|Author:||Goldhamer, D. A. ; Beede, R. H.|
|Book Group Author:||NA|
Regulated deficit irrigation (RDI) was evaluated on deep rooted, mature pistachio trees grown under high evaporative demand in the low rainfall southern San Joaquin Valley of California, USA, to assess the impact of deficit irrigation during various parts of the season to determine which period was most stress tolerant in terms of nut production. Pistachio nuts have a unique fruit growth pattern in which rapid kernel growth does not begin until 6 weeks after full shell size has been attained. Our hypothesis was that irrigation could be reduced during this period with limited negative effects on production. The season was divided into 3 preharvest periods, namely leaf-out to full shell expansion (Stage 1), full shell expansion to the onset of rapid kernel growth (Stage 2), and rapid kernel growth to harvest (Stage 3). Water deprivation during Stage 1 applied 7.2% less water than the near-fully irrigated control without any yield loss, based on mean values for the last "on" and "off" alternate bearing years of this study. Shell splitting (endocarp dehiscence) at harvest was significantly higher (10.4% relative to the Control) but was offset by nut weight reduction of 9.4%. Stage 3 water deprivation (53% less applied water than the control) reduced nut size, shell splitting, mechanical nut removal by tree shaking, and yield, while increasing kernel blanking and abortion. Postharvest water deprivation (5.0% less applied water than the control) had no significant negative effects on yield components. Six irrigation regimes that applied water at various rates were used to investigate Stage 2 behaviour. Even though there was no significant difference in yield components among the regimes, the best production occurred with deficit irrigation during Stage 2 at 50% of near-potential ETc during Stage 2 and 25% of near-potential ETc after harvest. This RDI regime saved 180 mm of water (23.2% of the control) and water use efficiency was higher (4.69 vs. 3.61 kg marketable fruit per mm water, for this RDI regime and the control, respectively).
|Pages:||538 - 545|
|Journal:||Journal of Horticultural Science and Biotechnology|
crop production, crop quality, crop yield, dehiscence,fruits, irrigation, nuts, pistachios, plant development, plant waterrelations, ripening, water management, water stress, water useefficiency, California, USA, Pistacia, Pistacia vera, Anacardiaceae,Sapindales, dicotyledons, angiosperms, Spermatophyta, plants,eukaryotes, Pistacia, Pacific States of USA, Western States of USA, USA,North America, America, Developed Countries, OECD Countries, UnitedStates of America, water resource management, watering, HorticulturalCrops (FF003) (New March 2000), Plant Water Relations (FF062), PlantProduction (FF100), Soil Water Management (Irrigation and Drainage)(JJ800) (Revised June 2002) [formerly Soil Water Management], CropProduce (QQ050), Food Composition and Quality (QQ500)