Grain hardness and protein content of milled rice grains and their relationship with infestation of rice weevil Sitophilusoryzae L., (Coleoptera: Curculionidae)

A study was carried out with eight varieties of milled rice of various sizes to find out the relationship between grain hardness, protein content and infestation of rice weevil Sitophilus oryzae L. Results indicated that Jyotirmayee was the susceptible variety having maxium adult population build-up of 445 numbers/50g rice, grain damage of 69.68 percent, protein content of 7.66 percent and least grain breaking force of 45.73 Newton. The experiment concluded that the infestation of rice weevil was significantly positively correlated with protein content and negatively with hardness. There was a positive correlation between weevil population build-up and percent grain damage and a negative correlation between grain hardness and protein content. The regression revealed that for each unit (Newton) increase in hardness, there was a 0.22% decrease in grain damage and for each unit (percent) increase in protein content, there was a 3.18% increase in grain damage.