Response of Pistachio to Low Soil Moisture Conditions1

Abstract

Abstract Staminate clone Israel 502 and ‘Kerman’ and ‘Lassen’ pistachio (Pistacia vera L.) on two rootstocks showed remarkable drought resistance under runoff farming in the Negev desert highlands. During favorable seasons, root distribution was fairly uniform down to 240 cm. Moisture depletion fluctuated between 58 and 477 mm during 1971-1974 because of great differences in flood water availability and scant annual rainfall (54–163 mm). Soil moisture was depleted in all strata well below the wilting point throughout the growing season in 1973 and from mid-July in 1974. Shoot growth terminated within 4–5 weeks. Although trunk growth continued at an even rate until August 1–15, the relative increment was 4.2–7% higher with the staminate clone. Extreme drought from the autumn of 1972 through 1973 (58 mm water depletion) did not prevent bud differentiation and high yields per tree (12.0 kg for ‘Kerman’, 9.5 kg for ‘Lassen’) in 1974.