Abstract:【Objective】The peach belongs to the Rosaceae family, subfamily Prunoideae, genus Prunus, subgenus Amygdalus L. It is native to China. As the origin center of peach, China has more than 4,000 years of domestication and cultivation history of peach, the most obvious feature is the rich genetic diversity and integrity of wild relatives and cultivated local varieties, and the future expansion of the world's peach genetic background depends on the exploration and utilization of wild relatives and landraces of Chinese peach. However, in the process of domesticating from wild species to local varieties, peaches have experienced a serious genetic resource crisis, losing about two-thirds of their genetic resource diversity. In the southern Xinjiang region of China, the germplasm resources of soil peach are extremely abundant, and these rich germplasm resources can provide a reliable genetic material basis for the sustainable development of peach industry. Although these genetic resources are abundant, the research on the germplasm and fruit traits of peach in southern Xinjiang is still limited, which seriously hinders the effective development and utilization of these resources. Therefore, 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, in order to provide a valuable reference for its development and utilization.【Method】In this study, the investigation of soil peach resources was carried out in southern Xinjiang from August to October 2023, and the experimental materials were collected from cities and counties in Kashgar, Hotan, Alar, Artush and other regions of Xinjiang, covering all counties and cities in the oasis of the Tarim Basin in southern Xinjiang. A total of 133 representative germplasm resources were collected and comprehensively evaluated, and then 17 descriptive traits and 5 quantitative traits were systematically identified and the variation types were analyzed.【Result】The phenotypes of 133 peach germplasm fruits in southern Xinjiang showed a wide range of variation types, and a total of 72 variation types were observed, with an average variation type of nearly 4.2, indicating that the variation types of 17 descriptive traits were abundant, among which the fruit date of maturity and fruit flavor variation types were the most, and the fruit date of maturity mainly occurred from middle August to late October, and the overall bias was mid-late maturity, accounting for 84.21% of the whole maturity period. The fruit flavor was moderately sour and sweet, accounting for 54.89%. Among the 133 peach germplasms in southern Xinjiang, the majority of fruit shape is flat round, followed by oblong and round. The flesh color is predominantly white, followed by green-white and yellow. According to the fruit type, Biological status of accession, fruit size, fruit shape, fruit flesh color, background color, flavor, Total Soluble Solid, yield and quality, 133 peach germplasm resources in southern Xinjiang were comprehensively evaluated and analyzed, among which 75 peach germplasms had different flush dark and light, and 8 peach germplasms in southern Xinjiang had no color on the surface of the fruit and the background color of the peel was green, which provided excellent germplasm resources for the selection and breeding of green peach. The flesh color of 16 peach germplasms in southern Xinjiang was yellow, and the yellow flesh color can be subdivided into yellow, yellow-white, and orange. These resources could be used for peach breeding of yellow-fleshed peach. The coefficient of variation is an important index to evaluate the diversity of germplasm resources . The coefficient of variation of the five quantitative traits was 17.39%~48.49%, and the average coefficient of variation was 24.22%. The coefficient of variation of single fruit weight was the largest, which was 48.49%. The largest single fruit weight is Zhanminlangan 6, weighing 202.00g. In contrast, Shache Green Meat Peach No. 5 is the smallest soil peach germplasm fruit, weighing only 20.19g. The soluble solids content of the fruit is an important indicator of quality, and the main components are soluble sugars and soluble acids. The soluble solids content of the fruit was between 8.43%~20.77%, with an average of 13.42%, and the soluble solids content of Pishan Green Meat Peach No. 7 was the largest, and the least soluble solids content was Hetian Green Meat Peach No. 4. The results indicated that Pishan Green Meat Peach No. 7 belonged to a germplasm resource with good fruit quality.【Conclusion】The 133 peach germplasms in southern Xinjiang were rich in descriptive trait variation types and had high coefficient of variation of quantitative traits. Among these resources, 8 peachy germplasm resources with green peel background color were finally screened, including Shache Green Peach No. 1, Shache Green Meat Peach No. 3, Shache Green Meat Peach No. 4, Shache Green Meat Peach No. 5, Shache Green Meat Peach No. 6, Shache Green Peach No. 11, Hetian Green Meat Peach No. 5, Hetian Green Flesh Peach No. 17, and 16 peach resources with yellow flesh in southern Xinjiang, including Shache Yellow Flesh Peach No. 1, Shache Yellow Meat Peach No. 2, Shache Yellow Flesh Peach No. 3, Shache Yellow Flesh Peach No. 5, Shache Yellow Flesh Peach No. 6, Shache Yellow Meat Peach No. 7, Shache Yellow Meat Peach No. 4, Shache Yellow Meat Peach No. 8, Hetian Yellow Meat Peach No. 1, Hetian Yellow Meat Peach No. 3, Pishan Yellow Flesh Peach No. 1, Pishan Yellow Flesh Peach No. 3, Pishan Yellow Flesh Peach No. 4, Hetian Yellow Flesh Peach No. 2, Yecheng Yellow Flesh Peach No. 1 and Pishan Yellow Meat Peach No. 2 can be used as high-quality germplasms for the breeding of green-skinned peach and yellow-fleshed peach, respectively.
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