MORPHO-PHYSIOLOGICAL RESPONSE OF TWO BROCCOLI CULTIVARS TO DIFFERENT IRRIGATION REGIMES

The results of a trial carried out in the two-year period 1990–1991 to evaluate the influence of different irrigation regimes on some morpho-physiological and yield characteristics of two varieties of broccoli (Orion e Gran Vert) are reported.

During the first year four irrigation regimes applied in the greenhouse were compared: maximum crop evapotranspiration (ETc) and restoration of 75, 50 and 25% of ETc. During the second year the two cultivars were compared in the field under ETc conditions.

Among the irrigation regimes, the best results were obtained with restoration of 100% ETc; yield reductions of 36, 66 and 92% were recorded in the treatments irrigated to 75, 50 and 25% Etc respectively. Orion gave a lower dry matter yield than Gran Vert in spite of a higher water use. Stomatal resistance data highlighted differences between both irrigation regimes and cultivars. Orion seems to exert a lesser stomatal closure control with a consequent lower resistance to water stress and a greater sensitivity to some non-infectious diseases such as "brown bead", "hollow stem" and "leafiness".