Impiego dei fitoregolatori in viticoltura: potenzialità e problematiche.

The use of plant bioregulators to regulate
physiological process occurring during plant growth
and development may represent an important tool for
growers. In viticulture, hormone treatments have been
mainly addressed to the reproductive developmental
cycle, taking into account that grapevine vegetative
activity can be successfully controlled by training
systems and agricultural practices. In this review we
discuss the role of various hormones in the control of
inflorescence development and berry growth and ripening.
The control of these processes may have relevant
implications for disease control in the vineyard
considering that the susceptibility of different grape
cultivars to Botrytis bunch rot, powdery mildew and
downey mildew attacks is closely correlated with
bunch architecture. The timing and the extent of ripening
is of considerable scientific interest, but has also
implications for the various grape industries (fresh
market, winery logistic and processing, as well as
grape withering). In viticulture several bioregulators
can be used to regulate events of reproductive developmental
cycle. However, the most important applications
regard the use of gibberellins to modify inflorescence
length and bunch architecture as well as
berry size in seedless varieties, and abscissic acid,
ethylene and brassinosteroids to improve quality traits
of berries. Auxins can be mainly used as inhibitors of
ripening; therefore, they can be applied to delay the
vintage without significant changes of global quality of
berries. A delayed ripening can be also achieved by
spraying 1-methylcyclopropene, an inhibitors of ethylene
action. The knowledge of these effects has been
significantly improved in the last years thanks to the
increasing availability of information concerning the
molecular basis of hormone action. In the future, this
information could be used to develop new strategies
in the control of reproductive developmental cycle. In
addition, crystallography X-ray is an important tool to
elucidate the structure of plant hormone receptors
and thus to select, from chemical libraries, small biomolecules
able to interact with them. This is a crucial
point to develop new molecules with a lower synthesis
cost, which is often the main constraint on the introduction
of new plant bioregulators.