STUDIES ON GENETIC VARIATIONS AND ESTERASE ACTIVITY OFHelicoverpa armigeraIN HIMACHAL PRADESH
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Date
2017
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UHF,NAUNI
Abstract
ABSTRACT Geographic variations among different populations of Helicoverpa armigera collected from six different locations viz. Kangra, Solan, Theog and Kinnaur (Himachal Pradesh), Bathinda (Punjab) and Hisar (Haryana) were studied. The variations regarding different morphometric traits, biology, life tables and esterase activity were investigated in the laboratory. In addition to this standard molecular technique RAPD-PCR was also utilized to study the variations among different populations. The studies revealed that the larval and pupal weight was the highest in the Theog population (558.27±11.03, 303.40±12.01 mg) followed by the Solan population (513.58±9.32, 289.61±7.02 mg), whereas, these were the lowest in the Hisar (479.89±9.93, 257.05±3.80 mg) and Bathinda (488.29±6.33, 267.17±3.85 mg) populations. Similarly, the forewing expanse was also the highest for the Theog population (16.94±0.29 mm) followed by the Solan (16.10±0.25 mm), while, it was the lowest for the Hisar (15.47±0.28 mm) population followed by Bathinda (15.53±0.20 mm). The total developmental period was the minimum in the Hisar population (29.24±0.25 days) followed by the Bathinda (31.59±0.30 days), Kangra (31.71±0.36 days), Solan (32.23±0.26 days) and Theog (33.52±0.52 days) population whereas, it was maximum in the Kinnaur population (35.29±0.61 days). The life table studies revealed that the true intrinsic rate of increase (rm) was the highest in the Hisar population (0.126) followed by the Bathinda (0.124), Theog (0.124), Solan (0.123) and Kangra (0.122) populations, whereas it was the least in the Kinnaur population (0.102). The RAPD-PCR studies were conducted with 24 random primers out of which 16 produced amplifiedPCRproducts. Theprimer OPA-05produced maximum 22amplified fragments followed by OPD-01 and OPD-02 producing 21 fragments each. Polymorphism of 71.88 per cent was observed among six populations of H. armigera. The dendrogram constructed after cluster analysis of the similarity coefficients showed three clusters. The Hisar and Bathinda populations formed the first cluster whereas, the Kangra, Solan and Theog populations formed the second cluster. The Kinnaur population formed a separate group individually. The studies on esterase activity of different populations showed that the Bathinda (415.85±7.36 µgm/g/min) and Hisar populations (401.75±1.93 µgm/g/min) had higher general esterase activity and the least enzyme activity was observed in the Kinnaur population (198.88±1.29 µgm/g/min) followed by Solan (241.33±1.69 µgm/g/min), Theog (243.33±2.30 µgm/g/min) and Kangra (292.75±3.94 µgm/g/min) populations indicating thereby a higher level of pesticide resistance in the populations of Punjab and Haryana compared to the populations collected from Himachal Pradesh. The determination of variations among these populations will be helpful in formation of region specific management strategy against this pest.
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