RESUMO -Realizou-se, sob condições de casa de vegetação, um experimento para avaliar o efeito de fontes e de doses de nitrogênio (N) na formação de porta-enxertos de limoeiro 'Cravo' em tubetes. Os tratamentos, combinações de duas fontes (nitrato de cálcio e uréia) e quatro doses de N (0,15; 0,30; 0,45; e 0,60 g L -1 ) e uma testemunha sem a adição de fertilizante nitrogenado, foram dispostos em delineamento blocos ao acaso em esquema fatorial, com quatro repetições. O fornecimento de N (10 mL de solução por tubete) foi iniciado 56 dias após a germinação, sendo repetido semanalmente, por 15 semanas. Observou-se, apenas, efeito de doses de N sobre a altura, diâmetro do caule e produção de matéria seca da parte aérea das mudas. Os efeitos das variações na dose de N sobre essas variáveis foram ajustados a modelos quadráticos de regressão, com valor máximo correspondente à dose média de 0,37 g L -1 de N, a partir da qual o crescimento das mudas foi reduzido. Para as raízes, a produção de matéria seca apresentou comportamento distinto também entre fontes de N, sendo que, para a uréia, a massa de raízes aumentou linearmente com a dose de N e, para o nitrato de cálcio, o efeito foi descrito por modelo quadrático, com valor máximo obtido para a dose de 0,35 g L -1 de N. As acumulações de N, P, K, Ca e Mg na parte aérea das mudas de limoeiro 'Cravo' acompanharam as variações na produção de matéria seca, sendo descritas por modelos quadráticos, segundo os quais a absorção de nutrientes foi limitada pela aplicação das doses mais altas de nitrogênio. Termos para indexação: propagação de citros, ambiente protegido, nitrogênio, Citrus limonia. NITROGEN FERTILIZATION ON RANGPUR LIME ROOTSTOCK PRODUCED IN DIBBLE TUBESABSTRACT -A greenhouse experiment was carried out to evaluate the effects of nitrogen sources and rates on growth of rangpur lime seedlings in dibble tubes. The treatments comprised the combinations of two sources (calcium nitrate and urea) and four rates of nitrogen (0.15; 0.30; 0.45; and 0.60 g L -1 ), and an additional control treatment without N fertilization. The treatments were disposed according to a randomized complete block design as a 2 x 4 + 1 factorial arrangement with four replications. Nitrogen fertilizers (10 mL per dibble tube) were applied weekly during 15 weeks, starting at 56 days after seed germination. The data revealed effects of N rates on plant height, stem diameter and shoot dry matter yield. The effects of the N rates on these parameters were adjusted to quadratic regression models with maximum values corresponding to the rate of 0.37 g N L -1 . The growth was reduced at rates higher than 0.37 g N L -1 of either calcium nitrate or urea. The effects of calcium nitrate and urea were different on root dry matter yield. For urea, root dry matter increased with the N rate, but for calcium nitrate the effect was described by a quadratic model, with maximum value corresponding to the rate of 0.35 g N L -1 . Nitrogen, phosphorus, potassium, calcium, and magnesium accumulation in the shoot...
Latania scale, (Hemiberlesia lataniae (Signoret)), is now established in the North Island of New Zealand. The significance of this pest and methods of distinguishing latania scale from greedy scale (Hemiberlesia rapax (Comstock)) and oleander scale (Aspidiotus nerii Bouche) are discussed.
-The knowledge of the phenotypic variation of cassava (Manihot esculenta Crantz) germplasm allows the estimative of the genetic variability to support the selection of contrasting genitors. Therefore, the aim of this work was to define homogeneous groups of cassava germplasm based on yield traits, disease resistance and root quality using K-means as a nonhierarchical method. Breeding values estimated by Best Linear Unbiased Predictor (BLUP) were used for the cluster analysis. The number of groups was defined according to the stabilization of the smallest within-group sum of squares. Seventeen clusters were defined to represent the diversity of the germplasm, whose number of accessions ranged from 7 (Group 15) to 69 (Group 9). In general, accessions belonging to Groups 1, 4, 7, 12, 15 and 16 showed good agronomic traits, such as high fresh root yield and starch yield (> 60.7 t ha -1 and 18.6 t ha -1 , respectively). In contrast, only Group 15 presented low bacterial blight severity. The groups obtained showed strong differences, as evidenced by the within-groups sums of squares values, which ranged from 215.1 (Group 15) to 2,338.3 (Group 8). The K-means algorithm allowed the formation of consistent groups based on yield traits, disease resistance and root quality. Therefore, the K-means algorithm was efficient in the formation of groups with low within genotypic variation, especially concerning large amounts of data, such as in cassava germplasm banks.
-The papaya borer weevil, Pseudopiazurus papayanus (Marshall), is generally considered a secondary pest, but it has been reported in high infestations in Northeast Brazil. This work aimed at evaluating the occurrence of P. papayanus and reporting its infestation level in papaya genotypes kept at the germplasm bank of Embrapa Cassava & Tropical Fruits (Cruz das Almas, Bahia, Brazil). The number of larvae, pupae and adults found in each plant of 65 Carica spp. genotypes and of three Vasconcella spp. genotypes was registered in three to fi ve plants of each genotype, by cutting the exsudating trunks lenghtwise. Papaya borer weevil was found in C. papaya and V. caulifl ora but not in those of V. quercifolia. Among the evaluated genotypes, 52.4% of those belonging to the Solo group were infested, against 25.0% of the Formosa group. Larval infestation was the best criterion for sorting out genotypes concerning this insect infestation. This is also the fi rst occurrence of the papaya borer weevil on V. caulifl ora.KEY WORDS: Insecta, papaya borer weevil, larval infestation RESUMO -A broca-do-mamoeiro, Pseudopiazurus papayanus (Marshall), é considerada praga secundária da cultura; entretanto, altas infestações têm sido registradas no Nordeste do Brasil. O objetivo deste trabalho foi avaliar a infestação de P. papayanus em genótipos de mamoeiro do banco ativo de germoplasma de Carica spp. da Embrapa Mandioca e Fruticultura Tropical, em Cruz das Almas, BA. Registrou-se o número de larvas, pupas e adultos em 68 genótipos, amostrando-se de três a cinco plantas/genótipo. As amostragens foram feitas em caules com exsudações. A broca-do-mamoeiro infestou plantas de C. papaya e V. caulifl ora, mas V. quercifolia não foi atacada. Entre os acessos de C. papaya infestados, 52,4% e 25,0% pertenciam, respectivamente, aos grupos Solo e Formosa. A amostragem de larvas foi o melhor critério para distinguir os acessos com relação à infestação pelo inseto. Esta é também a primeira ocorrência da broca-do-mamoeiro em V. caulifl ora.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.