Flavio Gilberto Herter

Chilling privation during dormancy period and carbohydrate mobilization in Japanese pear trees

The flower bud abortion is one of the main problems that limit commercial pear (Pyrus pyrifolia) production in the southern region of Brazil. Insufficient chilling during the dormancy period is known as the main factor of this problem. One of the hypotheses to explain this problem is that the starch mobilization and carbohydrate fluxes to the buds are impeded when mild temperatures occurred during winter. This study compared the total soluble sugars (TSS) and reducing sugars (RS) concentrations, the cell wall acid invertase (CWAI - EC 3.2.1.26) and sucrose-phosphate synthase (SPS - EC 2.4.1.14) activities in wood of branches and floral buds of Japanese pear trees cv. Housui, grafted on Pyrus calleryana and submitted to chilling conditions during the dormancy period. Treatments were: (i) natural conditions; (ii) continuous artificial chilling; (iii) alternating temperatures, and (iv) total chilling privation. TSS and RS contents, as well as CWAI and SPS activities in tissues of branches that received insufficient chilling were lower than those that received sufficient chilling during winter. The starch concentration was superior in wood tissues of branches kept under chilling privation. The chilling privation disturbs carbohydrate mobilization in pear trees, reducing the sucrose synthesis capacity in wood tissues (source) and sucrose importation by the floral buds (sink).

Budbreak in 'Imperial Gala' and 'Fuji Suprema' apples by use of Erger and calcium nitrate

Despite the high efficiency of some chemicals on budbreak induction of temperate fruit trees, the high toxicity showed by these compounds is one of the main problems related to its use. Preliminary results indicated that Erger®, an organic nitrogen compound, combined with calcium nitrate, has similar effect to hydrogen cyanamide, with the advantage of being less dangerous to the environment. Thus, the present study aimed to evaluate the efficiency of Erger® and calcium nitrate as budbreak promoter in apple trees. The experiment was carried out in Cacador/SC, in 2007, where was done the application of different budbreak promoters in Imperial Gala and Fuji Suprema apples. The budbreak promoters tested were Erger® 3% + calcium nitrate 3%, Erger® 5% + calcium nitrate 5%, Erger® 7% + calcium nitrate 7%, mineral oil 3.2% + 0.34% hydrogen cyanamide and control (without application). It was evaluated occurrence dates of early, full and end blooming stages, budbreak of axillary and terminal buds, axillary budbreak uniformity and fruit set. The budbreak promoters increased significantly axillary and terminal budbreak, and it increased the budbreak uniformity and the blooming overlap of Imperial Gala and Fuji Suprema apples. Because of negative effects on fruit set of Imperial Gala apples, it is indicated Erger® and calcium nitrate application at concentrations below 7%.

Hábito de frutificação e produção de pereiras sobre diferentes porta‑enxertos

The objective of this research was to evaluate the bearing habit and yield of pear cultivars (Pyrus communis) grafted onto quince (Cydonia oblonga) and callery pear (P.xa0calleryana) rootstocks. The experiment was carried out in the winter of 2009 and 2010, in a pear orchard conducted as central leader, at 1.0x5.0xa0m spacing, with three pear cultivars (Carrick, Packham, and Williams) combined with one callery pear (Clone D6 of P.xa0calleryana) and 15xa0quince rootstocks. The following variables were assessed: percentage of vegetative spurs, reproductive spurs, vegetative brindles, reproductive brindles and bourses; total number of flower buds; yield per plant; and productive efficiency. Bearing habit of pear cultivars is influenced by the rootstocks, mainly for reproductive spur formation. In general, there was an inverse relationship between the percentage of vegetative and reproductive spurs, and between productive efficiency and vigor for all scion and rootstock combinations. In order to enhance production, cultural management in orchards of the evaluated cultivars, especially on pruning, should be oriented according to the rootstock used and to the bearing habit of each combination.

Avaliação da necessidade de frio em pessegueiro

ABSTRACT - Chilling requirement was investigated in six peach [ Prunus persica (L.) Batsch] cultivars observing plants in containers, with one ortwo years, artificially chilled by 150, 300, 450, and 600 hours at 2oC, and in excised shoots that were periodically taken from the orchard during the restperiod. Chilling requirement of ‘Precocinho’ is 300 hours at 2oC (around 150 chilling units - CU - using Utah Model) or around 200 hours under 12oC;‘Riograndense’ and ‘Eldorado’ have 450 chilling hours at 2oC (225 CU) or 365 chilling hours under 12oC; ‘BR-1’ is 450 chilling requirement at 2oC (225CU) or 418 chilling hours under 12 oC; and ‘Planalto’ and ‘Della Nona’ are over 600 chilling hours at 2oC (>300 CU). It was not possible to estimatechilling requirement in ‘Della Nona’ using temperatures under 12 oC. Index terms: Prunus persica , endodormancy, adaptation. INTRODUCAO O desenvolvimento de plantas perenes de folhas caducas eafetado por fatores endogenos e exogenos. Quando as condicoesexogenas sao desfavoraveis, a planta reage, paralisando o crescimento.O mecanismo de controle da paralisacao e retomada de crescimento,apesar de pouco esclarecido, esta relacionado com a genetica e fisiolo-gia das plantas. A temperatura e, sem duvida, o principal fator exogenodesencadeador deste processo. Mauget (1987) cita que o principal efei-to da temperatura se refere a acao positiva das baixas temperaturas deinverno sobre a superacao da endodormencia.Quando as especies de clima temperado sao introduzidas emregioes tropicais ou subtropicais, manifestam diversos disturbios fisio-logicos, como: abertura de gemas de forma escalonada no tempo, redu-cao no numero de gemas brotadas, formacao de rosetas foliares, redu-cao na producao e longevidade e, em casos extremos, a propria sobrevi-vencia da planta e ameacada (Diaz et al., 1987; Herter, 1992). As flutuacoesde temperatura durante o inverno podem afetar negativamente a supera-cao da endodormencia nestas especies. Erez e Lavee (1971) e Erez et al.(1979) relatam o efeito adverso das altas temperaturas ciclicas sobre aendodormencia, podendo temperaturas elevadas, apos um periodo defrio, causar um atraso na brotacao.Um metodo tradicional de prever a necessidade de frio dasespecies e/ou cultivares consiste em submeter ramos inteiros, retiradosde arvores em diferentes epocas, a uma temperatura favoravel ao cresci-mento, computando o percentual de abertura de gemas apos 21 dias ouo numero de dias necessarios ao desenvolvimento de uma certa percen-tagem fixa, porem arbitraria, de gemas. Quanto maior for o porcentual deabertura aos 21 dias ou quanto menor o numero de dias para atingir oporcentual fixo, mais proximo da superacao da endodormencia encon-tra-se a cultivar ou especie estudada. Esta tecnica, ha muito tempo, vemsendo estudada para fixar as datas de fim de dormencia (Weinberger,1950; Erez e Lavee, 1971; Richardson et al., 1974; Kobayashi et al., 1982),porem o principal problema e nao considerar, ou nao permitir isolar, osefeitos das inibicoes correlativas entre as gemas vegetativas e a neces-sidade de calor necessaria para a antese.Outro metodo utilizado e o “teste das estacas de nos isolados”(Balandier, 1992; Herter, 1992). Fragmentos de ramos, contendo apenasum no com gemas, eliminando, assim, grande parte das inibicoescorrelativas, sao submetidos a temperatura e fotoperiodo adequados aocrescimento. O tempo necessario para abertura de uma gema, sob estascondicoes, mede a intensidade da dormencia. Os principais defeitosdeste metodo foram assinalados por Champagnat (1983), Mauget (1987)e Balandier (1992).Outro fator a ser considerado na quantificacao da dormencia ea necessidade de calor, verificado principalmente em gemas florais.Citadin et al. (2001) observaram diferencas entre gemas vegetativas eflorais de pessegueiro quanto a necessidade de calor e tambem entrecultivares. Neste sentido, e importante estabelecer uma metodologiaclara de determinacao da necessidade de frio durante a endodormencia,considerando as possiveis interacoes com a necessidade de calor.O objetivo deste trabalho foi determinar a necessidade de friode seis cultivares de pessegueiro, atraves de duas diferentes tecnicas.

The comparison of dormancy dynamics in apple trees grown under temperate and mild winter climates imposes a renewal of classical approaches

Key messageThis study is an important contribution to understanding of the dormancy dynamics of apple buds grown in contrasting climates, highlighting the main factors possibly involved in their control and the key role of rehydration.AbstractThe aim of this study was to compare the dormancy dynamics and the physiological status of vegetative and floral buds of apple cultivars grown during cold and mild winters. Long shoots bearing vegetative buds and short shoots bearing floral buds were regularly collected during two successive cycles at Marsillargues, France (2011/12, 2012/13) and Palmas, Paraná, Brazil (2012, 2013). The dormant state in vegetative buds was evaluated by the single-node cutting test and in floral buds by the Tabuenca’s test. The first approach highlighted important differences in the dormancy dynamics in both sites, clearly showing that: (1) the entry and the maximum level of dormancy are strongly correlated with cold winter temperatures; (2) the three classical phases of dormancy dynamics are difficult to differentiate under a mild winter climate; and (3) endodormancy, if it actually exists, is very weak and lasts only for a short time. Distinct temporal changes between both sites were found for flower primordia fresh and dry weight. The ecodormant state was linked to significant changes in dry weight and the capacity to quickly reach a water content of around 77xa0% according to the Tabuenca’s test. High temperatures in Brazil allowed a quick transition between endodormancy and ecodormancy compared to France where the rehydration period was long. The weak endodormancy associated with a quasi-absence of ecodormancy could explain the strong spatio-temporal heterogeneity of budburst and flowering under a mild winter climate. This may be useful for understanding the future phenology of trees under global warming conditions and for the selection of adapted cultivars.

Compatibility of pear cultivars on quinces rootstocks

A insuficiencia de estudos sobre compatibilidade de porta-enxertos e um dos fatores limitantes ao desenvolvimento da cultura da pereira (Pyrus sp.) no Brasil. A utilizacao do marmeleiro (Cydonia oblonga) como porta-enxerto para a cultura da pereira apresenta inumeras vantagens, entre as quais a reducao do vigor e a rapida entrada em producao; todavia, sua combinacao com algumas cultivares copa apresenta problemas de incompatibilidade de enxertia, podendo ocasionar a ruptura do caule das plantas no pomar. Objetivou-se, neste trabalho, avaliar a compatibilidade de enxertia de algumas cultivares de marmeleiros (Quince C e Adams) com pereiras (Packhams Triumph e Kieffer). As variaveis analisadas foram: diâmetro da seccao do tronco no ponto de enxertia, 5 cm abaixo e 5 cm acima do ponto de enxertia, diferenca do diâmetro entre porta-enxerto e copa, altura das plantas, volume e massa seca da copa e raizes. Alem disso, efetuou-se a observacao da conexao vascular no ponto de enxertia atraves da imersao da base das plantas (abaixo do ponto de enxertia), em solucao corante de Acido Fuccinico 0,08%. Concluiu-se que a cultivar Packhams Triumphapresenta compatibilidade de enxertia com o marmeleiro cultivares Adamse Quince C, enquanto o hibrido Kieffer apresentou sintomas morfologicos de incompatibilidade de enxertia com o marmeleiro cultivares Quince C e Adams.

Redução da poda hibernal e aumento da produção de pereiras 'Hosui' pelo uso de prohexadiona cálcio

Abstract – The objective of this work was to evaluate the vegetative growth control and fruit production capacity of Hosui pear, in response to prohexadione calcium use in Southern Brazil climate conditions. Different concentrations of prohexadione calcium (0, 275, 550, and 825 g ha -1 ) were applied on eleven-year-old Hosui pear trees grafted on Pyrus calleryana rootstock. The use of prohexadione calcium was effective in controlling the vegetative growth of Hosui pears and decreased winter pruning, by reducing total weight and number of pruned shoots. The control of vegetative growth, by prohexadione calcium use, favors the increase of fruit production capacity of Hosui pears, mainly at 550 g ha -1 concentration.Index terms: Pyrus pyrifolia , vegetative growth, plant growth regulator, fructification. Introducao A pereira ( Pyrus spp.) e amplamente cultivada no mundo, com producao estimada em 22,4 milhoes de toneladas no ano de 2009 (Food and Agriculture Organization of the United Nations, 2011), no entanto, seu cultivo no Brasil e reduzido, com producao de 14,9 a maximizar o problema de frutificacao, em razao do mil toneladas em 2008, o que representa cerca de 10% da demanda nacional, estimada em 150 mil toneladas ao ano (Nakasu et al., 2008).O reduzido cultivo da pereira no Brasil e atribuido a problemas tecnicos relacionados a baixa produtividade, em que se destaca a baixa frutificacao efetiva e o prolongado periodo juvenil, nas condicoes edafoclimaticas do pais. No Sul do Brasil, essas con-dicoes sao caracterizadas pela alta precipitacao pluvial anual, altas temperaturas no periodo de crescimento, periodos hibernais curtos e com insuficiente acumulo de frio, que favorecem o maior desenvolvimento vegetativo da pereira, principalmente quando sao utilizados porta-enxertos vigorosos em anos de baixa frutificacao (Hawerroth, 2011). Tais condicoes tendem aumento excessivo do desenvolvimento vegetativo das plantas, que afeta drasticamente a diferenciacao e a formacao de gemas floriferas.Pomares com plantas vigorosas reduzem a penetracao da luz no interior da copa (Prive et al., 2004), o que acarreta diminuicao da produtividade e da qualidade dos frutos, aumento do custo de poda,

Aumento da produção de pereira asiática pelo uso de fitorreguladores

The low fruit set in the Southern Brazil conditions is one of the limiting factors to pear production in the country. The use of plant growth regulators may minimize this problem. This study was carried out aiming to evaluate the effectiveness of different growth regulators and the combination of these substances on fruit set increase of ‘Shinseiki Asian pears. The application of growth regulators was performed when the pears have reached the full bloom stage. The experimental design was randomized blocks with four replications of one tree, with the following treatments: 1. control (no application); 2. thidiazuron (TDZ) 20mg L-1; 3. gibberellic acid (GA) 20mg L-1; 4. prohexadione calcium (PCa) 600mg L-1; 5. PCa 600mg L-1 TDZ + 20mg L -1 ; 6. PCa 600mg L -1 + AG 20mg L -1 ; and 7. AG 20mg L -1 + TDZ 20mg L -1 . When sprayed on full bloom stage, thidiazuron and gibberellic acid, and combinations of these substances, both at a concentration of 20mg L-1, increased significantly the fruit set and the fruit production of ‘Shinseiki’ pears. The use of prohexadione calcium, single or in combination with thidiazuron and gibberellic acid, did not increase the fruit production.

Avaliação de temperaturas hibernais na brotação de gemas de macieira utilizando ramos enxertados

ABSTRACT - Temperature is the main climate factor related to induction, maintenance and dormancy release in apple ( Malus domestica Borkh.). The inadequate chilling exposure in apples causes budbreak problems, resulting in decrease in yield potential. Thus, the knowledge of physiological principles and environmental factors determining the dormancy phenomenon, especially winter temperature effects, it is necessary for the efficient selection of cultivars in a productive region. In addition, it is indispensable to adapt the orchard management aiming to decrease the problems caused by lack chilling during winter. The objective of this study was to evaluate the influence of different thermal conditions during the dormancy period on budbreak of apple cultivars. One-year-old twigs of ‘Castel Gala’ and ‘Royal Gala’ cultivars, grafted on M7 rootstock, were submitted to temperatures of 5, 10 and 15oC for different exposure periods (168; 336; 672; 1,008 and 1,344 hours). After treatments execution, the plants were kept in a greenhouse at 25oC. Budbreak was quantified when accumulated 3,444; 6,888; 10,332; 13,776; 17,220 and 20,664 GDHoC after temperature treatments. The cultivars responded differently to temperature effect during the winter period. The temperature of 15°C during winter shows a greater effectiveness on ‘Castel Gala’ apple budbreak while in the ‘Royal Gala’ apples the temperatures of 5 and 10oC show better performance. ‘Castel Gala’ cultivar (low chilling requirement) may supply its physiological necessities, may be capable to budburst, even when subjected to higher temperatures in relation to ‘Royal Gala’ apples (high chilling requirement).

Fenologia, brotação de gemas e produção de frutos de macieira em resposta à aplicação de cianamida hidrogenada e óleo mineral

ABSTRACT PHENOLOGY, BUDBREAK AND APPLE FRUIT PRODUCTION BY HYDROGEN CYANAMIDEAND MINERAL OIL APPLICATION The budbreak promoters application is one of main management strategies used to decrease theproblems of insufficient winter chilling on temperate fruit trees. Because the influence of budbreakpromoters on productive behaviour of plants, detecting this effects along of productive season becameimportant. Thus, this study was carried out during 2007/2008 season, in Cacador, Santa Catarina State,Brazil, aiming to evaluate different hydrogen cyanamide and mineral oil combinations on phenology,budbreak and apple fruit production. The experimental design was a randomized block, with sixreplications, in factorial arrangement (5x2), with five budbreak promoter treatments (1. control; 2. mineraloil 3.2%; 3. mineral oil 3.2% + hydrogen cyanamide 0.20%; 4. mineral oil 3.2% + hydrogen cyanamide0.39%; 5. mineral oil 3.2% + hydrogen cyanamide 0.59%) and two cultivars (Imperial Gala and Suprema´sFuji). The budbreak promoters application anticipated and reduced the blooming period, increasing theblooming overlap between Imperial Gala and Suprema´s Fuji cultivars. The budbreak promoters equalizedand increased the budbreak in axillary and terminal buds, with the major budbreak level observed inImperial Gala cultivar with 0.44% of hydrogen cyanamide and 3.2% of mineral oil treatment. The increaseof hydrogen cyanamide concentration showed the tendency to decrease the fruit set. It was observeddifferent treatment responses on production and mean fruit weight, probably to be related to fruitproduction predominance in different frutification structures.