GENEVA® APPLE ROOTSTOCKS
Apple rootstocks currently available to the South African apple industry have various shortcomings. Disadvantages include excess vigour, low yield efficiency, lack of precocity, poor adaptability, and high susceptibility to pests and diseases. Recent studies have found some of the Geneva® rootstocks to be significantly more yield efficient and precocious than standard rootstocks.
HORTGRO Science currently has five rootstock evaluation sites with a ‘more dwarfing’ and an adjacent ‘more vigorous’ planting at each site. Evaluation trees were planted in the Grabouw (Oak Valley, Breëvlei), Langkloof (Helderwater) and in the Ceres (Bokveldskloof, Môrester) region.
Performance indicators in ongoing SA trails:
- G228 is in the same vigour class as M793, while G222 and G202 is considerably more dwarfing.
- G778 is more vigorous than M793 and seemingly in the same vigour class as MM109.
- At the same planting density, G778 seems to be more productive than MM109 and G228 more productive than M793.
- Early production (4th leaf) on G202 looks very promising.
Promising new selections – data from USA, Brazil and Italy:
- G41 highly yield efficient and very precocious, resistant to crown and root rot and wooly apple aphid.
- G213 is the most promising dwarfing apple rootstocks for ‘Gala’ in Southern Brazil, based on high annual yields and gives better budburst uniformity than M9. It is more vigorous than M9 Emla.
- G214 is one of the best replant performing rootstocks. It is very productive and tree size is larger than M9.
- G969 is highly yield efficient, resistant to crown and root rot and wooly apple aphid.
- G210 is precocious and productive. It has high resistance to wooly apple aphid, some tolerance to replant disease, and resistance to crown and root rot.
- G890 is more yield efficient than M7, is resistant to crown and root rot and wooly apple aphid.