When considering deficit irrigation, the most resistant period to water stress in olive crops is during the pit hardening. However, the determination of this period and the impact that water stress has on its onset or duration have not been clearly established. The aim of this work is to describe the impact of water stress on three processes that determine fruit development: fruit growth, endocarp hardening, and oil accumulation. This experiment was conducted between 2021 and 2022, in a plot with olive trees that were 3 years old at the beginning of the experiment. The young trees were of cv Manzanilla de Sevilla and were planted in a 4 × 1.5 m frame. The treatments were: Control, irrigated close to what is considered the optimum level in which the water status of the crop ensures the absence of water stress; RDI, with a moderate stress during the pit hardening stage; Rainfed and Traditional Rainfed. This latter was included only in 2022 using a 7 × 5 m frame. Traditional Rainfed was included to compare with Rainfed, these were similar in the maximum level of water stress but not in the duration. The fruit growth, oil accumulation, and endocarp hardness were measured for a period of 2 years. The hardness curves fit accurately established Period II which was the one with the fast hardness increases. The water potential was measured periodically on leaves at midday, whereby the minimum and average potential and the stress integral were obtained for each of the periods indicated before using pit hardness measurements. The results suggest that endocarp hardening was the process most resistant to water stress, as it showed very little variation from the seasonal pattern, despite the high levels of stress achieved. The fruit growth process was the most sensitive to water stress, but the recovery was fast in conditions of moderate water stress level. The oil accumulation started slowly during Period II, but its rate increased at the end of the period. This later process was moderately resistant to water stress. However, although the accumulation rate was faster during Period III, it was influenced by the water status during Period II. Cumulative water stress was related with fruit growth and oil accumulation processes. Endocarp development could be useful for determining a/the deficit irrigation period because of its almost constant pattern. These periods would permit water management optimization according to final use of the fruit (oil or table). However, continuous monitoring of water stress would be needed.

在考虑亏缺灌溉时，橄榄作物对水分胁迫最有抵抗力的时期是在坑硬化期间。然而，这一时期的确定以及水分胁迫对其发生或持续时间的影响尚未明确确定。这项工作的目的是描述水分胁迫对决定果实发育的三个过程的影响：果实生长、内果皮硬化和油脂积累。该实验于 2021 年至 2022 年间进行，地点是实验开始时树龄为 3 年的橄榄树。幼树为 Manzanilla de Sevilla 品种，种植在 4 × 1.5 m 的框架中。处理方法为： 控制，灌溉接近被认为最佳的水平，其中作物的水分状况确保不存在水分胁迫；RDI，在坑硬化阶段具有中等应力；雨养和传统雨养。后者仅在 2022 年才包含在内，使用 7 × 5 m 框架。传统雨养法与雨养法进行比较，它们在最大水分胁迫水平上相似，但在持续时间上不同。测量果实生长、油脂积累和内果皮硬度，为期两年。硬度曲线准确地符合建立的第二阶段，这是硬度快速增加的阶段。中午定期测量叶片的水势，从而在使用坑硬度测量之前获得每个时期的最小和平均势以及应力积分。结果表明，内果皮硬化是最能抵抗水分胁迫的过程，因为尽管达到了高水平的胁迫，但它与季节模式的变化很小。果实生长过程对水分胁迫最为敏感，但在中等水分胁迫条件下恢复较快。石油积累在第二阶段开始缓慢，但在该阶段末期加速。后来的过程对水分胁迫有一定的抵抗力。然而，尽管Ⅲ期积累速度较快，但受到Ⅱ期水体状况的影响。累积水分胁迫与果实生长和油脂积累过程有关。由于其几乎恒定的模式，内果皮的发育可用于确定缺水灌溉期。这些时期将允许根据水果（油或食用）的最终用途优化水管理。然而，需要持续监测水分压力。