EFFECT OF NITROGEN LEVELS ON PATTERN OF INCREMENTAL BIOMASS PARTITIONING IN RICE (ORYZA-SATIVA) AT DIFFERENT GROWTH-STAGES

A study was conducted during 1994-95 to changes in dry weight with tim e of each aerial component and new incremental biomass as being partit ioned into them in 2 rice (Oryza sativa L.) varieties, tall 'Swarnapra bba' and medium tall 'IR 36' at 5 different levels of N, viz 30,60,90, 120 and 150 kg N/ha at 10 days interval. Nitrogen levels influenced th e growth of all aerial components of the plant as well as the partitio ning of dry-matter at different developmental stages. Partitioning of dry-matter of leaves was maximum (0.526) during vegetative stage, whil e it attained a maximum value of 0.75 for stem during panicle-initiati on stage. The N-responsive 'IR 36' rice having high leaf N uptake (6.0 6 g N/m(2) average of all samplings) had higher partitioning coefficie nt to leaves (0.53) than that to the stem (0.47) and the converse was true with low-N responsive 'Swarnaprabba' rice.