QTL mapping of resistance to Fusarium ear rot using a RIL population in maize

• Published in: Molecular breeding 2008-10, Vol.22 (3), p.395-403
• Main Authors: Ding, Jun-Qiang, Wang, Xiao-Ming, Chander, Subhash, Yan, Jian-Bing, Li, Jian-Sheng
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Biotechnology; Breeding; Chromosome 3; Chromosomes; Corn; Ear rot; Epistasis; Fusarium; Gene mapping; Genetic distance; Identification methods; Life Sciences; Mapping; Marker-assisted selection; Markers; Molecular biology; Phenotypic variations; Plant biology; Plant breeding; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant Sciences; Quantitative trait loci; Zea mays
• ISSN: 1380-3743; 1572-9788
• DOI: 10.1007/s11032-008-9184-4

Fusarium ear rot is a prevalent disease in maize, reducing grain yields and quality. Resistance breeding is an efficient way to minimize losses caused by the disease. In this study, 187 lines from a RIL population along with the resistant (87-1) and susceptible (Zong 3) parents were planted in Zhengzhou and Beijing with three replications in years 2004 and 2006. Each line was artificially inoculated using the nail-punch method. Significant genotypic variation in response to Fusarium ear rot was detected in both years. Based on a genetic map containing 246 polymorphic SSR markers with average genetic distances of 9.1 cM, the ear-rot resistance QTL were firstly analyzed by composite interval mapping (CIM). Three QTL were detected in both Zhengzhou and Beijing in 2004; and three and four QTL, respectively, were identified in 2006. The resistant parent contributed all resistance QTL. By using composite interval mapping and a mixed model (MCIM), significant epistatic effects on Fusarium ear rot as well as interactions between mapped loci and environments were observed across environments. Two QTL on chromosome 3 (3.04 bin) were consistently identified across all environments by the two methods. The major resistant QTL with the largest effect was flanked by markers umc1025 and umc1742 on chromosome 3 (3.04 bin), explaining 13–22% of the phenotypic variation. The SSR markers closely flanking the major resistance QTL will facilitate marker-assisted selection (MAS) of resistance to Fusarium ear rot in maize breeding programs.