Most of the modern-day improved watermelon varieties succumb to various biotic and abiotic stresses mainly because of their narrow genetic base. Insights into the genetic diversity and population structure are crucial for broadening the genetic base and improving the adaptive value. The present experiment was conducted to study the genetic diversity and population structure of a germplasm panel comprising 336 Citrullus sp. accessions. Another objective was to formulate a core collection of Indian Citrullus sp. accessions. Data from 23 highly polymorphic microsatellite markers were used for genetic diversity and population structure analysis while both molecular and phenotypic data from 17 traits were used to formulate the core set. The markers yielded a total of 69 alleles with an average of three alleles per locus. Initially, the accessions clustered into two populations and an admixture group. Intra-population analysis revealed three and two statistically distinct subpopulations in Pop I and Pop II, respectively. The exotic collections were predominant in Pop I-A, Pop II-A and Pop II-B while the Indian accessions were preponderant in Pop I-B and Pop I-C. Pop I-B recorded the maximum magnitude of gene diversity and the highest number of alleles. The well-adapted Indian landraces could be deployed in future watermelon improvement programmes. The formulated core collection (n = 46; 23.71% of the entire collection studied) would ease in maintenance of the diversity present among indigenous Citrullus sp. accessions; would ease trait search while exploring Indian diversity and can be pooled with other collection(s) to form a global core of watermelon.

中文翻译：

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了解印度西瓜（Citrullus lanatus (Thunb.) Matsum. and Nakai）核心种质的遗传多样性、种群结构和发展

大多数现代改良西瓜品种屈服于各种生物和非生物胁迫，主要是因为它们的遗传基础狭窄。深入了解遗传多样性和种群结构对于拓宽遗传基础和提高适应性价值至关重要。本实验旨在研究由 336 个种质资源组成的种质资源组的遗传多样性和种群结构。瓜类sp。加入。另一个目标是制定印度的核心收藏瓜类sp。加入。来自 23 个高度多态性微卫星标记的数据被用于遗传多样性和种群结构分析，而来自 17 个性状的分子和表型数据被用于制定核心集。这些标记总共产生了 69 个等位基因，每个基因座平均有 3 个等位基因。最初，种质聚集成两个种群和一个混合组。种群内分析分别揭示了 Pop I 和 Pop II 中的三个和两个统计学上不同的亚群。异国情调的收藏在 Pop IA、Pop II-A 和 Pop II-B 中占主导地位，而印度的收藏在 Pop IB 和 Pop IC 中占优势。Pop IB记录了基因多样性的最大值和等位基因的数量。适应良好的印度地方品种可用于未来的西瓜改良计划。n= 46; 研究的整个馆藏的 23.71%）将有助于维持土著之间存在的多样性瓜类sp。加入；将在探索印度多样性的同时简化特征搜索，并且可以与其他集合合并以形成西瓜的全球核心。