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Paula M. Pijut and Melanie J. Moore

Juglans cinerea L. (butternut) is a hardwood species valued for its wood and edible nuts. Information on the vegetative propagation of this species is currently unavailable. Our objective was to determine the conditions necessary for successful stem-cutting propagation of butternut. In 1999 and 2000, 10 trees (each year) were randomly selected from a 5- and 6-year-old butternut plantation located in Rosemount, Minn. Hardwood stem cuttings were collected in March, April, and May. Softwood cuttings were collected in June and July. K-IBA at 0, 29, or 62 mm in water and IBA at 0, 34, or 74 mm in 70% ethanol were tested for root induction on cuttings. The basal end of cuttings were dipped in a treatment solution for 10 to 15 seconds, potted in a peat: perlite mixture, and placed in a mist bed for 5 to 8 weeks. Rooted cuttings were gradually hardened off from the mist bed, allowed to initiate new growth, over-wintered in a controlled cold-storage environment, and then outplanted to the field. For hardwood cuttings, rooting was greatest for those taken in mid-May (branches flushed out), 22% with 62 mm K-IBA and 28% with 74 mm IBA. Softwood cuttings rooted best when taken in June (current season's first flush of new growth or softwood growth 40 cm or greater) and treated with 62 mm K-IBA (77%) or 74 mm IBA (88%). For 1999, 31 out of 51 rooted softwood cuttings (60.8%) survived overwintering in cold storage and acclimatization to the field. For 2000, 173 out of 186 rooted softwood cuttings (93%) survived overwintering and acclimatization to the field. Chemical names used: indole-3-butyric acid-potassium salt (K-IBA); indole-3-butyric acid (IBA).

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T. Caruso, P. Inglese, F. Sottile, and F.P. Marra

Vegetative growth, fruit yields, and dry matter partitioning within above-ground components were assessed during three growing seasons for trees of an early ripening peach (Prunus persica L. Batsch `Flordaprince' on GF 677 rootstock) trained either to a free standing central leader (930 trees/ha) or to Y shape (1850 trees/ha). Individual trees trained to central leader gave higher fruit yield, had a significantly greater leaf area and accumulated more dry mass in above-ground components per tree than Y shape trees. The training systems did not differ in terms of yield efficiency (yield per trunk cross-sectional area) and leaf area index (LAI), but Y shape trees had a higher harvest index and fruit dry mass per ground area than central leader. Four years after planting, Y shape had 35% higher yield per hectare than central leader. The relative contribution of 1-year-old wood, shoot and leaf to the dry mass of the tree decreased with tree age. Four years after planting the dry matter partitioned to the >1-year-old wood components represented 60% of the total tree mass (excluding fruit) in both the training systems. Central leader trees had the highest relative vegetative growth rate during stage III of fruit development. Most starch depletion occurred from dormancy to pit hardening from the canopy main storage pools (>1-year-old wood), and was higher for central leader than Y shape trees. For the ease of management and the high crop efficiency, the Y shape can be successfully used for peach high density planting systems.

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Paula M. Pijut and Melanie J. Barker

Butternut trees are becoming endangered as a result of butternut canker disease; thus, it is desirable to propagate disease-resistant trees for screening and provenance tests. The objective of this study was to determine the conditions necessary for successful cutting propagation. In 1998, 10 trees were selected from a 4-year-old butternut plantation located in Rosemount, Minn. Hardwood cuttings were collected 30 Mar., 21 Apr., and 6 May. The auxins, indole-3-butyric acid-potassium salt (KIBA) in water at 0, 29, or 74 mmol·L-1 were tested for root induction. The basal end of cuttings were dipped in treatment solutions for 10 to 15 s and placed in a 1 peat: 1 perlite mixture in Deepots™ (D40) in a mist bed. Mist was applied for 5 s every 15 min. Greenhouse conditions were: 12-h photoperiod provided by high-pressure sodium lamps (60 μmol·m-2·s-1), 22 °C, and bottom heat of 27 °C (heating pads). Softwood cuttings were collected 20 May, 18 June, 30 June, and 23 July. Rooting treatment solutions and greenhouse conditions were the same as for the hardwood cuttings, except no heating pads were used. Rooted cuttings were planted in Treepots™ (10 × 10 × 36 cm) and gradually hardened off from the mist bed. Hardwood cuttings from the first two collection dates did not initiate roots. Best rooting (12.5%) was achieved on hardwood cuttings collected 6 May using 29 mmol·L-1 KIBA. Softwood cuttings rooted to some degree at all concentrations of rooting solution and at every collection date. The greatest rooting (70%) was achieved using 74 mmol·L-1 IBA. In general, best rooting percentages were achieved with softwood cuttings collected 18 June and 23 July and treated with 62 mmol·L-1 KIBA or 74 mmol·L-1 IBA. Both rooted hardwood and softwood cuttings were successfully acclimatized from the mist bed and many have initiated new growth.

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Stephen S. Miller, James R. Schupp, Tara A. Baugher, and Scott D. Wolford

Peach (Prunus persica L. Batsch) thinning is a costly and time-consuming but necessary practice to produce a crop of marketable size fruit. A number of mechanical devices and methods have been developed and evaluated to reduce the cost and time required for hand thinning peach. This report provides additional evidence that a Darwin string thinner can effectively thin peach at bloom and a spiked drum shaker can thin at bloom or at the green fruit (pit hardening) stage. Five trials were conducted over 2 years in grower orchards with trees trained to a perpendicular V system. A Darwin string thinner at 60% to 80% full bloom (FB) reduced crop load (fruit/cm2 limb cross-sectional area) on scaffold limbs by 21% to 50% compared with a hand-thinned control. At the 60% FB stage, a USDA-designed double-spiked drum shaker reduced crop load by 27% and in another trial, a USDA prototype single-drum shaker reduced crop load by 9%. Across all trials, the spiked drum shakers (single or double units) removed an average of 37% of the green fruit. All mechanical devices reduced the time required for follow-up hand thinning. Follow-up hand-thinning costs (US$/ha) were reduced an average of 27% by mechanical thinning devices over hand-thinned control trees. Fruit size was increased over hand-thinned controls by mechanical thinning in most, but not all, trials. A combined treatment of the Darwin string thinner at bloom followed by a drum shaker (single or double unit) at the green fruit stage produced the greatest net economic impact in a number of the trials. Despite overthinning in some trials, the mechanical thinning devices described provide a potential alternative to hand thinning alone in peach production.

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John C. Beaulieu, Karen L. Bett, Elaine T. Champagne, Daphne A. Ingram, James A. Miller, and Ralph Scorza

Many consumers do not buy peaches due to the fuzzy skin and seed stone and because out-of-season peaches do not possess optimum tree-ripe flavor. The feasibility of using a non-browning freestone peach to deliver high-quality fresh-cut products was investigated. Changes in fresh-cut flavor, texture, and postharvest attributes of commercial-ripe (CR) vs. tree-ripe (TR) harvested and shipped `Bounty' peach was assessed. Fresh-cut CR wedges had an initial firmness of 20.9 N, whereas TR wedges had 11.2 N. On day 2, firmness decreased roughly 3% to 12% and 35% to 45% for CR and TR wedges held at 1 °C, respectively. By day 5, CR wedges hardened (24.5 N) whereas TR did not return to their initial firmness; increasing marginally through day 7. Sensory panel hardness for CR did not change through storage, but with TR wedges, hardness decreased through day 2 then increased until day 7. Little variation was noted in the initial soluble solids for CR vs. TR wedges (11.7, vs. 11.4 °Brix, respectively). After 7 days storage, °Brix decreased 7.5% to 12% in CR and 4.5% to 12% in TR wedges. Yellow flesh color (b*) decreased in all CR and TR treatments through storage. Flavor compounds in expressed juice were analyzed by solid phase microextraction with GC-MS. Several peaks were identified that may be associated with flavor-related changes that occurred during storage. For example, low molecular weight acetates and 6C compounds almost disappeared during storage, whereas short chain fatty acids, lactones, and palmitic acid increased markedly through storage. In TR, the “fruity” descriptor decreased throughout storage and “sweet aromatic” increased slightly (day 2) then decreased through day 7.

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W.C. Fonteno and T.E. Bilderback

assistance of Beth Harden, Jerome Brewster, and Mary Lorscheider is gratefully acknowledged. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked

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Enio Tiago de Oliveira, Otto Jesu Crocomo, Tatiana Bistaco Farinha, and Luiz Antônio Gallo

, this article describes a complete micropropagation system involving disinfection, in vitro multiplication, rooting, and hardening followed by ex vitro acclimatization procedures used to attain that objective, thus producing thousands of Aloe vera

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James W. Olmstead, Amy F. Iezzoni, and Matthew D. Whiting

growth following anthesis; stage II, by a lag period of fruit growth coinciding with endocarp hardening and embryo development; and stage III, by a second period of exponential fruit growth ending with either harvest or physiological maturity. During

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. 424) report that apricots treated with benzyladenine (BA) at 100 ppm at the beginning of pit hardening stage were larger and firmer than untreated fruit. The study showed a practical benefit of a single application of BA at the end of pit hardening

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Bing Liu, Hong Zhou, Sha Cao, Yi-ping Xia, and Rajeev Arora

breeding azalea cultivars that may be resilient to vagaries of climate. Literature Cited Arora, R. Rowland, L.J. Ogden, E.L. Dhanaraj, A.J. Marian, C.O. Ehlenfeldt, M.K. Vinyard, B. 2004 De-hardening kinetics, bud development, and dehydrin metabolism in