Resistance of Bulgarian common bean varieties to a set of races of Colletotrichum lindemuthianum

Ivan Kiryakov, Dimitar Genchev

Abstract: The use of resistant varieties is considered to be the most efficient and economical approach to control the anthracnose in common bean. The aim of this study was: 1) Establishment of the disease reaction of 11 Bulgarian varieties of common bean to nine races of C. lindemuthianum; 2) Identification of race-specific genes based on the virulence of the races used. The study was conducted in greenhouse conditions during the period 2003-2016 and it included 11 varieties of common bean registered in the country. The varieties were grown in pots with soil and peat mixture, 12 plants per variety. Seven-day seedlings were inoculated with a spore suspension (106 spores/ml) of nine isolates belonging to the races 2, 6, 8, 22, 54, 64, 81, 256 and 520 of the pathogen. The results were recorded 10 days after inoculation by nine degree scale. Based on the middle disease incidence (MDI) the varieties were grouped into two groups: resistant (I-MR) with MDI = 1.0-5.0, and susceptible (S-MS) with MDI = 5.1-9.0. Varieties Dunav 1 and Pirina were resistant (I-MR) to eight of the nine races of C. lindemuthianum. The remaining nine varieties were resistant to one (GTB Ustrem), three (GTB Helis and Mizia), four (Beslet and GTB Blyan), five (Trakia and Radoil) or seven (Tarnovo 13 and Elixir) of investigated races of the pathogen. Virulence, respectively avirulence of races 2, 6, 22 and 54 to varieties Dunav 1 and Tarnovo 13 showed that resistance to the other races is controlled by allele of the locus Co-1, other than alleles Co-1, Co-12, Co-13, and Co-15. The resistance of variety Trakia is controlled by specific gene Co-1, the resistance of variety Pirina - by Co-12. The resistance of variety Elixir to the races 2, 6, 8, 22, 54, 256 and 520 is controlled by gene Co-3. The studied varieties are suitable donors in breeding for resistance to C. lindemuthianum.

Keywords: anthracnose; common bean; resistance

Date published: 2017-03-01