ABSTRACT Lima bean is an important crop in Northeastern Brazil and a source of food and income for farmers in the region. However, there have been few genetic studies on this species, which limits the knowledge available for use in breeding programs. The objective of this study was to estimate the relationship between cycle and production traits using canonical correlation analysis and to identify traits that can be used for the indirect selection of lima bean. The experiment was conducted at the Department of Plant Science of the Universidade Federal do Piauí, Teresina, in a randomized block design with five replications, in which 11 agronomic traits from six lima bean populations in the F3 generation originating from biparental crosses were evaluated in 2019. The data were subjected to canonical correlation analysis using the virtual environment R. The results showed that only the first coefficient of the canonical pair was significant (r = 0.5531) by the quisquare test, suggesting that the studied groups were not independent, as the cycle traits showed coefficients of large magnitudes in the relationship between groups. The canonical correlation results suggested that there is a linear association between cycle and production traits in lima beans, in which days to flowering, days to maturation, pod length, seed width, and seed thickness contribute the most to the association between groups.

ABSTRACT Intensification of the eutrophication process in surface water leads to an increase in the intensity and frequency of cyanobacterial blooms, compromising the availability of drinking water. Therefore, the aim of this study was to investigate the spatio-temporal dynamics of cyanobacteria and identify the most important nutrients for such dynamics in a semiarid artificial lake, the Orós reservoir, in north-eastern Brazil. Seventy-seven water samples were collected in 11 campaigns (six during the dry season and five during the rainy season) from seven points. The attributes under investigation were the Secchi transparency, turbidity, pH, apparent colour, electrical conductivity, total solids, total phosphorus, soluble orthophosphate content, total Kjeldahl nitrogen, ammonia content, nitrate content, and cyanobacteria dynamics, resulting in a total of 924 samples (number of campaigns × number of points × number of attributes). Principal component analysis and cluster analysis were used to investigate the significance and determinant attributes of the spatio-temporal dynamics of cyanobacteria. Of the 17 species of cyanobacteria identified, 10 accounted for 72.47% of the total accumulated variance. During the rainy season, four homogeneous groups of cyanobacteria formed, whereas during the dry season, only three groups formed. The greatest concentrations occurred during the dry season, notably for Aphanocapsa spp., Cylindrospermopsis sp., and Geitlerinema sp., which are potentially toxic and show a greater affinity to the physical attributes of water. Climate seasonality was decisive in the spatio-temporal dynamics of cyanobacteria, and high transparency values limited excessive proliferation of the dominant species.

ABSTRACT The rich genetic diversity and wide adaptation of rice (Oryza sativa L.) to different environments provide fundamental resources for its conservation and improvement. The analysis of canonical correlations can be used to increase the efficiency of selecting superior genotypes, as several traits are evaluated simultaneously. Thus, this study aimed to compare morphoagronomic traits and estimate the magnitude of the association and interdependence between two groups of traits in genotypes of special types of rice. The experiment was carried out between November 2020 and April 2021 at the Department of Plant Science of the Federal Rural University of Rio de Janeiro (UFRRJ), Seropédica - RJ. The experimental design consisted of randomized blocks, with four replications. Seventeen genotypes were evaluated, five of them consisting of white rice and eleven special types of rice. Two groups of variables were used to determine the canonical correlations, with group I composed of four morphological traits and group II composed of four yield components. Significant differences (P<0.01) were observed between genotypes for the eight evaluated traits. The first, second, and third pairs showed significant canonical correlations at a 5% probability, demonstrating that these groups are not independent. The selection of superior genotypes for production can be based on choosing plants with higher flag leaf thickness, higher height, and lower flag leaf angle.