Influence of shading effect on specific leaf weight of 'Fuji' and 'Gala' apples - meta-analysis
Influence of hail netting on vegetative characteristics of specific leaf weight in apple, though important, is not intensively studied and the results from published papers are inconsistent. This paper aims to apply the technique of meta-analysis in order to provide biometrically sound and scientifically valid insight into the effect of shade netting on specific leaf weight of apple. Meta-analysis is a technique that draws conclusive results from available metadata in the published papers. Meta-analysis also enables researchers to estimate the general effect size of interest. By conducting a search for valid scientific trials on shade net effect on specific leaf weight of apple eight studies were combined and metadata acquired from four different papers on Fuji and Gala apples. A matrix of 208 metadata with details related to control, standard deviation, type of netting, cultivar, sample size, trees, orchard and climate was prepared. The combined number of analysed leaves in the treatment groups was 1140 plus the equal number of leaves in the control groups. Results indicate that hail netting in general has a statistically significant influence on specific leaf weight of Fuji and Gala apples. Specific leaf weight generally decreases on apple trees grown under hail nets by 12.1%, or 1.01 mg cm‑2 in comparison to trees which are not covered with hail nets. This effect is significant for both Fuji and Gala apples under dark and bright nets. Even moderate shade provided by bright hail nets triggers a compensation mechanism in apple leaves which reduces the thickness of mesophyll and increases chlorophyll content. These modifications improve the efficiency of photosynthesis in shaded leafs.
Bosančić, B., Pecina, M. and Mićić, N. (2021). Influence of shading effect on specific leaf weight of 'Fuji' and 'Gala' apples - meta-analysis. Acta Hortic. 1308, 265-270
leaf characteristics, hail net, shade net, metadata, SLW