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During various ages of tree between 2002 and 2007, the effects of four rootstocks and two irrigation systems using a crop evapotranspiration-based (ETc) water scheduling on water use, tree growth, yield, and fruit quality at harvest in ‘Pacific Gala’ apple [(Malus ×domestica) Borkh] were studied. The use of ETc when a precise crop coefficient value (Kc), modified by percentage of ground shade (GS) and tree canopy maturity (M) was used, provided a reliable tool for irrigation scheduling of ‘Pacific Gala’ apple. Young trees with a full sprinkler (FS) system received an average of 872.3 mm (5616.8 L/tree), whereas those with full drip (FD) received 448.9 mm (2921.1 L/tree). However, when trees were mature, trees with a FS system received an average of 994 mm (6461.7 L/tree), whereas trees with a FD received 614.1 mm (3996 L/tree) of irrigation water per growing season. Trees on ‘Budagovsky 9’ (‘B.9’) had smaller trunk cross-sectional area (TCA) and higher yield efficiency, whereas those on ‘Supporter4’ (‘Sup.4’) had larger TCA and lower yield efficiency than those on other rootstocks in all years of the study. Trees on ‘Nic.9’ (‘RN29’) always had higher yield per tree as compared with those on other rootstocks. Trees on ‘RN29’ often had higher but trees on ‘B.9’ had lower fruit weight than did those on other rootstocks. Trees on ‘Sup.4’, despite their lower yields, had smaller fruits than those on ‘RN29’ every year and thus were not suitable for planting. Fruit from trees on ‘B.9’ and ‘Cornell-Geneva30’ (‘G.30’) often had higher soluble solids concentration (SSC) and starch degradation pattern (SDP) than those other rootstocks. Fruits from trees on ‘G.30’ also had lower firmness and higher stem-end cracking, suggesting that this rootstock advances maturity in ‘Pacific Gala’ apple. Trees with FS irrigation had higher TCA than those with the FD system. Trees with the FD system were more precocious and had higher yield per tree, yield efficiency, and fruit weight than trees with the FS system when they were young. However, these differences were not significant when trees matured. ‘Pacific Gala’ fruit from trees with FS consistently had better color than those with the FD system every year. Fruits from young trees with the FD system often had higher SDP and lower firmness than those from FS irrigation.

Many fruit growers in the Pacific Northwest region prefer to use a sprinkler system to produce high-quality fruit and to establish a cover crop in the orchard. However, water shortage mandates the use of more efficient methods of irrigation, such as drip. In this long-term experiment, the effects of seven irrigation systems for `Fuji' and two irrigation systems for `Gala' on five rootstocks on tree growth, water use, fruit quality, and mineral nutrients were studied. All forms of drip systems used less water than full micro-sprinkler (SP). Partial root drying sprinkler (PS) used 50% less water than SP. Trees with partial root drying drip and deficit drip had to receive 65% of full drip to survive. Each `Fuji' tree with SP used about 5397 L of water in 2004 and 5833 L in 2005, while each tree with full drip used 2403 L in 2004 and 3438 L in 2005. Thus, trees with full drip used 41% to 55% less water than those with SP system without any reduction in fruit quality. This leads to a major savings in the cost of fruit production. Fruit weight in trees with full drip was always greater than those with PS or deficit drip. Fruits with SP system had lower soluble solids than those with PS. Fruits from trees with partial drip had a higher starch degradation than those with other systems. Leaf minerals, particularly N and K, were affected by irrigation systems. `Pacific Gala' trees on B.9 rootstock were more precocious than those on Supporter-4 rootstock. In general, `Pacific Gala' on RN-29 had better tree performance and fruit quality than those on other rootstocks. The calculation of water requirements on a tree-use basis provided an excellent guide for drip irrigation.

In a long-term study between 2008 and 2011, the use of crop evapotranspiration (ETc), when a precise crop coefficient value (K _c) was used, provided a reliable irrigation scheduling for determination of water requirement for ‘Autumn Rose Fuji’ apple (Malus ×domestica Borkh) fully mature trees. Water use, yield, and fruit quality attributes at harvest were examined under various irrigation and nitrogen (N) systems that were scheduled using ETc. Trees with a full sprinkler (FS) system received ≈39% to 41% more water than those with a full drip (FD) system during the period of 2008–11 growing seasons. On average, mature trees with an FS system received 5927.6 L (944 mm), whereas those with an FD system received 3610.3 L of water per tree (554.9 mm) per growing season over the period of 2008 through 2011. Fruit from trees with FS and FD were larger, whereas those with 50% FS were smaller than those from all other treatments. Trees with 50% FS treatment received a higher volume of water but had smaller fruit size than those with 50% FD or 65% FD. Averaging values over 4 years revealed that applications of any form of deficit irrigation (DI), either by microjet irrigation or drip, increased fruit soluble solids concentration (SSC) and firmness but decreased water core at harvest. Considering yield, and quality attributes in this study, a well-calculated ETc-based FD irrigation system is recommended over any other irrigation regime. If application of deficit water is mandated, application of 65% FD is preferred over 50% FS, as trees with 65% FD treatment received less water while had larger fruit than those of 50% FS. Trees receiving 80 g N/tree had lower fruit color and russet than those receiving 40 g N/tree. However, other yield and quality attributes were unaffected by the rate of N fertigation.

‘Fuji’ apple (Malus ×domestica Borkh) has gained popularity in the past decades, but poor color of this apple mandates introduction of new strains. To pursue this objective, long-term effects of five ‘Fuji’ apple strains, consisting of ‘Autumn Rose’, ‘Desert Rose’, ‘Myra’, ‘September Wonder’, and ‘Top Export’ on RN 29 rootstock on fruit yield (in 7 years) and harvest time quality attributes (in 6 years) under climate conditions of southwest Idaho were studied during 2004–10. Fruit of ‘September Wonder Fuji’ trees were larger than those of other strains in 5 of 6 years. The type or pattern of peel color among the “low-coloring” and “high-coloring” strains varied widely. Fruits of ‘Autumn Rose Fuji’, ‘Myra Fuji’, and ‘Top Export Fuji’ always had less but ‘September Wonder Fuji’ and ‘Desert Rose Fuji’ had more red color. Fruit of ‘September Wonder Fuji’ had lower firmness but higher starch degradation pattern (SDP) than those of other strains every year as a result of the earlier maturity of this strain. Fruit of ‘Top Export Fuji’ had the lowest SDP among all strains. Fruit of ‘Autumn Rose Fuji’ tended to have lower soluble solids concentration in 3 of 6 years of this study. Considering all yield and quality attributes at harvest, ‘September Wonder’ was a great choice for an early-maturing and ‘Desert Rose’ was suitable for a late-maturing ‘Fuji’ strain. ‘Myra Fuji’ was particularly desirable for its attractive pink color that resembles bagged ‘Fuji’ without the expensive cost of labor associated with bagging.

Use of crop evapotranspiration (ETc), when a precise crop coefficient value (Kc) is used, provides a reliable tool (irrigation scheduling) for determination of water requirement. In this process, Kc should be modified by percentage of ground shade (GS) and tree canopy maturity (M). In an experiment in Idaho with ET-based irrigation scheduling, each tree with a full microjet sprinkler system received an average of 6461.7 L (994 mm), whereas each one with a full drip system used 3996 L (614.1 mm) of irrigation water. In general, deficit drip irrigation was shown to initially increase yield as a result of induction of stress and the production of a higher number of fruit spurs. However, production declined if the extreme water deficiency was repeatedly applied to the trees over several years. Using a microjet sprinkler system, a partial root zone drying regime reduced fruit size but slightly improved fruit color. Application of water at 65% full drip rate, applied on both sides of the tree row (DD), reduced fruit size. However, when the 65% of full drip rate was applied to only one of the alternating sides of the tree every other week (PRD), fruit size was larger than those with DD treatment.

Adaptability and feasibility of table grape (Vitis vinifera or Vitis labrusca), asian pear (Pyrus pyrifolia), and quince (Cydonia oblonga) production under the high desert conditions of southwest Idaho in the Intermountain West region of the United States were studied. ‘Alborz’ table grape was harvested between 1 and 15 Sept. and with proper thinning, this cultivar had outstanding clusters and berries and could be a successful table grape for planting at commercial scales in warmer spots under conditions of this study. ‘Kashishi’ and ‘Autumn Royal’ were late-season cultivars and had large berries with excellent quality. ‘Ralli’, also called ‘Anahita’ in the Intermountain West, had attractive clusters and berry color, but was sensitive to frost and had poor production. ‘Princess’ grape was harvested between 5 and 30 Sept. and had poor fruit set, but berries had outstanding flavor. ‘Niitaka’ asian pear had the largest and firmest fruit with the lowest soluble solids concentration (SSC) among all tested asian pears. ‘Semi Dwarf Shinko’ asian pear had larger fruit than ‘Kikusui’ and ‘20th Century’ but smaller than ‘Niitaka’. However, ‘Kikusui’ and ‘20th Century’ had excellent fruit flavor and quality. Thus, ‘Kikusui’, ‘20th Century’, and ‘Niitaka’ asian pears can be chosen for planting under condition of this study. ‘Aromantnaya’ and ‘Rich’ quinces matured earlier and had lower fruit firmness than other cultivars. These cultivars can be planted for early market. Based on this study, ‘Van Deman’ can be chosen for fresh consumption if sweet cultivars are in demand by the market. However, ‘Rich’ and ‘Smyrna’ quinces can be chosen if fruit with large size and bright yellow color is preferred.

The increasing scarcity of land and water for agriculture mandates an efficient use of these natural resources. Establishment of high-density orchards with the use of a size-controlling rootstock, in combination with a suitable canopy architecture, is an efficient method for fruit production. However, less attention has been paid to the use of size-controlling practices such as trunk girdling in these modern orchard systems. The impacts of two rootstocks, two tree architectures, and three levels of bark cambium cuts (girdling or scoring) on growth, yield, fruit quality attributes at harvest, and leaf nitrogen (N) in ‘Aztec Fuji’ apple (Malus domestica Borkh.) were studied in 2015 and 2016. Trees on Nic 29 had larger canopies, higher yields, and larger fruit, but lower fruit color, sunburn, and firmness than those on Bud 9. Trees with a tall spindle (TS) architecture had higher yield in 2016, higher fruit soluble solids and firmness in 2015, higher fruit russet in 2016, but shorter terminal growth in both 2015 and 2016 and lower leaf N in 2015 than did those with a central leader (CL) training system. Trees receiving a bark girdling in 2015 (BG15) or score girdling in 2015 and 2016 (SG1516) had significantly higher yield than trees on nongirdled trees (NOGD) in 2016. Bark girdling or score girdling in 2015 (BG15 or SG15) increased fruit weight (size), color, and firmness at harvest in the same year, although differences for score girdling were not always significant. However, BG15 or SG15 did not have a “carryover” effect and did not affect fruit size, color, or firmness at harvest in 2016. When bark scoring was repeated in 2016 (SG1516), fruit size was increased in 2016. On the basis of the results of this 2-year study, it appears that bark girdling in one year is sufficient to increase fruit size of the current year and the yield in the following year. If larger fruit size is the critical objective of fruit production, annual score girdling needs to be practiced. However, a further long-term study is needed to monitor the carryover effects of cambium girdling and scoring on tree performance and fruit quality attributes in the subsequent years.

Production of peaches (Prunus persica) in southwestern Idaho and other states in the intermountain western United States has increased during recent years, requiring information on the performance of modern cultivars in the region. Thus, a long-term project was conducted to investigate bloom date, harvest date, cumulative growing degree-days, fruit quality, and yield of various yellow- and white-fleshed peaches under conditions of southwestern Idaho during 2003 to 2007. The analysis of average response over these years indicated that ‘Snow Giant’, ‘Jupiter’, ‘Yuko King’, ‘Burpeach Six’, ‘Fairtime’, ‘Coral Star’, ‘July Sun’, and ‘Zee Lady’ bloomed earlier (5–7 Apr.), while ‘Sierra Gem’, ‘Fancy Lady’, and ‘Red Star’ bloomed later (11–12 Apr.) than other cultivars. ‘Crimson Lady’, ‘May Sun’, and ‘Sierra Gem’ were the earliest cultivars, had smaller fruit, and on average were harvested on 11, 13, and 24 July and needed 94, 96, and 103 days from full bloom to harvest, respectively. ‘Opal Moncav’, ‘August Flame’, ‘August Lady’, ‘Ryan Sun’, ‘September Snow’, ‘Yukon King’, and ‘Fairtime’ were harvested during the second half of September. The periods between bloom and harvest for these cultivars on average were 160, 163, 163, 168, 171, 173, and 177 days, respectively, and these cultivars often had greater soluble solids concentrations than other cultivars. ‘PF12B’ and ‘PF15A’ were “mid-season,” but ‘PF 20–007’ and ‘PF 24–007’ were “late-season” cultivars. ‘PF12B’, ‘PF15A’, ‘PF 20–007’, ‘Star Fire’, ‘Burapeach Six’, ‘Coral Star’, ‘All Star’, and ‘Zee Lady’ had higher yield than many of the other cultivars. While the “early-season” cultivars can be planted for regional and local market, the “mid-season” and “late-season” peaches are excellent choices for marketing during September and early October when production of the similar cultivars are already completed in warmer regions. Overall, ‘Sweet Dream’, ‘August Lady’, ‘Zee Lady’, ‘August Flame’, ‘Snow Giant’, ‘Saturn’, ‘Jupiter’, and ‘PF24–007’ showed satisfactory to great performance in this long-term evaluation.

Tree fruit rootstocks are used to influence precocity, tree size, fruit quality, yield efficiency, mineral uptake, and to withstand adverse environmental conditions. In this paper, we will briefly discuss the history and literature of apple (Malus domestica) rootstocks and their effects on scion tree growth, yield, fruit quality, leaf mineral nutrition, and photosynthesis. Then, the results of our long-term study on the effects of rootstocks on tree growth, yield, fruit quality and leaf mineral nutrition, and one season of photosynthesis measurement in `BC-2 Fuji' will be presented and discussed. In this study, `Fuji' trees on `Malling 9 NAKBAT337' (M.9) rootstock had the smallest trunk cross-sectional area (TCA), highest yield efficiency, and were the most precocious followed by those on `East Malling-Long Ashton 26' (M.26 EMLA) and `East Malling-Long Ashton 7' (M.7 EMLA). Trees on M.7 EMLA often had larger fruit with less color than those on M.9 and M.26 EMLA. Trees on M.7 EMLA frequently had greater leaf K than those on other rootstocks. Trees on M.26 EMLA always had greater leaf Mg than those on other rootstocks. Leaves from the current terminal shoots (CTS) of trees on M.9 had higher net photosynthesis and transpiration than those on M.7 EMLA rootstock during 1998 growing season.

The influence of three rates of nitrogen (N) and fruit bagging on fruit peel and flesh mineral concentrations and fruit quality in `BC-2 Fuji' apple (Malus domestica Borkh.) trees on Malling 9 (M.9) was studied. Increasing N application decreased fruit peel red color, fruit N, iron (Fe), and manganese (Mn). Fruit from trees receiving 10.72 oz (303.9 g) N per year had higher evolved ethylene and respiration during poststorage ripening tests. Bagging of fruit reduced fruit peel red color, soluble solids concentrations (SSC), and dry weight as compared to nonbagged fruit. Bagged fruit had higher N, potassium (K), and copper (Cu) than nonbagged fruit. Fruit peel had a greater percentage of dry weight, and higher concentrations of all tested minerals compared to fruit flesh.