1Department of Agricultural Entomology, University of Agricultural Science, Gandhi Krishi Vigyan Kendra, Bangalore – 560 065 (Karnataka) India.
2Agricultural Research Station, Kankanady, Mangalore – 575 002 Karnataka, India.
3Zonal Agricultural Research Station, V.C. Farm, Mandya – 571 405 Karnataka, India.
*E-mail: vijigall@gmail.com
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Fifteen resistant donors and fourteen standard differentials were screened separately against rice gall midge, Orseolia oryzae (Wood-Mason) populations in two field experiments during 2004–2006 at Agricultural Research Station, Mangalore, to monitor their reaction. Based on their reactions, evolution of new biotypes and population growth rates were studied. Among fifteen resistant donors, Phalguna (Gm2 gene), MO-4, Champaka, Shakti, Mahaveera, ARC 5984 (Gm5) and Bhumansan (Gm7+Gm8) recorded susceptible reaction during 2004–2006. Similarly, the reaction of 14 standard differentials, in four groups, during 2004–2006 recorded a progressive change in their reaction pattern against virulent rice gall midge populations. The growth rates of virulent populations were calculated as 0.31, 0.47 and 0.70 during 2004, 2005 and 2006 respectively.
Changing scenario, growth rate, Orseolia oryzae, biotypes, rice
