Brazil is the world's largest producer of common bean. Knowledge of the genetic diversity and relatedness of accessions adapted to Brazilian conditions is of great importance for the conservation of germplasm and for directing breeding programs aimed at the development of new cultivars. In this context, the objective of this study was to analyze the genetic diversity, population structure, and linkage disequilibrium (LD) of a diversity panel consisting of 219 common bean accessions, most of which belonging to the Mesoamerican gene pool. Genotyping by sequencing (GBS) of these accessions allowed the identification of 49,817 SNPs with minor allele frequency > 0.05. Of these, 17,149 and 12,876 were exclusive to the Mesoamerican and Andean pools, respectively, and 11,805 SNPs could differentiate the two gene pools. Further the separation according to the gene pool, bayesian analysis of the population structure showed a subdivision of the Mesoamerican accessions based on the origin and color of the seed tegument. LD analysis revealed the occurrence of long linkage blocks and low LD decay with physical distance between SNPs (LD half decay in 249 kb, corrected for population structure and relatedness). The GBS technique could effectively characterize the Brazilian common bean germplasms, and the diversity panel used in this study may be of great use in future genome-wide association studies.

Common bean (Phaseolus vulgaris L.) is one of the most important legumes for human consumption and is a staple food in the diet of the population of some countries of Latin America, Africa and Asia. The distinction between cultivars is based predominantly on morphological descriptors, which proved inefficient for the differentiation of some cultivars. This study had the objective of describing, distinguishing and evaluating the agronomic potential of 39 common bean cultivars of the carioca and black grain groups registered for cultivation in Brazil, based on 49 morphoagronomic descriptors and microsatellite (simple sequence repeat -SSR) markers. The morphoagronomic traits of each commercial group were characterized in four environments. Thirty-seven SSR markers were used for the molecular description. The morphological data, analyzed by the Shanonon-Weaver index, detected low variability among cultivars for qualitative data. On the other hand, the estimates of variance analysis, relative importance of the traits and hierarchical grouping analysis applied to the quantitative variables showed that the descriptors related to plant morphology were the most important for the carioca group, and those related to seed morphology were determining for the black group. The genetic parameters estimated for SSR markers by hierarchical and Bayesian cluster analysis identified 116 alleles, with 33 and 30 polymorphic loci and 24 and 22 private alleles for the carioca and black groups, respectively. The combined use of morphoagronomic and molecular descriptors improves the distinguishability of cultivars, contributing in a more efficient way to breeding and to the protection of cultivars.

No abstract

Bioforti cation is one of the strategies developed to address malnutrition in developing countries, the aim of which is to improve the nutritional content of crops. The common bean (Phaseolus vulgaris L.), a staple food in several African and Latin American countries, has excellent nutritional attributes and is considered a strong candidate for bioforti cation. The objective of this study was to identify genomic regions associated with nutritional content in common bean grains using 178 Mesoamerican accessions belonging to a Brazilian Diversity Panel (BDP) and 25,011 good-quality single-nucleotide polymorphisms. The BDP was phenotyped in three environments for nine nutrients (phosphorus, potassium, calcium, magnesium, copper, manganese, sulfur, zinc, and iron) using four genome-wide association multi-locus methods. To obtain more accurate results, only Quantitative-Trait Nucleotides (QTNs) that showed repeatability (i.e., those detected at least twice using different methods or environments) were considered. Forty-eight QTNs detected for the nine minerals showed repeatability and were considered reliable. Pleiotropic QTNs and overlapping genomic regions surrounding the QTNs were identi ed, demonstrating the possible association between the deposition mechanisms of different nutrients in grains. The accumulation of favorable alleles in the same accession was associated with a gradually increasing nutrient content in the grain. The BDP proved to be a valuable source for association studies. The investigation of different methods and environments showed the reliability of markers associated with minerals. The loci identi ed in this study will potentially contribute to the improvement of Mesoamerican common beans, particularly carioca and black beans, the main groups consumed in Brazil.

Mineral deficiency is worldwide one of the major problems associated with human health, and biofortification through breeding is considered an important strategy to improve the nutritional content of staple food in countries that face this problem. The assessment of genetic variability for seed nutrient contents is a first step in the development of a biofortified crop. From the germplasm bank IDR-IAPAR-EMATER, a set of 1,512 common bean accessions, consisting of local and commercial varieties and improved lines, was analyzed. High variability among the accessions was observed for all evaluated nutrient contents (P, K, Ca, Mg, Cu, Zn, Mn, Fe and S and protein). In the mean, the contents of the carioca and black market groups (Mesoamerican gene pool), were around 7% higher for the minerals Ca, Cu, Mn and Fe and between 2-4% higher for P, K, Mg and Zn than in the other groups with Mesoamerican and Andean common bean. Few differences were observed among the Mesoamerican accessions that belong to the carioca and black commercial groups. Wide variability was observed among the evaluated genotypes, and the concentrations of the best accessions exceeded the overall mean by 14-28%. Due to the high variability in the evaluated accessions, these results may contribute to the selection of promising parents for the establishment of mating blocks. The nutritional contents of many of the improved lines evaluated in this study were higher than those of the commercial cultivars, indicating the possibility of developing new biofortified cultivars.

The soils in the common bean-producing regions (Phaseolus vulgaris L.) of Brazil are usually acid and conta\y66\yin toxic levels of aluminum (Al) for plants. This ion causes yield losses by inhibiting root cell expansion, thus reducing water and nutrient uptake. This study investigates the optimal Al concentration for the screening of genotypes in hydroponics cultivation and tries to identify cultivars and lines for cultivation in Al-toxic soils. The study consisted of two series of experiments. In the first one, four cultivars were evaluated at five Al concentrations (0, 2.5, 5, 7.5 and 10 ppm) and in the second, four independent tests were carried out (1-carioca, 2-black, 3-red, and 4-white), each with seven genotypes and two Al concentrations (0 and 4 ppm). The optimized concentration of Al in the first stage was 4 ppm, which allowed the early identification of genotypes with less affected development under Al toxicity in the second stage. The common bean cultivars IPR Quero-Quero (carioca group), BRS Esplendor (black group), KID 44 (red group), and WLine 5 (white group) may be indicated for cultivation under Al toxicity.

The population growth trend in recent decades has resulted in continuing efforts to guarantee food security in which leguminous plants, such as the common bean (Phaseolus vulgaris L.), play a particularly important role as they are relatively cheap and have high nutritional value. To meet this demand for food, the main target for genetic improvement programs is to increase productivity, which is a complex quantitative trait influenced by many component traits. This research aims to identify Quantitative Trait Nucleotides (QTNs) associated with productivity and its components using multi-locus genome-wide association studies. Ten morpho-agronomic traits [plant height (PH), first pod insertion height (FPIH), number of nodules (NN), pod length (PL), total number of pods per plant (NPP), number of locules per pod (LP), number of seeds per pod (SP), total seed weight per plant (TSW), 100-seed weight (W100), and grain yield (YLD)] were evaluated in four environments for 178 Mesoamerican common bean domesticated accessions belonging to the Brazilian Diversity Panel. In order to identify stable QTNs, only those identified by multiple methods (mrMLM, FASTmrMLM, pLARmEB, and ISIS EM-BLASSO) or in multiple environments were selected. Among the identified QTNs, 64 were detected at least thrice by different methods or in different environments, and 39 showed significant phenotypic differences between their corresponding alleles. The alleles that positively increased the corresponding traits, except PH (for which lower values are desired), were considered favorable alleles. The most influenced trait by the accumulation of favorable alleles was PH, showing a 51.7% reduction, while NN, TSW, YLD, FPIH, and NPP increased between 18 and 34%. Identifying QTNs in several environments (four environments and overall adjusted mean) and by multiple methods reinforces the reliability of the associations obtained and the importance of conducting these studies in multiple environments. Using these QTNs through molecular techniques for genetic improvement, such as marker-assisted selection or genomic selection, can be a strategy to increase common bean production.

yield. Deviance analysis detected significant differences between the cultivars in both groups. 21Selective accuracy (Ac) was considered high for most of the traits. Broad-sense heritability (ℎ 2 ) 22 ranged from 0.05 to 0.72, but it was low for the trait yield (YLD). In the carioca grain group, the ℎ 2 23 values for the traits related to plant morphology were higher than in the black group. Nevertheless, 24the ℎ 2 values in the black group were higher in relation to the pod and seed traits. The correlations 25 for YLD were moderate but different in the two commercial groups studied. In the black group, 26variables related to the seed morphology were correlated with grain yield, and in the carioca group, 27 traits related to seed quantity. Based on the groupings, variability among the cultivars was 28 observed. Three distinct clusters were formed for the carioca group and four for the black group. 29Based on the predicted genetic values, genetic variability and the most adapted and stable cultivars 30were detected among the cultivars in the studied environments. 31