Multiplication des portes greffes

greffer.net >> Multiplication végétative

nicollas a écrit le 20/12/2012 11:04 (ref msg # 38051 )
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/10.10...


Morceaux choisis (désolé pas de traduction) :

Muliplication générative (semi)

  • 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.


Marcotage couché ou en touffe (layering et stooling - je ne sais plus le terme français adéquate...)

  • 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.
  • 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


Marcotage
  • Marcotting has occasionally been used as an aid to

  • propagating difficult-to-lay er fruit tree rootstocks


Boutures

  • 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.

  • 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.
  • Subsequent research indicated

  • that even better rooting of hardwood cuttings was
    achieved if their bases were heated to higher
    temperatures for shorter periods
  • Wounding the bases of winter cuttings is a well

  • tried technique for enhancing rooting success
  • Cuttings taken in the mid winter period usually root

  • and establish less successfully.
  • 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
  • For success when propagating leafless, hardwood

  • cuttings of rootstocks, they should have their bases
    dipped in solutions of IBA dissolved in ethanol or
    acetone
nicollas a écrit le 20/12/2012 11:19 (ref msg # 38052 )
J'étudie le sujet en ce moment, et la technique la plus facile me semble le marcotage avec buttage, mais cette dernière ne semble fonctionner que pour les PG de pommiers (et encore pas tous)

La méthode la plus universelle semble être le bouturage, mais demande l'utilisation d'hormone et une certaine température,

Éventuellement, le marcotage par couchage d'arbre semble prendre assez bien, mais ça fait quand même peur d'enterrer un arbre ...

Marginal mais intéressant, pour les PG qui rejettent/drageonnent , on peut prendre directement les rejets (j'ai lu ça pour Pixy)
floyd a écrit le 20/12/2012 14:02 (ref msg # 38054 )
Les extraits en anglais résument tout à fait la problématique de la multiplication végétative.
Nombreuses techniques avec des taux de réussites variables, ce qui incidemment justifie pleinement l'existence du présent forum.

Le condensé que tu nous fait, nicollas, est pleinement satisfaisant.
La conclusion que l'on peut en tirer reste classique; l'amateur peut recourir à des techniques demandant peu de matériels ou de savoir-faire… ou bien s'il a du temps et une certaine habitude, tenter des gestes et des protocoles plus élaborés.
Ces deux façons de faire sont présentes sur le forum.


greffer.net >> Multiplication végétative