Construction of Core Germplasm Collection Based on Phenotypic Characters in Luffa spp.
Luffa,a major melon vegetables in China,is a crop of gourd family and the silk gourd genus,which is rich in nutrients and favored by consumers.With the increasing number and type of luffa germplasm resources,it is increas-ingly difficult to screen and preserve the excellent materials of luffa.In order to construct a core germplasm bank of luffa,eliminate germplasm materials with serious homogenization,and improve the efficiency of lucerne breeding,this study investigated the genetic diversity of 244 luffa germplasm resources by using 18 phenotypic traits that are highly representative of luffa as indicators,and compared and analyzed eight different sampling ratios(5%-40%),and three different sampling methods(random cluster sampling,group cluster sampling and preferential cluster sampling)were compared to analyze the representativeness of the core germplasm of luffa candidates.The results showed that the phe-notypic genetic variation of lucerne germplasm resources was relatively rich,of which the largest Shannon index was leaf width,3.0,and the smallest was seed melon length,1.8.The most suitable sampling ratio was 20%using the com-prehensive analysis of the seven evaluation indexes,and the most suitable sampling method was group cluster sampling.Using this method for core germplasm library construction,the primary core germplasm obtained containing 51 lucerne germplasm resources,accounting for 20.90%of all the original germplasm resources,and compared with the original germplasm,13 of the 18 agronomic traits were in full agreement with the original germplasm in terms of the maximum and minimum values,and the characteristic values of most traits were the same as those of the original germplasm or the differences were relatively small.The T-test showed that the mean values of all phenotypic traits had no significant dif-ferences with the original germplasm,indicating that the core germplasm library constructed by the method has good representativeness and rich genetic diversity.This study could provide basic support for the collection,preservation and innovative utilization of lucerne germplasm resources in the later stage,and also lays a foundation for improving the efficiency of lucerne variety improvement.