Investigating early vigour in upland rice (Oryza sativa L.): Part I. Seedling growth and grain yield in competition with weeds

Leaf area at 6 DAS had the greatest direct effect on seedling dry matter accumulation at 12 DAS. Leaf area at 6 DAS, in turn, was associated with higher specific leaf area, greater dry matter partitioning to leaves at 4 DAS, larger embryos, heavier seeds, and earlier onset of photo-autotrophic growth. More than 90% of the variation in total rice seedling biomass at 12 DAS was associated with the parameters studied. Leaf area at 6 DAS and dry matter of rice seedlings are easily measurable traits that have potential to be used as an indirect tool for mass screening of rice for competitiveness against weeds.