Use of biostimulation to reduce alternate bearing in pistachio cultivation (Pistacia vera L.)

Alternate bearing represents one of the main challenges to pistachio yield stability, especially in rainfed orchards where water and nutritional stress intensify bud drop and limit crop regularity. Although its origin is partially genetic, alternation is exacerbated by competition between cluster growth and vegetative development, a phenomenon particularly marked in cultivars such as Kerman, where reduced annual shoot growth can result in fewer productive buds for the following season (Guney et al., 2023). In this context, biostimulation emerges as a valuable tool to promote physiological balance in the tree and improve yield continuity. This study presents the results obtained after two consecutive seasons of foliar application of Equilibrium®, a biostimulant based on L‑α‑amino acids and Ascophyllum nodosum extract. Treatments increased bud retention, reduced early fruit drop and improved both kernel yield and several fruit quality parameters, demonstrating their potential to mitigate alternate bearing and enhance crop profitability.