Agriculture Reference
In-Depth Information
regulators to enhance rooting, though some recommend a lanolin paste with
250 ppm IBA, 100 ppm 2,4,5-T, and IAA or IBA at 500 ppm.
Cuttings with two to three leaves from girdled and ungirdled branches of
'Brewster', 'Gui Wei' and 'Hei Ye', treated with the sodium salt of NAA, IBA
and their mixtures and misted or not in a polyethylene enclosure give poor
results. Others have obtained 93% rooting and 100% survival by using green,
woody cuttings dipped in 5000 ppm IBA and rooted under intermittent mist.
The variable and often low rate of success in litchi grafting is attributed
to stock-scion incompatibility, poor cambial contact, grafting at the wrong
physiological stage and poor management after graftage (Menzel, 1985).
Graft incompatibility is suggested when only 20% of girdled 'Brewster' scion
and 10% of 'Gui wei' are successful on rootstocks of the same cultivars.
Histological studies of the graft unions between 'Hei ye' and the above two
cultivars show a slow rate of proliferation of callus tissues. Currently, there
is generally a lack of knowledge on the graft compatibility between litchi
cultivars. Proper culture of rootstocks and preparation of scion-wood (girdling
for starch accumulation), proper stage of maturity of scion-wood, appropriate
post-graft environment, particularly high humidity, and other factors
contribute to more consistent success in grafting.
Grafting is used for longan, with semi-hard terminals as scions. The scions
are cleft-grafted into a node subtended by a leaf in Australia. This grafting is
done on to 12-18-month-old rootstocks. In China, whip grafting, side grafting
and budding are used. Top-grafting is used to top work large trees.
Field preparation
Deep ripping may be necessary if the soil is compacted. Liming to pH 5.0-5.5
should be carried out and manure incorporated before planting. Litchi
trees tolerate poor drainage but do not grow well in standing water. Surface
drainage should be installed if such conditions exist. If nematodes are
expected to be a problem, fumigation should be carried out. Longans require
well-drained alluvial soils for good development.
Transplanting and spacing
Sun-hardened trees (6-12 months old) can be planted out at any time of year
if there is sui cient moisture available and there is no chance of frost. Light
mulching (100 mm) after fertilization is benefi cial for young litchi trees.
Seedlings should start to produce fruit in 6-10 years and asexually propagated
trees in 3-5 years.
Spacings of 5-12 m, depending upon cultivar size, are used. 'Gui wei'
is a very vigorous tree, 'Hei ye' being moderate, while 'No mi ci' is a smaller
