Articles
The effects of summer and fall temperatures on bud endodormancy of some apple cultivar trees in a temperate climate area
Article number
1457_57
Pages
453 – 464
Language
English
Abstract
Many experimental trials in controlled environments on some boreal angiosperm tree species (e.g., Acer (Acer platanoides), black alder (Alnus glutinosa (L.) Moench), and birch (Betula spp.) indicated that the increase of late summer and autumn temperatures during endo-dormancy induction affected the timing of next spring bud burst.
In these species, the buds showed enhanced chilling requirement (CR) and delayed bud burst.
Few studies have been conducted on this topic in temperate fruit trees, where climate warming could affect bud CR. This study aimed to shed light on the effects of summer-fall temperatures on the physiology and phenology of apple buds during winter: the duration (days) of endodormancy, the CR evaluation, and the timing of bud burst.
Over 11 years, eight scab-resistant apple cultivars and two apple standard cultivars were evaluated for endodormancy completion in terms of Days (from January 1st each year according to the O.M. Heide method), chilling portion (CP), chilling unit (CU), and chilling days (ChD) accumulated.
Mean, maximum, minimum, and difference (maximum-minimum) daily temperatures were gathered for each month from August to December; moreover, periods of months with accumulating temperatures were fulfilled from August to December.
Data on endo-dormancy completion and temperatures were correlated, indicating that summer and fall temperatures had weak or no effect on the tested cultivars.
In contrast, late fall and winter accumulated temperatures showed strong, positive correlations, particularly with Days to reach endo-dormancy completion.
The results were not in line with those from past studies in controlled environments, likely due to fluctuations in diurnal temperatures during endodormancy induction of buds in outdoor conditions, and to the use of bearing trees instead of one-year-old seedlings of boreal-zone species, which are often used.
In these species, the buds showed enhanced chilling requirement (CR) and delayed bud burst.
Few studies have been conducted on this topic in temperate fruit trees, where climate warming could affect bud CR. This study aimed to shed light on the effects of summer-fall temperatures on the physiology and phenology of apple buds during winter: the duration (days) of endodormancy, the CR evaluation, and the timing of bud burst.
Over 11 years, eight scab-resistant apple cultivars and two apple standard cultivars were evaluated for endodormancy completion in terms of Days (from January 1st each year according to the O.M. Heide method), chilling portion (CP), chilling unit (CU), and chilling days (ChD) accumulated.
Mean, maximum, minimum, and difference (maximum-minimum) daily temperatures were gathered for each month from August to December; moreover, periods of months with accumulating temperatures were fulfilled from August to December.
Data on endo-dormancy completion and temperatures were correlated, indicating that summer and fall temperatures had weak or no effect on the tested cultivars.
In contrast, late fall and winter accumulated temperatures showed strong, positive correlations, particularly with Days to reach endo-dormancy completion.
The results were not in line with those from past studies in controlled environments, likely due to fluctuations in diurnal temperatures during endodormancy induction of buds in outdoor conditions, and to the use of bearing trees instead of one-year-old seedlings of boreal-zone species, which are often used.
Publication
Authors
G.A. Finetto
Keywords
rest, growth, disease, seasons, warming, investigation
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