Light interception and partitioning between shoots in apple cultivars influenced by training

Abstract

The effect of two training systems (Central Leader with branch pruning versus Centrifugal Training with minimal pruning, i.e., removal of fruiting laterals only) on canopy structure and light interception was analyzed in three architecturally contrasting apple (Malus domestica Borkh.) cultivars: 'Scarletspur Delicious' (Type II); 'Golden Delicious' (Type III); and 'Granny Smith' (Type IV). Trees were 3D-digitized at the shoot scale at the 2004 and 2005 harvests. Shoots were separated according to length (short versus long) and type (fruiting versus vegetative). Leaf area density (LAD) and its relative variance (xi), total leaf area (TLA) and crown volume (V) varied consistently with cultivar. 'Scarletspur Delicious' had higher LAD and xi and lower TLA and V compared with the other cultivars with more open canopies. At the whole-tree scale, training had no effect on structure and light interception parameters (silhouette to total area ratio, STAR; projected leaf area, PLA). At the shoot scale, Centrifugal Training increased STAR values compared with Central Leader. In both training systems, vegetative shoots had higher STAR values than fruiting shoots. However, vegetative and fruiting shoots had similar TLA and PLA in Centrifugal Trained trees, whereas vegetative shoots had higher TLA and PLA than fruiting shoots in Central Leader trees. This unbalanced distribution of leaf area and light interception between shoot types in Central Leader trees partly resulted from the high proportion of long vegetative shoots that developed from latent buds. These shoots developed in the interior shaded zone of the canopy and therefore had low STAR and PLA. In conclusion, training may greatly affect the development and spatial positioning of shoots, which in turn significantly affects light interception by fruiting shoots.

Microclimate alterations caused by agricultural hail net coverage and effects on apple tree yield in subtropical climate of Southern Brazil

“…The factors that appear to control the fruit yield of apple are the quantity of light energy that is intercepted by an orchard system, the proportion of that energy that is converted into available carbohydrate for partitioning and the amount of assimilate allocated to fruits (Lakso 1994;Stephan et al 2008;Yang et al 2016). The average incoming PAR in Vacaria, Southern Brazil, in the three spring-summer periods ranged between 7.4 MJ·m -2 ·day -1 under open sky and 4.2 MJ·m -2 ·day -1 under the hail net.…”

Effect of the use of anti‐hail nets on codling moth (Cydia pomonella) and organoleptic quality of apple (cv. Braeburn) grown in Alto Adige Region (northern Italy)

“…However, research focused on the effect of anti-hail nets on yield shows incoherent results: according to Iglesias and Alegre (2006) 1 the shade provided by the net reduced the apple fruit yield, whereas do Amarante et al 2 did not find any effect on yield. A reduction in the interception of light can affect the acids/soluble solids ratio 16 and the development of colour in apple skin, which is largely due to the accumulation of anthocyanins, 17 Contrasting results can be found in the literature regarding the effect of the use of nets on both these parameters. 1,2,14,18 -20 Little information is available about the effects of the use of anti-hail nets on the organoleptic quality of apple fruits.…”

Interceptação da luz pelo cajueiro

“…Porém a medição da PAR com sensores pontuais e a comparação entre dados medidos e simulados permite avaliar a possibilidade de se estimar a PAR interceptada em ramos de cajueiro, como feito em macieras por Stephan et al (2008).…”