+ Genotyping of phosphine resistance in North Indian populations of lesser grain borer, Rhyzopertha dominica (F.). Rahul Chandel, Vimal Dwivedi,Sakshi G, Shan P. Thomas, Rajesh., Chitra Srivastava ,Subramanian,S, Division of Entomology, IARI New Delhi-12 Introduction Results Post harvest losses of cereals due to attack of insects is estimated to 10-12% in India. Phosphine and methyl bromide are main fumigants to be used Methyl bromide is having environmental problems Phosphine is the primary fumigant used to protect the grains from insect pests. Phosphine is relatively inexpensive, easy to apply, leaves minimal residues and can be used in a wide range of storage types and commodities. The lesser grain borer Rhyzopertha dominica is the most destructive insect pests of stored grain. This pest has been controlled successfully by fumigation with phosphine for the last several decades, Strong resistance to phosphine in many countries has raised concern about the long term usefulness of this control method. High levels of resistance to phosphine in the insect pest have been detected in india. RD RPH2 GENE AMPLIFICATION FOR HOSHIYARPUR PUNJAB SAMPLES 100bp 200bp 300bp 315bp RD RPH2 RESTRICTION DIGESTION FOR HOSHIYARPUR PUNJABSAMPLES 315bp 207bp 108bp 50bp 100bp 200bp 300bp 150bp 1H 2H 3H 4H 5H 6H 7H 8H 9H 10H UNCUT 11H 12H 13H 14H 15H 16H 17H 18H 19H 20H UNCUT Objectives To study genotyping of phosphine resistance in North Indian populations of lesser grain borer, Rhyzopertha dominica (F.). Materials and Methods Wheat samples having storage insects were collected from nine different FCI and CWC godowns in north india. Phosphine gas was generated in a gas generation chamber by FAO, 1975 method The adult test insects were bio assayed with phosphine at two discriminating doses viz., Low concentration, 0.03 mg L-1 and high concentration, 0.25 mg L-1 . Mortaility of adults were ascertained seven days from the end of exposure period. For Molecular diagnosis of insect resistance DNA was extracted by CTAB method. Amplification of a gene associated with phosphine (rph2) was done using gene specific markers . Genotyping of resistance was done by using PCR- RFLP test . Gel analysis of PCR product done by electrophoresis. This study reveals the existance of strong resistance to phosphine in populations of R.dominca collected from storage godowns in Northern India. The study develops a diagnostic protocol for detection of phosphine resistance in field populations of R.dominica. r Phosphine Gas Generation References FAO 1975Tentative method for some major beetle pest of stored cereals with methyl bromide and phosphine. FAO method No. 16 FAO Plant Protection Bulletin,23,12-25. Collins, P. J., G. J. Daglish, H. Pavic and K. A. Kopittke. 2005. Response of mixed-age cultures of phosphine-resistant and susceptible strains of the lesser grain borer, Rhyzopertha dominica, to phosphine at a range of concentrations and exposure periods. Journal of Stored Products Research. 41: 373-385. Nayak M.K., Collins P.J., Pavic H. (2003). Developments in phosphine resistance in China and possible implications for Australia. In: Wright EJ, Webb MC and Highley E (eds). Stored Grain in Australia 2003. Proceedings of the Australian Postharvest Technical Conference. CSIRO Stored Grain Research Laboratory: Canberra, Australia, pp 156–159.