Water relations, biochemical-physiological and yield responses of olive trees (Olea europaea L. cvs. Arbequina and Manzanilla) under drought stress during the pre- flowering and flowering period

PIERLUIGI PIERANTOZZI; MARIELA TORRES; ROMINA BODOIRA; DAMIÁN MAESTRI

AGRICULTURAL WATER MANAGEMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 125 p. 13 - 25

0378-3774

In arid and semiarid regions from Argentina, where the main olive production areas are located, evapo-transpiration is high and rainfall is minimal during winter and spring months, as compared with theMediterranean region where winter rainfall precludes the need of irrigation in such period. The aim ofthe work was to study water relations, biochemical?physiological and yield responses of olive trees (Oleaeuropaea L., Arbequina and Manzanilla cultivars) under different drought stress levels applied during thepre-flowering?flowering period. Increasing levels of water deficit affected plant water relations as mea-sured by pronounced drops of stem water potentials (near −4.0 MPa) in treatments with severe waterdeprivation at the end of the flowering period. Deficit irrigation was associated with some leaf-levelbiochemical-physiological responses (accumulation of osmotically active substances, increased concen-tration of high molecular weight hydrocarbons and cuticle thickening), which can be interpreted asadaptation mechanisms of olive to water deficit. Water stress was also associated with increased lipidperoxidation and decreased levels of photosynthetic pigments, stomatal conductance and photosyntheticrate. During the first crop year analyzed, a significant decrease in fruit set and fruit yield was observedin treatments under water deprivation. Also, all treatments evaluated showed strong drops in fruitingand yield parameters during the second crop year suggesting a marked bearing pattern for both olivecultivars. From a practical standpoint, little irrigation (50% ETc) may be sufficient to maintain adequateplant water potentials for the coldest winter months, but high (75% ETc) or full (100% ETc) irrigation ratescould be needed by mid-August (approximately 2 months before flowering) to avoid detrimental effectsof water stress on biochemical?physiological and yield parameters of olive trees cultivated in areas withdry winter-spring season.