Firmness Tomato 2

Harvesting tomato fruit when ripening has set in would make maturity determination easier as it would be based on visible peel color and would assure full quality development. After harvest, ripening continues and softening advances, increasing the susceptibility of the fruit to handling damage and limiting the marketing period.

Ripening mutants in tomato genes such as colorless non-ripening ( NOR ) and ripening inhibitor ( RIN ) have been successful in modulating fruit firmness. Delaying ripening and softening may also be achieved by employing modified atmosphere packaging, however this increases the cost of packaging and handling of fruits. Existing methods to enhance fruit firmness in conventional plant breeding programs rely on screening fruit firmness differences in fruit harvested from mature plants. Fruit firmness is a quantitative trait involving many genes and yet the identity of the majority of these genes remains elusive.

The specific QTL described in this invention is located on Chromosome 3 and contains the Pectate Lyase gene. The presence of the QTL in cultivated material significantly increases the fruit firmness at the breaker development stage.