Phenotypic diversity analysis of 133 accession local peach germplasm in Southern Xinjiang

Abstract: 【Objective】The peach belongs to the Rosaceae family, subfamily Prunoideae, genus Prunus, and subgenus Amygdalus L.. It is native to China. As the origin center of peach, China has more than 4000 years of domestication and cultivation history, the most obvious feature is the rich genetic diversity of local cultivated varieties. In the Southern Xinjiang region of China, the germplasm resources of local peach varieties or Tu Tao are extremely abundant. But the studies on fruit traits of peach is still limited. The purpose of this study was to gain an in-depth understanding of the variation characteristics and diversity of phenotypic traits in peach germplasm in southern Xinjiang, so as to provide a valuable reference for its development and utilization.【Methods】In this study, the investigation on peach varieties were carried out in Southern Xinjiang from August to October 2023, and the experimental materials were collected in Kashgar, Hotan, Alar, Artush covering main counties in the oasis of the Tarim Basin. A total of 133 representative germplasm resources were collected and evaluated, and then 17 descriptive traits and 5 quantitative traits were identified and the variation types were analyzed.【Results】The phenotypes of 133 peach germplasm fruits in Southern Xinjiang showed a wide range of variation, and a total of 72 variation types were observed, with an average variation type of nearly 4.2, indicating thatthe variation types of 17 descriptive traits were abundant, among which the fruit maturity date and flavor variation types were wide, and the maturity date mainly occurred from middle August to late October, and the mid-late maturity accounted for 84.21% of the whole maturity period. The fruit flavor was banlenced sour and sweet, accounting for 54.89% . The majority of fruit shapes were flat round, followed by oblong and round. The flesh color was predominantly white, followed by green-white and yellow. According to the fruit type, biological status of accession, fruit size, shape, flesh color, background color, flavor, soluble solids, yield and quality, were evaluated and analyzed, 75 accession had different flush color, and 8 accession had no flush color, the background color was green. The flesh color of 16 accession was yellow. The coefficient of variation of the five quantitative traits was 17.39%-48.49%, and the average coefficient of variation was 24.22%. The single fruit weight was the largest, which was 48.49% . The largest single fruit weight is Zhanminlangan 6, weighing 202.00 g. In contrast, Shache Green No. 5 is the smallest, weighing only 20.19 g. The soluble solids content of the fruit was between 8.43%-20.77%, with an average of 13.42%, and the hightest soluble solids content is Pishan Green No. 7.【Conclusion】The peach germplasms are very rich and diversity in southern Xinjiang, with high ratio of phenotypic variaionts. Based on this study, we identified a total 8 accession were excellent accessions with green flesh, and 16 excellent yellow- fleshed accessions, which provided the important resources for future breeding, varieties.