| Maize is the most important cereal crop worldwide, whose gross production has once surpassed that of rice and wheat in 1998. Owing to its total amount and industrial potential, maize can't be replaced by any other crops in the development of national economy, especially for continued researches and developments of the products of animal husbandry, industry, soft drinks, adhesives, fuel and so on. Thus, people make great interest in corn researches. Aspergillus flavus is widespread in corn-producing areas around the world. The corn grain is highly vulnerable to Aspergillus flavus infection during harvest and storage period. The metabolite of aflatoxin is a powerful carcinogen. Aspergillus flavus infection not only decreases the quality of maize, but seriously harms the security of people and livestock. This paper set out to detect Aspergillus flavus-resistant genes in maize. The most efficient way against the contamination from Aspergillus flavus is resistance breeding of maize.The location of maize major Aspergillus Flavus-resistant QTL for molecular marker-assisted selection, as well as the resistive breeding at the molecular level, thereby reducing the Aspergillus Flavus contamination in production and giving a protection of human health.Parents RA (resistance), M5P (susceptible) and their segregation progenies F2:3 families were inculated with spores of Aspergillus Flavus. Disease levels were measured by grades from 1 to 10, SSR markers were emplyed to map QTL contributing resistance to Aspergillus Flavus infection.The results in this study are summarized as follows:1.Ristribution of resistant grades were evaluated among 181 seeds from the F2:3 population. Result, showed there were 32 resistant lines with disease grades 1-3,4 susceptible lines with grades 8-10,48 weak resistant lines with grades 5-8, and 93 middle resistant lines with grades 3-5.The resistance of the entire F2:3 population was close to the normal distribution.2. A total of 786 SSR primers were employed to screen polymorphisms between the high resistant inbred line RA and the high sensitive inbred line M5P.Finally,80 primers were proved to be robust, reliable, and polymorphic between two parental lines. Plants in F2:3 family which originaten from parents RA ang M5P were genotypes SSR markers.The linkage map covered 7 chromosomes with a total genetic distance of 447.27 cM.The average distance of the flanking markers was 10.91 cM.3. By interval mapping, Three resistance QTLs was detected on chromosome 5 and chromosme 6.QTL with LOD value 2.0 was between marker umc1155 and phi048 on chromosome 5, which could accounted for 8.7% of the phenotypic variance.Two QTLs with LOD value 2.66 and 3.02 on chromosome 6,which could account for 9.6% and 19.3% of the phenotypic variance,respecticely QTL with LOD value 3.02 could be a major QTL contributing resistance to Aspergillus Flavus infection. |
