RANA, RAJINDER SINGHARVIND, KUMAR2017-11-252017-11-252017-10http://krishikosh.egranth.ac.in/handle/1/5810036398ABSTRACT Geographic variations among different populations of Plutella xylostella collected from eight different locations viz. Solan, Palampur and Theog (Himachal Pradesh), Fatehgarh Sahib (Punjab), Sharnapur (Uttar Pradesh), Pantnagar (Uttarakhand), Hisar (Haryana) and Delhi were studied. Standard molecular technique RAPD-PCR was also utilized to study the variations among different populations. In addition to this the variations regarding different biology and life tables were investigated in the laboratory. The RAPD-PCR studies were conducted with 20 random primers out of which 12 produced amplified PCR products. A total of 73.03 per cent polymorphism was observed among eight populations of P. xylostella. 100 per cent polymorphism was observed with OPA-16 and OPAB-10 primers whereas, minimum polymorphism (40.00%) was observed in OPD-14 which produced 5 amplified bands. The values of similarity coefficient ranged from 0.50 to 0.70. Maximum similarity was observed between Solan and Theog populations (70.00), whereas, minimum similarity was observed between Delhi and Pantnagar populations of P. xylostella. The total developmental period was minimum in the Fatehgarh Sahib population (13.74 days) followed by the Theog, Pantnagar, Saharanpur, Solan, Delhi and Hisar, Palampur populations (14.72, 15.00, 15.73, 15.85, 16.92, 17.20 and 17.65 days, respectively. The life table studies revealed that the intrinsic rate of natural increase (rm) was the highest in the Theog population (0.242) followed by the Palampur (0.236), Saharanpur (0.232), Fatehgarh Sahib (0.221), Pantnagar (0.218), Solan (0.211) and Delhi (0.195) population, whereas it was least in the Hisar population (0.189). Continuous exposure of indoxacarb and chlropyrifos may result in biologically superior strain of diamonback moth as revealed by the increase in LC50 value from 17.06 ppm to 43.07 ppm for Solan and 21.70 ppm to 60.53 ppm to Fatehgarh Sahib population with 2.56 and 2.80 folds as compared with parent generation for indoxacarb. LC50 value increase from 102.67 ppm to178.61 ppm for Solan and 155.81 to 248.15 ppm with 1.74 and 1.59 folds as compared with parent generation for chlorpyrifos.ennullThesis