Cry1Ac resistance allele frequency in field populations of Helicoverpa armigera (Hübner) collected in Telangana and Andhra Pradesh, India. (May 2018)

• Record Type: Journal Article
• Authors: Kukanur, Vinod S.; Singh, T.V.K.; Kranthi, Keshav R.; Andow, David A.
• Is Part Of: Crop protection. Volume 107(2018)
• Page Start: 34
• Page End: 40
• Publication Date: 2018-05
• Subjects: Helicoverpa armigera -- F2 screen -- Cry1Ac toxin -- Bt resistance; Plants, Protection of -- Periodicals; 632.05
• DOI: 10.1016/j.cropro.2018.01.008
• Languages: English
• ISSNs: 0261-2194

Abstract

Abstract: Bt cotton expressing Cry1Ac insecticidal protein was introduced in India in 2002. Within a span of 12 years, Bt-cotton constituted more than 90% of cropping area covering 11.6 mHa. This large scale cultivation favours resistance evolution in target pests. One of the major factors that influences rate of resistance is frequency of resistance alleles. Using F2 screen methodology and a discriminating dose, we estimated the level of resistance to Cry1Ac toxin in field populations of Helicoverpa armigera (Hübner). We report an increase in Cry1Ac resistance allele frequency in field populations of H . armigera collected in Telangana and Andhra Pradesh states of India. Collective allele frequency was 0.085 (95% CI) for 2013 and 0.035 (95% CI) for 2014, which was 65 times and 29 times higher than the initial frequencies estimated during 2004. To prevent further increase in Bt resistance frequency in H . armigera, it is necessary to integrate other resistance management tactics that preserves pest susceptibility to Bt cotton. Highlights: Frequency of Cry1Ac resistance alleles was estimated in H. armigera populations collected in Telangana and Andhra Pradesh states, India. Cry1Ac resistance alleles frequency was estimated after 12 years of Bt cotton cultivation. High frequency of Cry1Ac resistance alleles was noticed in field collected population. Allele frequency increased nearly 65 times higher than the initial frequency estimated in 2004.