Assessment of Grain Preference Among Selected Rice Varieties by Field Rat, Bandicota bengalensis and House Rat, <em>Rattus rattus</em> in Sri Lanka

Rice is the staple food in Sri Lanka, where significant grain losses in storage are one of the key factors affecting food security. Rodents cause the highest losses in rice, mainly by Bandicota bengalensis and Rattus rattus in the Sri Lankan context. Rodent damage depends on factors mainly on storage management and the type of rice varieties. However, there is no information on varietal and grain preference by rodents. Hence the experiment was conducted to determine the grain preference of rodents for available 45 rice varieties. The study was conducted in the screen house (1.5m x 9m x 1.5m), modified by providing hiding places to rodents. Three trays filled with 250g of paddy seeds of each variety were placed inside the screen house. One day starved 100 rats were released into the experimental setup and allowed to feed. The remaining grain quantities were measured at 3, 5, and 7 days after release. The same procedure was followed separately for both species. The study revealed that grain losses were dependent not only on the rice variety but also on the rat species. At311, Bg409, and Bg250 were the most preferred varieties, whereas At307, Bw312, At303, Bg379/2, and Bw351 were the least preferred by B. bengalensis. Meanwhile, Bw367 and Bw453 were the highest preference of R. rattus, whereas the lowest were At373, Bg300, Bw400, At362, Bw351, At354, At311, and Bg450. It may be due to the different grain sizes and physicochemical and nutritional composition. However, comprehensive studies are necessary before adopting the findings to minimize post-harvest losses by rodents.