SCREENING OF SUITABLE VARIETY AND DATE OF SOWING ON THE PERFORMANCE OBSERVATION OF BORO RICE UNDER AEROBIC CONDITION IN DINAJPUR REGION

Abstract

Aerobic system of rice production is an eco-friendly and environmentally safe technology that helps to save 50-60% irrigation water in boro rice production. A field experiment was carried out at the Agronomy Research Field of Hajee Mohammad Danesh Science and Technology University, Dinajpur during boro season, 2014 to find out suitable rice varieties along with optimum sowing date for aerobic rice cultivation. The experiment was conducted with five varieties namely, BR16 (Shahibalam), BRRI dhan28, BRRI dhan29, BRRI dhan47 and BRRI dhan55 and three dates of sowing namely, January 01, January 11 and January 21, 2014, respectively. The experiment was laid out in randomized complete block design with three replications. Results showed that except only few parameters, the yield and yield contributing characters were significantly influenced by variety and date of sowing. Among five varieties, BRRI dhan29 was found significantly superior to all other varieties with respect to plant height, number of total tillers hill-1 , number of effective tillers hill-1 , number of total grains panicle-1 , number of filled grains panicle-1 , 1000 grain weight, grain yield, straw yield and biological yield. The highest grain yield (6.07 t ha-1 ) was obtained from BRRI dhan29 and lower grain yield (5.30 t ha-1 ) was found in BRRI dhan28. On the other hand, Yield decreased with delay in sowing date. Among three date of sowing, significantly highest grain yield (6.72 t ha-1 ) was obtained from sowing in January 01 and the lowest grain yield (4.35 t ha-1 ) was obtained from sowing in January 21. The effect of interaction between variety and date of sowing on grain yield, straw yield and biological yield were significant. In terms of economic return, the highest gross return, net return and benefit-cost ratio (2.63) were obtained from BRRI dhan29 and significantly the highest gross return, net return and benefit-cost ratio (2.82) were also obtained from the sowing in January 01. The interaction effect between variety and date of sowing on gross return, net return and benefit-cost ratio was significant. In Bangladesh, about 28% of the total cost for production of boro rice goes for irrigation and the scarcity of irrigation water from both underground and surface sources are increasing which in making the boro rice production at stake. Under this looming water crisis situation boro rice production could be sustained by using the technology that requires very less water like aerobic method. Therefore, the variety BRRI dhan29 planted at January 01 is the best suited to get higher yield and higher economic return under aerobic method of cultivation.