Effects of levels of nitrogen and potassium on yield and fruit maturation of irrigated guava trees in the São Francisco Valley

Abstract

-Yield and physical and chemical characteristics of 'Paluma' guava fruit were evaluated as a function of the harvest at different maturity stages, under influence of nitrogen and potassium fertilization, in Petrolina, State of Pernambuco, Brazil. Fertilizer rates were 67 kg N + 33 kg K 2 O, 133 kg N + 67 kg K 2 O, 200 kg N + 100 kg K 2 O and 267 kg N + 133 kg K 2 O per hectare. Fruits were evaluated at maturity stages 2, 3, 4 and 5, established according to peel color. Higher doses of N and K induced higher yields. Nevertheless, fertilization with 200 kg of N + 100 kg of K per hectare improved fruit quality, delaying ascorbic acid breakdown and conserving pulp firmness. Main changes took place at maturity stages 4 and 5, when the fruit should present ideal conditions for consumption, namely the increase on soluble solids and soluble sugars content. Index terms: Psidium guajava L., nutrition, maturity stages, fruit quality. EFEITOS DOS NÍVEIS DE NITROGÊNIO E POTÁSSIO NA PRODUTIVIDADE E NA MATURAÇÃO DOS FRUTOS DE GOIABEIRA IRRIGADA NO VALE DO SÃO FRANCISCORESUMO -O presente trabalho avaliou a produtividade e as características físicas e químicas dos frutos de goiabeira 'Paluma' em diferentes estádios de maturação, sob a influência de adubações nitrogenada e potássica, em Petrolina-PE. As plantas foram submetidas à aplicação de 67 kg N + 33 kg K 2 O, 133 kg N + 67 kg K 2 O, 200 kg N + 100 kg K 2 O and 267 kg N + 133 kg K 2 O por hectare, sendo os frutos avaliados nos estádios de maturação 2; 3; 4 e 5, caracterizados conforme a cor da casca. As maiores doses de N e K resultaram em maiores produtividades, mas as aplicações de 200 kg de N + 100 kg de K por hectare favoreceram a qualidade do fruto, resultando em menor degradação de ácido ascórbico e preservação da firmeza da polpa. As principais mudanças que ocorreram entre os estádios 4 e 5, quando o fruto apresentaria condições ideais para consumo, foram relativas ao acúmulo de sólidos solúveis e de açúcares solúveis. Termos para indexação: Psidium guajava L., nutrição, estádios de maturação, qualidade do fruto.

First survey of fruit fly (Diptera: Tephritidae) and parasitoid diversity among myrtaceae fruit across the state of Bahia, Brazil

“…As well, guava was the myrtaceous species that hosted the highest diversity of fruit flies. These results corroborate results from several studies in other states in Brazil (MALAVASI et al, 1980;SILVA et al, 1996;SOUZA FILHO et al, 2009).…”

“…The hosts E. uniflora and P. guajava were the preferred hosts of tephritids, with maximum rates of 306.7 pupae/Kg and 197.6 pupae/Kg, respectively (Table 1). These rates were higher than those reported by Malavasi et al (1980) in different locations in Brazil.…”

“…It is a well-represented family in the Atlantic Forest and comprises several commercially important species such as Psidium guajava L. (guava) and Eugenia uniflora L. (Surinam cherry) (GRESSLER et al, 2006). Brazil is the world's largest guava producer, and more than 50% of its total guava cultivated area is in the northeastern region, mainly in the states of Pernambuco and Bahia (MAPA, 2002;LIMA et al, 2008).…”

Água salina e esterco bovino líquido na formação de mudas de goiabeira cultivar Paluma

“…Seu fruto possui grande aceitação nos mercados interno e externo, em função do sabor agradável, aroma forte e qualidade proteica (Cavalcante et al, 2005a;Lima et al, 2008). Assim como outras fruteiras de importância econômica, é amplamente cultivada em áreas irrigadas no semiárido, situando-se entre as fruteiras de maior valor econômico para o Nordeste brasileiro (Gurgel et al, 2007;Freitas & Alves, 2008).…”

Fruit production and quality of guava as a function of biofertilizer and nitrogen fertigation in semiarid

“…'Baixinho de Santa Amália'. This way Paiva et al (2009) detach that the molecular processes responsible for major fruit changes during ripening is related to fruit firmness, which is one of the key attributes that guarantee fruit quality for in natura consumption, and fruit firmness is related with K nutrition, since, according to Lima et al (2008), K supports the maintenance of cell turgor and it contributes to tissue resistance, but the NK combination affects fruit firmness along the maturation stages. Additionally, the biofertilizer used in the present experiment had high K levels (Table 2), which probably favored the fruit firmness increasing with a maximum value at 2.5% of biofertilizer (Fig.…”