Growth analysis and temperature effects on olive bud development

The relationship between mean air temperature and relative growth rate (rgr) of flower bud weight was studied in the cultivars Canino and Leccino to estimate the base temperature for flower bud development. The response of bud rgr to temperature was expressed by a negative exponential function, which allowed the determination of the base temperature. The values obtained (3.5°C for Canino and 4.9°C for Leccino) were lower than those generally considered appropriate for olive. The estimated base temperatures were used to calculate heat summation for flowering and the time at which the heat accumulation begins, in comparison with 7°C and 12.5°C. The lower coefficient of variability was observed for the calculated base temperatures. Bud humidity content gradually increased some weeks before bud burst, indicating in advance the beginning of internal bud development