Eighteen dwarfing rootstocks, including six M.9 clones and two Vineland selections, were compared at 25 North American locations for 10 years. For most response variables, there was a highly significant location x rootstock interaction, so rootstock performance differed greatly from one location to another. The M.9 clones tested in this study had similar tree survival and yield efficiency (YE), but there were large differences in tree vigor. M.9 Pajam 2 and M.9 RN29 were nearly as vigorous as M.26, whereas M.9 Flueren 56 was least vigorous. Rootstocks could be grouped into five size categories. The most dwarfing rootstocks included P.22, M.27, P.16 and B.491, and these likely lack adequate vigor for commercial production. The second most dwarfing group of rootstocks were B.469 and Mark which produce trees of similar size. A group of slightly more vigorous rootstocks included V.3, B.9 and M.9 Flueren 56. Rootstocks similar in vigor to M.9 NAKBT337 included P.2, M.9 EMLA, M.9 Pajam 1, and O.3. The most vigorous group of rootstocks in the M.26 size class included M.9 RN29, M.9 Pajam 2, and V.1. Cumulative yield tended to be positively related to tree size, but had relatively low yields for its size. YE was significantly affected by rootstock at 14 locations. Trees on Mark had high YEs at most locations, whereas trees on B.491 had low YEs at many locations.

In 1994, trees of 'Gala' apple (Malus x domestica Borkh.) on 4 semi-dwarf rootstocks were planted at 20 locations in North America according to the guidelines established for cooperative testing by the North Central Regional Cooperative Project (NC-140). The four rootstocks were P.1, V.2, G.30, and M.26 EMLA. Four of the locations did not receive trees on P. I rootstock. Tree losses were greatest for G.30. Trunk cross-sectional area (TCSA) was generally largest for P.1 and smallest for G.30. TCSA was most variable for M.26: at some sites, trees on G.30 had larger trunks than trees on M.26. Tree height was usually greatest for P. I and tree spread was usually smallest for M.26 EMLA. Although results were not consistent for all sites, yield and yield efficiency tended to be highest for G.30 and lowest for P.1. Although the effect of rootstock was not consistent, cumulative yield efficiency tended to be lower for G.30 than for M.26 or V.2. Trees on P.1 and G.30 produced the most root suckers.

Cultivar and planting site are two factors that often receive minimal attention, but can have a significant impact on the quality of apple ( Malus × domestica ) produced. A regional project, NE-183 The Multidisciplinary Evaluation of New Apple Cultivars, was initiated in 1995 to systematically evaluate 20 newer apple cultivars on Malling.9 (M.9) rootstock across 19 sites in North America. This paper describes the effect of cultivar and site on fruit quality and sensory attributes at a number of the planting sites for the 1998 through 2000 growing seasons. Fruit quality attributes measured included fruit weight, length: diameter ratio, soluble solids concentration (SSC), titratable acidity (TA), flesh firmness, red overcolor, and russet. Fruit sensory characteristics rated included crispness, sweetness, and juiciness, based on a unipolar intensity scale (where 1 = least and 5 = most), and acidity, flavor, attractiveness, and desirability based on a bipolar hedonic scale (where 1 = dislike and 5 = like extremely). All fruit quality and sensory variables measured were affected by cultivar. The two-way interaction of cultivar and planting site was significant for all response variables except SSC, TA, russet, crispness, and sweetness ratings. The SSC: TA ratio was strongly correlated with sweetness and acidity sensory rating, but was weakly correlated with flavor rating. The results demonstrate that no one cultivar is ideally suited for all planting sites and no planting site is ideal for maximizing the quality of all apple cultivars.

'Fuji' and 'McIntosh' apple trees (Malus x domestica Borkh.) on CG.4814, CG.7707, G.30N (liners from stool beds), M.7 EMLA, M.26 EMLA, and Supporter 4 rootstocks were planted at six sites with 'Fuji' and seven sites with'McIntosh' as the scion cultivars throughout North America as a uniform trial coordinated by the NC-140 Technical Committee. Partial plantings were established at three sites per cultivar, and CG.6210 and G.30T (liners from tissue cultured plants) were included in four plantings with each scion cultivar. After five growing seasons, the only significant loss was of 'McIntosh' trees on CG.7707 (73% survived). Trunk cross-sectional area, tree height, and canopy spread were affected by rootstock and allowed partitioning of a portion of the rootstocks in this trial into preliminary size categories. CG.6210, G.30N, and G.30T resulted in semidwarf trees, similar in size to those on M.7 EMLA, but less prone to root suckering, greater yielding, and more yield efficient. CG.4814 resulted in large dwarf trees, similar in size to those on M.26 EMLA, but more prone to root suckering, greater yielding, and more yield efficient. Effects of CG.7707 and Supporter 4 varied with scion cultivar. CG.7707 resulted in semidwarf 'Fuji' trees, similar in size those on M.7 EMLA, with less root suckering, greater yield per tree, and similar yield efficiency. CG.7707 produced large dwarf 'McIntosh' trees, similar in size to those on M.26 EMLA, with slightly more root suckering and similar yield per tree, and similar yield efficiency. Supporter 4 produced large dwarf 'Fuji' trees, similar in size and performance to those on M.26 EMLA, and it resulted in semidwarf 'McIntosh' trees, similar in size to those on M.7 EMLA, with less root suckering, similar yield per tree, and greater yield efficiency.

Replicated studies were conducted from 1996 to 1999 to evaluate the effect of a metalized reflective film (RF) on red color development in several apple ( Malus × domestica ) cultivars that often develop poor to marginal color in the mid-Atlantic growing region. Film was applied to the orchard floor in the middle between tree rows or under the tree beginning 5 to 7 weeks before the predicted maturity date. Light reflected into the canopy from the RF was measured and compared with a standard orchard sod, a killed sod or various polyethylene films. Fruit color was estimated visually and with a hand-held spectrophotometer. Fruit quality (firmness, soluble solids, starch index) was determined from a representative sample of fruit. RF increased the level of photosynthetic photon flux ( PPF ) reflected into the canopy resulting in darker, redder colored `Delicious', `Empire', and `Fuji' apples with a greater proportion of surface showing red color. RF increased canopy temperature and fruit surface temperature. A white polyethylene film increased reflected PPF and fruit color, but generally not to the extent of the metalized RF. Large [>13 ft (4.0 m) height] well-pruned `Delicious' trees showed increased fruit color, especially when the RF was placed under the canopy, but `Empire' trees of similar size and a more dense canopy showed no effect. The effect of the RF was most pronounced in the lower portion [up to 8 ft (2.4 m) height] of the canopy. A high-density RF was as effective as a low-density RF and the high-density film was about 60% less expensive. A high-density RF may be a cost effective method to enhance red color on selected apple cultivars in the mid-Atlantic region. Comparisons between ethephon and the RF were variable: ethephon appeared to have more effect on color in `Empire' than the RF, but less effect than the RF on `Hardibrite Delicious'. Ethephon consistently advanced fruit maturity. Chemical name used: (2-chloroethyl)phosphonic acid (ethephon).

Abstract This chapter covers the production and handling techniques for apples that are to be processed as juice, cider, apple sauce, or slice or whole apples. The apple processing industry in the People's Republic of China is described, along with the important apple processing cultivars and fruit attributes for processing. Differences in cultural practices, harvest and handling techniques and delivery of the produce to the processing plant are discussed.

Excess vegetative growth is a major problem for many apple (Malus xdomestica) orchards in the United States. The plant growth regulator prohexadione-calcium (Phd-Ca) (Apogee(R)), a gibberellin biosynthesis inhibitor, reduces shoot growth when applied to apple trees. Beginning at petal fall (PF) to 10 days after PF a single spray or multiple low-dose sprays reduced shoot extension growth by 20% to 70%. Timing of the initial spray was more important than rate of application for significant early growth suppression. The degree of growth suppression following foliar sprays of Phd-Ca differed among cultivars. By reducing vegetative growth Phd-Ca reduced pruning time in mature apple trees, enhanced spray penetration to the center of the tree canopy, reduced aphid populations and reduced the incidence of the shoot blight stage of fire blight. When Phd-Ca was used to control growth in 'Stayman' apple trees, fruit cracking increased. When Phd-Ca was mixed and applied with a calcium chloride spray, the growth control activity of the Phd-Ca was reduced.

A partial compliment of the 1984 NC-140 apple rootstocks were planted in axillary sites in Ohio (Ripley), Pennsylvania (Biglerville), and Missouri (Mountain Grove). The following ten rootstocks were common to the axillary sites: SDL., MAC.1, CG.24, M.4, AL.800. M.7EMLA, P.1, M.26EMLA, CG.10, P.22. The rootstocks CG.24, CG.10 and AL.800 were unique to the axillary sites. Tree loss exceeded 30% in all axillary sites for AL.800 and in OH and PA for MAC.39. CG.24 and CG.10 had high loss in MO (60%) and OH (40%), respectively. CG.24 trees were similar in size to SDL. in all axillary sites. AL.800 was similar in size to SDL. in OH. but in PA and MO they were similar to M.7EMLA. CG.10 trees were similar in size to M.26EMLA in OH, but were smaller in PA and MO. CG.24 and AL.800 had cumulative yield and efficiency similar to SDL. in all axillary sites. CG.10 cumulative yield was similar to SDL. in OH, but lower in PA and MO. Yield efficiency of CG.10 was high in all axillary sites, similar to M.26EMLA.

Apple scab is the primary disease that drives commercial pesticide recommendations; therefore, the use of cultivars that are resistant to this disease would help in reducing chemical inputs in apple production. To date, there has been only limited information on the performance of the scab-resistant apple cultivars. In 1990 and 1991, apple cultivars that are resistant to apple scab were planted at two sites in Pennsylvania, one site was the Fruit Research and Extension Center (FREC) in south-central Pennsylvania, and the other was the Horticulture Research Farm (HRF) in central Pennsylvania. Horticultural characteristics measured were trunk cross-sectional area (TCSA), flowering characteristics, yields, and fruit maturity. Trees at the FREC produced fruit 1 year earlier than those at HRF. `Enterprise'/M.26 has been the most-productive cultivar at FREC, as measured by average total weight of fruit per tree. At HRF, `CO-OP 26'/M.26 had been the most-productive cultivar. At the end of the 1994 growing season, `CO-OP 26' and `Williams Pride', both on M.26, are the largest trees as measured by TCSA at HRF. At the FREC, `Enterprise' was the largest cultivar.

Fruit samples from commercial apple orchards were collected at 145 to 150 days after full bloom in 1985 through 1987. Color measurements were performed on each of 10 fruit at 8 points on the side circumference of each apple using a HunterLab D25 Optical Sensor. Results were recorded as lightness (L), and hue angle (empty set). Strains were compared to three standards: 'Redchief,' 'Sturdeespur' and 'Starkrimson.' Significant correlations were found between empty set and L in all orchards as well as between L values and consumer determinations of overall acceptability and perceived flavor. At all sites, 'Starkrimson' and 'Redspur' consistently had higher L values than any of the other strains indicating lighter colored fruit at harvest. Other strains that appeared to be lighter colored during the harvest period chosen include 'Wellspur,' and 'Redprince.' Within any one year there were significant differences between strains within an orchard. There was more variability within strains than among strains within orchards and years.