Achievements and limitations of contemporary common bean breeding using conventional and molecular approaches

Abstract

Common bean (Phaseolus vulgaris L.) improvement programs have been successful using conventional breeding methods to accomplish a wide array of important objectives. Specific achievements include the extension of range of adaptation of the crop, the development of cultivars with enhanced levels of disease and pest resistance and breeding lines that possess greater tolerance to drought. The most effective breeding method depends on the expression and inheritance of the trait to be selected and the target environment. Many bean improvement programs use molecular markers to facilitate cultivar development. In fact, several recent germplasm releases have used molecular markers to introgress and or pyramid major genes and QTL for disease resistance. Related species (P. coccineus and P. acultifolius) via interspecific hybridizations remain an important albeit long-term source for resistance to economically important diseases. Slow progress has been made in the improvement of traits such as adaptation to low soil fertility and tolerance to high levels of soluble Al in the soil using conventional breeding methods. The inability to directly measure root traits and the importance of genotype 9 environment interaction complicate the selection of these traits. In addition, symbiotic relationships with Rhizobium and mycorrhiza need to be taken into consideration when selecting for enhanced biological N fixation and greater or more efficient acquisition of soil P. Genomic examination of complex traits such as these should help bean breeders devise more effective selection strategies. As integration of genomics in plant breeding advances, the challenge will be to develop molecular tools that also benefit breeding programs in developing countries. Transgenic breeding methods for bean improvement are not well defined, nor efficient, as beans are recalcitrant to regeneration from cell cultures. Moreover, if issues related to consumer acceptance of GMOs cannot be resolved, traits such as herbicide tolerance in transgenic bean cultivars which would help farmers reduce production costs and decrease soil erosion will remain unrealized.

Transfer of Co-1 Gene Locus for Anthracnose Disease Resistance to Fresh Bean (Phaseolus vulgaris L.) Through Hybridization and Molecular Marker-Assisted Selection (MAS)

“…Kelly and Vallejo (2004) stated that SEactMcca molecular marker is successful in detection of germplasms carrying Co-1 gene and Co-1 2 , Co-1 3 alleles; however it is incapable of detecting the other alleles of Co-1 gene. It has been emphasized several times in the literature that markers of resistance genes of especially Andean origin are inadequate and it is a necessity to develop new molecular markers for other resistance genes of Andean origin (Kelly & Vallejo, 2004;Vallejo & Kelly, 2005;Beaver & Osorno, 2009). Since the aim of our study was to transfer the Co-1 gene to registration candidate lines (T23, TK57, TK1, Ç31, Ç28, T7, T26, TK15 and T21) that are known not to carry Co-1 gene of especially Andean origin from our previous studies (Madakbaş et al, 2009a), the six combinations of hybrid F 2 population were chosen confidently for use in the backcross studies because they have the resistant phenotype and they carry molecular Co-1 marker.…”

Genomics of Origin, Domestication and Evolution of Phaseolus vulgaris

“…Despite there still being limitations to contemporary common bean breeding, genomics-assisted techniques have been widely exploited in this species, and have enhanced the effectiveness of breeding programs and responses to selection (Beaver and Osorno 2009;Tuberosa et al 2011). Marker-assisted selection is often routinely used for traits controlled by major loci, although marker-assisted selection for complex quantitative traits still remains a challenging task in breeding programs (Miklas et al 2006;Tuberosa et al 2011).…”

Alternative markers linked to the Phg-2 angular leaf spot resistance locus in common bean using the Phaseolus genes marker database

“…In common bean, the well-established divergence between the Andean and Mesoamerican gene pools predicates a preference for Andean x Mesoamerican crosses to maximize polymorphisms at the molecular level (Kwak and Gepts, 2009;Vlasova et al, 2016). However, most crosses in bean breeding often involve parents from the same gene pool or even closely related parents to increase progress from selection and avoid hybrid weakness (Beaver and Osorno, 2009), thereby limiting the potential for polymorphism.…”