Physico-chemical basis of insect-resistance of traditional rice varieties against Sitophilus oryzae (L.).

Based on popularity and specialty, seven traditional rice varieties were tested for resistance reactions in terms of physicochemical properties against rice weevil, Sitophilus oryzae and compared with the improved high yielding rice varieties during 2019-2021. The result revealed that the aromatic rice variety Kon joha was the least suffered (11.67%) under the husked condition, whereas the aromatic traditional rice variety Bokul joha was the least suffered (53.00%) under the dehusked conditions at 18 days after infestation. Amongst the traditional varieties, the Black rice variety suffered maximum weight loss of 60.16% under de-husked conditions. All tested physical and biochemical parameters revealed a significant positive correlation with weight loss (r=0.87), total soluble protein (r=0.86), 1000 grain weight (r=0.74), moisture content (r=0.54), germination loss (r=0.89) and seed vigor loss (r=0.54) at 180 days of infestation under husked condition, while significant positive correlation with weight loss (r=0.91), starch content (r=0.98), crude protein content (r=0.94), L/B ratio (r=0.88), 1000 grain weight (r=0.50) and moisture content (r=0.87) at 180 days of infestation under de-husked condition. The rice grains possessing a high percentage of starch and protein, but a low per cent of crude fat was found more prone to infestation by S. oryzae. [ABSTRACT FROM AUTHOR]