Promoting survival rate and reducing adventitious root formation in inter-species Capsicum grafting

A grafted plant is a physical hybrid that combines desirable characteristics of the rootstock and scion. Although grafting is common and a commercially accepted horticultural production technique in tomatoes and cucurbits, commercialization of grafted peppers (Capsicum spp.) has been slow due primarily to low grafting survival rate. The objective of this study was to identify factors which promote graft survival rate and reduce adventitious root formation on Capsicum annuum L. grafted onto C. chinense Jacq. A factorial combination of four factors each at two levels were tested: 1) healing chamber type, plastic + cloth and cloth only, 2) foliar ascorbic acid application at 100 and 0 mg L-1, 3)seedling stem diameters of 1.5-2.0 and 2.1-2.7 mm, and 4) position of graft relative to rootstock cotyledons, either above or below. Optimization of survival rate greater than 90%, could be achieved by using the plastic + cloth healing chamber, a 100 mg L-1 foliar application of ascorbic acid and choosing large stem diameter seedlings. Position relative to cotyledons did not affect significantly graft success rate but dramatically reduced the formation of undesirable adventitious roots in the stem when the scion was grafted above cotyledons.