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With growing water shortages, agriculture faces the challenge of increasing water productivity (WP). In this work, WP of two main crops, peach and olive, is evaluated for different cultivars and deficit irrigation practices. WP in peach was estimated over 4-7 years for three cultivars (early, mid-season and late-maturing), two rootstocks and two deficit irrigation strategies. In terms of yield/total water supply, the late maturing cultivar subjected to mild deficit irrigation, gave the highest WP (4.1 kg m-3), compared to the mid-season (3.0 kg m-3) and early cultivar (1.9 kg m-3). Full irrigation reduced slightly the performance of the most productive cultivar (3.7 kg m-3). Performances of early and mid-season cultivars were affected by rootstock. Interaction between mild deficit irrigation and vigorous rootstock induced better WP. Experimental work in olives targeted WP under contrasted environments. In northern Tunisia (450 mm annual rainfall), average yield for three cultivars ('Picholine', 'Chetoui' and 'Mansanille') planted at 6×6 m spacing on a clay soil, varied between 3.9-4.7 and 4.7-6.1 t ha-1, respectively when irrigation was increased from 100 to 200 mm. Under these restrictive conditions, the highest WP values were obtained for 'Picholine', respectively 0.77 and 0.86 kg m-3. However, in southern Tunisia (200 mm rainfall), the 'Chemlali' cultivar, conducted under intensive planting (4×4 m) on sandy soils, showed a drastic increase in production. With irrigation water supply of 200-400 mm, average yield reached 10-12 t ha-1, and WP 2.1 kg m-3. Adaptation to water scarcity is discussed on the basis of the obtained results.

Introduction. Recent management trends in almond orchards have focused on intensification and high-density plantings using Prunus rootstock cultivars with different vigor traits. This investigation aims to prospect precocious detection of adequate scion-rootstock combination for almond. Materials and methods. Five almond cultivars (‘Tuono’, ‘Lauranne’, ‘Soleta’, ‘Belona’ and ‘Guara’) grafted on three peach and plum based rootstocks of different degrees of vigor (‘Garnem’, ‘Rootpac-40’ and ‘Rootpac-20’) were trained in super high-density planting in an experimental orchard. Tree vigor, tree water status, leaf chlorophyll content and quantum yield of photosynthesis system II (PSII) were monitored over two budding seasons. Results and discussion. ‘Garnem’ and ‘Rootpac-40’ were respectively the most and the medium vigorous rootstocks and induced the best tree water status, chlorophyll content and quantum yield of PSII for the tested almond cultivars. Scions grafted on ‘Garnem’ had the highest values of trunk cross-sectional area (TCSA), and almond scions were higher on ‘Garnem’, intermediate on ‘Rootpac-40’ and lower on ‘Rootpac-20’. Scions grafted on ‘Rootpac-20’ seemed to be the most dwarf phenotype. Moreover, ‘Rootpac-20’ performed the lowest values of stem water potential and showed various visual symptoms of chlorosis. Conclusion. Overall, ‘Rootpac-40’ exhibited a medium capacity to control tree vigor and well adapted to Mediterranean soil conditions.

Southern Tunisia is characterized by high evaporative demand and severe water deficit. Responses of pistachio cultivars to water deficit were evaluated. Physiological behavior was assessed using the following measures: net carbon assimilation, stomatal conductance, transpiration, photosynthetic efficiency, water use efficiency, and chlorophyll concentration. The local cultivars ‘Meknassy’, ‘Nouri’ and ‘Mateur’ achieved the best compromise between photosynthesis and transpiration, which maximized water use efficiency. In contrast, the foreign variety ‘Libye Rouge’ had lower net carbon assimilation, stomatal conductance, and photosynthetic efficiency. Chlorophyll concentration varied among local and foreign cultivars. Local cultivar ‘Thyna 1’ had the most chlorophyll at 0.17 mg/cm2.