Open Field Trial of Genetically Modified Parthenocarpic Tomato: Seedlessness and Fruit Quality - Genetic Engineering: Recent Developments in Applications - page 157

corresponding control but a 10-fold reduction in the seeds content. All other test-
ed parameters, with the exception of β -carotene, did not show relevant changes
between GM and not GM UC 82 tomatoes.
discussion
The open field trial of two transgenic tomato lines obtained from the processing
cultivar UC 82 showed that the DefH9-RI-iaaM gene was able to induce parthe-
nocarpic fruit development under open field cultivation conditions. Most (ap-
proximately 75%) of the fruits produced were seedless and, furthermore, seeded
fruits contained significantly less amount of seed (on the average the number of
seeds per fruit was 60-80% reduced) than both the corresponding untransformed
UC 82 control and the modern cultivar F1 Allflesh (Table 2). These results are in
accordance with those from field trial of eggplant where most of the transgenic
fruits were seedless [10] and confirmed that iaaM-induced parthenocarpy might
be used as a tool to reduce transgenic seed dispersal without the need to combine
it with male sterility. The significantly fewer number of seeds in DefH9-RI-iaaM
tomato (UC 82) fruits may represent a desirable trait for processing tomatoes
because the absence of seeds simplifies industrial activities which normally discard
the seeds from the paste.
Under the rather high temperature that occurred during flowering, fruit set
and growth, the DefH9-RI-iaaM parthenocarpic transgene allowed the produc-
tion of a significantly larger number of fruits compared to the untransformed cv.
UC 82. This indicates, at least under the conditions tested, an improved ability
of the DefH9-RI-iaaM plants to set fruits. Poor fruit set and dramatic reduction
in fruit size has been reported in tomato plants grown at 26°C under controlled
conditions [13]. DefH9-RI-iaaM parthenocarpic fruits had a shape similar to
that of the control and no malformations were observed, confirming the data
obtained for T0 plants [8]. The reduction of weight observed in parthenocarpic
fruit grown under open field conditions, might be due to the increased number
of fruits caused by the improved fruit set of parthenocarpic plants. A different
agronomical practice (i.e. watering, fertiliser regime, etc) apt for high fruit-set
lines (i.e. DefH9-Ri-iaaM GM) might improve fruit weight, and consequently
plant productivity.
Except for the color coordinate a* (red), the two transgenic parthenocarpic
lines showed no relevant variation of the technological properties (°Brix, pH, dry
matter, total acidity and firmness) compared to the untransformed control cv.
UC 82. Interestingly, all three genotypes in the UC 82 background differed from
the modern F1 hybrid Allflesh for the solid soluble content (°Brix value), which
is a very important trait for processing tomato. The presence of the transgene