The increasing trend in the world population and decreasing trend in the available agricultural land and water mandate a more efficient use of water and orchard land. Using new orchard designs with more efficient irrigation systems and rootstocks can result in lower water consumption (Fallahi et al., 2007a; Neilsen et al., 2006, 2008) while producing higher quality fruit (Autio et al., 1996; Behboudian and Mills, 1997; Behboudian et al., 2005; Fallahi et al., 2007a, 2007b; Naor et al., 2008; Neilsen et al., 2010). Rootstock can influence ripening, color, and shape of the scion fruit. Autio et al. (1996) in the 1984 NC-140 cooperative planting reported that apple fruit ripening was correlated with tree vigor and the most dwarfing rootstocks resulted in the earliest ripening. Rootstock can also influence scion leaf and fruit mineral concentrations and, thus, indirectly affect fruit quality and yield (Fallahi et al., 2001a, 2001b).
Ebel et al. (1993) in a comprehensive study in Washington State applied regulated deficit irrigation (RDI) to ‘Delicious’ apple trees early in the growing season to determine if fruit quality and storage life would be altered compared with well-watered trees. Internal ethylene concentration increased logarithmically earlier in RDI apples. At harvest, RDI fruit were smaller and had a higher SSC and lower titratable acidity (TA). Starch degradation was delayed in RDI fruit, and their color was unaffected. Firmness was unaffected when the effect of size on firmness was removed. The SSC of RDI apples remained higher during storage, but starch content, TA, firmness, and color were similar.
Leib et al. (2006) indicated that fruit size and yield of ‘Fuji’ apple in deficit irrigation (DI) were similar to those of partial root zone drying irrigation and conventional irrigation (CI) in the semiarid climate of Washington State. Naor et al. (2008) reported that yield and fruit size decreased as the rate of irrigation was reduced in ‘Golden Delicious’ apple in Israel. Previous reports have indicated that a reduction in water application may result in a reduction in apple firmness, relating this observation to the advanced maturity in fruit with water stress (Drake et al., 1981; Mills et al., 1994). However, other studies have shown that apples from non-irrigated plots were firmer than those from irrigated plots because fruit from non-treated plots had smaller size (Assaf et al., 1975).
Irrigation with a drip system uses lower water volume than sprinkler irrigation (Fallahi et al., 2007a; Proebsting, 1994). However, irrigation through microjet sprinkler systems can improve the establishment and maintenance of orchard floor vegetation. Microjet sprinklers also create a cooler environment in the orchards under the fruit-growing conditions of Washington and Idaho (E. Fallahi, personal observation).
Although there has been some progress in the understanding of microirrigation systems (Chun et al., 2001; Fallahi et al., 2007a; Neilsen et al., 1994, 2010; Yao et al., 2001; Zydlik and Pacholak, 2001), information on tree growth, yield, and fruit quality for new apple cultivars and rootstocks under various regimes of drip or microjet sprinkler irrigation systems in the Pacific Northwestern United States is lacking. Thus, the objective of this long-term experiment was to study the effect of four rootstocks and two irrigation treatments consisting of microjet sprinkler and drip systems using ETc-based water scheduling on water use, tree growth, yield, and harvest-time fruit quality attributes in ‘Pacific Gala’ apple at different ages of tree (different years of tree canopy maturity) during 2004–07.
Allen, R.G., Pereira, L.S., Raes, D. & Smith, M. 1998 Crop evapotranspiration. Guidelines for computing crop water requirements. FAO Irr. Drainage Paper 56. FAO, Rome, Italy
Assaf, R., Levin, I. & Bravdo, B. 1975 Effect of irrigation regimes on trunk and fruit growth rates, quality and yield J. Hort. Sci. 50 481 493
Autio, W.R., Hayden, R.A., Micke, W.C. & Brown, G.R. 1996 Rootstock affects ripening, color, and shape of ‘Starkspur Supreme Delicious’ apples in the 1984 NC-140 cooperative planting Fruit Var. J. 50 45 53
Bartram, R.D., Bramlage, W., Kupferman, E.M., Olsen, K.L., Patterson, M.E. & Thompson, J. 1993 Apple maturity program handbook. U.S. Dept. Agri. Res. Serv. Tree Fruit Research Station, Wenatchee, WA
Behboudian, M.H., Mpelasoka, B.S., Singh, Z. & Mills, T.M. 2005 Quality responses of deciduous fruit to deficit irrigation, p. 33–43. In: Dris, R. (ed.). Fruit: Growth, nutrition, and quality. WFL Publisher (Science & Technology), Helsinki, Finland
Chun, I.J., Fallahi, E., Colt, W.M., Shafii, B. & Tripepi, R.R. 2001 Effects of rootstocks and microsprinkler fertigation on mineral concentrations, yield, and fruit color of ‘BC-2 Fuji’ apple J. Amer. Pomol. Soc. 55 197 205
Drake, S.R., Proebsting, E.L., Mahan, M.O. & Thompson, J.B. 1981 Influence of trickle and sprinkle irrigation on ‘Golden Delicious’ apple quality J. Amer. Soc. Hort. Sci. 106 255 258
Ebel, R.C., Proebsting, E.L. & Patterson, M.E. 1993 Regulated deficit irrigation may alter apple maturity, quality, and storage life HortScience 28 141 143
Fallahi, E., Colt, W.M. & Fallahi, B. 2001a Optimum ranges of leaf nitrogen for yield, fruit quality, and photosynthesis in ‘BC-2 Fuji’ Apple. J. Amer. Pomol. Soc. 55 68 75
Fallahi, E., Chun, I.J., Neilsen, G.H. & Colt, W.M. 2001b Effects of three rootstocks on photosynthesis, leaf mineral nutrition, and vegetative growth of ‘BC-2 Fuji’ apple trees J. Plant Nutr. 24 827 834
Fallahi, E., Fallahi, B., Shafii, B. & Morales, B. 2007a Water use, tree growth, and leaf mineral nutrients of young ‘Fuji’ apples as influenced by different irrigation systems Acta Hort. 721 63 70
Fallahi, E., Ratnaprabha, R., Tripepi, R., Shafii, B. & Fallahi, B. 2007b Tree growth, yield, fruit quality, and mineral partitioning as affected by rootstock and irrigation methods Intl. J. Fruit Sci. 7 3 24
Kramer, P.J. 1983 Water relations of plants. Academic Press, New York, NY
Leib, B.G., Caspari, H.W., Redulla, C.A., Andrews, P.K. & Jabro, J.J. 2006 Partial root zone drying and deficit irrigation of ‘Fuji’ apples in a semi-arid climate Irr. Sci. 85 99
Mills, T.M., Behboudian, M.H., Tan, P.Y. & Clothier, B.E. 1994 Plant water status and fruit quality in ‘Braeburn’ apples HortScience 29 1274 1278
Naor, A., Naschitz, S., Peres, M. & Gal, Y. 2008 Responses of apple fruit size to tree water status and crop load Tree Physiol. 28 1255 1261
Neilsen, D., Neilsen, G.H., Gregory, D., Forge, T. & Zebarth, B.J. 2008 Drainage losses of water, N and P from micro-irrigation systems in a young, high density apple planting Acta Hort. 792 483 490
Neilsen, D., Neilsen, G.H., Herbert, L. & Guak, S. 2010 Effect of irrigation and crop load management on fruit nutrition and quality for Ambrosia/M.9 apple Acta Hort. 868 63 72
Neilsen, D., Smith, S., Frank, G., Koch, W., Alila, Y., Merritt, W., Taylor, B., Barton, M., Hall, J. & Cohen, S. 2006 Potential impacts of climate change on water availability for crops in the Okanagan Basin, British Columbia Can. J. Soil Sci. 86 909 924
Neilsen, G.H., Parchomchuck, P. & Neilsen, D. 1994 Fertigation of fruit trees: The B.C. experience, p. 191–199. In: Peterson, A.B. and R.G. Stevens (eds.). Tree fruit nutrition. Good Fruit Grower, Yakima, WA
O’Connell, M.G. & Goodwin, I. 2007 Responses of ‘Pink Lady’ apple to deficit irrigation and partial root zone drying: Physiology, growth, yield, and fruit quality Austral. J. Agr. Res. 58 1068 1076
Proebsting, E. 1994 Strategy development for managing drought, p. 39–50. In: Williams, K.M. and T.W. Ley (eds.). Tree fruit irrigation. Good Fruit Grower, Yakima, WA
Talluto, G., Farina, V., Volpe, G. & Lo Bianco, R. 2008 Effects of partial root zone drying and rootstock vigor on growth and fruit quality of ‘Pink Lady’ apple trees in Mediterranean environments Austral. J. Agr. Res. 59 785 794
Washington State University 2012 Washington State University Tree Fruit Research and Extension Center. 20 Mar. 2012. <http://www.tfrec.wsu.edu>
Yao, S., Neilsen, G.H. & Neilsen, D. 2001 Effects of water stress on growth and mineral composition of ‘Gala’ apple fruit Acta Hort. 564 449 456
Zydlik, Z. & Pacholak, E. 2001 Fertigation effects on the concentration of mineral components in the soil and leaves, and the yield and quality of fruit in two apple tree cultivars Acta Hort. 564 457 463