Articles
FIRST EXPERIENCES WITH CHILL-UNIT MODELS IN SOUTHERN BRAZIL
Article number
184_8
Pages
79 – 86
Language
Abstract
The Utah and North Carolina chill-unit models were tested at three locations in Santa Catarina and compared with the model of chilling hours below 7.2°C. At São Joaquim (1415 m elevation) the number of estimated chilling hours was very low during 1982, bud break of apple trees, however, was normal.
Apparently temperatures above 7.2°C and fluctuating temperatures affected chilling.
The chill-unit models considering a broader temperature range with positive or negative chill-unit contribution accumulated during 1982 a similar amount of chill-units in comparison with the other years.
In general, the chill-unit models showed better agreement with bud break data than did the number of hours below 7.2°C. Modifications of both models concerning cycle lenght of high temperature influxes resulted in notable increase in accumulated chill-units with the Utah model at the lower elevations.
The North Carolina model seems to be better suited for the conditions of Southern Brazil than the Utah Model.
Apparently temperatures above 7.2°C and fluctuating temperatures affected chilling.
The chill-unit models considering a broader temperature range with positive or negative chill-unit contribution accumulated during 1982 a similar amount of chill-units in comparison with the other years.
In general, the chill-unit models showed better agreement with bud break data than did the number of hours below 7.2°C. Modifications of both models concerning cycle lenght of high temperature influxes resulted in notable increase in accumulated chill-units with the Utah model at the lower elevations.
The North Carolina model seems to be better suited for the conditions of Southern Brazil than the Utah Model.
Publication
Authors
A. Ebert, J.L. Petri, R.J. Bender, H.J. Braga
Keywords
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