The Amazon is a center of diversity for Capsicum chinense Jacq., with wide genetic and morphological variability, but little exploration has been performed there to facilitate their improvement. This study aimed to characterize and evaluate C. chinense genotypes for the development of cultivars by determining the optimal size of the experimental plot and the minimum sample size to ensure a precise estimation of yield. A total of 23 genotypes were evaluated, and in multivariate analyses, the plants were characterized by 21 morphological descriptors and eight quantitative traits related to biometry and yield. The recommended sample size for fruit evaluation was defined based on simulations with subsample resampling and evaluation of the semi-amplitudes of the confidence interval of the mean estimate. The optimal plot size was estimated by the modified maximum curvature method. The similarity coefficients among the genotypes ranged from 0.54 to 0.93, indicating that the established clusters contained important information for future crosses. According to the sample size methodologies, 25 to 40 fruits should be sampled for valid evaluations of biometric traits. Experiments with five to eight plants per plot are recommended to test progenies of the species, ensuring good experimental precision combined with high selection accuracy for yield traits.

Gluconacetobacter diazotrophicus has been the focus of several studies aiming to understand the mechanisms behind this endophytic diazotrophic bacterium. The present study is the first global analysis of the early transcriptional response of exponentially growing G. diazotrophicus to iron, an essential cofactor for many enzymes involved in various metabolic pathways. RNA-seq, targeted gene mutagenesis and computational motif discovery tools were used to define the G. diazotrophicusfur regulon. The data analysis showed that genes encoding functions related to iron homeostasis were significantly upregulated in response to iron limitations. Certain genes involved in secondary metabolism were overexpressed under iron-limited conditions. In contrast, it was observed that the expression of genes involved in Fe-S cluster biosynthesis, flagellar biosynthesis and type IV secretion systems were downregulated in an iron-depleted culture medium. Our results support a model that controls transcription in G. diazotrophicus by fur function. The G. diazotrophicusfur protein was able to complement an E. colifur mutant. These results provide new insights into the effects of iron on the metabolism of G. diazotrophicus, as well as demonstrate the essentiality of this micronutrient for the main characteristics of plant growth promotion by G. diazotrophicus.

Sugarcane plays an important role in the agricultural economy of Pedras de Fogo, Paraíba, contributing to the economy in terms of generating jobs and income in the region. However, its production has been affected by challenges such as climate variations and traditional agricultural practices. The objective of this study was to analyze the productive dynamics of sugarcane in the municipality of Pedras de Fogo, PB, between 2004 and 2023, seeking to understand the factors that influence this production chain and offer subsidies for local development actions. The methodology consisted of analysis through a database, evaluating the variables: planted area, harvested area, quantity produced, productivity and production value. The results revealed a significant reduction in the cultivated area, which went from approximately 30.000 hectares (ha), in 2004 to approximately 18.000 ha in 2023, with emphasis on 2019, which presented the lowest production. Despite the reduction in area, a trend towards increased production was observed, reflected in the stability of productivity throughout much of the period. Therefore, to ensure the sustainability of the activity, it is necessary to invest in more efficient agricultural practices, adoption of technologies, adequate irrigation management and strengthening of public policies that support local producers.