Portal de Periódicos da CAPES

Deciduous Tree Fruit

2003; American Society for Horticultural Science; Volume: 38; Issue: 5 Linguagem: Inglês

10.21273/hortsci.38.5.901

2327-9834

F. G. Dennis, Jerome Hull,

Plant biochemistry and biosynthesis

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 (Erisoma langerum Hausman), and phytopthora root rot.Four of these-G.11,G.16, G.30, and G.65-have been released for commercial use; others are still under test (Robinson et al., 1997).G.16 is similar in vigor to M.9, G.11 (susceptible to woolly aphid) is similar to M.26, and G.30 forms a weak graft union with some scion cultivars and is best used in trellis systems.G.65 is only moderately resistant to woolly aphid, and is very dwarfing.A replacement for G.30 is expected to be released in 2004 (Robinson et al., 1997).Several size-controlling rootstocks for sweet cherry (Prunus avium L.) are either in use or are currently being evaluated.'Colt , a semidwarfing stock developed in England, is popular in California.The M x M series of rootstocks, thought to be hybrids of mazzard ( P. avium L.) and mahaleb (P.mahaleb L.) were selected from open-pollinated seedlings of P. mahaleb by Lyle A. Brooks of Daybreak Nursery in Oregon.Vigor ranges from semi-dwarfing to vigorous, only one selection (M x M 14) being dwarfing.