Effective temperatures and chilling requirement of two plum cultivars

• Autor(a) principal: Anzanello, Rafael
• Data de Publicação: 2020
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Agropecuária Catarinense (Online)
• Texto Completo: https://publicacoes.epagri.sc.gov.br/rac/article/view/1038
• topic: Horas de frio; brotação; Prunus salicina.; Chilling hours; budburst; Prunus salicina

Plum trees need to go through a period of low temperatures in the autumn and winter, in the dormancy phase, to achieve adequate budburst and flowering in the spring. The objective of this study was to characterize the effective temperatures and the chilling requirement to induce and overcome the dormancy period of two plum cultivars, Gulf Blaze and Letícia. Twigs of these cultivars were collected in orchards located in Veranópolis, RS, on 04/07/2017, before any chilling accumulation (hours of temperature ≤ 7.2 °C) had occurred. The twigs were cut into single-node cuttings (cuttings 7 cm long, containing a single composite bud), inserted in moistened phenolic foam and taken to incubator chambers at four temperatures (3°C, 6°C, 9°C and 12ºC) and six periods of treatment duration for the Gulf Blaze cultivar (0 to 500 CH) and nine periods for the ‘Letícia’ (0 to 800 CH). At each 100 CH, a portion of the cuttings was transferred to the temperature of 25°C for induction and evaluation of the budburst. The chilling requirement in the dormancy period was of 200 CH for the 'Gulf Blaze' and 600 CH for the 'Letícia'. The interval of effective cold temperatures to overcome dormancy was greater for the 'Gulf Blaze' (3°C to 12°C), compared to 'Letícia', which stayed between 3°C to 6°C.