Mapping Of Disease Resistance Genes And Related Candidate Clones And Molecular Marker Assistant Selection

Wheat is one of the most important cereal plants and is often invaded by many kinds of bacteria, fungi and insects. Now scientists are trying to clone some resistance genes in wheat or in its related species, then transfer them into elite varieties to improve their resistant characteristics. But until now there is no efficient way to clone resistance genes in wheat due to its such a large genome(1.6 x 10 10bp). Through all kinds of ways, we can get some candidate genes, after that we must map them to specific chromosomes and identify the possible relationships between these candidate clones and target genes. In this study, a set of Nullisomic-Tetrasomic lines of "Chinese-spring" were used to analyze the distribution and location of these candidate genes, then part of deletion lines of "Chinese-spring" were used to map some candidate genes onto a small part of a chromosome. At the same time, a population of recombinant inbred lines (RILs) were used to map resistance and related candidate genes onto the genetic map.1. Using a set of nulli-tetrasomic lines do RFLP analysis, 15 candidate clones were mapped onto 11 specific chromosomes.2. Primers were designed and part of deletion lines were used to do PCR analysis, mapping 3 clones to sub-arm regions of certain chromosomes. njs2 is mapped on the middle of the long arm of the 5 homoeologue group. njs4 is mapped onto the region between the break point of the deletion line 3BS-1 and 3BS-9.njs22 is mapped onto the region between the break point of the deletion line 6DS-2 and 6DS-4.3. Analyze the polymorphism of 6 candidate clones between the parents of the ITMI population, find one clone njs4 showing polymorphism between them when two parents were digested with EcoR I, then use the population digested with EcoR I to do analysis, make the probe located on chromosome 3B and 19.8cM to the marker Xgwm299.Molecular markers are widely used in genetic mapping, QTL analysis, and gene locus tracking in genetic research. Furthermore it is very useful in wheat breeding. Developing resistant varieties is a most useful and efficient way to struggle with diseases and is helpful to environment. Traditional way is to inoculate plant with certain pathogens, then select those plants showing resistance to the pathogen. Using this way, to some extent the selection efficiency is lower because of the inoculation efficiency and the environment is not suit for the pathogen. When using marker assistant selection, we can avoid this deficiency. In this study:1. SSR loci from 84 pairs of primer were mapped to specific chromosomes using a set of "Chinese Spring" Nulli-Tetrasomic lines. Among them, the result of 50 pairs primers is the same as the result on the net ,5 rsult is different from the result on the net .This study mapped SSRlici from other 29 primers to specific chromosome firstly.2. Three SSR loci amplified by primer BARC78 were located on chromosome 4VLand they can be used to trace 4VL ofHaynaldia villosa.