ISHS Acta Horticulturae 200: II International Symposium on Processing Tomatoes, XXII IHC
BASE-TEMPERATURE AND DATE OF PLANTING IN PROCESSING TOMATOES |
| Authors: | A.M. Calado, C.M. Portas |
| Abstract:
Relationships between base-temperatures, planting data and cropping cycles were studied in direct-seeded tomatoes ('Cal j') at three locations in the main processing areas: Coruche - Sorraia valley (1976/78), Azambuja - Tagus valley (1976) and Elvas - Caia valley (1976). Experimental trials belonged to the National Research Project on Mechanized Production of Tomatoes for Processing (METI). Base-temperatures for degree-days of growth were calculated by the X-intercept method using a regression equation between temperature and rate of development from seeding to harvest. Values for base-temperature of 6° C at Azambuja, 8° C at Coruche and 10° C at Elvas were obtained what shows an increase from areas with a warm early spring to the cooler one's. Degree-days of growth, estimated from these base-temperatures and those locations, were in average respectively 1 874, 1 567 and 1 784. From these data the length of cropping cycle in a normal meteorological year (average of 30 years) was calculated for several hypothetical data of planting: each 15 days from February the 1st until May the 1st. This length varies from 121 to 223 days. The statistical errors for these calculations were rather small. The fitting between the actual cycle and the estimated cropping cycle for Azambuja, Elvas and Coruche was very good. | |
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