Genetic Diversity And Elite Accessions Identification In Pepper Germplasm Introduced From Abroad

Pepper(Capsicum annuum L), as one species of Capsicum(Capsicum) of Solanaceae (Solanaceae), has abundant content of vitamin C, folic acid, magnesium and potassium, among these the content of vitamin C ranks first in vegetables. In pepper breeding, it is important to collect germplasm resources and study their genetic diversity. There is distant relation and great differences in genetics between domestic resources and foreign resources. Through introducting of foreign peppers, it would enrich the genetic background of domestic pepper, expand pepper germplasm resources, offer useful materials in genetic breeding of pepper, and ensure the rapid development of pepper industry. Screening elite resources is the basis of the quality and disease resistance breeding of pepper. In this experiment we used202pepper accessions collected from abroad as the test materials to evaluate the interesting traits such as good nutritional quality, low temperature and light tolerance, and phytophthora capsici resistance. Combining with agronomic traits, SSR markers, genetic diversity of this collection was analyzed. This research will provide elite materials and theoretical reference for germplasm collection, genetic research and breeding practices in pepper.1. Using software SPSS19.0,23major agronomic traits for plants, leaves, flowers, and fruits were investigated and perfomed statistical analysis. There was a big difference in a same trait between different materials. Diversity variations were also observed among different traits, in which the variation coefficient of the average weight was the largest, reaching at98.94%。2. Using software SPSS19.0, Q cluster analysis and principal component analysis, for main agronomic traits observed in202pepper accessions were performed. The results suggested that the tested materials could be divided into four groups with8subgroups. Cluster Ⅰ included three subgroups, cluster Ⅱ included five accessions, Cluster Ⅲ included three subgroups, Class Ⅳ has3accessions (65、186and73). Four main factors were suggested in principal component analysis, namely fruit traits factor, leaf size factor, style factor, anther color factor, which provided the useful data for the further utilization of this collection. 3. The levels of Vc, and soluble sugar of202pepper accessions were measured, resulting in12accessions with high Vc content and10accessions with high soluble sugar content. This will provide elite materials for pepper quality breeding.4. Nine pepper accessions with low temperature and light resistance were selected by using methods of cold-resistant progression and chlorophyll fluorescence measurement.5. The202tested materials were amplified by PCR amplification with22pairs of SSR primers. By using software NTSYS2.1, genetic diversity and principal coordinate analysis resulted in three main groups, which was related to their origins.6. Sixty one accessions were selected from202pepper accessions by screening with two pairs of primers linked to phytophthora capsici resistance. The method of cut stem inoculation was used for bio-assay identification, showing that41materials were resistance.