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Alan P. George*
* Principal Horticulturist, Queensland Horticulture Institute, Maroochy Research Center, Nambour, Queensland, Australia.1. INTRODUCTION
Apples and peaches were first introduced into Australia by both European and Chinese settlers at the end of the 1890s. Fruit quality and productivity of temperate fruits grown have been gradually improved through introduction and selection of better quality varieties, mainly from the USA. Over a period of time, the most suitable regions to grow these fruits have been selected. About 90% of Australias production is consumed domestically. Australia was a major exporter of apple to the UK in the 1970s. However, with the UK entering the European community our exports to this market collapsed. Since then, a major restructuring of most temperate fruit industries has occurred and now Australia has repositioned its exports to Japan and South-east Asia.
2. PRESENT SITUATION OF DECIDUOUS FRUIT CROP CULTIVATION
Australia grows a wide range of deciduous fruits including apple, pear, grape, nashi, peach, nectarine, plum, apricot, cherry and to a lesser extent persimmon, kiwifruit and blueberries. About 70% of the current production occurs in temperate regions. However, temperate fruit production in subtropical regions of Australia has increased rapidly during the past 10 years due to the ready availability of high-quality stonefruit germplasm from the University of Florida breeding programs (Sherman, et al., 1978; Sherman et al., 1984; Sherman, 1987) and the introduction of high quality non-astringent persimmon cultivars from Japan. Suitable agro-climatological conditions exist within many regions of Australia to grow these temperate fruits, and new industries are being developed in regions where none previously existed. Production statistics for different temperate fruits are presented in Table 1. Major production areas, varieties and rootstocks used are presented in Tables 2 and 3.
Table 1. Production Statistics for Temperate Fruits in Australia
Table 2. Major Deciduous Fruit Production Regions and Cultivars Grown
Table 3. Rootstocks Used for Different Deciduous Fruits Species in Australia
Major Harvest Periods
3. PRODUCTION OF PLANTING MATERIAL
The production of grafted or budded planting material is undertaken by a number of large private nurseries. Only selected cultivars of known performance are propagated commercially and all have been through a process of virus testing before release. The main methods of grafting are the approach grafting and cleft grafting. Propagated trees are normally containerised. A small number of high density orchards of stonefruit are using trees propagated from either softwood or hardwood cuttings. Seedlings are not used due to their genetic variability. Grafted trees are no longer produced by Government State Departments. A number of private organisations are now buying the rights for overseas varieties and collect royalties on the sale of trees (usually between $1-2 per tree). Breeding of new varieties is being conducted by State Government Research Centers and Universities. New varieties released by these agencies are normally patented.
4. ESTABLISHMENT OF ORCHARDS
Planning the orchard is a complex procedure. A brief overview of land preparation procedures is presented. A map of the intended orchard site with existing features (roadways, standing timber, gullies, slope direction etc) is made. Slopes of up to 15% are preferred as these are less susceptible to soil erosion, allow flexibility with row layout, and enable tractors and machinery to be operated safely across the slope. Slopes greater than 15% are avoided, but if used, require specialised design advice for terracing. Windbreaks and drains are normally installed before planting. Rows are run in a North-South direction where possible, and are normally deep-ripped prior to planting to improve drainage. Where possible, green manure crops are grown before planting. The main species used are hybrid forage sorghum for spring or summer plantings, and oats in autumn or winter.
In general, container grown trees can be planted at any time of the year, provided frost is not a problem, and adequate water is available and tree guards are used.
Tree training system, row and tree spacing also need to be determined before planting. A soil analysis is done prior to planting to determine nutrient problems. Suggested row and tree spacing for temperate fruits are contained in Table 4.
Table 4. Spacing Options for Most Temperate Fruits
Thorough pre-plant preparation is necessary to obtain good tree establishment and so that trees rapidly fill their allotted space. If soil amendments such as lime or dolomite or phosphorus are required, these are applied before planting because lime takes several years to move through the profile from surface applications. The surface soil is dug where the tree is to be planted with holes of about 1 m in diameter. About 300 g of lime if soil pH is low (<4.5), 300 g of superphosphate or rock phosphate, and 1 bucket of poultry manure (dried for 3 months) are incorporated into the top 20 cm of soil. Trees should be mulched after planting. No fertiliser will generally be necessary for the first few months or until trees start to put on new growth. Small amounts (about 80 kg of a 13:6:12 N:P:K mixed fertiliser per hectare) are applied every six to eight weeks during the first year. This may be stopped during the winter months.
5. CARE AND MAINTENANCE OF ORCHARDS
In Australia, due to increasing labour costs for thinning, pruning and harvesting, alternative methods of management and training of excessively vigorous temperate fruits are being developed. Currently orchardists have a choice of using a wide range of management systems. However, only 3 systems are currently used commercially; standard vase, palmette, and Tatura. Of these systems the palmette is the most widely used because of its ease of management and low labour costs compared with other systems. With stonefruit, excessive tree growth is controlled with several very low dosages of paclobutrazol applied 12-18 months after planting (George et al., 1993; George et al., 1996, unpublished data). The aim in the early stages of tree development is to prevent excessive shading and loss of fruiting wood.
Application of Manures and Fertilisers
Nitrogen appears to be the key element affecting fruit size of temperate fruits. Excessive N application increases vegetative growth and shading and results in a reduction in fruit size and quality. However, when paclobutrazol and N are applied together, fruit size may be increased by as much as 39% (George and Nissen, 1992). The improvement in fruit size may be attributed to 3 factors; increased photosynthetic capacity of leaves higher in nitrogen, delayed leaf abscission, and control of excessive vegetative growth (George et al., 1992). Potassium is the other major element affecting fruit quality. Potash may increase fruit size by as much as 8% (George et al., 1988a). In high rainfall regions, deficiencies of minor nutrients like B, Cu and Zn are common. These can be corrected through either foliar applications during the flowering and early fruit set period or through soil application. Late summer applications of minor elements may also be important to ensure availability within the tree for the next seasons flowering and early fruit development. The most commonly used fertilisers are straight inorganics. Very few organic fertilisers are used except for young trees at planting. Fertiliser rates are normally based on crop removal rates and an allowance is made for leaching and fixation losses.
Most temperate fruits are normally winter dormant pruned. Time of dormant pruning varies with cultivar. With low-chill cultivars, earlier pruning often gives earlier flowering; however, the reverse is true for high-chill cultivars. Summer pruning of stonefruit several times during the fruit development period has also been shown to increase fruit size by about 20%.
Newly planted trees find it difficult to compete with weeds for water and nutrients. Therefore, weed control in the immediate vicinity of the young trees is vital. This is achieved by mulching and spot spraying under and around the trees. Where weeds grow through the mulch they are either hand-weeded or spot-sprayed with herbicides. With young trees the most commonly used herbicide is paraquat. With older trees glyphosate is commonly used during the summer months in combination with paraquat.
The most commonly used mulches are coarse hay or straw such as sorghum stubble. The grassed inter-row area is also a valuable source of on-site mulch. Mulches are normally applied in spring. The mulched/sprayed area extends to just beyond the dripline of the trees, making it roughly two metres wide. Besides reducing weeds, mulching increases soil organic matter, improves soil structure and reduces root temperature fluctuations. It also increases water retention and may reduce irrigation requirements.
In Australia, all temperate fruits are irrigated. The preferred system is mini-sprinklers. Irrigation is scheduled according to either soil moisture content or tension as measured by tensiometers or gypsum blocks, respectively. More sophisticated methods of monitoring e.g. Environscan are being used in larger orchards. With high-chill stonefruit regulated deficit irrigation is used to control growth (up to 75%) without loss of yield or fruit size (Chalmers et al., 1981, 1984, 1985).
Control of Pests and Diseases
The most serious pests for the major temperate fruit species are: Queensland and Mediterranean fruit fly, fruit spotting bug, white peach scale, and oriental fruit moth, for stonefruits; codling moth, light brown apple moth, San Jose scale, two spotted mite, mealybug, Monolepta and dried fruit beetles for pomefruits; and bunch mite for grape. The most serious diseases for the major temperate fruit species are: shot-hole, rust, bacterial spot, leaf curl, brown rot, and transit rot for stonefruits; apple scab and Phytophthora for pomefruits; downy mildew, powdery mildew, anthracnose, and botrytis rot for grape. IPM programs are being implemented for most pests, the most being used to control scales, mealybugs and mites. Regular spraying for diseases during the active growth season of spring, summer and autumn is essential. A wide range of fungicides are used.
Intercropping is not practised in commercial temperate fruit orchards in Australia.
7. HARVESTING OF FRUITS AND YIELDS
The highest yields for temperate fruits have been recorded for apples on Tatura trellis (high-chill cultivars 40 - 60 MT/ha - Chalmers and van den Ende, 1975a, Van den Ende and Chalmers, 1982; McDermott et al., 1987, George et al., 1992a). High-chill stonefruits tend to be less productive with maximum yield of 40-50 MT per hectare. Due to their short development period, low-chill cultivars when planted at standard densities often yield only one third of the maximum yields recorded for later maturing, higher-chill cultivars planted at similar densities (low-chill cultivars 15 - 25 MT/ha). The maximum yields recorded for a range of temperate fruits in Australia are shown in Table 5. Yield benchmarking is a useful tool to evaluate if management inputs are achieving their target potential.
Table 5. Maximum Yield Potential Recorded from Temperate Fruits Grown under Different Production Systems
In terms of consumer acceptance of temperate fruits, fruit size, shape and colour are the most important fruit quality characteristics readily identified with and often these characteristics are culturally conditioned. With stonefruit, there is a preference for yellow-fleshed, very large size fruit. Small fruit size is the major quality defect of stonefruit in Australia. Fruit size is adversely affected by the short fruit development period (70-110 days), heavy crop loads (George et al., 1988a), excessive vegetative growth (Allan et al., 1993), low temperatures during the fruit development (Topp and Sherman, 1989b), and stress during the early post-budbreak period at the time of cell division (Hieke and George, 1995, unpublished data). Crop load can be adjusted by thinning, and excessive vegetative growth controlled by the use of growth retardants, pruning and cincturing.
Another major problem with temperate fruit early-maturing cultivars grown under higher rainfall in subtropical regions is their poor sugar content and flavor. Generally, late cultivars do not exhibit this problem. Fruit with better flavor and sugar levels are produced in drier regions and on sandy loam soil types. George et al. (1988a) have shown that heavy rainfall prior to harvest can cause fruit sugar levels to drop as much as 1.5° Brix. Besides environmental factors, many cultural practises have been shown to affect fruit sugar levels including crop load (George et al., 1988), cincturing (Allan et al., 1992; George et al., 1991), spring and summer pruning (George et al., 1988) and enclosing trees under cloches during the fruit development period. With stonefruit, non-melting fleshy cultivars may also be able to be left longer on the tree to develop higher sugar levels, without a corresponding softening of the flesh.
Most temperate fruit producers pack and market their own fruit, either directly to retail chains, or through the wholesale domestic market system. The main markets that temperate fruits are sent to include Brisbane, Sydney, Melbourne and Adelaide. Smaller quantities are sent to Tasmania, Western Australia, Northern Territory and Newcastle. Approximately 90% of all temperate fruit grown is marketed on the domestic market. Increasingly, temperate fruit is being purchased through retail chains with their market share increasing from 34% in 1990 to 47% in 1994.
Stone fruit imports to Australia in 1995/96 consisted of 1,193 tons of apricots (US$3.2m), 593 tons of peaches (US$1.5m) and 5 tons of plums (US$22,480). Imports were mostly from New Zealand. The USA is currently seeking access to the Australian market, and some interest has also been shown by Chile. These are not a major threat to Australian stonefruit growers as they are grown in the Northern Hemisphere and are out-of-season with Australian stonefruit. Australian stonefruit would generally be of higher quality and fresher which is important to the consumer.
Less than 10% of Australian temperate fruit is exported, with the major markets being Singapore and Hong Kong. However, this proportion is likely to increase to 20-25% (conservative estimate) over the next 5 years. In 1994, Australia exported 39,000 tons of apple mainly to South East Asia and Japan. Australian stone fruit exports are primarily of plums, with a major component being from Western Australia. Total Australian exports in 1995/96 were 6,331 tons, comprising 4,977 tons of plum, 592 tons of peach, 524 tons of nectarine, and 238 tons of apricot. Exports to Taiwan were given a boost in 1996/97 through a 1,000 tons quota for peach and plum to Taiwan. While plums account for 70% of all stonefruit exported to Asia the national association has reported that there is also a definite market niche for peaches and nectarines from mid-September to December. This is a time when there are no peaches and nectarines available from the USA who is the traditional supplier of the Asian markets.
Currently Australias export of stone fruit is limited; however, with rising production there is increased industry interest in exports. Exporters are either larger producers, or networks of producers, or buyers operating from the domestic wholesale markets. Export marketing of stonefruit needs to be better organised and planned in the future to make a serious impact on the target markets as the USA has developed. The Australian Fresh Stone Fruit Growers Association (AFSGA) is represented on the Horticultural Market Access Committee, and is closely monitoring opportunities for export to new markets particularly Korea, China and Japan.
Asian economies are generally becoming more affluent and western in their tastes. This means that the more traditional, well-known fruits, such as stonefruits, are increasing in popularity. The Singapore age group between 25 and 35 are developing more western tastes due to the fact that many are being educated in Australia and the USA. This western education has also changed the way they shop, with a preference for supermarkets compared with the traditional wet markets. This has triggered an increase in western supermarket chains moving into Singapore and the development of central warehousing facilities. This, allows for better handling of perishable products such as stonefruit and hence better quality products sold to the consumers.
Australia is the worlds second largest producer of golden style dried sultana, producing about 70,000 tons. Apart from dried grape products, few other temperate fruits are dried. High quality dried fruit products are becoming very popular in Asian markets, particularly in the new supermarket chains which have entire display areas for dried fruit only. Consequently, some R&D effort should be put into developing dried fruit products for export.
10. POTENTIAL FOR DECIDUOUS FRUIT DEVELOPMENT
The main strengths and weaknesses in deciduous fruit production are presented in Table 6.
Table 6. Main Strengths and Weaknesses of Temperate Fruit Production in Australia
11. CONSTRAINTS IN DECIDUOUS FRUIT PRODUCTION AND DEVELOPMENT
Both the Australian apple and stonefruit industry are well organised under the Australian Apple and Pear Association and Australian Fresh Stonefruit Growers Association (AFSFGA). These associations have implemented statutory R&D and Marketing levies. These are currently under review and are being pushed to be increased in 1998. The actual growers within the industry vary between highly entrepreneurial businesses to small family farms. Generally, it can be said that the growers are quite cohesive in their approach to further developing and improving their overall industry. The major constraints to further development are to improve the export marketing skills of growers/grower groups and to integrate current knowledge into marketing and production decision support systems.
12. GOVERNMENT POLICIES AND PLANS FOR RESEARCH AND DEVELOPMENT OF DECIDUOUS FRUITS
Research and Development
The associations impose compulsory levies on the sale of their products. About 60% of the levy is used for market development activities coordinated by the Australian Horticultural Corporation (AHC), and about 40% is used for Research & Development activities, coordinated by the Horticultural Research & Development Corporation (HRDC). Both the AHC and HRDC are Australian Government funded agencies. The Australian Center for International Research (ACIAR) which funds international R&D projects between Australia and developing countries has provided financial support for a major project on developing temperate fruits in Thailand. The benefits of this project should flow on to other Asian countries with similar climatic conditions. It could be used as a model for similar development in other countries as it integrates all components of production and marketing and emphasises training of researchers and growers. A list of some of the major research programs being funded by the Australian Government is presented in Table 7.
Table 7. Some Major Temperate Fruit Projects Funded by Australian Government and Grower Levies
Temperate fruit grower associations are now working on the following strategic priority areas:
Plans for Production Development and New Opportunities for R &D and Export
Education and Training Opportunities
Further training and development is required in the following key areas:
13. CONCLUDING REMARKS
A considerable amount of information exists on all aspects of production and marketing of temperate fruits. However, due to the complexity of the whole system and poor communication lines there is often little interaction between the grower, the market place and the needs of the consumer. Substantial gains in orchard profitability could be made through using a systems approach to management and marketing of horticultural products and the use of electronic data transfer systems.
Allan, P., George, A. P. and Nissen, R.J., 1992. Effects of different methods of thinning on Flordaprince peach. J. South. Afr. Soc. Hort. Sci., 2: 24-27.
Allan, P., George, A. P., Nissen, R.J., Rasmussen, T.S. and Morley-Bunker, M. J., 1993a. Effects of paclobutrazol on phenological cycling of low-chill Flordaprince peach in subtropical Australia. Scientia. Hortic., 53: 73-84.
Chalmers, D.J. and Van den Ende, B., 1975a. Productivity of peach trees: factors affecting dry - weight distribution during tree growth. Ann. of Bot., 39: 423-433.
Chalmers, D.J. Mitchell, P.D. and van Heek, L., 1981. Control of peach tree growth and productivity by regulated water supply, tree density and summer pruning. J. Amer. Soc. Hort. Sci., 106: 307-12.
Chalmers, D.J., Mitchell, P.D. and Jerie, P.H. (1984). The physiology of growth of peach and pear trees using reduced irrigation. Acta Hort., 146: 143-149.
Chalmers, D.J., Mitchell, P.D. and Jerie, P.H. 1985 The relation between irrigation, growth and productivity of peach trees. Acta Hort.,. 173:28328-8.
George, A.P. and Nissen, R.J. 1987. Growth control of low chill stonefruit using growth retardants and other management techniques. In: Proc. First National Low Chill Stonefruit Conf., N.S.W. Australia. (Ed. Ian Skinner) pp.132-133.
George, A.P., Nissen, R.J., Lloyd, J. and Richens, K., 1988a. Factors affecting fruit quality of low chill stonefruit in subtropical Australia. Acta Hort., 279: 559-571.
George, A.P., Nissen, R J. and Baker, J., 1988b. Effects of hydrogen cyanamide in manipulating budburst and fruit maturity of table grapes in south-eastern Queensland. Aust. J. Expt. Agric. 28: 533-538.
George, A.P. and Nissen, R.J., 1992. Effects of water stress, nitrogen and palobutrazol in flowering, yield and fruit quality of the low-chill peach cultivar Flordaprince Scientia Hortic. 49: 197-209.
George, A.P., Campbell, J.A. and Nissen, R.J., 1992a. Orchard management - An Overview. In: Proc. 2nd National Low-chill Stonefruit Conf., (Ed. J. Slack) Ballina Beach Resort, Ballina, NSW Agriculture, pp. 90-99.
George, A.P., Nissen, R.J. Campbell, J.A., 1992b. Control of flowering and fruit maturity in low-chill stonefruti using different management techniques. In: Proc. 2nd National Low-chill Stonefruit Conf., (Ed. J. Slack) Ballina Beach Resort, Ballina, NSW Agriculture, pp. 83-90.
George, A.P., Nissen, R.J. and Rasmussen, T., 1993. Effects of post-harvest topping, autumn cincturing and paclobutrazol on growth, yield and fruit quality of the low-chill nectarine cv. Sundowner in subtropical Australia. Aust. J. Expt. Agric., 33: 353-362.
George, A.P., Nissen, R.J., and Campbell, J.A., 1996a. Nutritional studies in low-chill stonefruit. Acta Hort., 409:99-109.
George, A.P., Nissen, R.J., Campbell, J.A., Rassmussen, T. and Allan, P., 1996b. Effects of paclobutrazol on growth and yield of low chill stonefruit in subtropical Australia. Acta Hort., 409: 109-111.
Leece, D.R. and Gilmour, A.R., 1974. Seasonal changes in leaf composition of peach. Aust. J. Expt. Agric. Anim. Husb., 14: 822-827.
Sherman, W.B., Knight, R.J. and Crocker, T.E., 1978. Peach and nectarine breeding and testing in warm parts of the world Proc. Tropical Reg. Amer. Soc. Hort. Sci. 22: 103-107.
Sherman, W.B., 1987. The low-chill peach improvement program: why, how, where,. In Proceedings of the First National Low-chill Stonefruit Conference. (Ed. J. Slack), Exotic Fruit Growers Association, Lismore, N.S.W. pp.16-18.
Topp, B.L. and Sherman, W.B., 1989. Location influences on fruit traits of low-chill peaches in Australia. Proc. Florida State Hort. Soc., 102: 195-199.
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