IMPROVING AROMATIC QUALITY OF BRRI dhan80 THROUGH MINIMIZATION OF NITROGEN AND SUPPLEMENTATION OF ZINC

Abstract

The experiment was conducted during the period of June to November, 2018 in the experimental field of Sher-e-Bangla Agricultural University, Sher-e-Bangla Nagar, Dhaka for improving aromatic quality of BRRI dhan80 through minimization of nitrogen and supplementation of zinc. The experiment consisted of two factors: Factor A: Levels of N (4) as - N 1 : 35 kg N ha -1 ; N 2 : 37 kg N ha ii -1 ; N 3 : 39 kg N ha : 41 kg N ha -1 and Factor B: Levels of Zn (4) as -Zn 1 : 4.0 kg Zn ha -1 ; Zn 2 -1 ; N 4 : 4.5 kg Zn ha : 5.0 kg Zn ha -1 ; Zn 4 : 5.5 kg Zn ha -1 . The experiment was laid out in split-plot design with three replications. The levels of N were assigned to main plot and levels of zinc to sub-plot. Result revealed that plant height, effective tillers, filled grains, weight of 1000-grains, grain yield, milled rice, protein content increased with increasing nitrogen level but amylose, proline and grain 2-Acetyl-1-pyrroline (2-AP) content decreased with increasing its levels. Zn had no significant effect on 1000 grain weight, grain yield and size of grain whereas, protein, Zn, proline and grain 2-AP content increased with increasing its levels. Among the 16 treatment combinations, the highest grain yield (4.23 t ha -1 ) was observed from N 3 Zn 4 treatment combination which was statistically similar with N 2 Zn 1, N 2 Zn 4,

N 3 Zn 3, N 4 Zn 2, and N 4 Zn 3. Significantly the highest protein content (8.58%-8.95%) was recorded from N 4 Zn 4, N 4 Zn 3 and

N 2 Zn 3 and the maximum Zn content (0.159 mg g -1 DW) was obtained from N 3 Zn 4 which was statistically similar with N 4 Zn 3 , N 3 Zn 3 and N 2 Zn 4 respectively while the maximum amylose (25.59%), proline (22.17 mg g -1 DW) and 2-AP content (0.87µg g -1 DW) was obtained from N 1

combination. From the present study it may be concluded that the rice growers may use 35- 37 kg N ha -1 and 4-5.5 kg Zn ha -1 along with other recommended fertilizers for producing good quality aromatic rice.