Usefulness of in vitro micropropagation for establishing plantations of self-rooted Hevea brasiliensis industrial clones
Industrial clones of Hevea brasiliensis have been traditionally propagated by bud-grafting. Although this technique is routinely used by planters - high multiplication rate, high budding success- it is liable to induce graft incompatibilities symptoms and physiological ageing of the planting material. Recent findings have confirmed that industrial clones produced by rooted (micro) cuttings on their own roots further to in vitro rejuvenation, grow faster and yield more latex than those derived from budding. The self-rooted industrial rubber tree clones planted at SoGB were first rejuvenated in vitro by somatic embryogenesis at Gent University in Belgium. The few emblings obtained were then micropropagated by axillary budding for producing a sufficient number of microcuttings for each clone. However the high constraints associated with the shipment of the in vitro microcuttings from Europe to Africa and poor acclimatization success rates prompted us to use these Belgium-produced in vitro plants as stock plants for mass clonal propagation by rooted cuttings at a much cheaper cost locally in the vicinity of the planting sites. Two industrial rubber tree genotypes produced by rooted cuttings have already been planted to compare their agronomic traits to those of the same clones but derived from traditional bud-grafts. Extending such comparative analyses to a greater number of clones will ultimately answer the basic question of knowing whether industrial rubber clones produced from rooted cuttings have a superior field behavior than the same material propagated by grafting. The respective multiplication rates, the time needed to get plantable material as well as the cost efficiency have also to be taken into consideration.
Masson, A. 2017. Usefulness of in vitro micropropagation for establishing plantations of self-rooted Hevea brasiliensis industrial clones. Acta Hort. (ISHS) 1155:585-594
cost efficiency, mass production, rejuvenation, rooted cuttings, somatic embryogenesis, stock plant