目的 分析罗汉果Siraitia grosvenorii种质遗传基础，以为其资源保护、品种改良和性状遗传结构解析提供依据。方法 采用SSR荧光分子标记对325份罗汉果及其近缘物种资源进行亲缘关系鉴定，并且进一步分析罗汉果遗传多样性、群体结构和构建其核心种质。结果 优选出的15对SSR荧光引物共检测到185个等位基因（平均为12.33个），平均香农信息指数（Shannon’s information index，I）为1.67，多态性信息含量指数（polymorphism information content，PIC）≥0.54；325份种质亲缘关系聚类在遗传距离0.95附近被划分为赤瓟、翅子罗汉果和罗汉果3个亚群，其中罗汉果亚群发现大量几乎无遗传差异个体，共鉴别获得140份具遗传差异的罗汉果初级核心种质。这些初级核心种质遗传分化系数（genetic differentiation coefficient，F_ST）为0.140，群体间、群体内、个体内遗传变异分别占总变异的14.0%、19.0%和67.0%，野生、地方和栽培种平均遗传距离分别为0.802 1、0.576 8、0.422 0，I分别为1.798、1.092、0.603；Jaccard遗传距离聚类分析在遗传距离0.8处被划分为9个亚群，群体结构和主成分分析均被划分为4个亚群。通过10%～70%比例随机抽样法，构建了32份核心种质，其采集地点占原始种质的94.12 %，等位基因数与原始种质的符合率为96.13%，I值为1.944 9。结论 优选出的15对SSR荧光引物多态性高，能有效鉴别罗汉果及其近缘物种赤瓟、翅子罗汉果。罗汉果初级核心种质存在中等程度遗传分化，遗传变异主要来自群体与个体内部，野生种与地方种遗传多样性高，栽培种遗传多样性低，存在4个明显基因库。构建的32份核心种质能充分代表原始种质地理来源与遗传多样性。

Objective To analyze the genetic basis of Siraitia grosvenorii germplasm resources in order to provide the basis for germplasm protection, variety improvement, and genetic structure of traits. Methods The genetic relationship of 325 germplasm resources of S. grosvenorii and its relative species were analyzed by fluorescently labeled SSR markers. Based on this, the genetic diversity and population genetic structure of S. grosvenorii were analyzed and its core collection was constructed. Results A total of 185 alleles were detected by 15 pairs of optimized SSR fluorescent primers (average 12.33 per pair of SSR primer) in these 325 germplasm resources, average Shannon’s information index of these alleles was 1.67, and polymorphism information content (PIC) were equal to or above 0.54. The 325 germplasm resources were divided into three subgroups by relative clustering analysis, namely Thladiantha dubia, Siraitia siamensis and S. grosvenorii at a genetic distance of 0.95. Among them, a great number of individuals of the S. grosvenorii subgroup were found to have almost no genetic differences. A total of 140 germplasm resources of S. grosvenorii with genetic differences were identified as a raw core collection. The genetic differentiation coefficient F_st of this raw core collection was 0.140. The percentages of genetic variation among populations, within populations, and among individuals in total variation of raw core collection were 14.0%, 19.0%, and 67.0%, respectively. The average genetic distance was respectively 0.802 1, 0.576 8 and 0.422 0, and Shannon’s information index I were respectively 1.798, 1.092, 0.603 for wild species, landraces, and cultivars. The raw core collection was divided into nine subgroups where genetic distance was 0.8 by clustering analysis of Jaccard genetic distance and four subgroups by population structure and principal component analysis. Random sampling ratios of 10%—70% were performed to establish a core collection with 32 germplasm resources. The core collection accounted for 94.12 % of original germplasm, and the coincidence rate between the allele number and the original germplasm was 96.13%, and Shannon’s information index was 1.944 9. Conclusion The polymorphism of selective 15 pairs of SSR fluorescent primers was high and could effectively identify S. grosvenorii and its related species, T. dubia and S. siamensis. The raw core collection of S. Grosvenorii is moderately genetically differentiated, with genetic variations mainly occurred within populations and individuals, high genetic diversity between wild and local species, low genetic diversity between cultivated species, and the existence of four distinct gene pools. The constructed 32 core collection could fully represent the original germplasm resources' geographical origin and genetic diversity.

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国家自然科学基金区域创新发展联合基金重点项目（U20A2004）；国家自然科学基金项目（32270398）；广西农业科学院科技发展基金项目（桂农科2022JM65，桂农科2018JZ36）；湖南省重点研发项目（2022NK2004）