Study on fruit diversity of wild seabuckthorn in Xinjiang

Abstract：【Objective】China is not only the most abundant place of the sea buckthorn plant germplasm resources, but also the center of plant differentiation, the original group and the origin of the seabuckthorn. Researches on the biological characteristics and characteristic differences of wild sea buckthorn in different areas of Xinjiang have not been reported so far. The aim of this study was to reveal the genetic diversity and variation of wild sea buckthorn resources in different populations in Xinjiang, and to provide reference for the exploitation, utilization and protection of the species【.Methods】From August to September of 2016, the mature fruits of wild sea buckthorn collected from 48 individuals from 6 populations derived from three different distribution areas of Altay, Ili and Aksu were used as research materials. 8 fruit characters (total sugar, vitamin C, total acid, ratio of sugar to acid, fruit color, flesh color, seed shape, seed color) were measured, respectively; and the morphological characteristics of fruits and seeds were observed according to the“reference standard and data standard of sea buckthorn germplasm resources”. The non-numerical characters were assigned and counted, separately. The coefficients of variation, relative range and population average value within and between the population variance components, phenotypic differentiation coefficients within and between the population mean square, F value and significance level were analyzed using DPS 7.05, Excel 2013 and SPSS 19.0 data processingsoftware. Furthermore, the Shannon Weaver diversity index and Simpson diversity index of fruit characters within each population were calculated separately, and the characteristic roots higher than 1 of the first 4 principal components was selected for further analysis.【Results】The average variation coefficient of fruit traits in wild seabuckthorn in Xinjiang was 40.11%, and the variation range was 21.77%-74.34%. The order of relative range and in average variation coefficient of different fruit characters was different, i.e. the variation degree between different fruit characters was different. The mean of differentiation coefficient of fruit characters between populations was 37.23%, and within the population was 62.77%. The diversity of fruit characters within populations is larger than that between populations, and variation within populations is the main source of variation of wild seabuckthorn in Xinjiang. The variation coefficients of the 8 fruit characters were different, among which the variation of fruit color was the highest (the average coefficient of variation was 74.34%) , and the relative genetic stability of the total sugar was lower (the average coefficient of variation was 21.77%) . The greatest differentiation coefficient of fruit characters was total acid (65.57%) , and the smallest one is flesh color (5.83%) . The average Shannon-weaver index and Simpson index of 6 wild seabuckthorn populations were 2.786 2 and 0.921 6, respectively. The highest fruit trait diversity was seen in the population of Habahe at 3.358 1 while the lowest was seen in the population of Zhaosu at 1.988 6. A rich genetic diversity existed between populations of wild sea buckthorn in Xinjiang. The cumulative contribution rate of the first 4 principal components of fruit traits was 81.46%, which could be used to describe most of the fruit traits.The contribution rate of principal component 1 was 23.19%, and the fruit quality index with higher load value was total acid. The contribution rate of principal component 2 was 21.62%, and the fruit quality index with higher load value was fruit color. The contribution rate of principal component 3 was 19.67%, and the fruit quality index with higher load value was total sugar. The contribution rate of principal component 4 was 16.98%, and the fruit quality index with higher load value was seed color.【Conclusion】The fruit characters of wild sea buckthorn in Xinjiang had high character difference and differentiation. The variation of fruit color was the biggest, while the variation of total sugar was the lowest.Phenotypic variation was the main source of the variation within population for Xinjiang wild sea buckthorn. The fruit trait diversity of Habahe population was the highest among the 6 population. The diversity of fruit sugar acid ratio was the highest in the 8 fruit traits. The total acid, fruit color, total sugar and seed color were the main factors that would cause the difference of fruit traits of Xinjiang wild seabuckthorn.