Differential resistance of maize germplasm to rice weevil, Sitophilus oryzae and angoumois grain moth, Sitotroga cerealella in stored maize

Abstract

The present study was conducted to evaluate maize germplasm by screening 26 and 22 inbred lines for resistance to Sitophilus oryzae and Sitotroga cerealella, respectively by ‘No Choice’ method under laboratory conditions (27±2°C and 60±5% RH). Progeny of emerging adults, grain damage, grain weight loss, median development period and susceptibility index were taken as parameters for this study. Significant differences were observed among inbred lines for the traits evaluated (p< 0.05). The genotypes WNCDMR11R 0913, WNCSKNY 4854 (2) and WNCDMR19RYDWS 1518 were found to be moderately susceptible to S. oryzae based on Dobie’s index (4- 7) and, 13 were susceptible (8-10) whereas, ten inbreds were highly susceptible (e>11). Similarly in case of S. cerealella, WNCDMR18RYD820171 and WNCDMR11R 0913 were found to be moderately susceptible based on Dobie’s index (4-7) and 11 were found to be susceptible (8-10), while nine lines were highly susceptible  e>11). WNCDMR11R 0913 was found to be moderately susceptible to both S. oryzae and S. cerealella and per cent weight loss observed on these moderately susceptible lines was in the range of 1.68 to 2.86, 3.85 to 3.9, respectively. The increasing F1 progeny emergence resulted in an increased grain damage and weight loss. The susceptibility index was inversely related with median development period (R2 = 0.71, 0.48), however number of F1 progeny emergence (R2 = 0.83, 0.75) per cent grain damage,(R2 = 0.86,0.86) and weight loss (R2 = 0.73, 0.81) by S. oryzae and S. cerealella, were positively related.