Int.J.Curr.Microbiol.App.Sci (2019) 8(11): 1839-1848 1839 Original Research Article https://doi.org/10.20546/ijcmas.2019.811.216 Frequency and Distribution of rph2 Gene in Tribolium castaneum Collected from Grain Supply Chain of Coimbatore, Kangeyam and Theni C. Taraka and S. Mohankumar * Department of Plant Biotechnology, Tamil Nadu Agricultural University, Coimbatore-641003, India *Corresponding author ABSTRACT Introduction India is the second largest producer of food grains and also a major exporter of cereals globally. Around 50 per cent of produce is stored by the farmers for their consumption and remaining surplus grains are procured by the government based stored grain agency like Food Corporation of India (FCI) and state warehouses. However, the wastage of food grains is witnessed due to lack of storage infrastructure and primitive grain handling mechanism. It is reported that post harvest grain losses in India is upto 12 to 16 million metric tons of food grains each year. The major loss is due to stored product insect pests which plays a key role in food grain deterioration and wastage is upto 5-10%. International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 8 Number 11 (2019) Journal homepage: http://www.ijcmas.com Resistance to insecticides is a worldwide issue for the major stored insect pests. Among several insecticides, phosphine (PH 3 ) gas is the most commonly used fumigant to protect the stored product from pests. Conventionally, a discriminating-dose bioassay is conducted to determine the phosphine resistance in stored insect pests. In the present study, the frequency of resistance is estimated in Tribolium castaneum (Herbst) populations collected from grain supply chain viz., (Grain processing unit, bulk grain storage godowns, ration shop, wholesale shop, retail shop and household) from three locations of Tamil Nadu, India. Based on a cleaved amplified polymorphic sequence (CAPS) method, each individual insect is analysed using restriction enzyme to detect strong resistance allele. Among the populations collected from grain supply chain of Theni, Coimbatore and Kangeyam, the samples (T. castaneum) from bulk grain storage showed the highest frequency of phosphine resistant allele of viz., 85.71, 78.33, 89.13%, respectively while as the lowest frequency of phosphine resistant allele was observed in household samples of Theni, Coimbatore and Kangeyam viz.,18.75, 34.48, 40.74%, respectively. Thus, strong phosphine resistance detected in beetle with the help of CAPS marker could be used for the improvement of management strategies for the given pest populations. Keywords Tribolium castaneum, Phosphine resistance, rph2 gene, CAPS marker Accepted: 17 October 2019 Available Online: 10 November 2019 Article Info