OPTIMISING STEM DIAMETERS OF WATERMELON CULTIVARS AND INDIGENOUS CUCUMIS SPECIES FOR IMPROVING COMPATIBILITY OF INTER-GENERIC GRAFTS
Inter-generic grafting of watermelon (Citrullus lanatus) cultivars onto Meloidogyne-resistant wild watermelon (Cucumis africanus) and wild cucumber (Cucumis myricoarpus) resulted into 64% mortalities of grafts. Possibly, this was due to unequal stem diameters at the graft union, with those of watermelon cultivars and Cucumis species being thicker and thinner, respectively. Optimisation was achieved by raising Cucumis species and Citrullus cultivars in 160- and 200-hole seedling trays, respectively. Primed seeds of Citrullus cultivars were planted seven days after emergence of Cucumis seedlings. Different seedling tray sizes, seed priming and sequential planting were all intended to optimise the stem diameters at the grafting union. At grafting, the stem diameter quotient (D2/D1) for each treatment was one, regardless of the grafted components. However, at 66 days after transplanting, D2/D1 was less than 1, suggesting that the rootstock portion grew faster than the scion part. Also, at 66 days 100% survival of grafts was registered, which translated to a relative improvement of 186%. In conclusion, the new technique in optimisation of stem diameters would promote the potential uses of Cucumis rootstocks in watermelon production for nematode management and might probably be expanded to other genera.
Pofu, K.M., Mashela, P.W. and Mafeo, T.P. (2013). OPTIMISING STEM DIAMETERS OF WATERMELON CULTIVARS AND INDIGENOUS CUCUMIS SPECIES FOR IMPROVING COMPATIBILITY OF INTER-GENERIC GRAFTS . Acta Hortic. 1007, 807-812
Citrullus lanatus, Cucumis africanus, Cucumis myricoarpus, inter-generic grafts, nematode resistance, watermelon