and downy mildew (DM) resistance using a set of 60 public and private maize inbred lines in Thailand. Genetic diversity and population structure in the set were calculated. A total of 489 alleles with an average gene diversity of 0.70 revealed two subpopulations among the 60 maize inbred lines. Analysis of variance resulted in significant effects of phenotypic values of tested entries, with significant effects of inbred lines, locations, and their interaction. In addition, the analysis of variance for broad sense heritability also indicated high heritability (0.97), and association analysis revealed three significant SSR-trait associations ( P  < 0.05). These three significant SSR loci have not been reported in previous linkage mapping studies. Our results suggest that new allelic variants associated with DM resistance in these germplasm collections should be useful to help identify new lines carrying alleles for DM resistance in breeding marker-assisted selection programs.