Cultivation

Two kinds of apple trees are differentiated: "Niederstammsorten" (low trunk species ) are commercially cultivated in plantations. "Hochstammsorten" (high trunk species) are found in extensively managed orchards, in which the harvest is lower. The diversity of mostly old species is large.

Apple trees grow mostly in temperate climate zones. The commercial cultivation of apples primarily takes place in Europe, New Zealand, Chile, Argentina and the USA.

Utilisation

The fruit is mostly consumed raw or processed to:

• marmelade, fruit preparation, applesauce, juice.
• pectin (gelling agent E440) is won from apple pomace.

Gene technology: aims of research and development

Agronomic traits

Resistance against pathogens

• Fungal resistance: improvement of resistibility towards fungal disease such as apple scab and powdery mildew. Apple scab, the most significant apple disease, is a fungal disease that overwinters in the leaves of the trees.

• Bacterial resistance to the bacterial disease known as fire blight that has spread throughout European countries in the last 30 years. Fire blight is highly contagious and there are no effective remedies to fight the disease.

Resistance against pests

• Insect resistance, e.g. to the codling moth

Qualita traits

Modified content of fruit sugar and alcohols

• Research of a GM apple that is compatible (modified content of polyphenol; polyphenol binds allergens) with allergy sufferers is being conducted in some countries (USA, Netherlands and Sweden)

• In the USA experiments with apple trees are taking place whose fruits are not getting brown.

Plant development

• Modified blossom time

• Modified ethylene production and therefore delayed maturity

• Modified rooting

• Male sterility, parthenocarpy: to reduce the risk of outcrossing, sterility concepts are pursued. Male sterile plants do not develop pollen. Under parthenocarpy, fruits without seeds are produced.

• Auto fertility: apple is not auto fertile. With auto fertility seeds could be used for cultivation. To date, a specific species has been vegetatively multiplied by grafting it into a bed.

Field trials with GM apples