Deciduous Tree Fruit

Abstract

On the occasion of the 75th anniversary of ASHS, Thompson, Faust, Martin, and Dewey (1979) individually reviewed the history of progress in temperate zone fruit physiology for the previous 75 years. The advances made during the last 25 years parallel advances in a wide range of sciences, including plant physiology, entomology, plant pathology, agricultural engineering, and computer science. New methods in instrumentation and biotechnology have changed the conduct of basic research in this area with implications that are only now being felt. Perhaps the greatest change has resulted from a greater awareness of the environmental impacts of technology, leading to a reevaluation of many of the old practices. New concepts, such as integrated pest management, organic horticulture, and environmental protection, have raised new issues that have yet to be resolved. The computers has revolutionized the collection and processing of data. The development of tissue culture for propagation of plants opened the door to its use for gene transfer, another revolutionary procedure that is currently in full flower with no end in sight. In this review we will discuss advances in tree fruit production, handling, storage, and marketing under three headings: changes in the plant, cultural practices, and postharvest procedures. Emphasis will be on applied rather than basic research. THE PLANT ROOTSTOCKS.In the 1970s size-controlling rootstocks-primarily semi-dwarfing stocks such as M.7, M.106 and M.111-were in wide use for apple (Malus ×domestica Borkh.), but not for other fruit trees; seedlings were the main source of rootstocks for stone fruit and pear. Some growers were using full-dwarfing stocks, primarily M.9, which requires support. Research was underway testing the characteristics of other apple rootstocks, including M.27, which is even more dwarfing than M.9, as well as introductions from Canada (Ottawa series), Sweden (Alnarp), Poland, the U.S.S.R. (Budagovsky series), and France (Pajam, a more vigorous selection of M.9). A long-term cooperative project (NC-140), partially funded by the USDA, has now provided well-documented information (e.g., Autio et al., 2001) on the effects of these rootstocks on growth and yield of the scion cultivars at many locations in the United States and Canada. As might be expected, interactions among rootstock, cultivar and location are common. Cummins and Aldwinckle (1983) of the Geneva Experiment Station in New York State, motivated by the belief that the best rootstocks for North American growers would be those developed in North America, initiated a program in 1968, beginning with open-pollinated seedlings of the dwarfing rootstock M.8. They subsequently crossed other rootstock clones with hardy cultivars and screened the seedlings for dwarfing effect, ease of propagation, resistance to insects and diseases, and many other characteristics. They have released four clonal rootstocks, three of which are resistant to fireblight [caused by the bacterium Erwinia amylovora (Burr)], woolly aphid (Eriso...

Blossom Thinners Reduce Crop Load and Increase Fruit Size and Quality of Peaches

“…This is consistent with the observations made by Byers and associates (2003) who reported that hand spray gun applications of 1170 L/ha almost defruited trees, whereas air-blast sprayer applications at the same water volume resulted in the desired crop load. According to some (Dennis and Hull, 2003;Lilleland, 1965) some species such as Prunus, in which leaf development occurs after flower opening, are less affected by foliar damage incited by caustic blossom thinners in comparison with species such as apple, in which leaf development occurs after flowering. A compounding reason for explaining greater leaf phytotoxicity to ÔHarrow DiamondÕ peach trees in our experiment is that in 2003, bloom occurred about 30 days later than average for the region.…”

Potential Abscission Agents for Raisin, Table, and Wine Grapes

“…Specific for mature citrus fruit loosening within a wide concentration range (Burns, 2002) 20, 200, 1000, and 2000 ppm Coronatine A natural compound produced by fermentation with Pseudomonas syringae pv glycinea; is classified as a methyl jasmonate biological mimic; loosens mature citrus fruit (Burns et al, 2003); causes transient chlorosis; expect %10% defoliation; does not cause young fruit abscission 200 ppm Dikegulac A pinching agent; in citrus, is thought to disrupt auxin-ethylene balance and accelerate abscission (Pozo et al, 2004); expect 15% to 20% leaf loss at certain times of the season 20, 200, 1000, and 2000 ppm Maxcel Benzyladenine, used as an apple-thinning agent (Dennis and Hull, 2003) 20, 200, and 600 ppm Methyl jasmonate A natural compound found in plants; thought of as an ''octadecanoid signal'' derived from lipid signaling; can advance many senescence-related processes such as color change; loosens mature citrus fruit but causes %20% defoliation when applied to citrus (Hartmond et al, 2000) 0.2, 2, 10, and 20 mM; %45, 445, 2240, and 4485 ppm VBC-30050 Proprietary compound 20, 200, and 500 ppm four representative clusters were collected from each of four vines and 10 rachis sections were prepared from each cluster. Fruit detachment force was measured from berries attached to each section as described previously.…”

Toward the valorization of olive (Olea europaea var. europaea L.) biodiversity: horticultural performance of seven Sicilian cultivars in a hedgerow planting system

“…Mechanization and intensification of agricultural systems strongly increased in the last 30 years to meet the higher request for food associated with population increase. In various crops, such as apple, the intensification of planting densities has been obtained adopting dwarfing or weak rootstocks (Brooks and Olmo, 1997;Dennis and Hull, 2003), but in olive the selection of rootstocks able to reduce the size of the scion has still not been achieved (Barranco, 2010;del Río et al, 2005;Barranco, 2010).…”