EFFECT OF NITROGEN DOSE ON SPIKELET STERILITY AND YIELD OF BORO RICE VARIETIES

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