Knowledge of genetic diversity and potential heterotic relationships among parental lines is of significant importance in hybrid rice breeding programs. In the present study, in order to understand the genetic diversity among 96 parental lines, they were characterized for their diversity with respect to their morphological traits (n = 12) and molecular markers using a set of 50 SSR markers. Morphological diversity was estimated using Mahalanobis D² statistics in terms of generalized group distance. Based on morphological diversity analysis, the 96 lines were grouped into 5 major and 13 monogenotypic clusters. In molecular marker analysis, the parental lines were consistently clustered into B (Maintainer group) and R (Restorer group) groups based on distance and model based approaches. Strong correspondence was observed between the pedigree of parental lines with molecular genotyping based grouping than morphological trait based grouping. From the results of the present investigation, it is evident that the available diversity among the two groups i.e., maintainer group (B) and restorer group (R) is sufficient for developing heterotic hybrids, but within the maintainer and restorer groups, the diversity is limited, the diversity among restorers was moderate, while it was low among the maintainers and hence efforts are needed for broadening their genetic base of parental lines for development and adoption of high-yielding hybrids.

中文翻译：

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杂交水稻杂种优势亲本系遗传多样性的评价。

在杂交水稻育种计划中，了解遗传多样性和亲本系之间潜在的杂种关系非常重要。在本研究中，为了了解96个亲本系的遗传多样性，使用了50个SSR标记对它们的形态特征（n = 12）和分子标记进行了表征。使用Mahalanobis D ²估计形态多样性根据广义组距离进行统计。根据形态多样性分析，将96个品系分为5个主要和13个单基因型簇。在分子标记分析中，基于距离和基于模型的方法，将亲本系一致地分为B（维护者组）和R（恢复者组）组。观察到的亲本系谱系与基于分子基因分型的分组比基于形态学特征的分组之间的强对应性。从本研究的结果来看，很明显，维持者组（B）和恢复者组（R）这两个组之间的可用多样性足以开发杂种杂种，但是在维持者和恢复者组中，多样性是有限，恢复者之间的差异中等