Development And Application Of SSR Markers In Juglans Regia

Walnut, also known as peca, is one of the world’s four major nuts, with rich nutritional value, and is an important nut crop in China. The best way to promote the development of walnut research is the molecular marker, because of the genome is unkown. Walnut transcriptome data for development of EST-SSR markers used in this study,7 local walnut varieties and ’Qinglin’×’Yuan Lin’ hybrid F1 generation is selected used to construct fingerprinting and to locate gene Anthracnose. The main results are as follows:1. From transcriptome database of J. regia,9613 unigenes were downloaded and analyzed. 1641 SSRs (microsatellite) were found by using the SSRHunter program. The frequency of SSRs was approximately 1/9.27 kb. Among them, AG/CT motift was the most abundant type in the di-nucleotide repeat categories respectively,followed by AT/AT.The dinucelotide repeats appeared to be the most abundant SSRs(83.67%), followed by trinucelotide repeats (11.15%), whereas the hexanuclotide repeats were less abundant. One hundred and one pairs of SSR primer with different types and the number of repeats were designed and synthesized, and 7 pairs of SSR primer with high polymorphic were screened from them.2. Molecular identification by 10 simple sequence repeat (SSR) markers were conducted on 7 cultivars of J. regia. WGR69, WGR281, WGA376,3 pairs of core primers were screened from 10 pairs of primers. Through these 3 pairs of primers could distinguish the 7 walnut varieties, with 2 pairs of primers could distinguish the 6 walnut varieties. Within species, the efficiency of BSE-SSR is higher than EST-SSR.3. Genetic diversity analysis using 10 pairs of SSR markers of 7 walnut varieties.7 walnut varieties were divided into 3 groups.’Reijia’ and ’Ruixiu’ clustered into one group, Xinjiang on the genetic background of ’LiaoningNo.1’ and ’Yuanfeng’ and ’Yuanlin’ three varieties were clustered into one group, the ’Xiangling’ and ’Qinglin’ two local cultivars could be clustered into one group, and the other is far twogroups of relationship. The results can provide some guidance for local walnut breeding.4. Using SSR markers, in order to Anthracnose Resistant Varieties’ Qinglin,’sense of colletotrichum species ’Yuan Lin’ and ’Qinglin ’×’ Yuan Lin’ F1 as a sample, to resistant locus detected of Anthracnose by the BSA method.194 SSR primers of walnut were used to test 87 samples,58 primers were differential in the parents have primer bands of, in the final screening of resistance associated,there were one pair of primers left. The SSR marker was converted to the SCAR marker, which more stable, to provide a prerequisite for future gene mapping, map based cloning, molecular marker assisted breeding.