CREATING A CORE COLLECTION OF SUPERIOR ALNUS NEPALENSIS TREES BASED ON PHENOTYPE AND MOLECULAR MARKER DATA

Abstract

Towards the improved preservation and management of high-quality germplasm resources for Alnus nepalensis , a total of 84 samples from 28 superior A. nepalensis trees were used as an original germplasm collection. An optimal strategy for the creation of a core collection of superior A. nepalensis trees was devised by comparing the validity of 18 germplasm subsets. Each of these germplasm subsets was configured using unweighted average clustering and improved minimum distance stepwise sampling methods that integrated six sampling proportions, three data types, and three genetic distance methods. The germplasm subsets for the original germplasm collection were evaluated by quantitative and qualitative trait independence tests according to the data types. The results revealed that the developed germplasm subsets based on phenotype data and Euclidean genetic distances at 55, 45, 35 and 25% sampling proportions; molecular marker data and Nei’s genetic distances at 55, 45, 35, 25 and 15% sampling proportions; and combined phenotype and molecular marker data and mixed genetic distances at 55, 45, 35 and 25% sampling proportions could represent the original germplasm collection. The strategy of phenotype values and Euclidean genetic distance were more appropriate than integrating the phenotype and molecular markers data and mixed genetic distance for the creation of a core collection for superior A. nepalensis trees.Considering the effectiveness, practicability, and cost of the development of a core collection for superior A. nepalensis trees, an optimal strategy included an unweighted average technique, improved minimum distance stepwise sampling method, SRAP markers data, Nei’s genetic distance, and a 15% sampling proportion.