Genotype - Associated Variation in Nutritional Indices of Helicoverpa armigera (Lepidoptera: Noctuidae) Fed on Canola

Abstract

In this study, the nutritional indices of the larval stages of Helicoverpa armig era (Hübner) were determined on 10 canola ( Brassica napus L.) genotypes (Talaye, Opera, Licord, Modena, SLM 046 , Hayula 420 , Zarfam, Okapi, RGS 003 and Sarigol) at 25 ± 1 ̊C, 60 ± 5% RH and a photoperiod of 16: 8 (L: D) hours. The third instar larvae reared on Talaye showed the highest value of Efficiency of Conversion of Ingested food ECI and Efficiency of Conversion of Digested food ECD (7.005±0.632 and 8.972±1.862, respect ively). However, the lowest value of ECI and ECD was on Licord (0.503±0.017 and 2.507±0.449, respectively). The highest (0.778±0.091) and lowest (0.594±0.059) Relative Growth Rate (RGR) of the fourth instar larvae were obtained on SLM 046 and Sarigol, respe ctively. Results indicated that the highest values of ECI and ECD for fourth instar larvae were on Talaye (6.300±0.585 and 8.880±1.954, respectively). The lowest value of the Relative Consumption Rate (RCR) and Approximate Digestibility (AD) of the fifth i nstar was recorded on Modena (5.193±0.629 and 38.625±11.340, respectively). The ECI and ECD values of the fifth larval instar were the highest on Talaye (9.893±0.889 and 19.655±0.966, respectively). The highest value of RCR and AD of the sixth instar was o n Okapi (7.781±0.665 and 82.223±1.922, respectively). Among different genotypes tested, the highest ECI and ECD of the whole larval instars (12.323±0.310 and 32.357±5.508, respectively) were observed on Talaye and the lowest ones (5.947±0.257 and 6.922±0.3 20, respectively) were on Okapi. Together, Talaye and Okapi were the most suitable and unsuitable genotypes, respectively, for H. armigera larvae . Keywords: Approximate digestibility, Brassica napus , Digested food, Ingested food, Relative growth rate.