Genetic Diversity and Population Structure of Common Bean (Phaseolus vulgaris L.) Landraces in the Lazio Region of Italy

Abstract

Common bean cultivation has historically been a typical component of rural economies in Italy, particularly in mountainous and hilly zones along the Apennine ridge of the central and southern regions, where the production is focused on local landraces cultivated by small-scale farmers using low-input production systems. Such landraces are at risk of genetic erosion because of the recent socioeconomic changes in rural communities. One hundred fourteen accessions belonging to 66 landraces still being grown in the Lazio region were characterized using a multidisciplinary approach. This approach included morphological (seed traits), biochemical (phaseolin and phytohemagglutinin patterns), and molecular (microsatellite loci) analyses to investigate their genetic variation, structure, and distinctiveness, which will be essential for the implementation of adequate ex situ and in situ conservation strategies. Another objective of this study was to determine the original gene pool (Andean and Mesoamerican) of the investigated landraces and to evaluate the cross-hybridization events between the two ancestral gene pools in the P. vulgaris germplasm in the Lazio region. Molecular analyses on 456 samples (four for each of the 114 accessions) revealed that the P. vulgaris germplasm in the Lazio region exhibited a high level of genetic diversity (He = 0.622) and that the Mesoamerican and Andean gene pools were clearly differentiated, with the Andean gene pool prevailing (77%) and 12% of landraces representing putative hybrids between the two gene pools. A model-based cluster analysis based on the molecular markers highlighted three main groups in agreement with the phaseolin patterns and growth habit of landraces. The combined utilisation of morphological, biochemical, and molecular data allowed for the differentiation of all landraces and the resolution of certain instances of homonymy and synonymy. Furthermore, although a high level of homozygosity was found across all landraces, 32 of the 66 examined (49%) exhibited genetic variability, indicating that the analysis based on a single or few plants per landrace, as usually carried out, may provide incomplete information.

Efficiency of RAPD and SCoT Markers in the Genetic Diversity Assessment of the Common Bean

“…The discovery of genetic relationships among plant genotypes based on DNA polymorphism may contribute to important knowledge leading not only to the simplification of the selection of germplasm for the breeding process but also to efficient conservation strategies [37,38] of genetic resources in gene banks. Many types of developed molecular markers have been used for the detection of genetic diversity in plants [30,31,[39][40][41][42][43][44][45].…”

Morphological and Genetic Characterization of Maize Landraces Adapted to Marginal Hills in North-West Italy

“…This result was not expected, since they have different names and were cultivated and sampled in different locations: the first one in the Parma Apennines (Albareto) and the second in Salsomaggiore, in the first hills closed to the Po valley. In traditional germplasms, cases of homonymy and synonymy are particularly abundant and have been reported for maize [27] and other crops [36,37]. Va227 and Va228 were genetically distant, even if they were cultivated and sampled in the same location and classified into the same agroecotype by Brandolini and Brandolini [2,5].…”

“…The pairwise F ST value for Va222 and Va223 (0.08) was one of the lowest and partially matched the PCoA results. and synonymy are particularly abundant and have been reported for maize [27] and other crops [36,37]. Va227 and Va228 were genetically distant, even if they were cultivated and sampled in the same location and classified into the same agroecotype by Brandolini and Brandolini [2,5].…”

Genetic Diversity and Relationship of Shanlan Upland Rice Were Revealed Based on 214 Upland Rice SSR Markers

“…Liu et al analyzed the genetic diversity of 1481 individuals using SSR markers and SNP haplotypes [21]. In addition, SSR also plays an essential role in the study of the genetic diversity of cowpea [22], barley [23], beans [24,25], maize [26], and other crops. Therefore, it is feasible to screen specific SSR primers for genetic diversity analysis of Shanlan upland rice to explore its geographical origin.…”