Assessment of Correlation and Path Analysis for Early Seedling Vigour Traits in Rice (Oryza sativa L.) under Laboratory Conditions

Abstract

Early seedling vigour (ESV) is a critical trait for successful crop establishment in direct-seeded rice systems, where rapid germination and uniform seedling growth provide a competitive advantage against weeds, ensure better stand establishment, and ultimately contribute to higher yield. The present study evaluated 180 rice genotypes under laboratory conditions to assess genetic variability and trait contributions to ESV through correlation and path coefficient analysis of seedling traits and vigour indices. The path coefficient analysis identified critical factors influencing the vigour indices root length was the primary driver of Seedling Vigour Index I (SVI I) in laboratory conditions, while shoot elongation traits dominated under dry direct-seeded rice environments. Seedling dry weight was the main direct contributor to Seedling Vigour Index II (SVI II) across both environments. Strong positive correlations were found among key traits especially between total seedling length and SVI I and between dry weight and SVI II. Overall seedling dry weight, shoot length, root length and total seedling length emerged as reliable selection indices for improving ESV. The findings underscore the critical role of multi-environment phenotyping in prioritizing traits for breeding rice adapted to direct-seeded systems. By identifying key contributors to early seedling vigour, this study provides valuable selection indices to enhance crop establishment and productivity in resource-efficient rice cultivation. This integrated phenotyping approach revealed substantial genetic variation for early seedling vigour, supporting the selection of genotypes with rapid early growth and biomass accumulation, essential for improving establishment and performance in DSR systems.