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.
AllenR.G.PereiraL.S.RaesD.SmithM.1998Crop evapotranspiration. Guidelines for computing crop water requirements. FAO Irr. Drainage Paper 56. FAO Rome Italy
AutioW.R.HaydenR.A.MickeW.C.BrownG.R.1996Rootstock affects ripening, color, and shape of ‘Starkspur Supreme Delicious’ apples in the 1984 NC-140 cooperative plantingFruit Var. J.504553
BartramR.D.BramlageW.KupfermanE.M.OlsenK.L.PattersonM.E.ThompsonJ.1993Apple maturity program handbook. U.S. Dept. Agri. Res. Serv. Tree Fruit Research Station Wenatchee WA
BehboudianM.H.MpelasokaB.S.SinghZ.MillsT.M.2005Quality 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
ChunI.J.FallahiE.ColtW.M.ShafiiB.TripepiR.R.2001Effects of rootstocks and microsprinkler fertigation on mineral concentrations, yield, and fruit color of ‘BC-2 Fuji’ appleJ. Amer. Pomol. Soc.55197205
DrakeS.R.ProebstingE.L.MahanM.O.ThompsonJ.B.1981Influence of trickle and sprinkle irrigation on ‘Golden Delicious’ apple qualityJ. Amer. Soc. Hort. Sci.106255258
EbelR.C.ProebstingE.L.PattersonM.E.1993Regulated deficit irrigation may alter apple maturity, quality, and storage lifeHortScience28141143
FallahiE.ColtW.M.FallahiB.2001aOptimum ranges of leaf nitrogen for yield, fruit quality, and photosynthesis in ‘BC-2 Fuji’Apple. J. Amer. Pomol. Soc.556875
FallahiE.ChunI.J.NeilsenG.H.ColtW.M.2001bEffects of three rootstocks on photosynthesis, leaf mineral nutrition, and vegetative growth of ‘BC-2 Fuji’ apple treesJ. Plant Nutr.24827834
FallahiE.FallahiB.ShafiiB.MoralesB.2007aWater use, tree growth, and leaf mineral nutrients of young ‘Fuji’ apples as influenced by different irrigation systemsActa Hort.7216370
FallahiE.RatnaprabhaR.TripepiR.ShafiiB.FallahiB.2007bTree growth, yield, fruit quality, and mineral partitioning as affected by rootstock and irrigation methodsIntl. J. Fruit Sci.7324
KramerP.J.1983Water relations of plants. Academic Press New York NY
LeibB.G.CaspariH.W.RedullaC.A.AndrewsP.K.JabroJ.J.2006Partial root zone drying and deficit irrigation of ‘Fuji’ apples in a semi-arid climateIrr. Sci.8599
NeilsenD.NeilsenG.H.GregoryD.ForgeT.ZebarthB.J.2008Drainage losses of water, N and P from micro-irrigation systems in a young, high density apple plantingActa Hort.792483490
NeilsenD.NeilsenG.H.HerbertL.GuakS.2010Effect of irrigation and crop load management on fruit nutrition and quality for Ambrosia/M.9 appleActa Hort.8686372
NeilsenD.SmithS.FrankG.KochW.AlilaY.MerrittW.TaylorB.BartonM.HallJ.CohenS.2006Potential impacts of climate change on water availability for crops in the Okanagan Basin, British ColumbiaCan. J. Soil Sci.86909924
NeilsenG.H.ParchomchuckP.NeilsenD.1994Fertigation 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’ConnellM.G.GoodwinI.2007Responses of ‘Pink Lady’ apple to deficit irrigation and partial root zone drying: Physiology, growth, yield, and fruit qualityAustral. J. Agr. Res.5810681076
ProebstingE.1994Strategy development for managing drought p. 39–50. In: Williams K.M. and T.W. Ley (eds.). Tree fruit irrigation. Good Fruit Grower Yakima WA
TallutoG.FarinaV.VolpeG.Lo BiancoR.2008Effects of partial root zone drying and rootstock vigor on growth and fruit quality of ‘Pink Lady’ apple trees in Mediterranean environmentsAustral. J. Agr. Res.59785794
Washington State University2012Washington State University Tree Fruit Research and Extension Center. 20 Mar. 2012. <http://www.tfrec.wsu.edu>
ZydlikZ.PacholakE.2001Fertigation effects on the concentration of mineral components in the soil and leaves, and the yield and quality of fruit in two apple tree cultivarsActa Hort.564457463