Sentinel Plots for On-Farm Bean Disease Assessment: A Strategic Tool to Guide Breeding for Smallholder Agriculture

Biotic constraints limit bean productivity across all growing regions, with most severe impact in tropical developing countries. Evaluation for disease resistance can be influenced by environment, management, and evaluation expertise, which imposes challenges for the development of better varieties with improved resistance on-farm. To increase data reliability, CIAT developed and implemented a coordinated strategy to capture disease severity information in the Lwengo district in Uganda where bean is widely cultivated by small farmers and disease pressure is high. We merged capacity from CIAT-Palmira, CIAT-Kawanda, and NARO-NaCRRI to define the best conditions and genotypes to generate meaningful phenotypic information. Methodology:A bean nursery (Meso and Andean) representing elite breeding lines, resistant parents, local varieties, some international differentials, and disease resistant and susceptible checks, was sown in two farms at Lwengo. CIAT’s evaluation 1-9 scale was used to evaluate severity for all diseases observed, considering three evaluations on leaves and one on pods. The maximum score on leaves was used to calculate cumulative probabilities considering three phenotypic categories: resistant, intermediate, and susceptible.