Assessment Of Genetic Diversity And Mapping Qtls For Resistance To Covered Smut In Oat

Oat (Avena L.) is a kind of crop for both food and forage. In recent years its nutritional value catch more and more people's attention, especiallyβ-glucan content, which can significantly lower blood lipids and regulate blood sugar. Now oat is gradually becoming an important functional food to prevent heart disease. The aim of this study was to assess of genetic diversity, identificate of covered smut resistance, and mapping covered Smut resistant QTL in oat germplasm resources. The main results of the study were summarized as follows:1. One hundred and seventy seven accessions of hulled oat with domestic and oversea origins were analyzed using 20 AFLP primer combinations. Selective amplification created 976 unambiguous bands, of which 185 bands were polymorphic. The percentage of polymorphic bands for each AFLP primer combination ranged from 9.3% to 35.9%, with the average of 19.0%. Shannon -Weaver indices of groups of accessions with diverse geographic origins varied from 0.19 to 0.34. This indicated that the genentic diversity of the 15 groups was significantly different, and the alien rescources was obviously greater than the domestic one . The results of PCA and UPGMA clustering analysis exhibited a good consistency, and were also consistent with geographic origins. All the accessions were classified into two categories based by PCAand UPGMA clustering analysis. One category covered mainly domestic accessions, the other category included accessions of Inner Mongolia and Qinghai as well as accessions from overseas. The exotic accessions were generally separated from domestic accessions while domestic accessions with different origins mixed up. This indicates that the relationship between domestic and oversea accessions was relatively far caused by lacking of effective exchange, and the domestic accessions of hulled oat were more homologous due to lack of diversity. It is important to promote the germplasm exchange with other countries and enrich the genetic diversity of hulled oat in China.2. The covered smut resistance of 458 accessions oat germplasm was tested in field under natural condition in 2006~2008. The results showed that the resistance to covered smut among these varieties were observable diverse in three years. There were 313 resistant oat varieties with the frequency of 68.3%, 37 moderate susceptible oat varieties with the frequency of 8.1%, 108 high susceptible oat varieties with the frequency of 23.6%. In combination with other Field traits survey results, 25 accenssions of naked oat germplasm resources with a good comprehensive traits were sreened out, Those accenssions were provided to breeders to use through a variety of technical means.3. The mapping F2 population with 155 individuals was derived from the Big Bright Luna Naked Oat / cross Rank7 (susceptible/resistant). The linkage map was constructed with 77 markers based on this population, which contented 17 linkage group. Total length of this map was 1192.7cM, with average distance of 15.5cM between adjcent markers. One putative QTL conferring resistance to covered smut of oat were detected on linkage group 1 and 14 respectively, accounting for 29.2% and 38.45% of the phenotypic variation.