STUDY ON COMPETITIVENESS OF AUS RICE VARIETIES AGAINST WEED INFESTATION

Abstract

An experiment on Aus rice was conducted at the Agronomy Research Field of Sylhet Agricultural University, Sylhet-3100 as well as in the farmer‘s field of Jaintapur and Gowainghat upazila, Sylhet to find out the competitiveness of Aus rice varieties against weed infestation. Five (5) commercial rice varieties viz. BR3, BRRI dhan48, Aloron, BRRI dhan43, Iratom-24 along with three (3) local cultivars Aina Miah, Doom and Kanihati were included in the research field trial. On the other hand, thirty farmer‘s field were surveyed along with researcher‘s managed trial was conducted to compare weed situation. In farmer‘s field, 5 (five) treatments namely the rice variety BR3, hybrid variety Aloron, BRRI dhan55, BRRI dhan48 and Aina Miah, a local low yielding rice variety/cultivar (LYV) were included. The experiment was started on April 2014 and was harvested on August 2014 depending on the variety. Eight weed species were recorded in the research field trial. Whereas 28 weed species were recorded in the farmer‘s field trial. The most prominent weeds in the experiment were Monochoria vaginalis, Digitaria sangunalis, Leersia hexandra, Cynodon dactylon etc. Among the rice varieties hybrid variety Aloron and BRRI dhan48 showed high competitiveness against weeds. Result indicated in research field that the local variety Aina Miah showed maximum plant height (105.4 cm) and Iratom-24 was the minimum (68.63 cm). The hybrid variety Aloron recorded the maximum panicle length (24.53 cm) and the minimum length (17.27 cm) was in the variety Doom. The highest number (103.53) of filled grains panicle was produced by the hybrid variety Aloron and lowest (41.87) by the variety BRRI dhan43. The highest grain yield (4.04 t ha -1 -1 ) was produced by the hybrid variety Aloron which was statistically identical with the variety BRRI dhan48 (3.19 t ha ) was recorded in local cultivar Doom which was at par with BRRI dhan43 (1.32 t ha -1 ) and Iratom-24 (3.06 t ha -1 ). The lowest yield (1.07 t ha -1 ) and local cultivar Kanihati (1.53 t ha -1 ). The highest weed competitive index was recorded in Aloron (2.27) and the lowest was recorded in Doom (0.42). In the farmer‘s field trial, the hybrid variety Aloron showed the highest grain yield (3.71 t ha -1 ) was recorded in LYV (Aina Miah). The highest weed competitive index (2.05) was recorded in BRRI dhan48, that was statistically identical with the variety Aloron (1.71) and the lowest weed competitive index (0.49) was recorded in BR3.

-1 ). The lowest grain yield (1.72 t ha -1