Genetic Diversity Analysis And Establish-ment Of The Primary Core Collection Of Pepper Germplasm Resources

Pepper, belongs to Solanaceae, genus Capsicum, is one of main fruit vegetables and important condiment in China. Core collection preserves the greatest genetic diversity by using the minimum population. It is a foundation for further collection, conservation and classification of germplasm, excavation of excellent genes and breeding work. Therefore, it is very significant for improving utilization efficiency of germplasm and deeper research to study the construction and evaluation of core collection of pepper.In this study, we studies genetic diversity of 409 pepper germplasm, construction methods, evaluation and improvement of core collection. The main conclusions are as follows:1. The collected germplasm resources have high genetic diversity. The genetic diversity indexes of 19 phenotypic traits range from 5.49 to 5.98. The maximum genetic diversity indexes were from fruit weight and calyx edge shape with 5.98, and the minimum is 5.49 which from filaments and anthers. The average genetic diversity index was 5.89. There were rich variations in many important traits. The correlation analysis of six quantitative traits shows that four traits, pepper fruit weight, fruit length, fruit width and flesh thickness were highly negative correlation with first flower node and piquancy. However, the four traits showed a significant positive correlation with each other except fruit width and fruit length.2. According to fruit shape index,409 original materials were divided into 5 groups. Based on the data of 26 phenotypic traits, four kinds of sampling ratio methods, five overall sampling sizes, two sampling methods and the role of grouping or not were compared. The result showed that 40% sampling size, logarithmic ratio method, and systematic cluster sampling fitted peppers primary core collection. So a primary core collection containing 164 copies of materials was built according the above program.3. The primary core collection was examined and evaluated by genetic diversity index(I), ratio of phenotype retained (RPR), accordance rate of the range, average and standard deviation, etc. The results show that:the core collection genetic diversity index for each trait was higher than raw materials; The RPR of 20 qualitative traits reached 96.5%; Mean, range, coefficient of variation in six quantitative traits were close to the original materials. And the three coefficient coincidence rate was higher than 80%. Base on the evaluation of representative of core collection, the material number of core collection were added, and the primary core collection with 166 materials was built according to phenotypic data.