Delayed Maturity


Breeding goal for fruits and vegetables

Many fruits like tomatoes, melons, and bananas are usually harvested before ripening. The firmness of unripe fruit facilitates mechanical harvesting and extends the period of time allowed for transport and storage.

For many fruits and vegetables, transgenic procedures have been used to develop cultivars with delayed maturity. This has been achieved by suppressing of the synthesis of polygalacturonase, an enzyme responsible for fruit softening.

Suppression of polygalacturonase production can be achieved by:
  • Inhibiting the production of ethylene (a plant hormone that triggers the ripening process) by introducing genes for enzymes that degrade ethylene precursors
  • Blocking the polygalacturonase gene using antisense technology

Transgenic tomatoes with extended shelf life were introduced to the US market: the FlavrSavr tomato was the first transgenic plant approved for commercialisation. It has since disappeared from the market. Calgene (now part of Monsanto) claimed that the limited success was due to low yields and suboptimal disease resistance. Some interpret the experience with the FlavrSavr tomato as evidence that marketing tomatoes as a specialty product is an unsuccessful strategy.

Fruits and vegetables with extended shelf lives can also be developed by conventional breeding methods.



See also:
Enzyme
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