Construction Of Xinjiang Wild Walnut Resource Database And Research On Methods Of Building Core Collection

Xinjiang wild walnut(Juglans regia L.) belongs to Juglandaceae, Juglans as perennial deciduous trees. It is only distributed in the Yili River Valley the Gongliu Wild Walnut Nature Reserve in China.This paper overviewed the general situation and present research status on wild walnut, and established the wild walnut germplasm resources basic database with the investigation and data, then discussed on construction methods of wild walnut by SSR molecular data of4457wild walnut samples, and eventually selected the51samples as core collection of wild walnut. The following are the main research results:(1) We established the wild walnut germplasm resources basic database using Microsoft Office Access2007database software. This database included4646trees’ height and diameter at breast height, bark smoothness, color and luster and growth potential of branches and other basic data of wild walnut trees and rhizoctonia, mite, branch blight, blackwater ink disease and decayed disease such as disease information, and418wild walnut fruit type and flowering data (there are318complete flowering datas). The database greatly reduces the management costs of germplasm resources of wild walnut, and could facilitate researchers and producers to quickly get accurate and detailed information about wild walnut trees.(2) Through the comparative analysis of reserved rate of average effective numbers of alleles, average Nei’s genetic diversity index and Shannon information index of117core collections, the results showed that the improved LDSS method is the most effective way to build wild walnut core collection.(3)51samples, covering1.14%of the original germplasm, were chosen as wild walnut core collections, t-test results showed that the core collection and original germplasm were not significant difference at0.05probability level, indicating that the core collection can well represent the genetic diversity of original group. Its average genetic distance is higher than the original group’s, indicationg that core collection reduced the original group’s genetic redundancy. In addition, fruit phenotype of core collection has covered all14types of fruit of original groups, indicating that core collection can represent the fruit type diversity of original group.(4) Finally, some suggestion on germplasm conservation of walnut resources were put forward, including updating the wild walnut germplasm resources database constantly, adding and sharinginformations between home and abroad, and preserving core collection via "in-situ" and "ex-situ"conservation menthods.