Conventional and Molecular Approaches towards Breeding for Disease Resistance and Tolerance in the Common Bean (Phaseolus vulgaris L.)

Abstract

As poverty limits access to animal protein in developing countries, people in developing countries turn to common bean, as a protein
source. Disease and pests can cause significant losses to common bean production. Control of these biotic constraints using agrochemicals can increase production costs and create the potential for contamination of the environment. Thus, resistance/tolerance represents a valuable disease and pest management tool for sustainable production of beans. Therefore, the development of cultivars with greater levels of disease and pest resistance has always been a primary objective of most common bean breeding programs. The development of cultivars with enhanced levels of disease and pest resistance has been hailed as one of the milestone achievements of breeding for bean improvement so far. Hence, this review paper is initiated with the objective of documenting the most important achievements of common bean breeding for disease resistance/tolerance using conventional and molecular breeding approaches and fetching (an important piece of knowledge and database for agricultural researchers and academicians in research and higher learning institutions and other stakeholders. With this end in mind, it starts with identifying major diseases of common bean (from the African and global perspective); describe each disease (the pathogen, mode of virulence, etc.); document resistance genes and resistant cultivars; and document molecular and conventional breeding approaches used international thus far, and associated results. Accordingly, such pieces of information have been presented section-by-section for common bean diseases: anthracnose, angular leaf spot, common bacterial blight, bean common mosaic (necrotic) virus (BCMV/BCNMV), and bean rust. The information reviewed here is believed to be useful in the areas of common bean improvement and breeding. The achievements garnered thus far, though immense, have not been utilized uniformly throughout the world. Besides, the pathogenic epidemiology, virulence, sources of host resistance, etc. have not been sufficiently studied and documented. Similar review
papers are recommended for major insect pests and nematodes attacking the crop.