The effect of age and type of rootstock, method of scion placement and light intensity levels on the performance of Uapaca kirkiana (Muell. Arg) micrografts cultured in vitro

A study was done to investigate the effects of age and type of rootstock, method of scion placement and light intensity on successful micrografting in Uapaca kirkiana, a miombo woodland fruit tree. Experiments were conducted to determine the interaction between the effects of age and type of rootstock and method of scion placement; and age and type of rootstock and light intensity. In the first experiments, rootstocks at ages 2-, 3-, 4- and 5-months; type of rootstock: rooted and unrooted; and method of scion placement: cleft and side grafting were used. Treatments for the second experiment included rootstocks at ages 2-, 3- and 4-months; type of rootstocks: rooted and unrooted; and light intensity levels of 0, 45, 135 and 225 µMm-2s-1. Results indicate that cleft grafting gave higher percentages (49.3%) than side grafting (47.9%). The performance of the micrografts arising from rooted rootstocks was better compared with unrooted rootstocks. The mean number of roots per micrograft from rooted rootstocks was 2.3 as compared to 1.6 roots from unrooted rootstocks. The optimal level of success can be achieved when 3-month old rooted rootstocks are used for micrografting and the cultures are incubated under an illumination of 45 µMm-2s-1 with a possible graft take of at least 60%.UNISWA Jnl of Agric Vol 10 2001: pp22-2