Un article intéressant sur la multiplication des porte-greffes :
Temperate fruit tree rootstock propagation, par Webster
The reasons for temperate fruit tree rootstock development are briefly outlined and the principal methods of rootstock propagation described. Although ease‐of‐propagation was once the principal criterion when selecting clonal rootstocks, other rootstock attributes, such as resistance to pests, diseases, and unfavourable climatic conditions or ability to dwarf the scion, have now become of greater priority. New and improved methods of propagation have aided this shift in priorities by enabling propagation of recalcitrant clones. Nevertheless, new methods of propagation which bring about partial rejuvenation of the rootstock also have disadvantages. Micropropagated rootstocks frequently sucker profusely and may also show increased burrknotting.
PDF : http://www.tandfonline.com/doi/pdf/10.1080/01140671.1995.9513912
Morceaux choisis (désolé pas de traduction) :
<b>
Muliplication générative (semi)</b>
<ul><li>> In species such as apple, where viruses are
thought not to be transmitted through seed and
where nurseries in some parts of the world find it
difficult to maintain the health status of virus-free
clonal rootstocks, seedling rootstocks may have
clear benefits. Seedling propagation also offers the
potential for avoiding transmission of root-borne
diseases such as crown gall
The uniformity of performance of seedling
rootstocks may, however, be improved to some
extent by: (1) using seed of a single clonal variety
(e.g., 'Red Delicious' apple or 'Bartlett' pear) or
seed from a self-fertile cultivar grown in a
monoculture; (2) using seed collected from virusfree
mother orchards planted in isolation (e.g.,
Pontavium and Pontaris Prunus avium lines of Mazzard rootstocks available in France); and (3)
using seed of apomictic rootstock selections.</ul>
Marcotage couché ou en touffe (layering et stooling - je ne sais plus le terme français adéquate...)
<ul>
<li>> Another occasional problem with stooling
concerns the high proportion of sub-standard shoots
produced by some apple rootstock clones on mature
stoolbeds. One solution to this problem, suggested
by Vasek & Howard (1984), is to harvest the layers
biennially rather than annually.
<li>> Stool and layer beds are also subject to attack
from numerous soil-borne pests and diseases. Many
nematode species severely limit production, as do
attacks by bacterial</ul>
Marcotage
<ul><li>> Marcotting has occasionally been used as an aid to
propagating difficult-to-lay er fruit tree rootstocks</ul>
Boutures
<ul>
<li>> Usually, cutting techniques have been developed to
aid the propagation of recalcitrant rootstock clones
or to circumvent disease, soil or site problems
experienced with the more conventional division
techniques.
<li>> For successful propagation using any type of
cutting there are three principal considerations.
First, the propagule must be healthy and in the
appropriate physiological condition; this is achieved
by good stockplant management before cutting
excision. Second, the cutting may need physical or
chemical treatment to aid its rooting and, finally,
the cutting must be placed in an environment
conducive to survival, root induction, and/or root
development.
<li>> Subsequent research indicated
that even better rooting of hardwood cuttings was
achieved if their bases were heated to higher
temperatures for shorter periods
<li>> Wounding the bases of winter cuttings is a well
tried technique for enhancing rooting success
<li>> Cuttings taken in the mid winter period usually root
and establish less successfully.
<li>> Stockplant manipulation may occasionally be
used to aid rooting of hardwood cuttings. Fachinello
et al. (1988) have shown that in Brazilian conditions
girdling shoots of MM. 106 on stockplants, c. 15
weeks before their collection as cuttings, may
enhance dry weight and also subsequent rooting
<li>> For success when propagating leafless, hardwood
cuttings of rootstocks, they should have their bases
dipped in solutions of IBA dissolved in ethanol or
acetone</ul>
