Molecular identification of bean cultivars for partial resistance to Colletotrichum lindemuthianum based on SCAR markers

Bean anthracnose disease caused by Colletotrichum lindemuthianum is one of the most important bean diseases in Iran. In this study, the presence of disease resistance genes was investigated using SCAR primers in 12 Iranian bean cultivars. Also, disease symptoms were evaluated based on the disease severity index in the greenhouse condition. Amplification of SCAR markers SAS13, SY20, SZ04 and SB12 indicated the presence of Co-42, Co-4, Co-6 and Co-9 resistant genes respectively. Cultivars Akhtar, Derakhshan, Almas, Talash and Koosha contained Co-42, Co-4 and Co-6 resistance gene revealed by amplification of SBB14, SC08 and SZ20 markers accordingly. Co-42 gene was detected in Goli and Naz cultivars and Co-4 and Co-42 genes were present in Pak, Sadri and Khomein cultivars. Co-42 gene that is linked to SH18 marker was observed in Dorsa and Shokofa cultivars. The presence of Co-2 resistance gene was observed only in Almas cultivar. Co-5 gene linked to SAB3 marker was only observed in the related differential cultivars. Phenotypic evaluation for disease symptoms showed that out of 12 cultivars studied, four (Naz, Almas, Dorsa and Shokofa) showed resistance reaction and two (Akhtar and Goli) were moderately resistant. Based on the disease severity index, these cultivars were considered relatively resistant. Simultaneous analysis of molecular and phenotypic data showed that only the two markers of SQ4 and SH18 succeeded in band amplification in resistant cultivars Diamond, Shokofa and Dorsa. The results of this study will be of help in producing resistant bean cultivars to anthracnose disease by resistance gene pyramiding.