Sustainable Use of Plant Bioregulators in Pear Production

Dussi, María Claudia

doi:10.17660/actahortic.2011.909.40

Cited by 18 publications

(10 citation statements)

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“…Use of chemical thinners has been adopted by pear producers throughout the world, primarily with the compounds 6-BA and 1naphthaleneacetic acid (NAA) (Asín et al, 2009;Curetti et al, 2010;Dussi, 2011) but also, more recently in the United States with ABA (Arrington et al, 2017;Einhorn and Arrington, 2018;Greene, 2012). These compounds vary in their efficacy when used as postbloom thinners, generally between petal fall and 16-mm fruitlet diameter.…”

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confidence: 99%

Postbloom Thinning of ‘Bartlett’ Pear with Metamitron

Elsysy¹,

Hubbard²,

Einhorn³

2020

horts

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Metamitron is a relatively new postbloom thinning compound for pome fruits that inhibits the photosystem II (PS II) pathway of photosynthesis. Reduced assimilation of carbohydrate by metamitron action may lead to a carbohydrate deficit that promotes fruit abscission. We have evaluated the thinning efficacy of metamitron rate and, to a limited extent, application timing for ‘Bartlett’ pear in five separate trials over 3 years (2015–17) in northern Oregon. Comparisons were made to a nontreated control and, depending on the trial, a commercial standard thinning compound [benzyladenine (6-BA) or abscisic acid (ABA)]. Application timings ranged between 7- and 16-mm fruit diameter depending on the trial. Metamitron markedly inhibited photosynthesis (PN), typically for a duration of 2 to 3 weeks, although longer persistence was observed in two trials. Generally, PN was reduced linearly with increasing metamitron rate, but the effect varied by rate and year and may have been enhanced by high temperatures. Metamitron effectively thinned in four of five trials whereby pear fruit set was negatively and linearly related to rate. Rates of 200 to 300 ppm were efficacious and produced target crop loads. In only one trial, increasing concentrations (600 ppm) led to greater thinning. Metamitron significantly thinned ‘Bartlett’ pears when applied between 10 and 13 mm. In contrast, early application timing (≈7 mm) had little effect on fruit abscission. Fruit size increased with decreasing crop load and thus was significantly improved by metamitron. Interaction between biological and environmental factors likely contributed to year-to-year variability in efficacy.

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confidence: 99%

Postbloom Thinning of ‘Bartlett’ Pear with Metamitron

Elsysy¹,

Hubbard²,

Einhorn³

2020

horts

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“…However, many papers did not report weather conditions during their studies. Following application of chemical thinning agents, a higher level of fruit abscission is observed with weather conditions that favour reduced carbohydrate levels in the tree, in particular low light levels and elevated temperature after treatment [79,80]. Lack of untreated controls in trials [58,70] can lead to difficulties in interpreting trial results as the background crop load level is unknown.…”

Section: The Future Of Chemical Thinningmentioning

confidence: 99%

“…This approach has been confirmed by Schmidt and Auvil [26] who recommended that it is advantageous to make multiple applications using different materials to improve chances for success, and Wertheim [16] who noted that combination sprays of two different thinning agents and sequential sprays may cause more thinning than compounds used separately. Dussi [80] also noted that for effective thinning, it is important to consider different "thinning programs" appropriate to the cultivar, integrating diverse products, doses and timings. Awareness of the impact of weather conditions before, during and after application on chemical absorbance and efficacy can also reduce unpredictability.…”

Section: The Future Of Chemical Thinningmentioning

confidence: 99%

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Managing Crop Load in European Pear (Pyrus communis L.)—A Review

Bound

2021

Agriculture

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Reducing levels of fruit set is often desirable in many European pear (Pyrus communis L.) cultivars. With a negative linear relationship between crop load and fruit size, crop load management early in the season minimises wastage of tree carbohydrate resources and provides maximum benefits in terms of fruit size and quality. There are several tools available for managing crop load including hand thinning, chemical thinning, photosynthetic inhibition through shading or application of chemicals, mechanical thinning and pruning. While hand thinning is the most accurate method of reducing excessive crop loads, there are some major drawbacks. With awareness that the early thinning offered by chemical thinning provides distinct advantages with regard to fruit size and other quality parameters, chemical thinning is gaining increasing acceptance in pear production. Some chemicals are used worldwide for thinning, but there are differences between countries and growing regions on recommended application timing and concentrations. The risks involved in chemical thinning can be mitigated by use of a structured approach, using a sequential spray program with both bloom and post-bloom thinners. Knowledge of conditions that impact the carbon balance of the tree and the ability to make use of carbon-deficit conditions are likely to improve the predictability of chemical thinning. Mechanical thinning has potential as a thinning tool, with advantages over chemical thinning in that it is environmentally friendly, can be used in organic production and is not weather dependent. Although artificial bud extinction has not been trialled on pears to date, it has been shown to be economically viable in apple. As it is a precision crop load management method that minimises tree resource wastage, it should be given serious consideration. As growers require large annual yields of high-quality fruit, the aim of this review was to examine current and potential crop load management methods for European pear cultivars and provide a portfolio of available options that can be integrated into a systematic approach for managing crop load.

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“…A combinação de citocininas e giberilinas na fruticultura apresenta respostas e funcionalidades diferentes, dependendo da cultura e época de aplicação. Em pessegueiro foi observado o favorecimento do crescimento de ramos laterais (Rufato et al, 2004), o aumento no pedicelo de frutos de macieira (Dabul & Ayub, 2005), o aumento da frutificação efetiva em peras (Dussi, 2011) e a melhora do formato e tamanho dos frutos de maçãs e peras (Leite et al, 2006;Dussi, 2011).…”

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Produção e qualidade de pêssegos, cv. Jubileu, com uso de fitorreguladores

et al. 2014

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O presente trabalho objetivou avaliar a produção, o retorno da floração e a qualidade físico-química dos frutos de pessegueiro após a utilização de Promalin® (BA + GA4+7) em diferentes doses e épocas de aplicação. O experimento foi realizado no Centro Agropecuário da Palma, na Universidade Federal de Pelotas, no município do Capão do Leão - RS, no ano de 2012. Foram utilizados pessegueiros do cultivar Jubileu, com 13 anos de idade, enxertados sobre o portaenxerto Capdeboscq e com densidade de 1.481 plantas ha-1. Os tratamentos foram: plantas sem aplicação (controle), plantas tratadas com benziladenina (BA) + giberilinas (GA4+7) nas doses de 50 e 100 mg L-1, aplicados 10 dias após a plena floração (DAPF) e 30 DAPF. Foram avaliados a produtividade das plantas e os atributos de qualidade físico-química dos frutos. A aplicação do fitorregulador a 30 DAPF resultou em um incremento de 6,62 kg por planta e proporcionou frutos de maior calibre (> 65 mm); no entanto, não houve diferença estatística entre as doses de 50 e 100 mg L-1. Independentemente das doses utilizadas neste trabalho, a época de aplicação (30 DAPF) foi o fator preponderante para a eficiência dos fitorreguladores no aumento da produção por planta, massa média, diâmetro e firmeza de polpa dos frutos de pessegueiro cv. Jubileu. O número total de gemas floríferas nos ramos é reduzido com a aplicação BA + GA4+7.

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Sustainable Use of Plant Bioregulators in Pear Production

Cited by 18 publications

References 0 publications

Postbloom Thinning of ‘Bartlett’ Pear with Metamitron

Postbloom Thinning of ‘Bartlett’ Pear with Metamitron

Managing Crop Load in European Pear (Pyrus communis L.)—A Review

Produção e qualidade de pêssegos, cv. Jubileu, com uso de fitorreguladores

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