Fisiologia e fenologia da brotação de estacas de cultivares de figueira induzidas pelo frio artificial
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Data
2020-08-24
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Universidade Estadual Paulista (Unesp)
Resumo
A figueira é uma frutífera de clima temperado já difundida em diversas regiões do Brasil, entretanto, dentre as cultivares disponíveis, predominantemente Roxo de Valinhos tem sido cultivada comercialmente. Essa frutífera requer frio para garantir o sucesso da brotação, entretanto, existem poucas informações na literatura sobre o assunto, o que pode ocasionar em determinações inadequadas de cultivo, para regiões com tipos climáticos distintos. Nesse contexto, objetivou-se avaliar a fisiologia e fenologia da brotação de estacas de cultivares de figueira, submetidas ao frio artificial. As estacas das cultivares Roxo de Valinhos, Brown Turkey, Pingo de Mel, Troyano e White Genova foram coletadas no final do inverno e padronizadas com 20 cm de comprimento. Posteriormente, foram acondicionadas em câmara fria (8±0,5ºC) e submetidas a 0, 40, 80, 120 e 160 horas de frio artificial. Para fenologia da brotação, realizou-se o teste biológico de “estacas de nós isolados”, sendo as estacas de 7 cm colocadas em condições controladas (23±1ºC, UR 85% e fotoperíodo de 16 horas). Quanto à fisiologia da brotação, determinou-se as atividades da SOD e da POD, e os teores de carboidratos e de nitrogênio total. Para fenologia da brotação avaliou-se a velocidade, tempo médio e taxa final de brotação, taxa de brotações vigorosas e tempo médio para surgimento de folhas abertas. O delineamento experimental utilizado foi inteiramente casualizado, em parcelas subdivididas. As cultivares de figueira comportaram-se diferentemente quando foram expostas aos níveis de acúmulo de horas de frio, promovendo alterações fisiológicas e fenológicas tanto no repouso vegetativo quanto na brotação das gemas, confirmando que responderam de forma diferente às condições climáticas de cada ciclo agrícola. ‘Roxo de Valinhos’ e ‘Pingo de Mel’ exigiram menos HF para quebrar a dormência, enquanto ‘Troyano’ exigiu mais. O teste biológico de “estacas de nós isolados” permitiu avaliar a saída do repouso vegetativo e a fenologia entre as cultivares de figueira. Variações no tempo médio de brotação e na taxa final de brotação de cultivares de figueira podem estar relacionadas às exigências de baixas e altas temperaturas. Em uma escala de menor para maior exigência em horas de frio artificial para brotação das gemas, as cultivares foram classificadas em: Pingo de Mel < Roxo de Valinhos < Brown Turkey < White Genova < Troyano. As cultivares avaliadas possuem potencial para diversificação da ficicultura nacional, além do figo ‘Roxo de Valinhos’, tradicionalmente cultivado. Este primeiro relato sobre a necessidade de baixas temperaturas das estacas de figueira no Brasil, facilitará a criação de programas de melhoramento genético para cultivares com baixo requerimento de frio.
The fig trees grow in temperate climate, however it has also been widely cultivated in many regions of Brazil. Roxo de Valinhos is the most important fig cultivar in Brazilian commercial fig production. Figs requires chill hours to guarantee a successful sprouting, nevertheless there are few researches on this topic, which can causes inappropriate recommendations for crops, mainly because of the differences in the climate classification of some regions. Thus, the aim of the present study was to evaluate the sprouting physiology and phenology of fig cultivars submitted to artificial chilling hours. The cuttings of Roxo de Valinhos, Brown Turkey, Pingo de Mel, Troyano and White Genova cultivars were collected in late winter and standardized at 20 cm length. They were stored in a laboratory cold chamber at 8±0.5ºC and then subjected to 0, 40, 80, 120 and 160 hours of artificial chilling. For bud phenology, the single node cuttings biological test was performed on 7 cm cuttings placed under controlled conditions at 23±1ºC, RH of 85%, and a 16-hour photoperiod. Regarding the physiology of sprouting, carbohydrates and nitrogen contents, and the activity of antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD) were determined. Sprouting vigor was evaluated by velocity, average time, final sprouting rate, vigorous sprouting rate and average time for open leaf appearance. Results detected that cultivars behaved differently by promoting physiological changes and phenological when exposed to different amounts of chill hours, confirming that they responded differently to the climatic conditions of each agricultural cycle. The cultivars Roxo de Valinhos and Pingo de Mel required fewer chill hours than ‘Troyano’ to end the rest vegetative period. The single node cutting biological test allowed the evaluation of rest vegetative and phenology overcome of among fig cultivars. Variations in the average time sprouting and final sprouting rate of fig cultivars may be related to the requirements of low and high temperatures. On a scale from lower to higher demand in artificial chilling hours for bud sprouting, the cultivars were classified as: Pingo de Mel < Roxo de Valinhos < Brown Turkey < White Genova < Troyano. The evaluated cultivars have potential to diversify the national fig orchards, besides fig 'Roxo de Valinhos', traditionally cultivated. This first report on the fig stem cuttings chilling requirement in Brazil will facilitate the breeding programs for low chilling requirement cultivars.
The fig trees grow in temperate climate, however it has also been widely cultivated in many regions of Brazil. Roxo de Valinhos is the most important fig cultivar in Brazilian commercial fig production. Figs requires chill hours to guarantee a successful sprouting, nevertheless there are few researches on this topic, which can causes inappropriate recommendations for crops, mainly because of the differences in the climate classification of some regions. Thus, the aim of the present study was to evaluate the sprouting physiology and phenology of fig cultivars submitted to artificial chilling hours. The cuttings of Roxo de Valinhos, Brown Turkey, Pingo de Mel, Troyano and White Genova cultivars were collected in late winter and standardized at 20 cm length. They were stored in a laboratory cold chamber at 8±0.5ºC and then subjected to 0, 40, 80, 120 and 160 hours of artificial chilling. For bud phenology, the single node cuttings biological test was performed on 7 cm cuttings placed under controlled conditions at 23±1ºC, RH of 85%, and a 16-hour photoperiod. Regarding the physiology of sprouting, carbohydrates and nitrogen contents, and the activity of antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD) were determined. Sprouting vigor was evaluated by velocity, average time, final sprouting rate, vigorous sprouting rate and average time for open leaf appearance. Results detected that cultivars behaved differently by promoting physiological changes and phenological when exposed to different amounts of chill hours, confirming that they responded differently to the climatic conditions of each agricultural cycle. The cultivars Roxo de Valinhos and Pingo de Mel required fewer chill hours than ‘Troyano’ to end the rest vegetative period. The single node cutting biological test allowed the evaluation of rest vegetative and phenology overcome of among fig cultivars. Variations in the average time sprouting and final sprouting rate of fig cultivars may be related to the requirements of low and high temperatures. On a scale from lower to higher demand in artificial chilling hours for bud sprouting, the cultivars were classified as: Pingo de Mel < Roxo de Valinhos < Brown Turkey < White Genova < Troyano. The evaluated cultivars have potential to diversify the national fig orchards, besides fig 'Roxo de Valinhos', traditionally cultivated. This first report on the fig stem cuttings chilling requirement in Brazil will facilitate the breeding programs for low chilling requirement cultivars.
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Palavras-chave
Ficus carica L., Frutífera de clima temperado, Ficicultura, Zoneamento agroclimático, Fruit of temperate climate, Fig orchards, Agroclimatic zoning