Container-grown apple (Malus ×domestica Borkh.) trees were exposed to soil compaction created by changing soil bulk density (SBD) to determine the effect of compaction levels, rootstock, and moisture stress on mineral nutrition, leaf gas exchange, and foliar carbohydrate levels. With SBD of 1.0, 1.2, and 1.4 g·cm-3, there was no interaction of rootstock and soil compaction for growth of `Melrose' trees on nine rootstocks. Trees grown in a SBD of 1.2 g·cm-3 had a greater dry weight than trees at 1.4 g·cm-3 bulk density. Increasing SBD to 1.5 g·cm-3 reduced shoot length, total leaf area, leaf size, and dry weight of leaves, shoots, and roots. The interaction between rootstock and SBD was significant and total dry weight of `B.9', `G.16', `G.30', and `M.7 EMLA' was less influenced by 1.5 g·cm-3 soil than trees on `M.26 EMLA' and `MM.106 EMLA'. Withholding moisture for 10 days at the end of a 70-day experiment caused 8% to 25% reduction in growth in a non-compacted (1.0 g·cm-3) soil with much less effect in a compacted soil. Prior to imposing the moisture stress by withholding water, net photosynthesis (Pn) was reduced 13% and transpiration (E) 19% by increasing bulk density to 1.5 g·cm-3. Following 7 days of moisture stress in non-compacted soil, Pn and E were reduced 49% and 36%, respectively, with no such reductions in the compacted soil. Increasing SBD to 1.5 g·cm-3 caused a decrease in the leaf concentration of quinic acid, myoinositol, and sucrose and an increase in fructose and glucose. Trees growing in 1.5 g·cm-3 had reduced concentrations of N, Ca, Mg, Mn, Na, and Zn, and increased P, K, B, and Fe in leaves.
D.C. Ferree, J.G. Streeter, and Y. Yuncong
D.C. Ferree, J.R. Schupp, D.S. Tustin, and W. Cashmore
Flower and spur characteristics of eight apple cultivars were determined at bloom and following cell division and related to fruit growth over the season. Flower number per spur was higher in `Jonagold', `Fiesta', `Southern Snap', `Royal Gala', than in `Red Chief Delicious', `Pacific Rose' and `Fuji', and the latter three cultivars also had the lowest total flower dry weight per spur. Generally, pedicel length of the king flower was shorter than the lateral, with `Fuji' having the longest king flower pedicel and `Red Chief' and `Pacific Rose' the shortest. At full bloom, `Jonagold' and `Fiesta' had the most leaves/spur, followed by `Fuji', `Southern Snap', `Royal Gala', `Pacific Rose', with `Red Chief' having fewer leaves/spur than all other cultivars. Leaf area/spur was highest in `Jonagold', `Fiesta', `Royal Gala', and `Fuji', followed by `Southern Snap', with `Red Chief' and `Pacific Rose' having lower leaf areas and fruit set than all other cultivars. At the end of cell division, `Fuji' and `Jonagold' had the highest leaf area per spur and `Fuji' and `Royal Gala' the highest bourse leaf area. `Braeburn' and `Red Chief' had lower bourse leaf areas than all other cultivars. `Royal Gala', `Southern Snap', and `Fuji' had the longest bourse shoots and `Red Chief' the shortest.
W. Alan Erb, David C. Ferree, Frank D. Morrison, Mark Pyeatt, and Richard Ryer
This study was conducted at three locations (Manhattan, Kan.; Wichita, Kan.; Wooster, Ohio) for 3 years (1994–1996). At bloom, 2-year-old limb sections from `Smoothee', `Jonagold', `Empire', and `Rome' on M.9EMLA, Bud 9, Mark, Ottawa 3, or M.26EMLA were evaluated for flowering and vegetative, spurs (5 cm or less), short shoots (5–15 cm) and long shoots (>15 cm). In mid-August, spur quality was estimated by randomly selecting five spurs per cultivar rootstock combination. There were significant location and year differences for all the morphological and spur quality characters measured. Across locations and years, the following characteristics were consistently high for the cultivars listed: stem density of flowering spurs for `Empire'; and leaf area, bud-diameter and average leaf size per spur for `Jonagold'. The most consistently high characteristics across locations and years for the rootstocks were for stem density of flowering spurs for Mark and leaf number, leaf area, bud-diameter, and average leaf size per spur for M.26EMLA. Stem density for flowering short shoots was highest for `Smoothee' and M.9EMLA in Wooster, `Jonagold' and Bud 9 in Wichita and `Rome', `Jonagold', and Bud 9 in Manhattan. Flowering long shoot stem density was highest for `Smoothee', `Jonagold', and M.26EMLA in Wooster, `Smoothee' in Wichita, and `Jonagold' and Ottawa 3 in Manhattan. There were some significant cultivar by rootstock interactions. The most-consistent interactions across locations and years were for stem cross-sectional area, stem length, stem density of flowering spurs, and flowering short shoots and bud-diameter per spur.
Joseph C. Scheerens, Todd E. Steiner, Artemio Z. Tulio Jr., Mustafa Ozgen, Diane D. Miller, R. Neil Reese, A. Raymond Miller, and David C. Ferree
Eight unique varietal grape juices were examined for their antioxidant characteristics and commercial potential compared to that of commercial `Niagara' and `Concord'. Grape juices were cold-pressed from mature grapes, clarified, preserved, analyzed for pH, soluble solid and titratable acidity levels, pasteurized at 73 °C for 12 seconds, and sampled for microbial testing. A preliminary panel of 41 routine evaluators assessed all juices for 18 quality characteristics against known and blind controls. Based on these results, `Reliance', `Traminette', and New York 73 juices were presented to a 107-member panel of untrained judges. Panelists rated experimental juices against commercial controls for color, appearance, aroma and flavor intensity, sweetness, tartness, overall quality, and preference. Among juices tested, `Reliance' and NY 73 offer the greatest potential as specialty grape juices. `Traminette', `Chardonel', `Chambourcin', and NY 62 may also have potential as grape juice cultivars, if processed to improve their color and clarity. Small juice lots were hand-pressed from mature grapes and examined for total anthocyanin and phenolic content, antioxidant characteristics (DPPH and FRAP) and levels of individual phenolic compounds via GC-MS. Total anthocyanin and phenolic contents of experimental juices varied from 0–1460 μg·gfw-1 and 1001–2850 μg·gfw-1, respectively, and were highest in NY 73. Estimates of antioxidant activity differed slightly among tests, but activity appeared highest in `Chambourcin' and NY 73 and lowest in `Reliance'. Levels of individual compounds varied substantially among juices.