Integrating genotypic and phenotypic approaches for blast resistance selection in rice (Oryza sativa L.) segregating populations through marker-assisted selection

Abstract

The present study aimed to develop blast-resistant homozygous recombinant lines through marker-assisted selection (MAS) in segregating populations derived from the cross between Pusa Samba 1850 and CO55. Unlike backcross-based approaches, selection was focused on F2 derived recombinants and their advancement to homozygosity. Foreground selection using gene-specific markers for Pi54, Pi1 and Pita enabled the precise identification of resistant genotypes. In the F2 population, a limited number of plants were identified as homozygous for single, double and triple gene combinations. Selected plants were advanced to F3 generation, where fixation of resistance genes was confirmed. Phenotypic screening revealed variation in blast resistance despite genetic fixation, indicating genotype-environment interaction. Three recombinant lines showed strong resistance against blast disease and these lines were further advanced to the next generation. Genetic variability analysis showed high heritability (80–100 %) and significant genetic advance for key traits. Correlation and path analysis identified number of productive tillers (NPT) and thousand seed weight (TSW) as major contributors to yield. Superior recombinant lines such as 7–36, 11–28 and 107–25 exhibited strong blast resistance and desirable agronomic performance. The study demonstrates that MAS combined with pedigree selection is an effective strategy for developing improved homozygous recombinant lines with durable blast resistance.