Abstract:
A research work was carried out at the Agronomy Farm, Shcr-e-Bangla Agricultural
University, Dhaka during the period from November 2006 to June 2007 in order to determine
the suitable nitrogen doses to observe the growik performance and to increase the yield by
reducing spikelet sterility in boro rice. the experiment comprised four doses of nitrogen
no nitrogen, half of the recommended dose of nitrogen, recommended dose olnitrogeit and
double of the recommended dose of nitrogen; and four varieties viz, l3ltltl dhan29, BRRI
hybrid dhan I, Sonar Bangla- I and I lira-273. The experiment was set up in a split-plot design
with three replications. Experimental results indicated that nitrogen doses had significant
effect on plant height, tillers hill
4
, dry niatter weight hilF
1
, effective tillers hihI', non-
effective tillers bill
1,
panicle length, grains panicle", unfilled grains panid&', spikelet
sterility, grain yield, straw yield, biological yield and harvest index. Recommended dose of
nitrogen showed the highest grain yield (9.2 t ha
4
) and the lowest spikelet sterility (%) than
no nitrogen and other doses of nitrogen treatments. All the studied characters except panicle
- length and harvest index varied significantly due to varieties. Among the varieties, llira-273
out yielded BRRI dhan29, BRRI hybrid dhanl and Sonarbangla-1 by US, 0.61 and 0.38
ha4
, respectively which is mainly attributed to the highest number of grains panicle" (1000)
and markedly lower level of spikelet sterility (14.34 %). Combination of the recommended
dose of nitrogen and Uira-273 showed the best performance in terms of producing the highest
grain yield by significant reduction of the spikelet sterility than other interaction treatments
