Post-anthesis dry-matter accumulation and its partitioning in different wheat (Triticum aestivum) genotypes under varying growing environments

An experiment was conducted in micro-plots during winter (rabi) seasons of 2000–2001 and 2001–2002 at Hisar on 5 wheat genotypes (‘PBW 343’, ‘NIAW 34’, ‘UP 2338’, ‘HD 2428’ and ‘Raj 3765’) subjected to different growing environments by sowing on normal date (25 and 20 November) or late (3 January and 24 December), to study post-anthesis dry-matter accumulation and its partitioning. The total dry matter as well as its partitioning into leaves, stems, roots, spikes and grains was reduced significantly at anthesis and maturity under late sowing compared with normal date of sowing. The reduction in dry-matter partitioning into leaves, stems and roots was 31.3, 12.0 and 21.9% at anthesis; while at physiological maturity it was into leaves, stems, roots, spikes and grains was 31.7, 34.3, 22.4, 31.3 and 38.5% respectively. Partitioning of dry matter at anthesis indicated the maximum contribution from stems (35.9%), followed by roots (34.6%), leaves (15.5%) and spikes (14.0%); whereas at physiological maturity, the spikes contributed the maximum (38.4%), followed by roots (25.9%), stems (25.5%) and leaves (10.4%) towards total dry matter. Among the genotypes, ‘PBW 343’ and ‘NIAW 34’ produced significantly higher total dry matter as well as spikes and grain weight at maturity under both normal and late sowing. A significantly positive association of grain weight with total dry matter, stem weight, root weight and spike weight under normal and late sowing indicated that higher biomass yield and its maximum partitioning into spikes improved the grain yield of wheat.