Marker assisted transfer of anthracnose resistance gene Co-5 to elite French bean (Phaseolus vulgaris L.) background

Anthracnose caused by Colletotrichum lindemuthianum is one of the most prevalent and severe disease of beans. Anthracnose resistance to most of the prevalent races in the state is provided by Co-5 gene. Therefore, deployment of this gene is more relevant as the lines developed under this study harboring Co-5 gene have potential to impart resistance against prevalent races. Hybridisation between a resistant genotype, TU having bean anthracnose resistance gene Co-5 and elite cultivar Arka Komal was done and further advanced to generate F_1, BC₁F_1, BC₂F₁ and BC₂F₂ plants. Co-5 gene linked SCAR marker SAB3 was used for screening of hybridity of F_1, BC₁F_1, BC₂F₁ and BC₂F₂ plants/pods. The results of the foreground selection in these plants revealed that out of a population of 50 BC₂F₂ plants, 36 plants portrayed Co-5 gene. Further foreground selection with SAB3 SCAR marker, revealed lack of segregation in 12 progenies. Screening of these progenies by detached pod and germinated seed dip methods using race 3 of C. lindemuthianum, validated Co-5 resistance in all 12 BC₂F₃ progenies. All 12 Co-5 gene-positive BC₂F₄ progenies were evaluated for 17 agronomic traits including 8 qualitative and 9 quantitative traits. Evaluation identified AKTU 19 and AKTU 33 lines that possessed better elite background. These progenies can further be advanced to isolate variety/(ies) directly or as prebred donor of anthracnose resistance gene Co-5 in the future breeding programmes.