MICROGRAFTING SPEEDS GROWTH AND FRUITING OF PROTOPLAST-DERIVED CLONESOF KIWIFRUIT (ACTINIDIA-DELICIOSA)

Protoplast-derived shoots (protoclones) of kiwifruit (Actinidia delici osa) were cleft grafted directly from in vitro conditions onto mature rootstocks under field conditions on several different dates from June to August in 1987 and 1988. Shoots were taken from culture vessels, p repared for a cleft graft, placed in a cleft on a rootstock, covered w ith a glass culture tube and sealed with cotton fibres. Other plants w ere self-rooted in vitro and planted in the field to compare the growt h rates and maturity rates of the two plant types. The grafting succes s rate depended upon the time of the year the graft was made and the c are given to the scion and stock after grafting. Grafted plants flower ed and set fruit two to three years earlier than self rooted plants. T his technique can shorten the time required to examine the phenotype o f in vitro-derived plants and could be useful to propagate difficult-t o-root clones.