Pitanga (Eugenia uniflora L.) cultivation has increased rapidly around the world, but most seedlings come from sexual propagation and thus present high genetic variability and respond differently to environmental conditions. This work studied the phenology and thermal requirement of pitanga genotypes in the Brazilian semiarid. Forty‐eight genotypes were evaluated in 2017 and 2018 in an experimental farm at the Federal Rural University of Semiarid, Mossoró, Brazil. The time and thermal requirement for phenological stages from fruit pruning to harvesting, and fruit production were evaluated. Highly productive and precocious genotypes were identified, and six groups were arranged based on dissimilarity.

Background and Aims: Determining the leaf area is essential for studies on growth, propagation, and ecophysiology of forest species. Developing quick, practical, and accurate methods is needed to estimate leaf area without destroying leaves. Therefore, this research aimed to obtain an equation from regression models that meaningfully estimate the leaf area of Erythroxylum pauferrense using linear dimensions of its leaf blades.Methods: For this purpose, 1200 leaves were randomly collected from different plants in the Mata do Pau-Ferro, a state park located in Areia city, Paraíba state, Brazil. Equations were fitted from simple linear, linear without intercept, quadratic, cubic, power, and exponential regression models. Next, the best equation was selected by checking the following assumptions: higher determination coefficient (R²) and Willmott's index (d), lower Akaike information criterion (AIC) and root mean square error (RMSE), as well as the BIAS index closest to zero.Key results: Based on the criteria used, all equations fitted using the product of length by width (L.W) can estimate the leaf area of E. pauferrense.Conclusions: The equation ŷ=0.6740*LW from the linear model without intercept significantly estimates the leaf area of E. pauferrense in a quick and practical way (R²=0.9960; d=0.9953; AIC=1231.61; RMSE=0.4255; BIAS=-0.0130).

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This work aimed at evaluating the effects of the nutrients on the protein content of cowpea grains. The trial was carried out in completely randomized design, in the Instituto Federal do Ceará (Federal Institute of Ceará), Limoeiro do Norte, Ceará State, Brazil, between October and November 2018. Grains of 10 cowpea cultivars were evaluated about its mineral nutrient phosphorus, potassium, calcium, magnesium, sulfur, chlorine, iron, zinc, copper, manganese, boron, sodium and protein contents. The seeds of the cultivars were obtained from the farmers market in three municipalities of the Ceará State, Brazil, in the crop year 2017. The components of variances within and between families were computed by analysis of variance, and the genetic variance and correlation were therefrom estimated. The statistical analyses of variance, Pearson’s correlation and Path analysis were carried out. The protein content broad sense heritability was 60.47%, and the other cowpea traits evaluated had high broad heritability values, ranging from 49.91% (sulfur content) to 99.69% (zinc content). No mineral nutrient content presented any genotype correlation with protein content, that is, no gene function is related to mineral nutrients and protein accumulation. Potassium (0.44), chlorine (0.38) and calcium (0.35) presented the higher path coefficients in protein of cowpea accumulation but are still weak indices (<0.50) to be indicated for screening. In screening cowpea cultivars for protein content, potassium and related traits are not the most important but present some degree of dependency with protein accumulation in the grains, resulting from path effects.

Area foliar de Erythrina velutina Willd. (Fabaceae) a partir de equações alométricas. A estimativa da área foliar é de fundamental importância para avaliar o crescimento, desenvolvimento e propagação das plantas. Este trabalho teve como objetivo ajustar e identificar modelos de regressão para estimar a área foliar de Erythrina velutina a partir das dimensões lineares do folíolo central das folhas. Duzentas folhas simples foram coletadas de árvores matrizes de E. velutina em fragmentos florestais no município de Mossoró, estado do Rio Grande do Norte, Nordeste do Brasil. A equação para estimativa da área foliar de E. velutina foi ajustada a partir de modelos de regressão linear, linear sem intercepto (0,0), quadrático, cúbico, potência e exponencial. As melhores equações foram aquelas com maior coeficiente de determinação (R²), coeficiente de correlação de Pearson (r), índice de Willmott (d) e índice CS (CS), e com o menor critério de informação de Akaike (AIC) erro absoluto médio (MAE) e erro quadrático médio (RMSE), e índice BIAS mais próximo de zero (BIAS). As equações ajustadas pelo produto comprimento pela largura (LW) apresentaram os melhores critérios para estimar a área foliar, portanto, se ajustam melhor aos modelos de regressão utilizados. Portanto, a equação ŷ = 1,4755*LW ajustada usando o modelo linear sem intercepto é a mais adequada para estimar a área foliar de E.