Fruit and Vegetable Quality

hybrid seed production), respectively, have been approved for commer-
cial use. In the United States, five lines or cultivars of tomato with de-
layed softening and ethylene ripening characters have been approved by
the FDA and USDA for commercial release.
Besides tomato and potato, a variety of other transgenic fruit and veg-
etables have appeared on the stage since 1995. These include broccoli,
carrot, chicory, cranberry, eggplant, grapevine, pea, pepper, raspberry,
strawberry and watermelon. After transgenic modifications of quality
parameters had been successfully tested in tomato, the respective ap-
proaches were extended to a variety of fruit and vegetables. In 1997,
field releases were conducted for apple, melon and pepper with altered
product quality, for strawberry with delayed softening by transfer of a
polygalacturonase inhibitor protein gene and for tomato with delayed
ripening and increased solids characteristics (Table 2.6).
A promising future prospect is genetic engineering of parthenocarpic
fruit, which recently was exemplified for eggplant (Rotino et al., 1997).
In this case, a gene from the phytopathogenic bacteria Pseudomonas sy-
ringaepv. savastanoiencoding synthesis of the auxin precursor in-
dolacetamide was put under the control of an ovule-specific promotor
and transferred into eggplants. The transgenic plants acquired the ca-
pacity to form seedless, marketable fruits in the absence of pollination
under normal growth conditions. In addition, the transgenic plants de-
veloped marketable fruits without application of exogenous plant hor-
mones under low temperature/light conditions, which are otherwise
prohibitive for fruit set in untransformed eggplants. It can be expected

38 QUALITY AND BREEDING—CULTIVARS, GENETIC ENGINEERING

Crop Trait Investigator

Apple Altered product quality Univ. of Berkeley

(not specified)

Melon Altered fruit ripening Agritope

Pepper Altered fruit ripening DNAP

Enhanced aroma

Strawberry Delayed softening (PG-inhibitor protein) DNAP

Delayed ripening

Tomato Delayed ripening; increased solids Zeneca

Table 2.6. Field Releases for Transgenic Quality Traits

in Fruit and Vegetables in 1997.

Source:USDA/APHIS/BSS.