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Item Identification of morphoagronomic traits correlated with the N use efficiency in coffee(Editora UFLA, 2025-04-29) Moura, Waldenia de Melo; Ribeiro, Poliane Marcele; Soares, Luciana Gomes; Silva Júnior, Antônio Carlos da; Ferreira, Tatiane Cravo; Gravina, Geraldo de Amaral; Martinez, Hermínia Emília PrietoThe study of nutritional efficiency is an expensive process, as it requires extensive planting areas, several years of evaluation and the destruction of plants. To mitigate these difficulties, a strategy would be to identify easily measurable traits associated with nutritional efficiency in growing a nutritional solution. Thus, the objective of this study was identify morphoagronomic traits correlated with the N-efficiency indices in to assist in selecting coffee genotypes for environments with N restriction. Twenty arabica coffee genotypes were grown in a nutrient solution with a low concentration of nitrogen (1.0 mmol L-1). The experiment was conducted in a randomized block design with three replications. There was variability among the coffee genotypes for all the traits evaluated. Most of the traits evaluated showed greater genetic than environmental influence on phenotypic expression. Heritability (H2) was greater than 70% for most of the traits evaluated, with an emphasis on plant height and internode length, which also had the highest relative variation indices (RVIs). The associations between morphoagronomic traits and nutritional efficiency indices revealed greater contributions of genotypic correlation than of environmental correlation. Among the traits associated with nutritional efficiency indices, stem diameter has the potential for use in breeding programs for the selection of cultivars that present greater nitrogen efficiency in environments with nitrogen restriction.Item Nitrogen metabolism in coffee plants subjected to water deficit and nitrate doses(Instituto de Tecnologia do Paraná - Tecpar, 2023-03-24) Rocha, Brunno César Pereira; Martinez, Hermínia Emília Prieto; Ribeiro, Cléberson; Brito, Danielle SantosNitrogen uptake is essential for coffee growth and development, resulting in important effects on the biomass and final crop yield. Thus, like most nutrients, nitrogen is absorbed by the roots using water as a mean of transport, so that water stress and nitrogen can directly and indirectly affect various physiological processes. The aim of this paper was to evaluate the nitrogen metabolism in young plants of four varieties of coffee trees (Coffea arabica L.) submitted to water deficit (WD) and nitrogen supply. We have done a triple factorial (2 x 4 x 4) experiment entirely randomized. The plots received combinations of high or low N doses (7mmol/L and 2.8 mmol/L NO3 -), four water potentials (0; -0.4; -0.8; and -1.6 Mpa), and four varieties (Mundo Novo IAC379-19, Acauã F6 of IBC - PR 82010, Catuaí Vermelho IAC 44, and Catuaí Amarelo IAC 62). One hundred and forty days after the I of the experiment (140 days after the beginning of N stress and 82 days after the beginning of WD stress) the activity of the enzymes nitrate reductase (NR) and glutamine synthetase (GS), concentration of nitrate, free proline, amino acids (TAA), and total proteins were determined in samples of leaf and root tissues. There were differences between varieties independently of WD and N dose for leaf NR, being ‘Acauã’ the cultivar that presented the highest and ‘Catuaí Vermelho’ the lowest value to this trait. The WD promoted an increase on the proline concentration in the roots. With low N dose, the activity of GS presented linear increases in response to WD. It was concluded that in young coffee plants under WD, proline can be involved in the osmotic adjustment, having its synthesis in the roots increased. Under WD, plants with good nitrogen nutrition presented larger leaf concentration of soluble amino acids and total soluble proteins. The varieties studied do not present differentiated responses to WD.