Multivariate analysis of 110 green super rice (GSR) lines for morpho-physiological diversity attributes.

Abstract

Genetic diversity present in rice genotypes plays a crucial role in improving breeding strategies and developing high-quality cultivars. This study evaluated genetic diversity, agronomic performance, and disease resistance across 110 unique rice cultivars over two growing seasons (2021-2022) using an alpha-lattice design. Ten morpho-physiological and yield characteristics were assessed along with resistance to brown leaf spot (BLS) in natural field conditions. The combined analysis of variance indicated highly significant genotypic effects (P < 0.01) across all traits, with broad-sense heritability values varying from 8.83% for days to maturity to 45.56% for plant height. K-means clustering effectively categorized genotypes into five distinct groups. Cluster 4 demonstrated the highest yield at 10.64 t ha⁻¹, characterized by early flowering, whereas Cluster 5 attained significant productivity of 10.2 t ha⁻¹ due to its large grain size. The distribution of BLS resistance demonstrated considerable variation across clusters (χ² = 50.1, P < 0.001). Cluster 1 presented 60% highly resistant genotypes, while Cluster 2 displayed 60% resistant genotypes, with no entries classified as susceptible. Notable performers comprised NGSR.18 with a multi-trait score of 70.77%, GSR1 achieving a yield of 12.76 t ha⁻¹, and GSR34, GSR49, GSR50 exhibiting high resistance to BLS. The correlation analysis demonstrated genetic independence between yield and disease resistance, thereby supporting the feasibility of simultaneous improvement. The findings offer significant genetic resources for the development of high-yielding, disease-resistant rice cultivars.