ISHS Acta Horticulturae 713: VI International Peach Symposium
EVALUATION OF CHILLING REQUIREMENT IN PEACH THROUGH GRAFTED TWIGS |
| Authors: | A. Wagner Jr., C.H. Bruckner, L.D. Pimentel, M.A.D.O. Morgado, C.S. Sediyama, M.C. Raseira Bassols |
| Keywords: | Prunus persica, rest breaking, blooming, leafing |
| Abstract:
One of the important traits for peach adaptation is the chilling requirement. Among the methods used for chilling requirement estimation are the evaluation of detached twigs, individual buds, and plants in containers submitted to controlled chill. However, such methods have limitations in their applications. This work evaluated the chilling requirement of three peach cultivars (‘Rei da Conserva’, ‘Setembrino’ and ‘Relíquia’), using one-year-old twigs grafted in the fall. The work was carried out in the Department of Plant Science, Federal University of Viçosa (MG), Brazil, from April to June, 2004. Twigs of the last growth season containing vegetative and flower buds were collected and top grafted, on April 20th, on seedlings previously potted in 5L plastic containers, containing the mixture soil + sand (2:1 v/v). No chilling units were accumulated before the twigs were collected. After grafting, the plants were left for 20 days in a greenhouse to form the graft union, and then submitted to the chilling treatments (50, 100, 150, 200 and 400 chilling units, according to the Utah model), under 5±1°C and 85±2.5% relative humidity. The grafted plants were taken to a greenhouse at the end of each chilling treatment and 28 days later the percentages of flower and vegetative budbreak were evaluated. In the greenhouse, the photoperiod was natural, and the temperature varied between 23.51°C to 13.11°C. The chilling requirements of ‘Rei da Conserva’, ‘Relíquia’ and ‘Setembrino’ were estimated to be approximately 200, 150 and 150 chilling units, respectively. | |
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