MARKER-ASSISTED INTROGRESSION OF BROWN PLANTHOPPER RESISTANCE INTO TELANGANA SONA RICE VARIETY

Increasing outbreaks of brown planthopper threaten the productivity of elite rice cultivars despite significant advances in varietal improvement. Telangana sona, a widely cultivated rice variety valued for its higher yield and grain quality, is susceptible to brown planthopper infestation. The present study aimed to introgress the brown planthopper resistance Quantitative Trait Locus (QTL) qbph-1-1 from the resistant donor M229 into the genetic background of Telangana Sona using a Marker-Assisted Backcross Breeding (MABB) approach. The breeding and evaluation work was carried out during kharif 2021 to kharif 2022 at the Regional Sugarcane and Rice Research Station (RS&RRS), Rudrur, Nizamabad, Telangana, with phenotypic screening conducted under controlled conditions at the Entomology glasshouse, ICAR-Indian Institute of Rice Research (ICAR-IIRR), Rajendranagar, Hyderabad. Among 21 BC1 F1 plants, ten were identified as heterozygous for qbph-1-1 and advanced through backcrossing to generate the BC2 F1 population. Foreground screening of 61 BC2 F1 plants identified 17 individuals carrying the target QTL, of which ten consistently exhibited strong phenotypic resistance with low damage scores, establishing a clear genotype-phenotype association. Selfing of selected BC2 F1 plants resulted in a BC2 F2 population, wherein genotyping of 600 plants identified 131 individuals, homozygous for qbph-1-1. All marker-positive BC2 F2 plants expressed resistant to moderately resistant reactions under controlled infestation, confirming stable resistance upon fixation of the target QTL. The integration of molecular foreground selection with rigorous phenotypic screening enabled the rapid development of brown planthopper-resistant lines while retaining the agronomic identity of Telangana Sona.