Screening of Common Bean (Phaseolus vulgaris L.) Accessions for Their Resistance to Fungal Diseases

Abstract

Common bean (Phaseolus vulgaris L.) is the most cultivated and consumed legume in the western highlands of Cameroon. Despite its socio-economic importance, its cultivation encounters several problems among which pests and diseases contribute significantly to yield reduction. In order to improve the productivity of common bean, a varietal screening trial was set up in the locality of Dschang to study its resistance to fungal diseases in 2020 and 2021. Thus, 32 bean accessions, including 17 climbing and 15 dwarf were cultivated in a completely randomized block design. Data collection involved agronomic characteristics such as growth variables and yields, as well as diseases identification. The International Centre for Tropical Agriculture (CIAT) scale was used to assess disease incidence and severity. Data analysis was carried out using R software as statistical tool. Results showed that the climbing accession Mac 55 gave the highest yield in two years of the trial (4.57 t.ha^-1 and 3.66 t.ha^-1 respectively). Three major fungal diseases were identified in the field: angular leaf spot (ALS), floury leaf spot (FLS) and rust. Mancha 3 was among the most ALS susceptible accessions with an incidence of 100%, while RWR 3194 and Banguem were among the most resistant accessions to ALS (33.33%), 70 days after sowing (DAS). Concerning FLS, Banguem and Guzan local were among those with the highest incidence (100 %) while Losakia and Nuv 6 were among those with the lowest incidence (6.67 %) in 2020. Losakia and Kabo-6F9-8-27 were the accessions with the highest incidence (80 %) related to rust in both years. At the end of the study Mac 55 and RWR 3194 could be recommended as high yielding and also with a good resistance to the main fungal diseases encountered