Integrating Phenotypic Evaluations with a Molecular Diversity Assessment of a Brazilian Collection of Common Bean Landraces

Abstract

Common bean {Phaseotus vulgaris L.) is the most important legume crop for direct human consumption in Brazil. Overall patterns of genetic diversity of common bean in the country are not well understood. Hence, this study sought to integrate morphological and agronomic evaluations with prior molecular diversity data from a geo-referenced collection of Brazilian common bean. Our sample included 279 randomly chosen landrace accessions from the main growing regions of beans in Brazil. Eighteen morphological and three agronomic characters (yield and susceptibility to common bacterial blight and rust diseases) were evaluated in field conditions in Brazil or California. Results show that the sample was diverse morphologically but did not include all the morphological variability described in domesticated common bean outside Brazil. Several accessions showed clear morphological differences in spite of having the same name. The integration of the current morphological and agronomic evaluations with a prior 74-marker diversity assessment of the same landraces improved the identification of five subpopulations identified on the basis of microsatellite diversity. These subpopulations could be distinguished by their morphology, the type and frequency of the market classes they included, and the frequency of susceptibility to diseases. This information will facilitate the management and use of P. vulgaris genetic diversity in Brazil.

Genetic diversity and population structure of common bean (Phaseolus vulgaris L) germplasm of Ethiopia as revealed by microsatellite markers

“…than Mesoamerican accessions. This contrasted with results from other related studies (Asfaw et al, 2009;Burle et al, 2011;Okii et al, 2014 a,b). Such differences may be attributed to differences in genetic samples and respective sampling methods employed.…”

“…The considerable presence of admixture and switching of membership in some instances was supported by the PCoA and NJ analyses. These agree with some previous reports (Asfaw et al, 2009;Blair et al, 2010b;Burle et al, 2011;Okii et al, 2014b). In addition, the PCoA and NJ analyses in terms of geographic/ecological sampling of accessions indicated that accessions from different collection sites clustered together, which implied there was significant exchange of planting materials among farmers in different growing regions in the country.…”

“…The separation of bean accessions into the two gene pools was also evidenced in the NJ and PCoA analyses. Five cluster groups were identified, which supports the findings reported in previous studies (Kwak and Gepts, 2009;Burle et al, 2011). Furthermore, the presence of moderate admixture level agrees with previous reports (Asfaw et al, 2009;Blair et al, 2010b;Okii et al, 2014b).…”

Expression profiling and sequence diversity of novel DREB genes from common bean (Phaseolus vulgaris L.) and their association with drought-related traits

“…An intermediate level of genetic diversity was found within common landraces from Brazil when compared to the overall diversity of the species . A significant morphological variability has been verified as well, although not all morphological variability observed for P. vulgaris (BURLE et al, 2011). The study of geo-referenced landraces from Andean and Mesoamerican background revealed the latter was four times more frequent than the former (BURLE et al, 2011).…”

“…The country also holds a huge variety of landraces that have been traditionally cultivated by small farmers over years . There are indications that landraces from the group Mulatinho, in northern Minas Gerais state, have considerable drought tolerance compared with other groups but more studies need to be performed toward its understanding (BURLE et al, 2011).…”