Pecan (Carya illinoinensis) is a deciduous nut tree that is well adapted to loamy bottom land sites (Sparks, 2002). Most pecan seeds are normally germinated and grown in field nurseries for one season, budded the second year, and then dug and sold as bare root trees. The root system predominantly consists of a taproot with weak lateral roots during the first year after pecan seed germination. The taproot will penetrate the soil up to 2 m unless stopped by a water table or an impervious layer by the first season’s end. In contrast, lateral roots are typically limited and will not begin abundant development until the second year. Vertical roots develop from the primary lateral roots at least by the fourth year (Sparks, 2005). Pecan trees, in their native habitats, have been classified as a phreatophyte (a plant that characteristically roots to the water table) (Sparks, 2002). Failure to successfully transplant pecan trees is commonplace and could be a result of the lack of adequate lateral root formation. Newly planted trees may become established promptly, may make a semblance of growth for several years and finally become established, or may fail entirely and die (Laiche, 1980).
Root pruning (Harris et al., 2001; Keever et al., 1986; Laiche, 1980; McCraw and Smith, 1998; Smith and Johnson, 1981; White and Payne, 1982) and growth regulator application (Matta and Storey, 1981) can influence top growth and root branching and therefore increase transplant survival. Previous research has focused on root pruning and transplanting of 2-year-old (McCraw and Smith, 1998) or 3-year-old (Smith and Johnson, 1981; Wood, 1996) pecan trees. Research has not been conducted to determine if pruning the roots shortly after germination stimulates lateral root formation. Similarly, little work has been attempted to consider the effects of taproot pruning in young pecan seedlings back to different lengths on root regeneration. The objective of this study was to determine if root pruning at different periods after seed germination affects pecan seedling root and shoot growth and to evaluate different degrees of taproot pruning on root initiation.
BaralotoC.ForgetP.M.2007Seed size, seedling morphology, and response to deep shade and damage in neotropical rain forest treesAmer. J. Bot.94901911
FinérL.OhashiM.NoguchiK.HiranoY.2011Fine root production and turnover in forest ecosystems in relation to stand and environmental characteristicsFor. Ecol. Mgt.26220082023
FletcherE.H.IIIThetfordM.SharmaJ.JoseS.2012Effect of root competition and shade on survival and growth of nine woody plant taxa within a pecan [Carya illinoinensis (Wangenh.) C. Koch] alley cropping systemAgrofor. Syst.864960
KeeverG.CobbG.McDanielR.MukhopaphyayA.1986Response of seedling pecan trees to container size and root pruning. Proc. SNA Res. Conf. 21:81–84
LaicheA.J.KilbyW.W.OvercashJ.P.1983Root and shoot growth of field-grown and container-grown pecan nursery trees 5 years after transplantingHortScience18328329
LynchD.J.MatamalaR.IversenC.M.NorbyR.J.GonzalezM.A.2013Stored carbon partly fuels fine-root respiration but is not used for production of new fine rootsNew Phytol.199420430
MattaF.StoreyJ.1981The effects of container design, BA, and GA3 on root and shoot growth of seedling pecan trees [Carya illinoensis]HortScience16652653
McCormackM.L.EissenstatD.M.PrasadA.M.SmithwickE.A.2013Regional scale patterns of fine root lifespan and turnover under current and future climateGlobal Change Biol.1916971708
WhiteA.W.Jr1980Effects of topsoil-subsoil fertilizer and lime amendments on top and root growth of ‘Stuart’ pecan seedlings in a simulated Norfolk soil profileHortScience17380381