Abstract Brown rot and blossom blight caused by fungi of the genus Monilinia are the most important peach diseases. The increased concern with the environment and the health of workers and consumers, as well as the emergence of fungus isolates resistant to the main fungicide molecules favor control strategies such as genetic resistance. The objective of this study was to adjust a phenotyping protocol for evaluation of resistance/susceptibility to blossom blight in peach, as well as to quantify the antioxidant compounds present in the petals of these flowers and their correlation with the disease incidence and severity. The experiment was arranged in a randomized complete block split-split plot design, the plot being four concentrations of Monilinia fructicola conidia; the subplot two phenological flower stage; and the sub-subplot four peach genotypes. The quantification of antioxidant compounds and their correlation with susceptibility to blossom blight was performed in the four genotypes analyzed. Phenotyping was more efficient when concentrations between 400 and 4,000 conidia mL-1 were used, regardless of phenological flower stage. The phenolic compounds, anthocyanins and antioxidant activity are positively correlated among them, and negatively correlated with the blossom blight incidence and severity. In order to estimate the blossom blight susceptibility, it is recommended to use flowers at the pink or bloom stage, inoculum equivalent to 20-200 conidia per flower, and perform the evaluation at 96 hours after inoculation. This study suggests that more intense pink flowers have a higher content of antioxidant compounds and less blossom blight susceptibility.

Abstract Squash is a food that meets the requirements of a healthy diet and is highly appreciated by consumers for its mild flavour and high nutritional value. In southern Brazil, many farmers grow several pumpkin landraces that are widely used in food. The consumption of its fruits and derivatives benefits human health due to the bioactive compounds, minerals, and antioxidants in the fruit pulp, making pumpkin a functional food. The objective of this study was to characterize the bioactive compounds, antioxidant activity, and minerals in the pulp of fruits of pumpkin landraces (Cucurbita maxima) from southern Brazil. Phenolic compounds, carotenoids, antioxidant activity, and minerals were evaluated in 10 accessions of pumpkin landraces from the Cucurbitaceae Genebank of Embrapa Temperate Agriculture (Pelotas, RS, Brazil). In mature fruits, the seeds and peels were discarded, and opposite longitudinal slices of pulp were manually prepared for analysis. All analyses were performed in triplicate. The data obtained showed genetic variability in total phenolic compounds, carotenoids, antioxidant activity, and minerals. Accessions C49, C307, and C216 had high levels of total phenolic compounds and carotenoids and high antioxidant activity. Of these accessions, accession C49 had the highest antioxidant capacity (504.1 μg·g-1). C216 and C178 were high in copper and iron, and the latter was highest in potassium, calcium, and phosphorus. Thus, accessions C216 and C178 have great potential for exploitation by genetic improvement programs for the development of biofortified cultivars in efforts to promote consumer health.

Resumo Para frutíferas de caroço o potássio (K) está relacionado com a qualidade dos frutos. O objetivo deste trabalho foi avaliar diferentes doses de adubação potássica nas características físico-químicas e compostos bioativos de frutos de pessegueiros ‘Esmeralda’. O experimento foi desenvolvido em pomar comercial no município de Morro Redondo, Rio Grande do Sul, Brasil, entre as safras de 2014 e 2017. As doses de potássio aplicadas foram 0, 40, 80, 120 e 160 kg K2O ha-1. Avaliou-se: coloração da polpa, firmeza da epiderme e da polpa, sólidos solúveis (SS), pH, acidez titulável (AT), relação SS/AT, compostos fenólicos totais, carotenóides totais e atividade antioxidante. O aumento das doses de K reduziu o teor de compostos fenólicos e a atividade antioxidante nos pêssegos nessa mesma safra. Os parâmetros de qualidade dos frutos, como a acidez titulável e firmeza da polpa não apresentaram alterações com a adubação potássica dos pessegueiros nas quatro safras avaliadas. Entretanto, os sólidos solúveis, relação SS/AT, croma, °Hue, firmeza da epiderme e compostos bioativos são influenciados pelas doses de K, mas dependem também das condições climáticas e da safra em análise.

Abstract For stone fruit the potassium (K) is related to fruit quality. The objective of this work was to evaluate different amount of potassium fertilization in the physical-chemical characteristics and bioactive compounds of ‘Esmeralda’ peach fruits. The experiment was carried out in a commercial orchard in the municipality of Morro Redondo, Rio Grande do Sul, Brazil, between the seasons of 2014 and 2017. The potassium doses applied were 0, 40, 80, 120 and 160 Kg K2O ha-1. It was evaluated: pulp color, peel and pulp firmness, soluble solids, pH, titratable acidity, SS/AT, total phenolic compounds, total carotenoids and antioxidant activity. The increase in K doses reduced the phenolic compounds content and the antioxidant activity in the peaches in the same harvest Fruit quality parameters, such as titratable acidity and firmness of the pulp did not show changes with the potassium fertilization of the peach trees in the four harvests cycles evaluated. However, soluble solids, SS/AT, chroma, °Hue, peel firmness and bioactive compounds are influenced by the amount of K, but also depend on the climatic conditions and the crop under analysis.

RESUMO O objetivo do presente trabalho foi avaliar o efeito de intensidades de poda na produção e na qualidade dos frutos de mirtileiro. O material vegetal utilizado foi mirtileiro da cultivar Misty. O fator estudado foi poda, em diferentes intensidades: sem poda; poda leve; poda-testemunha e poda drástica. O delineamento experimental foi em blocos ao acaso, com 4 repetições. Foram avaliadas a produção total de frutos, o tamanho de frutos, as características fisico-químicas como: pH, teor de sólidos solúveis totais (SST) e acidez total titulável (ATT), os compostos bioativos como: compostos fenólicos, antocianinas totais e atividade antioxidante. As plantas que receberam poda drástica apresentaram maiores médias em produção e tamanho de frutos. As maiores concentrações de compostos fitoquímicos no mirtilo ocorreram à medida que a poda foi mais drástica. O uso de diferentes intensidades de poda pode modificar o comportamento produtivo e a qualidade pós-colheita dos frutos.

ABSTRACT The objective of this study was to evaluate the effect of pruning intensity on yield and quality of blueberries fruits. It was evaluated the cultivar Misty. The treatments were: absence of pruning; light pruning; regular pruning and drastic pruning. The experimental design was randomized blocks with four replications. The variables analyzed were fruit production, fruit size, pH, total soluble solids (TSS) and total titratable acidity (TTA), and the bioactive compounds such as phenolic compounds, anthocyanins and antioxidant activity. The plants that received drastic pruning showed higher averages of production and fruit size. The highest concentrations of phytochemical compounds in blueberry fruits occurred as pruning was more drastic. The use of different intensity of pruning can modify the productive behavior and postharvest quality of fruits.