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.

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.

Genetic diversity studies and molecular characterization offer crucial insights into preserving germplasm and maximizing its utility effectively. Therefore, the present study aimed to verify the genetic diversity, population structure and linkage disequilibrium in a set of maize (Zea mays L.) germplasm adapted to South Brazil composed of 351 inbred lines of field corn, popcorn and sweet corn. Through genotyping‐by‐sequencing (GBS), we identified 291,633 high‐quality single nucleotide polymorphism (SNP), with 57% common across the three maize types. Unique SNPs were also discovered: field corn (24,618 or 8%), popcorn (17,000 or 5%) and sweet corn (479 or 0.16%). Bayesian analysis revealed two distinct population groups: one encompassing popcorn lines and another combining field and sweet corn lines. The fixation index (Fst) indicated minimal differentiation between field and sweet corn. Conversely, field and sweet corn lines exhibited higher nucleotide diversity than popcorn. Linkage disequilibrium analysis showed quick decay, significantly affected by population structure and kinship. From this diverse germplasm, future genome‐wide association studies (GWAS) can be used to identify genomic regions and genes of interest in maize.

Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli, is the main bacterial disease affecting the production of beans (Phaseolus vulgaris L.), with significant impacts on Brazilian agriculture. The search for resistant genotypes is a fundamental strategy, given the prevalence and persistence of the pathogen in tropical conditions. Therefore, this study aimed to identify candidate genes for resistance to CBB through association mapping studies, using 126 Middle-American bean genotypes from the germplasm bank of the Instituto de Desenvolvimento Rural do Paraná. A randomized block design with four replications was used. The inoculation method was by cutting the leaves with scissors, using the isolate Xap-139y at a concentration of 10⁷ CFU·mL^-1, and the variables final score and area under the disease progress curve (AUDPC) were evaluated. The expected performance of the means and the genetic parameters were estimated using the Selegen software. The GEN203 genotype was considered resistant for AUDPC and final score. Using multi-locus models (FASTmrMLM, ISIS-EM-BLASSO, mrMLM, pLARmEB), we identified 11 quantitative trait nucleotides associated with CBB resistance and 48 candidate genes in the resistance response. These genes act in several metabolic pathways, suggesting a complex polygenic inheritance. This work contributes significantly to understanding the genetic basis of resistance to CBB and the development of bean cultivars with better adaptability and productivity in regions affected by the disease.

Phyla scaberrima (Verbenaceae) is a herbaceous species distributed from Mexico to Panama. Because of its well-known sweet properties and other medicinal uses, this species is cultivated in South America and the Caribbean. Phyla scaberrima has been arbitrarily extracted from nature, resulting in a severe reduction in its gene pool. In this study, we developed and characterized 11 simple sequence repeat markers for P. scaberrima to determine the genetic variability and patterns of population structure of the species. Fifty-six alleles were detected in a sample of 48 individuals belonging to 3 different populations. The average number of alleles per locus was 5.09, while the polymorphic information content ranged from 0.000-0.587. The observed and expected heterozygosities varied from 0.000-0.543 and from 0.000-0.651, respectively. Two loci exhibited significant deviation of the expected Hardy-Weinberg proportion. The 11 primer pairs were also tested for cross-amplification to 6 species of the related genus Lippia. The transferability rate ranged from 4 loci in Lippia florida and L. rotundifolia to 6 loci in L. corymbosa and L. microcephala. The 11 primer sets were shown to be valuable tools for population genetic studies in P. scaberrima and in species of the genus Lippia in which primer transferability was detected.