Effect of crop load on fruiting and leaf photosynthesis of 'Braeburn'/M.26 apple trees

Abstract

Four-year-old apple (Malus x domestica Borkh.) trees cv. 'Braeburn' on M.26 rootstock were thinned at full bloom to establish six crop loads ranging from a heavy crop to a deflowered treatment. At harvest, mean yield per tree varied from 0 to 38 kg and mean fruit weight ranged from 225 g in the heaviest cropping treatment to 385 g in the lightest cropping treatment. Light cropping resulted in a significant advance in fruit maturity as indicated by background color, starch/iodine score and soluble solids. There were small differences in leaf photosynthetic rate among the treatments when shoot growth was active. However, in early January, coincident with cessation of shoot growth and maximum rate of accumulation of fruit weight, leaf assimilation rate was reduced by as much as 65% on the deflowered trees compared to the trees carrying the heaviest crop. Leaf assimilation rate showed a curvilinear response to crop load at this time, with little increase in leaf assimilation when crop load exceeded 12 fruit m(-2) leaf area.

Late‐season temperature effects on the carbon economy and tree performance of ‘Royal Gala’ apple (Malusdomestica) trees

“…Short-term rates of photosynthesis of the 'Royal Gala' leaves during the treatments, typically c. 6 |Amol m-2 s-1 , were relatively low compared to other measured rates of photosynthesis in apple leaves (Flore & Lakso 1989;Wünsche et al 1996;Palmer et al 1997). However, the rates measured in the present study compared favourably with rates for apple trees without crop or taken a considerable time after harvest (cf.…”

Examining growth, yield and bean quality of Ethiopian coffee trees : towards optimizing resources and tree management

“…Similar findings were documented for coffee in (Vaast et al 2005;Vaast et al 2006) and other fruit tree species, e.g. apple (Palmer et al 1997) and peach (Corelli-Grappadelli and Coston 1991). The current study also revealed smaller relative variability the larger the mean bean dry weight (Figs.…”

Effect of Pruning Severity and Branch Quality on Fruit Set and Fruit Dry Weight of ‘Packham’s Triumph’ Pears (Pyrus Communis L.)

“…The source was little affected by the pruning treatments, therefore an improved fruit: leaf relationship cannot explain the larger fruit. Palmer et al (1997) reported that leaf assimilation is stimulated by crop productivity (increase in sink size) and that the leaf assimilation rate is curvilinear with crop load for 'Braeburn' apples, up to a maximum crop of 12 fruit m -2 leaf area. In non-bearing trees the leaf assimilation rate was at times 64 percent lower rate than that of heavy cropping trees.…”