Evaluation of chilling requirement and heat accumulation in three European pear cultivars and genotypes

M. Ebtedaei, K. Arzani, S. Sarikhani
Temperate fruit trees require different amounts of winter chilling for flowering. The knowledge of chilling and heating requirements is necessary for manipulating fruit production and making proper orchard management decisions. This study was conducted to assess the chilling and heat requirement of three European pear cultivars and genotypes (‘Sebri’, ‘Shahmiveh’, and ‘A-95’ genotype) under controlled environment conditions. The experiment was carried out in a completely randomized design with three treatments (pear cultivars/genotype) and three replications. ‘A-95’ is a promising chance seedling selected throughout the pear breeding program at Tarbiat Modares University (TMU), Iran. The twigs of the studied cultivars/genotype were exposed at 4±1°C for 0, 300, 600, 800, 1000, and 1200 Utah chill unit (CU). Also, heat accumulation was assessed based on the growing degree hours (GDH) model. The results showed that the studied pear cultivars/genotype require 1000 (in ‘Shahmiveh’) to 1200 CU (in ‘Sebri’ and ‘A-95’) for breaking bud dormancy. Also, heat accumulation of the pear cultivars/genotype ranged between 2700 to 3066 GDH. A negative correlation was observed between chilling requirement and heat accumulation. Our results showed that excessive amounts of chill hours partially reduce heat accumulation. In general, the interaction of chilling requirement and heat accumulation control bud break and flowering time, and both of them play an important role in breaking bud dormancy and flower anthesis.
Ebtedaei, M., Arzani, K. and Sarikhani, S. (2021). Evaluation of chilling requirement and heat accumulation in three European pear cultivars and genotypes. Acta Hortic. 1315, 69-76
DOI: 10.17660/ActaHortic.2021.1315.11
https://doi.org/10.17660/ActaHortic.2021.1315.11
chilling requirement, GDH model, budbreak, flower anthesis, superior genotype
English

Acta Horticulturae