Fruit crops have been one of the earliest plant systems where root dynamics have been studied, but in recent years, there have been many advances in our understanding of this important component of the crop. The amount of annual root production can be affected by plant photosynthesis, which can be affected by leaf area and light interception. It also can be affected by carbohydrate demand from competing sinks. High crop loads typically lead to reduced root growth. Limited pruning and irrigation can also lead to greater root production. Timing of root growth of fruit crops has been often reported as bimodal, with a large peak in late spring and a second peak in the fall. There more examples where this pattern has not been found than where it has. Root growth in New York commonly occurs during the summer. Root growth in the fall may be much less common than generally realized, although each location needs to be evaluated independently. Root life span of many fruit crops like apple, peach and grape is typically about 60 d although it can range from less than 30d to more than 100d depending on the root population. In a species with tough coarse roots like citrus, root lifespan may be more on the order of 300 d. Limited research suggests that small diameter roots near the soil surface and born in early summer typically have the shortest life spans. Root life span may also be diminished if roots have higher nitrogen concentration or if their respiratory costs exceed the benefits they provide to the plant.
Keywords: Vitis, Citrus, Malus, Prunus, Gala, root longevity, root phenology, root production