Cultivation

Papaya (Carica papaya), also known as tree melon, is cultivated worldwide in the tropics and subtropics. The main producing countries are Brazil, Mexico, Nigeria and India. In 2005, approximately 6,75 million tons were produced worldwide.

Utilisation

The fruit is mostly consumed raw or is processed to:

• fruit juice, marmalade, fruit products or to an exotic flavour component, e.g. for ice cream or puddings.

Because of their high levels of vitamins and certain enzymes (papain) papayas have been considered a ''wonder fruit''. Several health-promoting products and dietary supplements are prepared from papaya.

Gene technology: aims of research and development

Agronomic traits

Resistance against pathogens

• Virus resistance: ''immunisation" of papayas through transfer of the gene for the envelope protein of the pathogenic virus (particularly papaya ringspot virus – PR virus)

  PR viruses are a major problem in papaya cultivation; they can lead to a drastic loss of yield. In Hawaii during the 1990s, half of the papaya harvests were lost due to PR virus infections. The development and cultivation of virus-resistant papayas have largely solved this problem. After the success in Hawaii, other papaya variants are being developed in different regions that are resistant to the viruses prevalent in those areas. A cooperation project, in which international companies and establishments from India, Indonesia, Thailand, Malaysia, the Philippines and Vietnam are taking part, is working on the development of a virus-resistant papaya for the South-East Asian region

• Fungal resistance
  
  

• Bacterial resistance

Resistance to pests

• Insect resistance

Plant development

• Modified ethylene production and thus delayed maturity

Field trials with GM papaya

Utilisation of GM papayas