Variability in Morpho-biochemical Traits Associated with Pod Borer (Helicoverpa armigera) Resistance in Pigeonpea Pods

Abstract

Pigeonpea contributes to food and nutrition security among poor households in urban and rural areas. Globally it is characterized by stagnant and unstable yield due to its susceptibility to various stresses including the pod borer (Helicoverpa armigera) which causes substantial damage to the crop and may result in absolute economic yield loss. The existing cultivated pigeonpea are susceptible to pod borer with only a few genotypes reported to be tolerant based on pod and seed damage. Limited information is available on morphological and biochemical traits associated with pod borer resistance among the existing genotypes. This study was therefore carried out to identify diversified sources of resistance against pod borer damage. The study was set up to assess traits that may contribute to pod borer resistance among 12 selected elite pigeonpea genotypes in three replicates and means were separated based on LSD test using Genstat software. The field study was carried out in Kerio Valley during the long rains of April-September of 2017. The genotypes varied significantly for all the parameters measured at P≤0.05 with a mean of 608.33 g/100 g (crude protein), 175.61 mg/100 g (total phenol), 19.85 mg/100 g (total flavonoid), 0.448 mm (trichome length), 210.6 / 4 mm2(trichome density) and 0.353 mm(depth of locules). Significant negative correlation was also observed between total phenol, total flavonoid, depth of locules, trichome length and trichome density with pod damage. However, a positive correlation was recorded between crude proteins with pod damage.  These results reveal that, host plant resistance is an association of several morphological and biochemical traits. Therefore, these genotypes with elevated levels can be selected and utilized in breeding towards improving resistance to pod borer in pigeonpea.