Possible Detection of the Rice Gall Midge (Orseolia oryzae) Resistance Genes in Rice Genotypes Using Relevant Markers

The Asian rice gall midge (Orseolia oryzae) poses a significant threat to rice (Oryza sativa L.) cultivation, causing substantial yield losses of 0.8 % of the total production, amounting to US $ 80 million annually. Use of resistant rice varieties offers an effective strategy for managing this pest, particularly through the incorporation of multiple resistance genes. This study utilized functional (gm3, Gm4, Gm8) or linked molecular markers (Gm1, Gm2, Gm11, and gm12) to identify resistance alleles associated with gall midge resistance genes in a collection of rice genotypes. The results revealed the presence of multiple resistance alleles in various combinations in several genotypes, like PTB 20, RP 6290-22, RP 6749-7-19, RP 6810-20 and Karma Mahsuri. However, it appears that presence of multiple alleles may not always confer absolute resistance to this pest as evident from the performance of these lines in multilocation evaluation trials. This would ensure better deployment of resistant genes ensuring location specific gall midge management.