Physiological quality of rice seeds, subjected to insect infestation during storage

Abstract

The aim of this study was to evaluate the physiological quality of rice (Oryza sativa L.) seeds submitted to infestation by Rhizopertha (Fabricius, 1792) and Sitophilus sp., isolated or in combination, for 180 days, in laboratory. Seeds of BR-IRGA 410 were stored in plastic vessels and incubated at 27°C. The physiological quality of seeds was determined by germination percentage, greenhouse emergence, emergence speed index, electrical conductivity, and chemical composition of seeds. The populations of Rhizopertha dominica were more effective in reducing rice seed vigor in storage than that of Sitophilus sp. Stored rice seeds infested by populations of Rhizopertha dominica and Sitophilus sp. presented decreased germination percentage and greenhouse emergence, and increased leakage of solutes when infested by 20 insects/100 g. The determination of chemical composition of stored rice seeds infested by Rhizopertha dominica and Sitophilus sp. appeared to be insufficient to evaluate the physiological quality. The emergence speed index was most related with the greenhouse emergence, and therefore with the physiological quality.