Effect of genotype and rooting hormone on rooting of Litchi chinensis "microcuttings" - preliminary results

Clonal propagation of litchi (Litchi chinensis) in South Africa is carried out primarily by air-layering, and grafting onto seedling rootstocks. However, while air-layering is the most successful method for commercial vegetative propagation of litchi, it has a number of challenges. The major limitation is the number of suitable branches that can be air-layered per tree. In the current study, leafy 'microcuttings' were rooted under intermittent mist with rooting percentage ranging from 30 to over 80%. Rooting was influenced not only by genotype but also by rooting hormone used. Just hardened-off green wood cuttings 10-12 cm in length, 4-5 mm in diameter and supporting two to three leaves, were used as cutting source. Leaves were trimmed before the base of the cuttings were dipped in a commercial rooting preparation containing indole-3-butyric acid in powder form or a liquid commercial preparation containing a indole-3-butyric acid/1-naphthaleneacetic acid combination. A well-drained rooting medium was used and cuttings rooted within seven to nine weeks with roots being visible at the base of the seedling tray cells. Rooted cuttings were transplanted into 2-L potting bags for acclimatisation and establishment. The resulting plants were upright in stature and uniform in growth.