Simone Rodrigues da Silva

Fluxo de seiva e fotossíntese em laranjeira 'Natal' com clorose variegada dos citros

The objective of this work was to evaluate the effects of citrus variegated chlorosis (CVC) on sap flow, gas exchanges and photochemical activity in Natal sweet orange plants with and without CVC under field condition. Diurnal courses of sap flow, leaf water potential, CO2 assimilation rate and transpiration, stomatal conductance, potential and effective quantum efficiency of photosystem II were evaluated. The experiment was arranged in a random block design with five repetitions. Healthy plants showed sap flow values around 1.9 times higher than injured ones. Injured plants exhibited reductions of 43, 28 and 33% in CO2 assimilation rate, stomatal conductance and leaf transpiration, respectively. CVC-affected plants showed dynamic photoinhibition. Since healthy and injured plants showed similar diurnal course of effective quantum efficiency, the possible influence of photorespiration on photochemical apparatus in CVC-affected plants is discussed. Reductions in CO2 assimilation rate, transpiration and sap flow of injured plants were induced by low stomatal conductance values, which was probably due to the xylem vessel colonization by Xylella fastidiosa.

Ponto de colheita e maturação de frutos de camu-camu colhidos em diferentes estádios

The objective of this work was to determine the harvest point and to characterize the postharvest of camu-camu (Myrciaria dubia) fruit harvested at different maturity stages. The fruits are harvested at four maturity stages, defined by skin color: green, reddish‑green, red‑greenish, and purple. Fruit were cold‑stored at 22±1°C and 85±5% RH. It was used a completely randomized design, split‑potted in time, with five storage periods: 0, 3, 6, 9, and 12 days. Evaluations were made for: respiratory activity; ethylene production; skin color, determined with the hue angle and chromaticity coordinates a* and b*; firmness; fresh matter weight loss; contents of chlorophyll, anthocyanins, soluble solids, and ascorbic acid; titratable acidity; and rot incidence. Peaks of CO2 and ethylene production occurred after harvest. The contents of chlorophyll and anthocyanins varied according to the changes in skin color, from green to purple, which confirmed fruit ripening. The contents of ascorbic acid ranged from 759.02 mg per 100 g, in the green stage, to 1,071.12 mg per 100 g, in the purple one. Fruit harvested with complete purpled skin had reduced postharvest life. Best postharvest quality for camu-camu is achieved when skin color is red-green.

Viroid species associated with the bark-cracking phenotype of 'Tahiti' acid lime in the State of São Paulo, Brazil

Viroids have been used as graft transmissible dwarfing agents (GTDA) in several countries, mainly to reduce growth of citrus trees, thus increasing their density in orchards. In the State of Sao Paulo, Brazil, plants of the acid lime Tahiti are usually grafted with a complex of GTDA, presumably viroids. The aim of the present work was the identification and molecular characterization of the viroids infecting trees of acid lime Tahiti displaying Quebra galho (bark-cracking). Viroids were identified and characterized by biological indexing in Etrog citron, Northern-blot hybridization, RT-PCR, cloning and complete sequencing of the RNA genomes. Citrus exocortis viroid (CEVd), Hop stunt viroid (HSVd) and Citrus dwarfing viroid (CDVd) were found in different combinations. Although we have not been able to infer a direct relationship between the agronomical performance and symptom severity with the presence of a specific viroid or viroid combination, the differences in the severity of Quebra-galho symptoms among different trees is probably associated with the presence (or absence) of CEVd, with its interaction with other viroids perhaps determining the different phenotypes observed in the field.

Reação de variedades e clones de laranjas a Xylella fastidiosa

Citrus variegated chlorosis (CVC) is a serious disease, caused by Xylella fastidiosa, being the most important to the Brazilian citriculture. The usual measures of control show less efficient or practice and they are very expensive. The use of resistant varieties is showed as the most efficient, consisting the aimed of this research. The objective of the present work was study the behavior of varieties and clones introduced in relation to X. fastidiosa. Were studied 59 varieties and clones of sweet oranges and 2 sour oranges introduced from France, Italy and Portugal. The experimental layout was a complete randomized block design, with 4 replicates and 62 treatments, with Pera variety as control. Each treatment had two plants, one inoculated and the other without inoculation. For the pathogen inoculation was used the grafting approach with infected seedlings. For the disease incidence measurement was used qualitative data, positive or negative, while for the severity it, was used a note scale based on CVC symptoms confirmed through the PCR tests. The sour oranges varieties Beja and Sr. Pinto and the sweet oranges Navelina ISA 315, Navelina SRA 332 e Newhall Navel SRA 343, have not presented leaves symptoms until 27 months after inoculation.

Viroides em citros

Os viroides sao os menores fitopatogenos conhecidos. Constituidos por uma molecula de RNA de fita simples, circular, que nao e encapsidada e nao codifica proteinas, sao capazes de se replicar de maneira autonoma nas celulas do hospedeiro. Os viroides de citros pertencem a familia Pospiviroidae (cujos membros apresentam uma regiao central conservada, replicam-se no nucleo das celulas hospedeiras e nao apresentam atividade ribozimatica) com cinco especies: Citrus exocortis viroid, CEVd (Pospiviroid), Hop stunt viroid, HSVd (Hostuviroid), Citrus bark cracking viroid, CBCVd (Cocadviroid) e Citrus bent leaf viroid, CBLVd e Citrus dwarfing viroid, CDVd (Apscaviroid). Alem disso, Citrus viroid original source (CVd-OS) e mais recentemente, Citrus viroid V (CVd-V) foram propostas como especies tentativas do genero Apscaviroid. Os viroides de citros sao transmitidos via enxertia e disseminados principalmente pela propagacao de material contaminado. Sabe-se que os viroides de citros infectam praticamente todas as especies do genero Citrus e afins. Porem, ha somente duas doencas importantes descritas em citros, induzidas por viroides: (i) a exocorte; (ii) e a xiloporose (ou cachexia). Apesar dos viroides induzirem sintomas severos, ou simplesmente afetarem o tamanho das arvores, muitas especies de citros sao assintomaticas, sendo o controle baseado em medidas preventivas, como utilizacao de gemas livres de viroides aliadas a metodos confiaveis de indexacao. A proposta desta revisao e apresentar ao leitor os recentes avancos nas pesquisas com viroides de citros, principalmente na taxonomia, distribuicao geografica, metodos de deteccao, limpeza e indexacao, epidemiologia e controle, alem do historico e importância desses patogenos para a citricultura mundial.

Qualidade e maturação de tangerinas e seus híbridos em São Paulo

The extension of tangerine offering both for internal and external markets is limited by the large amount of seeds present in the main cultivars, the occurrence of peel injures caused by diseases and the small fruit production during the hottest periods of the year. This work was aimed to characterize the fruit quality and maturation period of 46 tangerines and hybrids grown in the field at the Estacao Experimental de Citricultura de Bebedouro (EECB), located in Bebedouro county, in Sao Paulo State, Brazil. Tangerines and their hybrids (tangors and tangelos) were introduced from germplasm banks of Italy, Portugal, Spain and France, and the study was conducted during the years of 2001/2002 and 2002/2003. External fruit quality was assessed by measurements of fruit height and diameter, fruit mass and peeling facility, as well as the internal quality characteristics, such as seed number, total soluble solids content, total titrable acidity, juice content, ratio and pulp content. Two cultivars produced good quality and early ripening fruits that may be offered in the local marketinperiods oflow fruitoffer,asalternatives to the Cravotangerine.Fourcultivars that presented good quality and a moderate maturation precocity may be introduced as alternatives for the Ponkan cultivar.

Cultivo do mirtilo: atualizações e desempenho inicial de variedades de baixa exigência em frio no Estado de Säo Paulo

In recent years, South American commercial blueberry production has gone through important changes imposed by a larger offer of fresh fruit from the main producers, thus leading to drastic price reductions during main harvest season, from December to February. One alternative solution to this situation is to grow early or late fruit ripening varieties, harvested at the beginning or at the end of the harvest period. In 2010 new blueberry varieties with low winter chilling requirements were introduced to Brazil, which were developed by the University of Florida and may be planted under hot weather conditions, showing earlier fruit bearing when compared to the traditional varieties grown in Brazil so far. Those low chilling requirement blueberries have an undeniable potential for early fruit production in hot regions with no chill hours during winter, with increased crop profitability to growers. For an adequate establishment of these varieties in Brazil, crop management strategies should be validated in regions with no chill hours, due to the lack of technical information on blueberry crop under such particular conditions. First field trials with early-bearing blueberry varieties are currently being conducted in the State of Sao Paulo for evaluating plant growth and fruit yield and quality under no chilling incidence, being these exceptional conditions met by few countries in the world.

Field performance of "marsh seedless" grapefruit on trifoliate orange inoculated with viroids in Brazil

Some viroids reduce citrus tree growth and may be used for tree size control aiming the establishment of orchards with close tree spacing that may provide higher productivity than conventional ones. To study the effects of citrus viroids inoculation on vegetative growth, yield and fruit quality of Marsh Seedless grapefruit (Citrus paradisi Macf.) grafted on trifoliate orange (Poncirus trifoliata (L.) Raf.), an experiment was set up in January 1991, in Bebedouro, Sao Paulo State, Brazil. The experimental design was randomized blocks with four treatments with two plants per plot: viroid isolates Citrus Exocortis Viroid (CEVd) + Hop stunt viroid (HSVd - CVd-II, a non cachexia variant) + Citrus III viroid (CVd-III) and Hop stunt viroid (HSVd - CVd-II, a non cachexia variant) + Citrus III viroid (CVd-III) and controls: two healthy buds (control), and no grafting (absolute control). Inoculation was done in the field, six months after planting by bud grafting. Both isolates reduced tree growth (trunk diameter, plant height, canopy diameter and volume). Trees not inoculated yielded better (average of eleven harvests) than inoculated ones but the productivity was the same after 150 months. Fruit quality was affected by viroids inoculation but not in a restrictive way. The use of such severe dwarfing isolates for high density plantings of grapefruit on trifoliate orange rootstock is not recommended.

Produção e atributos de qualidade de cultivares de macadâmia no sudoeste do estado de Säo Paulo

A macadâmia apresenta-se como uma importante alternativa para a fruticultura paulista, principalmente pela sua rusticidade e pelo valor alcancado por seus frutos. No entanto, estudos relacionados ao seu desenvolvimento e as suas caracteristicas produtivas e quimicas sao necessarios para a adequada escolha da cultivar. Com o objetivo de caracterizar o desenvolvimento e a producao de diferentes cultivares de macadâmia nas condicoes climaticas, no sudoeste do Estado de Sao Paulo, foram conduzidos experimentos instalados no municipio de Dois Corregos-SP, nos ciclos produtivos de 2009/2010 e 2010/2011, para avaliacao do ciclo fenologico da cultivar HAES-344, o desempenho produtivo, a caracterizacao fisica e o perfil de acidos graxos das cultivares HAES-344, HAES-660, IAC 1-21, HAES-816, IAC 4-20, IAC Campinas-B, Aloha e IAC 4-12 B de macadâmia. O intumescimento de gemas ocorreu de maio a junho, a antese de final de julho a inicio de agosto e a queda de frutos de fevereiro a marco. As cultivares HAES-344, IAC 1-21 e IAC 4-12 B apresentaram a maior producao. A cultivar HAES-816 apresentou os maiores valores para as variaveis diâmetro da casca e da amendoa e massa da amendoa. Para a taxa de recuperacao de noz (TR), os melhores resultados foram obtidos pelas cultivares HAES-344, HAES-660 e Aloha. As cultivares HAES-660 (68,48%), IAC 4-20 (66,88%) e IAC 1-21 (66,76%) apresentaram as maiores porcentagens de oleo. Todas as cultivares apresentaram em sua composicao os acidos palmitoleico, palmitico, oleico, linoleico e linolenico.

Desempenho da tangerineira 'Span Americana' em diferentes porta-enxertos

This study aimed to evaluate plant growth and fruit yield and quality of Span Americana mandarin on different rootstocks, under the climatic conditions of Bebedouro, state of Sao Paulo. The experimental orchard was planted in 2003 using 6 m x 3 m spacing, and was drip irrigated since 2006. The following rootstocks were studied: the Carrizo and Troyer tetraploid citranges [Citrus sinensis (L.) Osbeck × Poncirus trifoliata]; the trifoliates (P. trifoliata) Davis A and Flying Dragon: Catania 2 Volkamer lemon (C. volkameriana Tenn. et Pasq.); HRS 849 [(C. aurantium L. cv. Smooth Flat Seville x P. trifoliata cv. Argentina)]; Orlando tangelo (C. reticulata Blanco × C. paradisi Macf.), and CravoRangpur lime (C. limonia Osbeck). Mean cumulative yield, productive efficiency and early-bearing yield were calculated for the 2007-2009 period. Plant size and mean plant growth rate was calculated from the annual variation in canopy volume during 2005 through 2008. Fruit quality was assessed in 2006 and 2007. Under irrigated conditions, the Davis A trifoliate and the HRS 849 induced good horticultural performance to Span Americana mandarin and may be used as alternative rootstocks. For high-density plantings, the rootstocks Flying Dragon trifoliate and the Troyer and Carrizo tetraploid citranges may induce better performance to the trees.