Colletotrichum lindemuthianum race spectrum and resistant sources against most prevalent races in the North-western Himalayas: A three decade meta-analysis

Bean anthracnose caused by Colletotrichum lindemuthianum is a significant disease of north-western (NW) Himalayas. In the past 30 years, a lot of research work has been performed in India to understand the Phaseolus vulgaris-C. lindemuthianum interface. In the present investigation, we compiled the information and performed a meta-analysis on virulence and resistant sources with an aim to identify the number of bean anthracnose races prevalent in India. We also calculated their virulence and resistance index and additionally identified the broad spectrum resistant common bean landraces. By now 269 C. lindemuthianum isolates from NW region have been inoculated to common bean differential set and 71 distinct bean anthracnose races are present in India. Frequency of few bean anthracnose races like 17 (18.30%), 503 (18.30%), and 513 (23.94%) is higher indicating that they are most prevalent. Bean anthracnose race 503 is common to Himachal Pradesh, Uttarakhand, and Jammu and Kashmir. Among the differential bean cultivars, G 2333 is resistant to all the races followed by AB 136, which is resistant to 70 races (268 isolates). Breeders can reconnoitre these two genotypes to breed common bean varieties resistant to anthracnose. Among the NW landraces, KRC-5 and KRC-8 are resistant to 24 and 12 anthracnose races, respectively and can be a good source of anthracnose resistance. Genetic studies have resulted in identification of major anthracnose resistance genes in both these cultivars. However, it is necessary to map these major genes and comprehend the molecular basis of innate immunity in KRC-5 and KRC-8 common bean landraces. Our understanding of P. vulgaris– C. lindemuthianum has undoubtedly increased but we still do not know about the precise function of pathogen effectors and molecular basis of anthracnose resistance.