Characterization of Rice (Oryza sativa L.) Germplasm for Early Seedling Vigour-related Traits under Direct Seeded Condition

In pursuit of boosting rice production while maintaining economic feasibility within resource constraints, the shift from the traditional puddled-transplanted rice system to direct-seeded rice is gaining significance. Early seedling vigour (ESV) is an important character crucial for direct-seeded rice to outcompete and suppress weed growth. This study evaluated hundred rice germplasm accessions for their early seedling vigour-related traits. Mesocotyl and coleoptile lengths, chlorophyll content, alpha-amylase, speed of emergence, shoot and root characteristics, and vigour indices exhibited notable variability as indicated by their high PCV and GCV. Moreover, they were predominantly under the influence of additive gene effects, as illustrated by their high heritability and genetic advance as per cent of mean. This suggests that these traits are heritable and could be effectively exploited through selective breeding efforts. Positive correlations were found between seedling vigour and traits like emergence (%), speed of emergence, chlorophyll content, and alpha-amylase activity. Based on PCA, Vigour index-I, II, total seedling length, and chlorophyll contents were regarded as major discriminators in rice germplasm for direct seeded traits. The superior genotypes for seedling vigour such as Honduras and Gharib, could be used as donors in the rice breeding programs to develop direct seeded rice cultivars.