QTL Mapping For Resistance To Furasium Moniliforme Ear Rot Using Recombinant Inbred Lines In Maize

Maize ear rot is one of the prevalent diseases in the world.The disease can be caused by more than 20 species of fungi. Fusarium moniliforme and Fusarium graminearum are two predominant pathogens of the disease in china. The disease not only causes severe yield losses and quality decrease, the toxin produced by some fugi also pose a potential threat to animal and human life and health. Cultivation and planting resistant hybrids are the economical and effective way to control ear rot disease,In this thesis , the resistant inbred line BT-1 and susceptible inbred line N6 as parental materials, a mapping population of 250 recombinant inbred lines (RILs) was produced by single-seed way and the marker linkage map with 207 SSR markers was constructed, QTL analysis on the resistance was conducted by field inoculation . Researches on QTL mapping of resistant gene of ear rot are made,the main results are as followed:1. A total of 250 F8 RIL individuals derived from BT-1 and N6 was used to construct genetic linkage map.The genetic linkage map contained 207 SSR markers,which spanned a total length of 1826.9cM with an average of 8.8 cM between two markers.the order of markers was basically consistent with the IBM map. on the 10 linkge groups, the biggest distance between two markers was 32.3 cM.2. QTL analysis were conducted by interval mapping (IM) and joint composite interval mapping(CIM).In 2007, two QTLs was identified by the two methods, one on chromosome 3 flanked by markers umc2256 and bnlg1144 explained 8%-11% of the phenotypic variation , the other on chromosome 4 flanked by markers umc1651and dupssr28 explained 8%-15% of the phenotypic variation. In 2008, two QTLs was identified by the two methods, one on chromosome 3 flanked by markers umc2256 and bnlg1144 explained 9%-12% of the phenotypic variation, the other on chromosome 4 flanked by markers umc1964 and mmc0371 explained 15%-17% of the phenotypic variation. QTL analysis were done on the mean resistance of the two years, only one QTL was identified, which on chromosome 3 flanked by markers umc2256 and bnlg1144 explained 8%-13% of the phenotypic variation. In a word, the major resistant QTLs were located on chromosome 3 and 4, which were similar to previous studies.The two major resistant QTLs were identified in the two years'experiments, which would be used for fine mapping and make-assisted selection.3. QTL analysis were also conducted on the relative agronomic traits: days to tasseling, days to pollen, days to silk, days to pollen and tassel branch number.The QTL controlling tassel branch number on chromosome 4 and the QTL controlling resistance were showed in the same marker interval.