Major research and extension programs
Over more than a century, South Australia’s stone fruit industries have been supported by a comprehensive range of research and technology development programs based at Blackwood, Berri, Loxton and Lenswood research centres. This section provides an overview of the key research and development programs delivered to stone fruit industries.
Stone fruit growers were also supported with specialist horticultural advisers based at regional offices (principally Waikerie, Berri, Renmark, Loxton, Nuriootpa, Lenswood and Blackwood). The first specialist horticultural advisers were appointed in the Riverland (the main stone fruit district) in late 1926 (Mr F.R Arndt – Upper Murray and Mr H. Beriman – Lower Murray).
The Riverland adviser network was at its height in the 1960s and 1970s with specialist staff providing expertise in disease and insect identification, running numerous identification training events, and advising growers on treatment and management strategies. Some of the many participants in this network included Bill Baskett, Brian Bidstrup, Greg Botting, Rev Cant, Murray Cooper, Cec Grasby, Dick Henderson, John Jennings, Tom Simes, Bill Pollitt, Milton Spurling, John Steed, and Ross Wishart, with regional leadership from Geoff Thomas.
Specialist irrigation extension programs were delivered by the Irrigation Crop Management Service under the initial leadership of Keith Watson.
Industry and crop surveys
In 1953–54, the Department of Agriculture appointed W.E. (Wally) Mount as a Canning Fruit Survey Officer to conduct surveys of canning fruit plantings and forecast anticipated crops in River Murray districts (funded from the new Commonwealth Extension Services Grants). Data from these surveys proved very valuable in assisting the canning industry to recover from the devastating 1956 floods. Some canning pear surveys were also conducted in the Adelaide Hills and other districts.
A new series of River Murray Horticultural Crop Surveys commenced in 1970 and continued into the 1980s and 1990s. Crop Survey Officers Mick Harwood and Brad Smith operated initially from the Berri office and did these surveys every 2 years in all South Australian irrigation districts along the River Murray, and Lindsay Point in Victoria. These surveys provided planting information for horticultural industries, processors, water management authorities and government agencies.
Aerial photos from the Department of Lands were used as the basis for the ground survey where each landholder was interviewed. This created a planting plan for each property. These very detailed surveys collected tree number and area data, variety, rootstock and tree age information, and details of the irrigation systems in use. Over time, new technologies were introduced including the computer databases and mapping.
During the 2006 to 2010 drought, specialised aerial surveys were used to identify areas of trees being taken out of production and measure the impact of reduced River Murray water supplies on industries, the regional economy and communities.
Over time, data from these surveys became increasingly important for water and natural resource management. Today, the SA Murray Darling Basin Natural Resources Management Board and the Murray Darling Basin Authority are the main organisations with an interest in gathering irrigator planting data.
Peach variety breeding and introductions
The South Australian Department of Agriculture has played a key role introducing new stone fruit varieties for orchardists. In the early 1900s, Blackwood Experimental Orchard had a key role in assembling collections of varieties and supplying bud wood to commercial nurserymen. In 1928, Blackwood Experimental Orchard held a collection of 114 apricot, 213 cherry, 82 nectarine, 371 peach and 368 plum varieties.
Berri Experimental Orchard also played a key role in developing improved production systems for new varieties. Further information about the role of Blackwood and Berri Experimental Orchards is provided later in this article.
A major peach variety evaluation program has operated at Loxton Research Centre for many years. Between 1962 and 1976, Frank Gathercole managed a major canning peach assessment trial to evaluate maturity, colour, yield, cling vs freestone, and other characteristics for 32 varieties sourced from the USA, South Africa and the NSW peach breeding program. Some variety trials were also planted at Simarloo (30 peach and 15 Japanese plum varieties were evaluated) and other large peach growers at the time.
Red centres were a problem in peaches used for drying. To reduce this problem, Frank Gathercole ran a breeding program crossing Flavortop nectarine with Kirkman peach. The program produced about 80 promising seedlings, but none proved of commercial value. Subsequent further breeding of these by Darren Graetz has seen the development of a handful of peaches devoid of pigmentation that can be dried to completion in full sun. These are currently being trialled by a number of growers.
Variety assessment work declined following the introduction of Plant Variety Rights legislation, and importation of patented varieties from the US and other countries by large nurseries.
Apricot breeding program
Stonefruit Research Officer, Frank Gathercole commenced a dried apricot breeding program in 1979 to improve fruit firmness at maturity and increase sugar levels. The main dried apricot variety, Moorpark, ripened unevenly with green shoulders and a soft tip making it difficult to handle and unsuitable for mechanical harvesting. It also had much lower sugar levels than dried apricots imported from Middle Eastern countries.
In 1983, a study tour of Turkey and Syria investigated varieties and production techniques. Seed from a number of varieties was imported and grown into seedlings under quarantine. These were then crossed with Trevatt. In the late 1980s, the selection Rivergem was identified, licensed to the ANFIC nursery group, and released to growers in 1998.
Following Frank Gathercole’s retirement in 2003, SARDI researcher Darren Graetz took over as breeder and Michael Rettke provided post harvest and consumer testing research. This team continued the development of new drying, fresh market and canning apricot varieties at Loxton Research Centre, assessing for superior yield, fruit firmness, flavour, size, drying ratio and suitability for mechanical harvesting.
In 2005, the new dried apricot varieties Riverbrite, and River Ruby were released. In 2011 after extensive testing in several districts along the River Murray, River Early was released to replace the early Story variety. While all these new varieties are now being planted commercially by dried apricot growers, River Early is having the largest impact.
Active breeding and crossing ceased in 2007, but evaluation of the 40,000 crosses produced continues with Dried, Fresh and Canning Associations. It is anticipated that the breeding program will release several very impressive new drying varieties in the near future. The SARDI apricot breeding program has also produced a potential new canning variety, Bounty (a replacement for Trevatt). Bounty has been licensed to SPC Ardmona and commercial trial plantings have been established in the Shepparton region.
Cherry variety development
Adelaide Hills cherry growers historically selected “sports” within commercial orchards to produce new varieties such as Driver’s Drooper.
In 1972, 17 cherry varieties were imported from overseas, with this material being processed through quarantine facilities at Northfield Laboratories. Virus infected lines were treated with meristem heat therapy, a budwood block was planted at Lenswood Horticultural Centre, and trial plantings were made on 6 properties in the Adelaide Hills. Information about performance of these varieties was supplied to national cherry grower meetings and Department of Agriculture staff in NSW and Victoria.
Dr Andrew Granger initiated the SARDI Australian National Cherry Breeding Program at Lenswood Horticultural Centre in the early 1980s. Initially it was a State funded program, but became a nationally funded program in 1998. This program pioneered the use of isozyme and DNA screening of seedlings to speed evaluation for desired fruit and yield characteristics. Following Dr Granger’s departure from SARDI, Darren Graetz took over management of the breeding program in 2005.
The SARDI cherry breeding program was a traditional breeding program that used sexual hybridisation to produce seedlings. It used imported germplasm from North America and Europe (with a large self fertile composition) and local well adapted Australian selections. The program aimed to breed sweet cherries with attributes of large fruit size, rain crack resistant fruit, self fertility, precociousness, and wide adaptation to Australian growing conditions. Final crosses were performed in 2007 and the results of these were planted as seedling trees in 2009.
The Australian National Cherry Breeding project concluded in June 2014 after nearly 30 years. The program identified approximately 130 promising new large sized, well adapted cherry lines with improved rain cracking resistance. The majority of these were selected in the final 5 years of the program, and evaluation is still needed to determine their commercial potential.
SARDI has grafted and stored all the promising lines and potentially useful breeding material at its secure Nuriootpa Research Centre site.
Cherry Growers of South Australia are evaluating the remaining national breeding program lines against 7 comparators on 3 rootstocks in the Adelaide Hills. The rootstocks being used are the industry standard Mazzard F12/1, the precocious Krymsk 5 (ANFIC) and Giesela 6 (Graham’s FacTree). It is envisaged that this program will provide a further series of new varieties and recommendations about suitable rootstock combinations.
To date, the program has released 6 varieties:
- Sir Don and Sir Tom (1998)
- Dame Roma (2001)
- Dame Nancy, Sir Hans and Sir Douglas (2002)
- A trial release of the new line 1H.RE has also been established.