Prevalence of variation among American bollworm (Helicoverpa armigera) collected from different host plant in Punjab-Pakistan

Abstract

American bollworm (Helicoverpa armigera) is poly-phagous pest which infects major fiber, pulses and vegetable crops, e.g., cotton, soybean, chickpea, brinjal, tomato, peas, beans, okra, and chili in Pakistan. Farmers use the different dosage of insecticides to control American bollworm on various crops that might be due to the existence of genetically diverse American bollworm population. So, it is essential to explore and get an understanding of this genetic variation existing among American bollworm, feeding on different host plants. The current study was conducted to observe the genetic variation existing among seven American bollworm populations by RAPD-PCR system collected from host plant including cotton, pea, green bean, chili, green chili, tomato and okra. Overall, 210-bands were obtained from thirty RAPD primers, out of these, 34-bands were polymorphic, and 176-bands were monomorphic. PIC values ranged from 0.2149 to 0.5014, with a mean of 0.2838. Genetic similarity ranged from 92.38% (produced by cotton and peas) to 99.52% (produced by chili and green beans) and the genetic distance range from 0.48% to 7.92%. A most important result was the clustering of the population occurring on green bean, chili, green chili, tomato and okra in one cluster. In contrast, the population occurring on cotton and pea were designated separate clusters, respectively. These results showed that population occurring on cotton and pea were most dissimilar to other populations indicating that populations are closely related to each other. There might be an interspecific crossing frequency among these populations.