Role of trichomes on leaves and pods for imparting resistance in chickpea [Cicer arientinum (L.)] genotypes against Helicoverpa armigera (Hübner)

Abstract

In chickpea, trichomes provide a potential resistance mechanism against Helicoverpa armigera (Hübner). The present study was conducted to evaluate the trichome density and trichome length on leaves and pods on nine genotypes of chickpea. Two types of trichomes were observed, i.e. non-glandular (on leaves) and glandular (pods). Few glandular trichomes were observed on leaves and a very few non-glandular trichomes were observed on pods. Highest number of non-glandular trichomes on leaves (33.66 trichomes/mm2) were observed in chickpea genotype 5282. Minimum number of glandular trichomes were observed on pods of genotype GL 25016 (12.66 glandular trichomes per mm2). In case of leaves, genotypes ICCL 86111 and GL 25016 recorded maximum non-glandular trichome length of 347.23 and 301.53 ?m, respectively. However, genotypes GL 25016, RSG 963 and 5282 rec-orded maximum glandular trichome length of 538.33, 564.97 and 432.61 ?m, respectively in pods. Density of non glandular trichomes on leaves showed significant and negative correlation with number of eggs, larval population, larval survival and per cent pod damage. However, density of glandular trichomes on pods showed significant and positive correlation with number of eggs , larval population of H. armigera, larval survival and pod damage. Length of non-glandular trichomes on leaves and glandular trichomes on pods showed non-significant and negative correlation with number of eggs, larval population of H. armigera, larval survival and pod damage. Hence, genotypes with more pubescent leaves, lesser pubescent pods and longer trichomes (both on leaves and pods) should be preferred for developing H. armigera tolerant chickpea genotypes.