Exploration of environmental variables for peach floral bud cold hardiness prediction in western Colorado

Cold damage to reproductive tissue is the greatest limiting factor for peach production in the intermountain west.
A greater understanding of the environmental variables which influence cold hardiness is necessary to be able to reliably predict the current level of cold hardiness.
In this study, cold hardiness of ‘Redhaven,’ ‘Sierra Rich,’ ‘Suncrest,’ and ‘Cresthaven’ was measured for a four-year span from 2016 to 2020. Hardiness data was analyzed along with climate data to determine which climate data were significant drivers of cold hardiness throughout difference stages of dormancy.
Maximum, minimum, and mean temperature data were found to be strongly correlated with lethal temperature data (LT₅₀) for at least four subsequent days.
To better account for the extent to which the previous four days’ temperatures impacted hardiness, aggregated temperature variables made of the average of the previous maximum 
(T_{max, 1-4}), minimum (T_{min, 1-4}) and mean (T_{Avg, 1-4}) temperatures were also tested and found to have strong correlations.
Seasonal progression variables photoperiod length, day of year, chill hours (0-7.2°C), dynamic chill portions, and growing degree days (base temperatures 0, 5, and 7°C) were also tested to determine the effects of each at different phases of dormancy.
The correlation coefficients between T_max,1-4, T_min,1-4, T_avg,1-4 and LT₅₀ were 0.67, 0.85 and 0.84 respectively prior to 700 chill hours (nominal endodormancy barrier), and 0.59, 0.45, and 0.70 after 700 chill hours.
Post-chill correlations between LT₅₀ and growing degree days with base thresholds of 0, 5 and 7°C were 0.90, 0.82 and 0.74 respectively.
These data shed light on the specific relationships between peach cold hardiness and environmental conditions in western Colorado.

X International Peach Symposium

D.G. Sterle, I.S. Minas

Prunus persica, differential thermal Analysis, DTA, cold hardiness, growing degree days, correlation, maximum temperature, minimum temperature, mean temperature, climate data, lethal temperature, endodormancy, ecodormancy, chill satisfaction

https://doi.org/10.17660/ActaHortic.2022.1352.38