During that stage, the benefits of clonal rootstocks in the avocado industry were only beginning to dawn, and Westfalia started to propagate this tree and include it in trials to determine the production of it as a clonal rootstock, as well as its’ repeatable tolerance to root rot. Trees were grafted with the scion ‘Hass’ in the nursery and planted in field trials in which the tree always showed the same superior tolerance to root rot as the original seedling. South African trials have since then indicated that ‘Dusa®’’ is superior to ‘Duke 7’ (the previous industry standard rootstock) both in terms of yield and root rot resistance. This finding is consistent with research conducted in both Australia and California where up to a 20% yield advantage has been recorded.
After the application for Plant Breeders Rights was filed, the first commercial Dusa® trees were planted on Westfalia Fruit Estates in 2003 and the first trees were sold to outside farmers in 2004 with a planting in the Kiepersol area. Currently trees on Dusa® rootstock are planted throughout South Africa including the Eastern and Western Cape where it is doing well under colder conditions. Dusa® plant material was also exported to numerous countries including Australia, Israel and the USA to test its’ capabilities under different growing conditions. Here it showed similar promise, and currently Dusa® is protected by Plant Breeders’ Rights throughout the avocado producing world. Currently, Dusa® trees are sold commercially in the USA, Chile, Australia and New Zealand. Of the 1 million trees sold to date, about 50% was planted in South Africa, while the majority of the rest was sold in the USA.