Agriculture Reference
In-Depth Information
(a)
(b)
(c)
(d)
(e)
Fig. 4.7.
Girdling is used to aid in inducing
fl
owering (a). To protect young trees
that are susceptible to full sunlight, simple structures such as palm fronds are used
(b), to plastic shade structures (c) and wrapping pineapple fruit with paper to reduce
sunburn (d). Some crops may need to be protected from rainfall (e) during
fl
owering
and fruit development, with rain shelters built over the crop in the
fi
eld.
possibly due to imprecision that is inherent in cutting a tree with a saw or
knife blade.
Girdling and scoring are used in some fruit trees for dif erent purposes.
In the case of layers or air layers (marcotts or gootees), a 3 cm-wide ring of
bark is removed at the point just below the zone where new roots are expected
to arise; the interruption of the phloem fl ow stimulates adventitious root
formation above the girdle. Sometimes the branch from which grafting or
budding material is to be obtained is girdled below these buds 2 or 3 weeks
before material is to be removed. The objective is to induce bud swelling, which
results in higher grafting and budding success rates.
Another objective of girdling is to stimulate fl owering. In very hot areas
with no cool or dry period to induce mango fl owering, a 3-cm girdle is done on
a primary branch to induce fl owering. The problem is that 5% of the branches
often die. The girdling technique is also used on avocados, macadamias and
litchis, in order to improve fl owering, fruit set or fruit size. For better fruit
set, girdling or scoring should be done at petal fall, while for larger fruit size
