Ângela Celis de Almeida Lopes

Mimosa L. comprises approximately 620 species of socioeconomic and environmental importance, with about half occurring in the Brazilian Cerrado. Despite this diversity, cytogenetic studies in the genus remain limited, with most restricted to chromosome counts. We investigated 11 populations of seven Mimosa species, focusing on the heterochromatin distribution (CMA ⁺ bands), and nuclear DNA content. Polysomaty was observed in root meristem cells of six species, absent only in M. verrucosa , in which only diploid cells were detected. Variation in the number, position, and intensity of CMA ⁺ bands was detected both within and among populations. The number of CMA ⁺ bands ranged from four in M. caesalpiniifolia (diploid cells) to 104 in M. candollei (octaploid cells), with no apparent phylogenetic pattern. Polysomatic cells generally showed a proportional increase in CMA ⁺ bands with ploidy level. Nuclear DNA content varied from 1C = 0.64 pg ( M. sensitiva ) to 1C = 1.55 pg ( M. arenosa ), with no correlation ( r = 0.1417) between ploidy and DNA content. Our results, together with previous reports, indicate that polysomaty is a frequent genomic feature in Mimosa , likely associated with environmental adaptation, growth and development. This study represents the first intra- and interpopulation assessment of heterochromatin variation and nuclear DNA content across multiple Mimosa species, providing novel insights into heterochromatin dynamics and genome organization in this diverse cytogenetically understudied legume genus. This article aligns with SDG 15 (Life on Land) of the UN Agenda for Sustainable Development.

Rising temperatures resulting from climate change present a significant limitation to lima bean (Phaseolus lunatus L.) production, especially in hot and semiarid regions. This study evaluated lima bean genotypes under elevated-temperature conditions to identify heat-adapted lines based on vegetative, physiological, and yield-related traits. Measurements included vegetative growth parameters, gas exchange, photosystem II quantum efficiency, photosynthetic pigments, agronomic traits, and grain yield across 16 genotypes, encompassing both improved lines and landrace varieties. Significant differences were observed among genotypes for all evaluated characteristics, demonstrating considerable genetic variability. Lines H25-64, H94-31, and H25-54 exhibited superior physiological performance, as indicated by higher photosynthetic efficiency and favorable agronomic traits under elevated temperatures. Notably, line H81-32 displayed low growth and physiological performance but achieved the highest grain yield and hundred-grain weight, suggesting efficient allocation of photoassimilates to reproductive sinks. In contrast, lines H25-56 and H25-67 demonstrated high CO2 assimilation and stomatal conductance, yet this physiological advantage did not translate into increased grain yield. Landrace varieties exhibited traits linked to rusticity and morphological adaptation, such as larger pod dimensions, underscoring their value as sources of adaptive alleles. Multivariate analyses revealed that productivity under elevated temperatures is more closely associated with physiological efficiency than with vegetative biomass accumulation. The identified lines constitute promising parental materials for breeding programs targeting the development of heat-tolerant lima bean cultivars suited to warming environments, thereby supporting the sustainability of production systems under climate change.

The genetic diversity of germplasm collections must be characterized to conserve and use the genetic resources of Capsicum spp. efficiently. Evaluation of this germplasm allows superior genotypes to be selected for breeding programs. In this context, the objective of this study was to characterize and estimate the genetic diversity among Capsicum spp. genotypes in Floriano, Piauí, Brazil, using multivariate analyses. Thirteen genotypes were evaluated in a completely randomized design with three replicates and one plant per plot. Thirteen qualitative traits and 13 quantitative traits were assessed. Significant differences were detected among genotypes for all quantitative traits evaluated, indicating genetic variability among the accessions studied. According to Scott-Knott mean grouping, plant height formed nine distinct classes, whereas stem diameter had the fewest groups, with only three classes. The combined analysis of quantitative and qualitative traits was effective for determining genetic divergence among pepper genotypes. The genotypes GENZ3, GEN28, and GEN37 produced fruits with potential for fresh consumption or sauce processing. The genotypes GEN38, GEN40, GEN75, and GEN77 had traits consistent with ornamental use. These findings provide information for Capsicum breeding programs focused on fresh-market and ornamental uses.

Lima bean (Phaseolus lunatus L.) is an important socioeconomic legume in northeastern Brazil, particularly among small- and medium-scale farmers. Despite its nutritional value and role in food security, crop yield is often compromised by diseases such as anthracnose. This study aimed to evaluate six groups of lima bean populations at the fifth generation (F5), derived from crosses between genotypes conserved in the P. lunatus Active Germplasm Bank at the Universidade Federal do Piauí, which differed in morphological traits and levels of anthracnose resistance. Populations were grown under field conditions and evaluated for agromorphological and phytopathological traits, including yield, seed morphology, and disease resistance. Statistical analyses were performed using restricted maximum likelihood/best linear unbiased prediction and likelihood ratio test methods with the aid of SELEGEN, R, and Genes software. Among the populations, significant phenotypic variability was observed. Population P6 was notable for its earliness, a desirable trait that contributes to disease escape; P2 and P4 showed white seed coats and commercially attractive seeds, whereas P4, P5, and P6 exhibited superior performance in pod, seed, and anthracnose resistance traits. The presence of BGP-UFPI 832 genotype in the most promising crosses suggests its potential to transmit favorable alleles. These results indicate that populations P4, P5, and P6 are potential candidates for breeding programs focused on developing higher-yielding, locally adapted, and anthracnose-resistant cultivars.

Lima bean (Phaseolus lunatus L.) is a legume of high socioeconomic value with great potential to contribute to food security. However, it is increasingly affected by genetic erosion. In this study, 43 lima bean accessions from the germplasm collection of the Federal University of Piauí (PGB-UFPI, Brazil) were analyzed, comprising 27 domesticated and 16 wild accessions. Genetic characterization was performed using five chloroplast microsatellite markers (cpSSRs). All analyzed loci were polymorphic, each presenting two alleles per locus, resulting in the identification of eight distinct haplotypes. Analysis of molecular variance (AMOVA) revealed that 94% of genetic variation occurred between groups. Principal Coordinate Analysis (PCoA) indicated the formation of two distinct clusters, supporting the hypothesis of multiple domestication events and highlighting genetic differentiation between wild and domesticated accessions. Haplotype diversity was higher among wild accessions than among domesticated ones. The use of cpSSR markers was effectiveness for assessing the genetic diversity of lima beans, underscoring the need to conserve both wild and domesticated accessions. These findings provide essential insights for guiding genetic conservation strategies and strategic use of germplasm in breeding programs.

The scarcity of improved lima bean (Phaseolus lunatus L.) cultivars in Brazil has made it difficult to reach new production levels. This study aimed to select early and high-yielding lima bean lines with commercially desirable seed traits. Forty F6:8 generation lines from the Breeding Program of the Universidade Federal do Piauí were evaluated in Tianguá (Ceará state) and Teresina (Piauí state), in Brazil. Variance components, genetic parameters and the Mulamba & Mock selection index were estimated for the statistical analyses. The more prominent traits, in terms of genetic gains, were number of days to flowering, number of pods per plot, grain yield and plant height, indicating favorable conditions for selection. The lines exhibited genetic variability regarding number of days to flowering, reinforcing the potential for selecting early lines. In the simultaneous selection of desirable agronomic traits, the lines H81-32, H25-59, H25-56, H25-66, H25-57 and H81-34 exhibited a superior performance in Tianguá, whereas H50/86-35, H25-64, H81-34, H25-66, H25-54, H25-60, H50/86-36, H25-58, H50/86-38 and H50/86-37 were highlighted in Teresina. H81-34 and H25-66 were promising in both environments, whereas H25-56 was notable for its white seed coat, a desirable trait for the consumer market.

Lima bean (Phaseolus lunatus L.) is a socioeconomically significant crop in the Northeast region of Brazil, providing income and food security. This study aimed to evaluate the breeding strategy of the lima bean breeding program at the Universidade Federal do Piauí by estimating genetic parameters, analyzing agronomic trait relationships and predicting genetic gains. Six breeding populations were assessed, and 13 agronomic traits were evaluated. The estimated heritabilities (h2) were high, indicating favorable conditions for selection. The correlation coefficients indicated strong associations among most traits, particularly those related to pods and seeds. These findings indicate that the simultaneous improvement of multiple traits is unfeasible under the current breeding framework, as with any other breeding program. Thus, it is essential to prioritize selection targets such as cycle and quality of pods and seed. The H01 population was notable because of its short cycle and white-seeded phenotype, both being desirable traits for breeding. The H81 and H94 populations also showed potential, exhibiting commercially relevant traits such as large seed size and high 100-seed weight.

The objective of this study was to obtain anthracnose-resistant lima bean progeny by artificial hybridization. The study was conducted at the Agricultural Sciences Center of the Federal University of Piauí (UFPI), Teresina – Piauí. For the F₂ phytopathological evaluation experiment, a completely randomized experimental design was used with four replicates per progeny and a plot consisting of one plant. For inoculation, the CT4 isolate of Colletotrichum truncatum was used at 10⁶ spores/mL, and a control plant was inoculated with autoclaved distilled water. Ten trifoliate leaves of each genotype were scanned from the intermediate region of the plant using ASSES 2.0. After assessing the severity, the average ratings for each population were calculated, classifying them into five categories according to the resistance. To conduct the analysis of variance, the severity data were transformed by √x + 1 and grouped by the test proposed by Scott and Knott (P < 0.05). All analyses were performed using the R and GENES programs. Seven days after inoculation, the progênies were divided into three groups. Groups “A” and “B” corresponded to genotypes classified as highly susceptible and group “C” to genotypes classified as moderately resistant and highly resistant. The genotypes BGP-UFPI 220, BGP-UFPI 251, BGP-UFPI 798, BGP-UFPI 832, BGP-UFPI 1000, and BGP-UFPI 1002 can be used as parents in lima bean improvement programs. Progenies that were moderately resistant and highly resistant, totaling sixteen, were selected for use in breeding programs aimed at anthracnose resistance.

Effects of abiotic stresses, such as high temperature, on plants are exacerbated by climate change. Lima beans exhibit higher tolerance to high temperatures than the common beans. Understanding the tolerance of lima bean landrace germplasm to high temperatures is important to improve their breeding. Therefore, in this study, we aimed to examine the high temperature responses of lima bean landrace varieties obtained from the Phaseolus Germplasm Bank at Universidade Federal do Piauí (BGP-UFPI, Brazil) in two environments. Five landraces showing the best performance in emission of flowers and number of pods formed (UFPI-945, UFPI1037, UFPI-876, UFPI-1036, and UFPI-1064) were evaluated in two cultivation environments, natural (29 ºC) and controlled (37 ºC), using a completely randomized design with four replications, with each plot consisting of a single plant. Analysis of variance and Tukey’s test (P < 0.05) were performed for 12 quantitative traits, followed by Pearson’s correlation analysis. Lima beans exhibited genetic variability in high temperature tolerance in both natural and controlled environments. Specifically, UFPI-1064 exhibited superior performance with higher pod thickness and width and number of flowers and lower flower and pod abortion than the other varieties in both natural and controlled environments. Pearson's correlation analysis revealed positive and strong correlations between the number of flowers and flower abortion in the natural environment and number of pods and seeds per pod in the controlled environment.