Apple Orchard Plant Improvement
The SA apple industry was originally established using a range of planting material introduced from England by early immigrants. Over the years, there were various programs to import new varieties and root stocks from overseas, or select and breed new varieties in Australia with the aim of improving orchard productivity and the quality of fruit available to consumers.
Varieties
The success of varieties in the early days of apple growing in the Adelaide Hills depended on a number of factors including the ability to keep well without refrigeration, a broad range of maturity periods (from early varieties such as Gravenstein to late varieties such as Democrat), suitability for export, market acceptance, and compatibility for cross pollination.
In about 1920 a collection of several hundred apple and pear varieties was established at the Blackwood Experimental Orchard in Coromandel Valley. This helped identify the varieties most suited to South Australia’s climate and conditions. Selections from this collection were later established at the Lenswood Research Centre in the 1960s. It is unsure what impact this collection of stock and scion material had on apple variety development as there was no appreciable apple breeding carried out in this state. Rather, trial and error, established which varieties were best suited to local conditions.
The establishment of cool stores in the Adelaide Hills enabled varieties to be marketed over a longer period of time. Some varieties stored better than others.
Export requirements also became more clear-cut as overseas markets were established. Varieties such as Cleopatra, Rome Beauty and Granny Smith were favourites for export markets.
For many years, Jonathan was the preferred variety on local markets. The emergence of new varieties such as Golden Delicious and several Red Delicious types provided good competition. The development of controlled atmosphere (CA) storage further increased the storage life and improved out-turn quality of varieties such as Jonathan and Delicious.
In the early 1960s Senior Horticultural Adviser in the Department of Agriculture, David Kilpatrick undertook a study tour of apple growing in the USA and came home keen to search for “spur type”. Delicious sports which were inclined to be very precocious bearers in compact semi-dwarf trees. He soon found two sports and in due course several other Red Delicious spur type varieties became available from the USA. Kilpatrick also found a spur type Granny Smith at Cudlee Creek in 1964.
Australian Apple Breeding programs
There have been two major apple breeding programs in Australia. The most successful has been that led by John Cripps of the WA Department of Agriculture by John Cripps of WA Dept of Agriculture. He established a large range of crosses during the 1980s and 1990s and eventually produced the varieties Cripps Pink (trademarked as Pink Lady) and Sundowner. These have become very popular worldwide because of their attractive appearance, eating and keeping qualities. Both varieties are sold under trade mark or plant breeding rights restrictions.
At Stanthorpe in Queensland, a project led by Les Baxter and Steve Tancred began in 1986 aimed to develop commercially acceptable varieties resistant to the Black Spot fungus. At least two Red Delicious type varieties with good resistance to the disease have been released, but neither has gained the acceptance of the WA varieties to date.
SA orchardists have been quick to plant these newer and more popular varieties to cater for consumer demand here and overseas.
Rootstocks
Many early apple orchards were grown on seedling rootstocks because of the ease with which they could be propagated and their good vigour. There were also some plantings on Winter Majetin which was a very vigorous stock and produced very large trees.
The appearance of Woolly Aphis (Eriosoma lanigera) which infested the roots and lower parts of trees necessitated a move to resistant rootstocks. The most promising of these was Northern Spy which had semi-dwarfing characteristics. Most of the apples trees in SA were worked on to Northern Spy rootstocks during the 1930s to 1970s.
Since the introduction of the Woolly Aphis parasite Aphelinus mali in about 1922 the effects of the woolly aphis have been reduced, but some other protection such as rootstock resistance is still warranted.
In the 1930s to 1960s Blackwood Experimental Orchard provided bud sticks of apple material infested with Woolly Aphids but also parasitized with Aphelinus mali, to growers who wanted to establish parasites in their orchards.
The demand for higher yields, closer planting and trellising brought with it a trend towards more dwarfing stocks. The Malling and Merton series of dwarfing rootstocks were introduced into Australia from the East Malling Research Centre located in Kent, UK for assessment. One of the early favourites was Malling 9 (M9) which was the most dwarfing in the series. Other contenders were M26 and Malling Merton 102 (MM102), MM 106 and MM111. Of these M9 was classed as susceptible to aphid attack and M26 moderately susceptible, the rest were classed as resistant. Stool beds of several of the Malling and Malling Merton series were maintained at the Blackwood Orchard and some were later transferred to Lenswood Research Centre.
Today, virtually all new orchards are established on improved rootstocks.
Balhannah Nurseries current catalogue lists a wide range of rootstocks as being available for apples, including M9, M26, Ottawa 3, MM102, M7, MM106 and Northern Spy. There seems to be growing concern in the industry that the widespread use of Woolly Aphis susceptible dwarfing rootstocks is encouraging a build up and spread of the pest.
Apple root stocks at Lenswood Research Centre, October 1974
Nurseries and propagation
One of the prominent nurseries servicing Adelaide Hills apple growers was that of H. Wicks who had been trained in nursery work at Suttons’s Nurseries, Reading, England and took over a general nursery run by Charles Pitt at Payenham in 1887. As the business expanded Wicks’ sons established new nurseries at Balhannah and Highbury to cater for the growing needs of apple growers.
Wicks Balhannah Nurseries became a prominent supplier and in recent years following the retirement of Malcolm Wicks, was taken over by Joyson Orchards. It still trades as Balhannah Nurseries even though it is now located at Charleston.
Hackett’s Nurseries in Adelaide were also suppliers of apple trees to Hills growers in the early days.
The large Victorian company Fleming’s Nurseries currently supplies a wide range of apple varieties, on a number of rootstocks, to SA growers.
Quality assurance in propagation material
Following the successful establishment of the Renmark Bud Selection Society for citrus propagation in the 1960’s a SA Pome Fruit Improvement Committee was formed and still functions with an office at Lenswood and Michael Stafford the secretary. The SA Pome Fruit Improvement Committee has played a key role in adoption of new varieties and fostering the planting of improved bud lines by orchardists. SA Pome Fruit Improvement Committee in South Australian Apple and Pear Industry Organisations.
This group is now part of APFIP (Australian Pome Fruit Improvement Program Ltd.) with SA representatives Michael Stafford (Chair), Robert Green and Kym Green all of Lenswood.
After the establishment of the Monash Repository for horticultural propagation material in the Riverland in 1971, APFIP established certified rootstock stool beds there. This service ceased in 2005 and the production of APFIP certified rootstocks is now licensed to commercial nurseries. A new repository for certified rootstocks and varieties has been established at Cambridge in southern Tasmania. A list of rootstock material currently available through APFIP includes M26, M9 and MM106.
Fruit tree nurseries formed their own association, ANFIC (Australian Nurserymen’s Fruit Improvement Company) in order to formalize their industry and deal with patented plant material, some which came in from overseas where similar industry organisations were operating.
ANFIC is a member of PrevarTM an international joint venture company established to develop and globally commercialise new apple and pear varieties and products.
The granting of plant patents to Nurserymen to protect new varieties and material brought in from overseas occurred in the 1970s. This Plant Breeders Rights (PBR) scheme is administered in Australia by the Commonwealth Government and all applications must be registered with IP (Intellectual Property) Australia.
The administration of the PBR scheme is understandably difficult because of the relative ease with which plant material such as budwood can be acquired and propagated.
Virus testing
As with other horticultural crops the elimination of viruses in apple propagation material has produced significant increases in yield and tree health. There are at least four viruses infecting Australian apple trees and Horticulture Australia Limited (HAL) is sponsoring research to enable the production and use of virus free propagation material via APFIP.
In the 1970s the Department of Agriculture’s Plant Improvement Unit at Northfield obtained selected clones of Northern Spy rootstock and subjected them to a heat treatment regime which was hoped to rid the material of all known detrimental pome fruit viruses. Of the 14 candidates plants, only one was found to be free of all known viruses, and this was used to establish stool beds for use by commercial nurserymen.
Further reading
van Velsen, R. J. (1982). Plant Improvement Program Progress Report. Department of Agriculture South Australia Plant Industry Division Report 8, 15 and 16.
Reworking orchards
There has been continuous interest in top working of trees to upgrade old orchards and rapidly change to more up-to-dare varieties. The first South Australian Department of Agriculture Bulletin (No 322) covering the topic was written by R Fowler, E Leishman and HH Orchard. In 1972 the results of a trial first established at Blackwood in 1958 that compared various reworking methods and was published by Bob Cowley and Lew McMaster in the Journal of Agriculture.
Disease resistance
Resistance to Black Spot and other diseases as well as Woolly Aphid resistance is being investigated in projects managed by HAL through APFIP.
“Designer” techniques are being investigated to produce trees that have inbuilt resistance to disease and insect pests.
Further reading
Kilpatrick D.T.; (1964) New semi dwarf “spur type” granny smith; South Australian Department of Agriculture Journal of Agriculture Sept 1964
Kilpatrick D.T.; (1964) Two new red delicious sports found; South Australian Department of Agriculture Journal of Agriculture Dec 1964.