Phenotypic Screening of Rice Pyramided Lines against Asian Rice Gall Midge Population at Warangal, Telangana, India
E. Sravanthi *
College of Agriculture, Rajendranagar, Hyderabad, Professor Jayashankar Telangana Agricultural University, Telangana, India.
S. Malathi *
Agricultural College, Warangal, Professor Jayashankar Telangana Agricultural University, Telangana, India.
A. P. Padmakumari
ICAR−Indian Institute of Rice Research, Hyderabad, Telangana, India.
S. N. C. V. L. Pushpavalli
Institute of Biotechnology, Hyderabad, Professor Jayashankar Telangana Agricultural University, Telangana, India.
B. Pushpavathi
College of Agriculture, Rajendranagar, Hyderabad, Professor Jayashankar Telangana Agricultural University, Telangana, India.
R. Shravan Kumar
Regional Agricultural Research Station, Warangal, Professor Jayashankar Telangana Agricultural University, Telangana, India.
*Author to whom correspondence should be addressed.
Abstract
The Asian rice gall midge, Orseolia oryzae (Wood-Mason), is an important insect pest of rice that causes significant yield losses. The present study was conducted to evaluate four rice genotypes (WGL-1119, IBT-WGL-2, Abhaya, and Aganni) carrying gall midge resistance genes together with a susceptible check (TN-1) against the local gall midge population at the Regional Agricultural Research Station, Warangal, Professor Jayashankar Telangana Agricultural University, Telangana, during the wet season of 2023. The test genotypes were assessed at 30, 50 and 75 days after transplanting (DAT) using per cent plant damage (% PD) and silver shoot damage (% SS). At 50 DAT, TN-1 recorded the highest infestation (95.00% PD and 15.82% SS), confirming adequate pest pressure. Test genotypes were scored based on the damage recorded at 50 DAT according to the standard procedure. Aganni showed a highly resistant reaction with no infestation by gall midge. The gene pyramided lines WGL-1119 (Gm1 + Gm4) and IBT-WGL-2 (Gm4 + Gm8) recorded <10% PD and <1% SS damage, indicating a resistant reaction, whereas Abhaya exhibited susceptibility. At 75 DAT, pyramided lines continued to exhibit low damage and were statistically comparable to Aganni. Aganni consistently recorded ‘nil’ plant and silver shoot damage even at 75 DAT, demonstrating strong and stable resistance against the Warangal gall midge population. The findings indicate that Aganni and the two gene-pyramided lines, WGL-1119 and IBT-WGL-2, are promising sources of gall midge resistance for use in rice breeding programmes targeting the local gall midge biotype.
Keywords: Host plant resistance, Gall midge, Orseolia oryzae, rice, field screening, silver shoots