Articles
The endodormancy period of some apple cultivars is affected by fall and winter rainfall during a decade of investigation
Article number
1457_55
Pages
435 – 444
Language
English
Abstract
The overcoming of endodormancy (rest) in boreal and temperate trees is linked to certain climatic factors.
Mainly, chilling temperatures and photoperiod are considered the most important factors; others (rain, mist, dew, wind, intensity of light, etc.) have received limited study.
However, in the past, some scientists found that natural precipitation and mist treatments can reduce the chilling requirements of buds and advance bud break in spring.
These studies were carried out over short periods (one to two years) or in protected conditions and considered a few cultivars of temperate fruit trees.
To have a broad understanding of how rainfall during the autumn-winter period can interfere with bud dormancy, monthly data were collected from September to December over 11 years (2010 to 2021); moreover, months with cumulative rainfall were rounded up.
Eight scab-resistant apple cultivars and two apple standard cultivars were taken into consideration to evaluate the endo-dormancy 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 day (Cannell M.G.R. and SmithR.I.) accumulated.
The data on endo-dormancy completion and rainfall were moderately negatively correlated, indicating that rainfall wetting the buds reduced their chilling requirement; accumulated rainfall in autumn showed the strongest negative correlations, mainly with chilling days to reach endo-dormancy completion; the cultivars had different habits in relation to the tested chilling-method calculation.
The results were in line with previous studies, underscoring that rainfall can help reduce the chilling requirement, although it is not actually accounted for.
The effect of rainfall on the reduction of chilling requirement and/or endodormancy period of buds could be linked to the leakage of plant growth inhibitors from the scales and/or to the accumulation of useful chilling temperatures during rainfall.
Mainly, chilling temperatures and photoperiod are considered the most important factors; others (rain, mist, dew, wind, intensity of light, etc.) have received limited study.
However, in the past, some scientists found that natural precipitation and mist treatments can reduce the chilling requirements of buds and advance bud break in spring.
These studies were carried out over short periods (one to two years) or in protected conditions and considered a few cultivars of temperate fruit trees.
To have a broad understanding of how rainfall during the autumn-winter period can interfere with bud dormancy, monthly data were collected from September to December over 11 years (2010 to 2021); moreover, months with cumulative rainfall were rounded up.
Eight scab-resistant apple cultivars and two apple standard cultivars were taken into consideration to evaluate the endo-dormancy 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 day (Cannell M.G.R. and SmithR.I.) accumulated.
The data on endo-dormancy completion and rainfall were moderately negatively correlated, indicating that rainfall wetting the buds reduced their chilling requirement; accumulated rainfall in autumn showed the strongest negative correlations, mainly with chilling days to reach endo-dormancy completion; the cultivars had different habits in relation to the tested chilling-method calculation.
The results were in line with previous studies, underscoring that rainfall can help reduce the chilling requirement, although it is not actually accounted for.
The effect of rainfall on the reduction of chilling requirement and/or endodormancy period of buds could be linked to the leakage of plant growth inhibitors from the scales and/or to the accumulation of useful chilling temperatures during rainfall.
Publication
Authors
G.A. Finetto
Keywords
buds burst, one-year-old shoot, spur, plant growth regulator, leaching
Online Articles (96)