Resistance assessment of three cry1Ab Transgenic Rice varieties against Naranga aenescens Moore (Lep.: Noctuidae)

Phyllophagous larvae of Naranga aenescens, a one of the most important pest of rice, causing a severe reduction in photosynthetic area and plant yield. Fifty percent of insecticides employed in rice fields are targeted at lepidopteran insects. Transformation of rice with Bt genes is a common approach to confer resistance to insect infestations. In this study, three transgenic varieties, Khazar, Neda and Nemat, were studied for the resistance to N. aenescens larvae in greenhouse condition. Larval mortality and feeding, were significantly different between transgenic and non-transgenic varieties. Mortality rate of first and third larval instars was about 100% in the transgenic varieties four days after infestation. However, the rate of larval mortality was less than 10% in the non-transgenic varieties at the same time. The leaf area consumption by third larval instars of Naranga aenescens in transgenic varieties, Khazar, Nemat and Neda were 6, 9 and 11.8% witch were significantly less than the nontransgenic varieties with 42.6, 46.6 and 51.1% damage respectively. The transgenic varieties showed high levels of resistance to N. aenescens larvae.