Superação da dormência de cultivares de mirtileiro em ambiente protegido com cianamida hidrogenada e óleo mineral

Abstract

RESUMO -O mirtileiro é uma frutífera de clima temperado que necessita de frio no outono/inverno. A insuficiência de frio pode provocar deficiente e desuniforme brotação e floração, com reflexos na produção. A pesquisa realizada na Universidade de Passo Fundo-RS, teve por objetivo estudar a superação da dormência de cultivares de mirtileiro (Georgiagem, Climax e Aliceblue) em ambiente protegido, tratadas em 25-07-2007 com cianamida hidrogenada (CH), nas doses de 0,52% e 1,04% (1% e 2% do produto comercial Dormex®), com a adição de 0,5% de óleo mineral (OM), comparando com plantas sem tratamento. As plantas encontravam-se no terceiro ciclo vegetativo e no primeiro de produção. O plantio foi realizado em 2005, no espaçamento de 0,7 m x 2,0 m, com irrigação por gotejamento. De acordo com os resultados obtidos, a aplicação no final de julho de CH + OM concentrou e uniformizou a floração e antecipou a brotação das cvs. Georgiagem e Clímax. A cianamida hidrogenada, nas concentrações de 0,52% e 1,04% (1% e 2% de Dormex®), combinado com 0,5% de óleo mineral, não teve efeito na porcentagem de brotação, mas reduziu a produção, evidenciando efeitos fitotóxicos. Termos para indexação: Vaccinium sp., brotação, florescimento, frutificação. DORMANCY BREAKING OF BLUEBERRIES CULTIVARS IN A PROTECTED ENVIRONMENT WITH HYDROGEN CYANAMIDE AND MINERAL OILABSTRACT -Blueberry require chilling hours accumulation at the fall/winter. Insufficient cold accumulation can cause deficient and desuniform sprouting and blooming, with negative consequences on yield. The research conducted in Passo Fundo University, Rio Grande do Sul state, had the objective of studing the dormancy breaking of blueberries cultivars (Georgiagem, Climax and Aliceblue) under greenhouse conditions, submitted to treatments with hydrogen cyanamide (HC) at the doses of 0.52% and 1.04% (1% and 2% of the commercial product Dormex®), with the addition of 0.5% of mineral oil (MO), and compare them to a control, without hydrogen cyanamide treatment. Planting was made in December 2005, at a 0.7 m x 2.0 m space, with drip irrigation. The plants were evaluated in the third vegetative cycle and first production. The results showed that chemical induction of dormancy breaking at the end of July shortened and standardized flowering, and in the cultivars Georgiagem and Climax advanced bud break. The use of HC at the concentrations of 0.52% and 1.04%, in combination with 0.5% of MO, did not affect the sprouting percentage, but reduced the yield, mainly the highest concentration, with evidence of phytotoxic effects.

Advances in the production of temperate fruits in the tropics

“…Uniform bud break and flowering is essential to improve tree productivity and growth as well as to reduce the length of time for harvest to occur. The use of chemical products to induce bud break and flowering can be a useful alternative to minimize problems of insufficient chilling in temperate fruit trees (Hawerrothet et al, 2009;Coletti, Nienow, & Calvete, 2011). Hydrogen cyanimide can be used in addition to or combined with mineral oil (Jaldo, Berettoni, Ale, & Forns, 2009;Campoy et al, 2011).…”

Peaches phenology and production submitted to foliar nitrogen fertilizer and calcium nitrate

“…Among main products present in market to stimulate sprouting, hydrogen cyanamide is known as the most effective (SEGANTINI et al, 2015), but its high toxicity have been restricted in many countries (LEONEL et al, 2014). Such restriction has stimulated the search for other compounds to induce sprouting in temperate fruits, such as potassium nitrates (ELSABAGH, 2014); calcium (NACHTIGALL;CAMELATTO, 1997); mineral oils (OLIVEIRA et al, 2008); and garlic extracts (OLIVEIRA et al, 2009).…”

Nitrogen fertilizer affects the chemical composition of the substrate, the foliar nutrient content, the vegetative growth, the production and fruit quality of blueberry

“…Among the difficulties for the expansion of this crop in Brazil, it is cited the high cost of implementation, with correction of fertility and acquisition of seedlings (Coletti et al, 2011;Fischer et al, 2012). In addition, there is a lack of information about its management, particularly with regard to fertilization, which is currently carried out based on research results from other traditional producing regions.…”