Effect of nitrogen on yield, yield components and contribution from the pre-anthesis assimilates to grain yield of three photosensitive rice (Oryza Sativa L.) cultivars

Abstract

The experiment was conducted in the Agronomy field laboratory of Bangladesh Agricultural University to find out the pre-anthesis contribution to grain yield in selected rice varieties (BR22,BR23 and Nizersail ) of Bangladesh. Total tiller no./m2, no. of effective tillers /m2, spikelet no./panicle, % filled grain, 1000 grain wt, straw yield and grain yield varied significantly in different cultivars . Grain yield was highest in BR23 (5.08 t/ha) followed by BR22 (4.59 t/ha). Levels of N significantly influenced all the crop characters studied except 1000 grain wt. Increasing N level increased grain and straw yield. The interaction effect between cultivar and N was significant for effective tiller no./m2, spikelet no./panicle, % filled grain, grain yield and % contribution to grain yield from pre-anthesis assimilates. Pre-anthesis assimilate contribution to grain yield was greatest with no N application (28% in BR22 and BR23), and was lowest at 120 kg N/ha (3% in Nizersail). The pre-anthesis assimilate contribution showed a negative relationship with increased N application. However, this relationship varied for different cultivars with BR 23 showing a greater capacity to mobilize pre -anthesis assimilates than BR22 and Nizersail.