Journal of Advances in Biology & Biotechnology

The Asian Rice Gall Midge is one of the most important pests of rice, causing substantial yield losses in major rice-growing regions. WGL-962 (Warangal Vari-2) is a high-yielding, short-duration rice variety with medium slender grains; however, it is susceptible to gall midge infestation. To improve gall midge resistance in this variety, the resistance gene Gm4 was introgressed from the donor parent DRR 2313 through marker assisted pedigree breeding. A total of 33 advanced breeding lines developed from the cross WGL 962 × DRR 2313 were evaluated during Kharif 2025 at the Regional Agricultural Research Station, Warangal, through phenotypic screening and molecular confirmation to identify gall midge-resistant lines. Molecular screening was carried out using the functional marker LRR-del for confirmation of the presence of the Gm4 gene. Among the 33 lines evaluated, 19 lines were found positive for the Gm4 resistance gene. The phenotypic evaluation of the lines carrying the Gm4 resistance gene under field conditions revealed that, one line, WGLB-25-7, exhibited a highly resistant reaction with no damage, while two lines, WGLB-25-1 and WGL 2259, showed resistant reactions. The remaining 16 lines were categorized as moderately resistant. These identified resistant lines may serve as valuable genetic resources for the development of gall midge-resistant rice varieties with desirable agronomic traits.