Temperature Requirements of Pistachio (Pistacia vera L. cv. Kerman) and Identification of Suitable Cultivation Areas in Semi-Arid Central-Western Argentina

In recent years, interest in pistachio production has increased significantly in Argentina, although cultivation remains largely confined to specific regions. The objectives of this study were: i) to determine the specific thermal requirements of cv. Kerman for optimal flowering and fruit development under semi-arid conditions, and ii) to use GIS-based modelling to identify suitable land for its expansion. To this end, phenological observations were collected from a commercial orchard in San Juan Province between 2013 and 2022. Thermal requirements for flowering and fruit ripening were calculated using hourly temperature data through the Dynamic Model (chill portions, CP) and Growing Degree Hours (GDH) and Days (GDD). Partial Least Squares (PLS) regression was applied to identify chilling and forcing periods. These parameters were then extrapolated to 72 weather stations across Argentina to evaluate regional suitability. Results indicated that a minimum of 47 CP, 4,150 GDH, and 2,200 GDD are required for optimal flowering and fruit maturation. GIS-based modelling classified land as suitable, marginally suitable, or unsuitable based on these thermal thresholds. Highly suitable areas were identified in the central-western regions. Additional factors, such as late spring frosts and rainfall during flowering and ripening, were integrated to refine the suitability map. The resulting global suitability map identified approximately 64,411 km² as optimal for pistachio cultivation, coinciding with regions of low frost and rainfall risk. This study highlights the potential for expanding pistachio production in Argentina’s semi-arid zones, with considerations for climate trends, frost exposure, and water availability.