Strategies To Improve Root Development, Tree Growth And Management Of Apple Nursery Trees

Poliana Francescatto, Terence Robinson and Jaume Lordan 

Dept. of Horticulture, NYSAES, Cornell University, Geneva, NY, USA 

Currently, tree fruit nursery stock is graded on the basis of caliper size and the number of feathers. From a physiological standpoint, the root system and nutrient reserves in nursery trees are the two critical components for the establishment success of most high-density apple planting. Successfully establishing a transplanted apple tree depends primarily on rapid root growth. Furthermore, initial root development of a newly planted tree is supported by energy stored within the trunk, branch, and root tissues. Tree nutrient status (mainly nitrogen) and carbohydrates accumulated in permanents structures of the tree during the previous growing season plays an important role in determining initial tree growth in the spring. Therefore, such nutrient and carbohydrate status is an important quality attribute of nursery trees and has a direct impact on the field and economic performance of newly planted orchards. The better the quality of the nursery material the better growth and earlier productivity can be achieved in established orchard.  

In agriculture, tree inoculation with arbuscular mycorrhizal fungi deserve special interest due to the great advantages provided by this symbiosis between the tree and fungus. Mycorrhizal fungi are obligate symbionts and need to be associated with the root of their hosts to obtain carbon from the photosynthesis. In exchange, they provide nutrients and water that are extracted from the soil, reflecting in the improvement in plant growth. Enhanced seedling survival, increased plant growth rate, thus reducing time spent in the nursery, saving on fertilizer cost; and increase in production and product quality are some of the benefits provided by mycorrhizae.