The Bases of Productivity in Apple Production Systems: The Role of Light Interception by Different Shoot Types

Abstract

<jats:p>Although apple (<jats:italic>Malus domestica</jats:italic> Borkh.) system yield differences are generally related to whole-canopy light interception, this study tested the hypothesis that these orchard yields are related primarily to total light intercepted by the spur canopy. Seasonal leaf area development of different shoot types, exposed bourse shoot leaf net photosynthesis, fruit growth, whole canopy light interception (by image analysis of fisheye photographs) and relative light interception by different shoot types (by a laser assisted canopy scanning device) were estimated within four 14-year-old `Empire' apple production systems (slender spindle/M.9, central leader/M.7, central leader/M.9/MM.111 and Y-trellis/M.26). The final LAI values were CL/M.7 = 1.8, CL/9/111 = 2.3, SS/M.9 = 2.6 and Y/M.26 = 3.6. Exposed leaf net photosynthesis showed few differences and was not dependent upon the production system. Yields of the pyramidal shaped tree forms were 40 to 42 t·ha<jats:sup>-1</jats:sup> while Y-trellis produced 59 t·ha<jats:sup>-1</jats:sup>, with similar fruit sizes. Again, yields were primarily related to the percentage of light intercepted by the whole canopy, 48% to 53% for conic forms versus 62% for the Y-trellis system. Laser analyses showed that the Y-trellis system intercepted about 20% to 30% more light with the spur canopy than the conic tree forms, supporting the hypothesis. Yields were better correlated with spur canopy LAI and spur canopy light interception than with extension shoot canopy LAI and light interception.</jats:p>

Identification and stability of QTLs for fruit quality traits in apple

“…Nonetheless, a statistical analysis in 2005 of fruit from 50 of these M9-grown genotypes showed that there were no significant differences in quality traits relative to fruit derived from the same 50 genotypes grown on their own root systems. This was perhaps surprising because it is known that light interception, canopy size and crop load are important factors in determining final fruit quality (Wunsche et al 1996(Wunsche et al , 2005. Therefore, it might have been expected that fruit from genotypes on dwarfing rootstocks would have higher°Brix contents and a smaller size, due to an improved light penetration and less vegetative growth, respectively (Wunsche and Lakso 2000;Wunsche et al 2005).…”

Environment and position of first bud to break on apple shoots affects lateral outgrowth

“…In the case of outgrowth from reproductive buds, the length and diameters were considered to be those of the longest bourse shoot. Lateral shoot lengths were either used in analyses as actual lengths or put in length categories with accepted physiological differences (Costes et al 2006;Wünsche et al 1996): spurs (\5 cm); brindles (C5 and \20 cm); and long shoots (C20 cm). Basal diameter was used to calculate cross-sectional area (CSA) for each of the Budbreak precedence refers to the position of the first bud on the shoot to reach green tip.…”

“…Preformation is the production of unexpanded metamers and organs prior to expansion which generally occurs after a period of dormancy, and neoformation is the formation of organs and metamers immediately followed by their expansion (Barthélémy and Caraglio 2007;Hallé et al 1978). Shoots can be classified based on their length (Costes et al 2006; Lespinasse and Delort 1993;Wünsche et al 1996), as well as their degree of preformation and neoformation (Guédon et al 2006). Short shoots, or spurs, are entirely preformed and internodes do not elongate.…”

Light interception in apple trees influenced by canopy architecture manipulation

“…The contribution of the various shoot categories to tree productivity is now well documented and, as a general trend, whole-tree yield has been shown to strongly depend on light interception by the spur canopy (CorelliGrappadelli et al 1994;Lakso et al 1999;Wünsche et al 1996;Wünsche and Lakso 2000). This probably arises from both morphological features of short as compared to long shoots, the former having higher leaf to shoot ratios (Lauri and Kelner 2001), and faster carbon exportation capacity early in the season (Sansavini and CorelliGrappadelli 1992).…”