Analysis Genetic Effects And QTL Mapping Of Fusarium Moniliforme Ear Rot Resistance In Maize

Ear rot, caused by Fusarium moniliforme, is a serious disease of maize (Zea mays L.) in the world, especially in the southwest of China. Development and cultivation of resistant hybrids are the effective strategy to control Fusarium moniliforme ear rot. Therefore, we had made systematic researches on the hereditary variation regularity and QTL mapping of Fusarium moniliforme ear rot resistance. The main results are followed.1. F₁,BC₁, BC₂,F₂ derived from the single cross between R15 (resistant) and Ye478 (susceptible) and the two parents were evaluated for reaction to Fusarium moniliforme with artificial inoculation in different environments. The results showed that resistance to ear rot in maize is quantitative, and highly influenced by the environment. The parents were estimated to contain at least five resistant genes to Fusarium moniliforme ear rot and additive, dominant and additive xdominance-epistatic effects were in the genetic effects of maize ear rot.2. A total of 230 F₂ individuals derived from R15 (resistant) ×Ye478 (susceptible) was used to construct genetic map. The integrated molecular genetic linkage map was constructed by the 151 SSR and 88 AFLP markers, which spanned the genome of about 3463.5 cM with an average of 14.5 cM between two markers. QTL analyses were conducted using joint composite interval mapping (CIM). In Ya'an, six QTLs on chromosomes 2, 3, 4, 6 and 9 explained between 8.3 and 25.7% of the phenotypic variance; and in Mian Yang, four QTL on chromosomes 1, 6, 7 and 9 that accounted for 11.3-26.4% of the total phenotypic variance. Only 2 QTLs on chromosome 6 and 9 coincided in both environments, confirming the strong influence of the environment on these traits. The additive, dominant and partial dominant effects were in the genetic effects of maize ear rot.3. Six QTLs for plant height were identified on chromosomes 2, 3, 4 and 6 accounting for 9.4-26.3% of the total phenotypic variance. Four QTLs of ear height on chromosomes 2, 4 and 8 explained between 13.21% and 27.73% of the phenotypic variance. The main QTLs of Fusarium moniliforme ear rot resistance was really in the R15, and it was not linkage to plant height and ear height, which provided technology and material basis for marker-assisted selection (MAS) and clone gene.