ABSTRACT
The objective of this research was to determine sensibility coefficients for potato under water deficit (ky) for isolated growing stages and for the whole lifecycle of the plant, using the model suggested by Doorenbos & Kassam. The experiment was conducted in an area of Red structured Latossolic soil, at the ESALQ Campus, Piracicaba, SP, Brazil. The experimental design consisted of randomized blocks, with eight treatments and four replications, corresponding to the occurrence of: (i) isolated water deficits at each of three growth stage, (ii) water deficit for two stages, (iii) water deficit for the all three growth stages studied. Water deficit applied was equivalent to half of the water needs of the crop. Results indicated that the sensibility coefficients decreased in the following order, for the different growing stages of the crop: initial tuber formation, tuber development and vegetative stage (when the three stages were considered separately). For conditions of deficit in two stages, values of ky were above 1, reaching the highest value for the deficit situation corresponding to initial tuber formation and tuber development.
Key words:
Solanum tuberosum; sensibility coefficient; growth stages