Diversity of Common Bean (Phaseolus vulgaris L.) Landraces and the Nutritional Value of their Grains

Grain legumes are considered major sources of dietary proteins, calories, certain minerals and vitamins, and they are the most widely cultivated and consumed crops worldwide. Among them are the common beans, whose major production volumes came from landraces cultivated in traditional farming systems. The objective of this study was to evaluate the phenotypic diversity of a set of common bean landraces from Mexico based on the agromorphological traits and nutritional composition of the grain in the context of traditional farming systems. Different field and laboratory data were collected and complemented with secondary information published in refereed journals and research reports. The results showed that there are significant differences in the morphological and physiological traits of the plant, pod and grain among groups of common bean landraces of different geographic origins, which were associated with different indigenous groups. Similar patterns were observed in the contents of anthocyanins, polyphenols, flavoinds and minerals as well as antioxidant activity. In the evaluated population groups in each region, there are outstanding populations in terms of agromorphological traits and the nutritional value of the grain that can enable a participatory breeding initiative guided by regional objectives. Some populations from Sierra Norte, Oaxaca, presented higher values in Zn and Fe, and populations from Estado de Mexico exhibited high polyphenol and flavonoid values but stable agronomic behaviour

Genetic diversity analysis of common beans based on molecular markers

A core collection of the common bean (Phaseolus vulgaris L.), representing genetic diversity in the entire Mexican holding, is kept at the INIFAP (Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias, Mexico) Germplasm Bank. After evaluation, the genetic structure of this collection (200 accessions) was compared with that of landraces from the states of Oaxaca, Chiapas and Veracruz (10 genotypes from each), as well as a further 10 cultivars, by means of four amplified fragment length polymorphisms (AFLP) +3/+3 primer combinations and seven simple sequence repeats (SSR) loci, in order to define genetic diversity, variability and mutual relationships. Data underwent cluster (UPGMA) and molecular variance (AMOVA) analyses. AFLP analysis produced 530 bands (88.5% polymorphic) while SSR primers amplified 174 alleles, all polymorphic (8.2 alleles per locus). AFLP indicated that the highest genetic diversity was to be found in ten commercial-seed classes from two major groups of accessions from Central Mexico and Chiapas, which seems to be an important center of diversity in the south. A third group included genotypes from Nueva Granada, Mesoamerica, Jalisco and Durango races. Here, SSR analysis indicated a reduced number of shared haplotypes among accessions, whereas the highest genetic components of AMOVA variation were found within accessions. Genetic diversity observed in the common-bean core collection represents an important sample of the total Phaseolus genetic variability at the main Germplasm Bank of INIFAP. Molecular marker strategies could contribute to a better understanding of the genetic structure of the core collection as well as to its improvement and validation

SEED MANAGEMENT SYSTEMS OF \u3ci\u3ePhaseolus\u3c/i\u3e USED BY FARMERS FROM OAXACA, MÉXICO

The management and conservation of landraces and wild germplasm of Phaseolus have influenced the diversity levels reported in previous studies (Worthington et al., 2012; Soleri et al., 2013; Chávez-Servia et al., 2016). Oaxaca is located at southern Mexico and it is a complex state due its accidental geography and variable climatic composition influenced by the Gulf of México and the Pacific Ocean (García-Mendoza et al., 2004). The state of Oaxaca is divided into eight ethno-cultural regions (INEGI, 2017; http://www.inegi.org.mx) clearly differentiated by the presence of ethno-linguistic groups and a wide variety of landscapes, weather, wildlife and vegetation. The main linguistics families in Oaxaca are ‘Zapotecos’, ‘Mixtecos’, ‘Chinantecos’, ‘Mixes’, ‘Triquis’, and ‘Mazatecos’; they summarize sixteen different groups each one divided in linguistic variations (Ordóñez, 2000). Agriculture is the leading activity of these ethnical groups and they maintain landraces that have been inherited (Espinosa-Pérez et al., 2014) by his ancestors including the involved knowledge for the conservation and agronomic management. The aim of this work was to analyze and characterize seed management systems by farmers from Oaxaca, Méxic

PHYLOGENETIC ANALYSIS OF \u3ci\u3eMacrophomina phaseolina\u3c/i\u3e (Tassi) Goid. FROM COMMON BEANS AND OTHER HOSTS

The fungus Macrophomina phaseolina (Tassi) Goid. (MP) is the causal agent of charcoal rot disease that affects more than 100 plant families worldwide and causing significant yield losses (Hernández-Delgado et al., 2011). Despite the broad host range, only a single species is currently recognized: M. phaseolina (NCBI, 2017; http://ncbi.nlm.nih,gov). Charcoal rot disease is favored by drought and high temperatures stresses. MP symptoms are characterized by dark lesions at seedling stems that after cover the complete plant destroying vascular vessels. Finally, systemic chlorosis, wilting, defoliation and microsclerotia and pycnidia growing on stem epidermis are distinguished (Kaur et al., 2012). Recently, Sarr et al. (2014) reported two species within the genus Macrophomina: M. phaseolina and M. pseudophaseolina supported by slight differences on conidia morphology and phylogenetic analysis based on five loci on MP isolates from Senegal and other countries. Our results support that even M. phaseolina shows a broad genetic variability due host and geographical origin variations, no species or subspecies are evident (Reyes-Franco et al., 2006). The aim of this work was to analyze MP isolates from different host and geographical origins based on four genetic markers and to determine their phylogenetic relationships

INTRA - AND INTER-SPECIES VARIABILITY AND GENETIC RELATIONSHIPS IN WILD AND CULTIVATED BEANS FROM MEXICO

Beans (Phaseolus spp.) and maize are major staples in Mexican food. Studying the genetic diversity of wild and cultivated Phaseolus species is a major challenge for conservation and exploitation. We suggest that new information should contribute to improving our knowledge of intra and inter-species genetic variability as well as the genetic relationships among domesticated species of Phaseolus in México. In addition, the increased knowledge could improve the conservation of Phaseolus genetic resources throughout Mexico and provide a global overview of the importance of an integrative use of Phaseolus in common bean breeding (Hernández-Delgado et al., 2015). This work had two aims: to characterize the genetic variability among and within four domesticated species of Phaseolus, and to estimate the relationship and genetic structure of populations in germplasm of P. acutifolius, P. coccineus, P. lunatus and P. vulgaris. The intra- and inter-species variability and genetic relationships in germplasm from P. acutifolius, P. coccineus, P. lunatus, and P. vulgaris was analyzed. Twelve accessions of each species were collected from throughout Mexico and compared with the following controls: P. albescens, P. coccineus subsp. striatus var. purpurascens, P. parvifolius, and P. xolocotzii as well as the bred cultivars (P. vulgaris) Negro Jamapa, Negro Papaloapan, Pinto Centauro, and Pinto Coloso. Germplasm was analyzed with 15 simple sequence repeat (SSR) markers, six genic and nine inter-genic, which amplified 292 alleles (225 intergenic and 67 genic markers). Values of expected (He) and observed (Ho) heterozygosity per accession and SSR were calculated, and Molecular Analysis of Variance (AMOVA) was performed. Genetic structure of populations and coancestry values were determined using STRUCTURE V 2.3.3 (Pritchard et al., 2010) and STRUCTURE HARVESTER V 0.6.92 (Earl and vonHoldt, 2011)

IDENTIFICATION AND MAPPING OF QTLS ASSOCIATED WITH RESISTANCE TO \u3ci\u3eMacrophomina phaseolina\u3c/i\u3e AND DROUGHT STRESS IN COMMON BEANS

Common beans (Phaseolus vulgaris L.) are native from Mexico. The crop has a great economic and social importance and it is a major source of protein and essential nutrients. Drought is the main stress factor on bean production in Mexico and frequently is combined with high incidences of diseases caused by fungi, bacteria, viruses or nematodes. One emerging pathogen in beans and other crops is the fungus Macrophomina phaseolina (Tassi) Goid., causal agent of charcoal rot which incidences are favored by water deficits (Hernández-Delgado et al., 2011; García-Olivares et al., 2012). This work was developed to apply DNA molecular markers to develop a genetic map for identification of molecular markers associated to genes that confer resistance to combined charcoal rot disease/drought stress. A population of 94 RILs F2:9 from crosses between BAT 477 (resistant to both charcoal rot and water stresses) and cv. Pinto UI-114 (susceptible) was generated. Evaluations of reactions to M. phaseolina and drought stress were conducted under both field and controlled conditions. Controlled evaluations were conducted in Reynosa, México; field experiments were carried out in Rio Bravo, Cotaxtla and Isla, México and were described by García-Olivares et al. (2012). A genetic linkage map was built with genotypic data obtained with 30 +3/+3 AFLP marker combinations which generated 476 polymorphic markers, 190 of them segregating in a 1:1 ratio. Finally, QTLs associated with resistance to both stresses were identified using R ver. 2.10.1 (R Development Core Team, 2012

Análisis de la estructura poblacional del frijol ayocote (Phaseolus coccineus L.) Mediante AFLP

ABSTRACT Ayocote beans (Phaseolus coccineus L., 2n=2x=22) are a legume native from Mexican highlands; this is one species that has been poorly studied, despite its importance for human feeding and its potential for Phaseolus breeding of disease resistance as well as against some abiotic factors as cold tolerance. The aim of this study was to determine the population structure of 117 collections of P. coccineus from 15 locations of the Huasteco Karst from Puebla, Mexico, plus five controls in order to to know the degree of genetic variability present in Mexican native germplasm materials of P. coccineus by using the Amplified Fragment Length Polymorphism (AFLP) molecular marker strategy. The optimum genetic structure indicated a delta K value = 3. The polymorphism was 87.4% and the AMOVA confirmed the low genetic differentiation among accessions (Fst = 0.067), the genetic variance explained among and within populations was 6.7 and 93.3%, respectively. Cluster analysis did not show groupings based on germplasm origins.RESUMEN El frijol ayocote (Phaseolus coccineus L.; 2n=2x=22) es una leguminosa originaria de las zonas altas de México; es una especie que ha sido poco estudiada a pesar de su importancia para consumo humano y el uso potencial en el mejoramiento de la resistencia de Phaseolus a enfermedades y factores abióticos (tolerancia a bajas temperaturas). El objetivo del presente estudio fue determinar la estructura poblacional de 117 colectas de P. coccineus correspondientes a 15 localidades del Carso Huasteco del estado de Puebla, México, más cinco testigos para conocer el grado de variablidad genética existente en germoplasma criollo mexicano de P. coccineus mediante la técnica de polimorfismos en longitud de fragmentos amplificados (AFLP). La estructura poblacional indicó un valor delta K = 3. El polimorfismo fue del 87.4% y el AMOVA confirmó la baja diferenciación genética entre accesiones (Fst = 0.067), la varianza explicada entre y dentro de poblaciones fue 6.7 y 93.3%, respectivamente. El análisis de conglomerados no mostró agrupamientos definidos con base en el origen del germoplasma

CHARACTERIZATION OF ENVIRONMENTS WHERE WILD BEANS (\u3ci\u3ePhaseolus\u3c/i\u3e spp.) ARE DISTRIBUTED IN MEXICO

The characterization of germplasm based on environmental conditions of each collecting site by using GIS may help to understand the genetic variability of germplasm collections as well as associations with ecological adaptation. Ecogeographic analysis is needed to develop any conservation plan regarding distribution and representativeness. The genetic variability of domesticated species of Phaseolus spp. is well represented in germplasm banks. However, there is a deficit of seed from wild species and these accessions are poorly documented. The objective of this study was to determine the climatic adaptation of wilds species of Phaseolus throughout México. The germplasm included 29 species and two subspecies of Phaseolus belonging to the germplasm bank of the Centro de Biotecnología Genómica-IPN at Reynosa, México. Sites of collection were georeferenced by calculating latitude and longitude coordinates based on passport collection data. Data included 101 site coordinates matrix describing (i) climatic variables: monthly average temperature and precipitation; elevations (WorldClim, Hijmans et al., 2005); (ii) photoperiod (NOAA Solar calculator, http://www.esrl.noaa.gov/gmd/grad/solcalc/index.html); and (iii) climatic type (Medina-García et al., 1998). The environment information was obtained with the DIVA-GIS software ver. 7.1.7 (Hijmans et al., 2004; http://www.diva-gis.org)