New Zealand apple production is dominated by the export market, and sensitive to increases in world apple supply by alternative suppliers; just ask Braeburn growers what this can mean.
Our long distance from consumer markets means that economic viability can be maintained only by continuing to supply markets with premium, rather than commodity produce. According to John W. Palmer, at the HortResearch Nelson Research Centre in Motueka, this will only be achieved through the rapid introduction of new cultivars, further improvements to fruit quality and reductions in the cost of production. It appears intensive planting systems on dwarfing rootstocks may offer the key to future success.
In many parts of the world, high prices paid for new cultivars have been a strong catalyst for intensive systems on dwarfing rootstocks. Local trials on two Nelson orchards have shown production at year 2 on Royal Gala/M9, at 2200 trees/ha, yielding 80 t/ha of fruit by year 5. These results illustrate how rapidly new cultivars could be introduced, allowing rapid, consumer driven change, from obsolete varieties to new, more attractive premium products.
"The real benefits are improved fruit quality," says Mr Palmer. "Improved precocity - that's the time at which the orchard comes into bearing - reduced production costs, and probably a reduced amount of spray that you need on the tree. Certainly the spray targets are much easier to hit, and the people in the south Tyrol in Italy, when they switched to smaller trees, claimed they were using less chemicals per hectare."
Potential concerns with the system include sunburn, woolly apple aphid, insufficient understanding, a lack of experience and management skills with intensive systems, and a perceived lack of quantity and quality of dwarfing rootstocks from nurserymen in New Zealand. A major concern is cost.
"It costs more because you are putting in more trees, maybe 2-3 times as many as a conventional system, so the establishment cost is high. With this, is the greater risk of investing much more money, therefore a greater risk of not recovering what you were hoping for." Mr Palmer adds.
An advantage of intensive systems is the fruits' increased exposure to light, and therefore improvements to fruit quality. In our high solar radiation environment, this may not be so desirable.
None of the widely available dwarfing M9 apple rootstock is resistant to woolly apple aphid, a pest which caused serious damage in the early part of the century, with infestations of root systems. Aphelinus mali, a parasite introduced in the 1930's, is now widely distributed, but it parasitizes aphids only on aerial parts of the tree.
Serious woolly aphid infestations however, are hopefully a thing of the past, "everyone uses such an effective spray programme, nobody ever sees it today. But interestingly, South African orchardists have seen the breaking down of resistance to the 'Northern Spy' gene, that was bred into the original Malling-Merton rootstocks to provide aphid resistance."
John W. Palmer recommends nurserymen put more material into stool beds for future demand, together with "a raft of issues to do with quality, such as careful maintaining of irrigation, inducing breaks - more feathering of trees, which can be done successfully chemically, and I think the trees in the last year in the nursery, have got to be growing very fast, with no stresses."
"Ideal dwarfing trees should have 8-10 feathers, positioned somewhere between 0.80m - 1.10m above the soil surface, with a tree height about 1.7m."
Local trials have shown good results. "Certainly Royal Gala and Pink Lady have done very well, and people are planting the new varieties as well, such as Pacific Beauty on dwarfing rootstocks."
Mike Simpson, general manager of Waimea Nurseries Ltd in Appleby, agrees that in the past, plantings on M9 dwarfing rootstocks have been limited by supply, but nurseries are rapidly increasing stocks of trees for planting in the coming winter season.
"We have 6 base varieties, all well feathered and on M9, including Pink Lady, Royal Gala, Brookfeild and GS494."
"Dwarf and compact trees are absolutely essential for the survival of the industry, and is the broad industry directive."
And Mr Palmer adds that dwarfing trees and high density orchards in the Nelson Marlborough region "offer tremendous potential."
The International Dwarf Fruit Tree Association will hold it's annual conference in Napier, Hawkes Bay on February 6th -9th 2000, with guest speakers from Canada, the UK, the Netherlands and all the main apple growing regions of USA, presenting information on fruit tree management from a truly global perspective - the first time in its 42 year history to be held outside North America. New Zealand has been selected because of our modern and very productive orchards, our high fruit quality, our success as an exporter and innovation through introduction of new varieties to the rest of the world.
The week before the IDFTA conference in Napier, pomologists from all over the world will attend a more scientific Orchard Systems Symposium in Nelson, involving the International Society of Horticultural Science, and sponsored by the NZSHS, therefore giving local people, unable to attend the conference, the opportunity for cross-fertilisation of ideas from across the world-wide growing community.
Part of the symposium will featured a special open evening, on Tuesday 1st February 2000, at Seifrieds Vineyard, giving growers an opportunity to hear one of the foremost experts on intensive systems in the world, Dr Bob Wertheim from Zealand, The Netherlands.
