Cultivation

Commercially, walnuts are mainly grown in China and the USA. Other producing countries are, among others, Iran, Turkey, Ukraine, France and India.

Utilisation

Walnut trees are mainly grown for their nut harvest. The fruits are consumed dried or are processed to foodstuffs and food ingredients:

• Nuts and nut products

• Also: cooking oil

By-products:

• The wood of walnut trees is attractive and very hard. Since walnut trees are rarely grown for their wood, there is only a limited supply and it is mainly used in high-quality articles, mostly as veneer.
• The green husk of the walnuts contains dyes and tanning agents and can be used for dyeing hair and textiles.

Gene technology: aims of research and development

Plant development

• Modified root formation: natural walnut trees have a sturdy, deep-reaching taproot, but weaker secondary root system. An aim of these gene modifications is to increase the root system in the upper layers of the soil for a better uptake of nutrients.

• Modified flowering time, to allow a more effective harvest.

Agronomic traits

Resistance to pests

• Insect resistance

Resistance against pathogens

• Fungal resistance
  

• Virus resistance
  
  

• Bacterial resistance

Field trials with GM Walnuts