Genetic structure of Lima bean (Phaseolus lunatus L.) landraces grown in the Mayan area

Abstract

Lima bean (Phaseolus lunatus L.) is an important crop in the Mayan culture. The Mayan area, considered as a main center of Mesoamerican diversity, has been divided into two subareas: the Mayan lowlands and the Mayan highlands. The Yucatan Peninsula is part of the Mayan lowlands and holds the highest number of Lima bean landraces of Mexico, but Lima beans are in high risk of genetic erosion due to intensification of the traditional Mayan agriculture. However, information on genetic diversity of Lima beans of the Mayan highlands is lacking. By using 46 landraces collected in the Mayan area (23 from each subarea) and 73 ISSR loci (intersimple sequence repeats), we analyzed the structure, diversity and genetic relationships of Lima beans of this part of Mesoamerica. High levels of diversity (H BAY = 0.45) and genetic structure (F ST = 0.66) were found for the whole Mayan area. Genetic diversity in the Mayan lowlands was apparently higher than the Mayan highlands (H BAY = 0.44 and 0.36, respectively); but differences were not statistically significant. Genetic structure between the subareas was high (AMOVA = 30% of total variation), most landraces grouping according to their geographic origin. This study shows the importance of the Mayan culture in the diversification and conservation of Lima beans. The results provide important information that should be considered when implementing strategies to collect Lima bean landraces and planning in situ and ex situ programs to conserve these landraces in the Mayan region.

Structure and Genetic Diversity of Nine Important Landraces of Capsicum Species Cultivated in the Yucatan Peninsula, Mexico

“…Rai et al [37] suggested that the lack of polymorphism for SSRs markers between genotypes of Capsicum may limit their application for Capsicum. Regardless of the type of marker used, the level of differentiation observed in this study can also be attributed to the degree of domestication of the species under study, as reported by Camacho-Peréz et al [38] and Martínez-Castillo et al [39] for cultivated landraces of lima bean; ISSR markers have a higher level of polymorphism compared to SSR markers in cultivated varieties. The formation of the subgroup that contains the landraces Bobo, Dulce and Xcat'ik2 strongly supports the suggestion of González et al [40] that Bobo is a progeny from a spontaneous cross between Xcat'ik and Dulce landraces and validates the existence of natural crosses between Capsicum species cultivated in sympatry [37].…”

Determining relevant traits for selecting landrace accessions of Phaseolus lunatus L. for insect resistance

“…Seeds of 27 landraces accessions of lima beans ( P. lunatus ) were collected in the states of Quintana Roo, Campeche and Yucatán in the Yucatan peninsula from home gardens and rural markets. Information on the origin and genetic characterization of landraces is available in previous studies carried out by the Centro de Investigacion Cientifica de Yucatan (CICY), in Martínez-Castillo, Colunga-García & Zizumbo-Villarreal (2008) and Camacho-Pérez, Martínez-Castillo & Mijangos-Cortés (2008) ( Table 1 ). Seeds were tested for germination, and only those lots with germination above 85% were sown.…”

Phenotypic Dispersion of Landrace Lima Bean Varieties Using Multidimensional Scaling

“…Often, this germplasm is maintained in landrace seed banks, presenting great genetic variability for agronomic traits of interest (Santos et al, 2002). However, Camacho-Pérez et al (2018) emphasize the reduction of genetic diversity in landrace varieties mainly due to changes in traditional agriculture and market preferences, assuming this as a global problem with high risk to the food security of future generations.…”