Effect of Water Stress on the Yield of Indeterminate-Growth Green Bean Cultivars (Phaseolus vulgaris L.) during the Autumn Cycle in Southern Spain

Common bean is typically cultivated in the Mediterranean basin, an area where water scarcity could limit yield. This species has a broad range of food uses (seed or pod) and very diverse growth patterns (indeterminate or determinate), which hinders any deficit irrigation strategy. The aim of this work was to evaluate the response of the vegetative and reproductive growth stages to water stress in beans of indeterminate habit. During two consecutive Autumn seasons (2020 and 2021), two cultivars of green bean were grown in a greenhouse in Seville (Spain). The experimental design was a split plot with four replications. One of the factors considered was the cultivars Helda, and Perfección Blanca; and the other was the irrigation strategy: a control treatment, which received 100% of crop evapotranspiration, and a regulated deficit irrigation (RDI) treatment, with 30% of the water applied to the control. In both seasons, significant differences were found between cultivars, but irrigation only reduced branch development around 50%. Reproductive growth was not markedly affected, although a clear diminishing trend of approximately 25% was measured in P. Pod length and the number of non-commercial pods were not importantly impacted by irrigation in any of the cultivars. Moderate water stress conditions did not reduce the quality and quantity of the yield. Therefore, the current irrigation strategy could increase water savings with low or no yield reduction.