Identification of superior rice genotypes through genetic variability and association analysis for early seedling vigour and yield under wet direct-seeded rice (Oryza sativa L.)

Abstract

Direct-seeded rice (DSR), identified as a resource efficient rice production technology often faces challenges associated with poor crop establishment and inadequate early seedling vigour. The present study assessed genetic variability and genetic parameters for early seedling vigour (ESV) and yield-related traits, and determined their associations and direct and indirect effects on grain yield under wet DSR conditions. Sixty-four rice genotypes, including 59 genotypes and five checks, were evaluated at the Wetland Farm, S.V. Agricultural College, Tirupati, Andhra Pradesh, during Rabi 2024-2025. Ten ESV and ten yield-related traits were evaluated. Analysis of variance revealed significant differences among genotypes for all traits. High genotypic and phenotypic variability, coupled with high heritability and genetic advance, was observed for seedling vigour index II, seedling dry weight, root-to-shoot ratio, number of filled grains panicle-1, number of grains panicle-1, and grain yield plant-1, indicating good scope for selection. Grain yield plant-1 showed significant positive correlations with seedling dry weight, seedling vigour indices I and II, number of panicles plant-1, number of filled grains panicle-1, number of grains panicle-1, 1000-grain weight, and culm diameter. Path analysis identified number of grains panicle-1, 1000-grain weight, number of panicles plant-1, and culm diameter as having the highest positive direct effects on grain yield. MTU 3626, NLR 3648, and NLR 3091 were identified as promising genotypes combining superior ESV and grain yield. The findings suggest that integrating early seedling vigour with major yield-contributing traits could improve selection efficiency for developing high-yielding rice genotypes adapted to wet DSR conditions.