Assessment of Drought Tolerance in Rice Landraces via Seedling-Based Indices

Abstract

Landraces serve as a vital reservoir of genetic diversity, offering allelic variation crucial for breeding resilient cultivars. However, with the increasing frequency and intensity of drought due to climate change, identifying drought-resilient rice varieties is crucial to ensure sustainable rice production. Although, Nepal hosts a vast diversity of rice landraces, yet their potential for drought stress tolerance remains underexplored. This study evaluated 25 rice landraces for drought tolerance at the seedling stage using a completely randomized design (CRD) in 250 ml disposable cups under three moisture regimes: 60% field capacity (FC), 100% FC, and saturated conditions. Ten quantitative traits were analyzed, and significant variation was observed among landraces and across moisture conditions. Correlation analysis suggested that, under 60% FC, root length showed a significant positive correlation with shoot length, root: shoot ratio, and fresh root weight, whereas a negative correlation was noted between root: shoot ratio and root number. Germination percentage remained unaffected by moisture conditions. Principal component analysis revealed a positive connection of root length and root-to-shoot ratio towards 60% FC, while shoot length, fresh weight, dry weight, and root number were associated with saturated conditions. Among the landraces, Manamurey demonstrated superior performance across studied traits. These findings highlight the potential of specific landraces for drought resilience and emphasize the need for further evaluations at vegetative and reproductive stages to confirm their utility in breeding programs.