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  • Author or Editor: Shahla Mahdavi x
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Selection of dwarfing rootstocks that facilitate optimum production of high-quality fruit is crucial in modern high-density apple orchards. In addition to tree growth and yield, rootstocks can influence fruit maturity of scion cultivars in apples. In this study, the impact of 17 rootstocks on fruit maturity, yield, and quality attributes of ‘Aztec Fuji’ apples (Malus domestica Borkh.) at harvest were evaluated in a season when all trees were in a “full-crop” condition. Keeping sealed fruit at room temperature, a typical climacteric pattern was observed in ethylene evolution, respiration, and oxygen consumption, peaking after 5–7 days in fruit from trees on all rootstocks. During the ripening period, ethylene evolution and respiration rates in fruit from trees on Supp.3, G.3001, and G.202 were often in the high-range category, whereas those on CG.4004, CG.4214, G.41N, and B.9 were in the midrange category and those on M.9Pajam2, M.26EMLA, and G.11 were in the low-range category. Evolved ethylene and respiration in fruit from trees on M9.T337 steadily and slowly increased from 7 days after harvest (7DAH) to 13 days after which harvest (13DAH) ethylene sharply increased, signaling occurrence of climacteric peak, while respiration declined after the peak of 13DAH. In fruit from trees on most rootstocks, the rates of oxygen consumption had inverse relationships with the rates of respiration, so that fruit from trees on M9.T337 had higher and those on G.41N and Supp.3 had lower rates of oxygen consumption. Trees on G.41N, CG.4004, and M.26EMLA had higher and those on CG.4003 had lower yield per tree than trees on other rootstocks. Trees on B.9 and M.9T337 were most yield efficient among trees on all rootstocks. Trees on CG.4004 had larger fruits than those on other rootstocks. Considering all fruit maturity, quality, and yield attributes, CG.4004 seems to be a good choice of rootstock for ‘Aztec Fuji’ under the conditions of this study.

Open Access

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.

Free access

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.

Free access