Effects of Water Stress on Vegetative Growth and Productivity of Fruit Trees

Abstract

Generally, water stress reduces yield in annual crops. However, for mature fruit trees, this relationship may not hold in many situations, thus providing the opportunity for saving water without losing production. Indeed, even an increase in productivity may be achieved as we better learn how to manipulate processes within the tree through moderate water stress. Several areas of research have shown promising results. The reduction of irrigation after harvest of early maturing peaches and plums has demonstrated substantial savings of water with no loss of production. Peaches can suffer fruit quality problems such as doubling and deep suturing, but these can be overcome with well-timed irrigations in the previous late summer. Water stress imposed before harvest has also shown some promise. Reports from Australia have demonstrated significant increases in yield and fruit size in peach and pear, although researchers in other locations have generally been unable to replicate these results. The timing and/or rate of stress development appear to be critical factors. Under the right conditions, stress can alter the allocation of resources between vegetative and fruit growth. Before implementation of these practices can be achieved, further research will need to focus on developing good tools for measuring stress in the trees, obtaining a better understanding of adaptation of trees to rapidand slow-developing stress, documenting the effects of stress on vegetative and fruit growth during different times of the season, and understanding the interaction of stress with other factors such as fruit load.