It is essential to elucidate genetic diversity and relationships among related varieties of origin and landraces for improving the breeding process. Since rice breeding has improved agronomic traits such as yield and eating quality during green revolution, modern rice varieties are originated from narrow genetic resource and closely related. To resolve the population structure and genetic diversity in bold type rice varieties of southern India, we used a total of 81 rice genotypes by 100 simple sequence repeat markers composed of 36 improved varieties and 45 landraces, which are representative and important for bold type grain rice breeding. The landraces exhibit greater gene diversity than improved lines, suggesting that landraces can provide additional genetic diversity for future breeding. Clustering by Ward method was done to establish a relationship among the 81 rice genotypes. All the genotypes were clustered into mainly 5 clusters. Principle component analysis revealed that the first principal component revealed 42.87% variation, while the second component showed 14.01% variation. Among the eight morpho-physiological and plant production traits studied, the relative water content and spikelet fertility percentage contributed towards maximum diversity. Principle co-ordinate analysis evidently differentiated the genotypes to high yielding varieties with common ancestry. Population structure analysis also obviously classified the genotypes into high yielding susceptible and indigenous tolerant groups. These old varieties and landraces present in crop germplasm collections represent a strategic reserve of genetic variation that can be tapped for varieties and understanding of stress response and developing new varieties that are physiologically adapted to highly variable, climate-resilient environments.

中文翻译：

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印度南部粗型稻种的遗传多样性和种群结构分析

阐明相关起源品种和地方品种之间的遗传多样性和关系对于改进育种过程至关重要。由于水稻育种在绿色革命中提高了产量和食用品质等农艺性状，现代水稻品种起源于狭隘的遗传资源，且关系密切。为解析印度南部粗粒型水稻品种的种群结构和遗传多样性，我们利用由36个改良品种和45个地方品种组成的100个简单序列重复标记共使用了81个水稻基因型，对粗粒型水稻具有代表性和重要意义。配种。地方品种比改良品系表现出更大的基因多样性，这表明地方品种可以为未来的育种提供额外的遗传多样性。通过 Ward 方法进行聚类以建立 81 个水稻基因型之间的关系。所有基因型主要分为5个簇。主成分分析显示，第一主成分变异42.87%，第二主成分变异14.01%。在研究的八种形态生理和植物生产性状中，相对含水量和小穗肥力百分比有助于实现最大的多样性。原理坐标分析明显将基因型区分为具有共同祖先的高产品种。种群结构分析也明显地将基因型分为高产易感组和土着耐受组。