Core collection construction of Ningxia tomato germplasm resources based on phenotypic traits

In order to solve the problems of large quantity of tomato germplasm resources, high conservation difficulty, heavy renewal burden and low breeding efficiency for fine varieties in Ningxia region, the genetic diversity of 20 phenotypic traits for 480 tomato germplasm resources was analyzed by correlation analysis, principal component analysis and cluster analysis. Euclidean distance and unweighted pair-group method with arithmetic means (UPGMA) were used, and then the methods of random sampling, preferential sampling and deviation sampling were separately used to construct core collections according to 10% sampling ratio, and the representation of core collections was evaluated. The results showed that the 480 tomato germplasms had rich genetic diversity and could be divided into six groups when the Euclidean distance was 1.25. Three groups of core collections R1, P1 and D1 were successfully constructed, among which R1 and D1 separately constructed by random sampling method and deviation sampling method were consistent with the construction principle of core collection, and all the three groups of core collections had good heterogeneity, and P1 constructed by preferential sampling method obtained greater genetic variation. In a word, the core collections of tomato germplasm resources constructed in Ningxia provide scientific methods for the conservation of tomato germplasm resources and breeding of new varieties, and also provide theoretical references for the related research of germplasm resources.