The diversity of apple cultivars on the market gives consumers a choice that often depends on the appearance of the fruit. The 'Pinova' cultivar requires at least 1/3 of the fruit to be red colored. Insufficient colouration can be a problem as it reduces the market value of the fruit. Agricultural practice such as foliar application of phosphorus fertilisers can improve the colour, but no such trials have yet been carried out for the 'Pinova' cultivar. Our objective is to investigate the effect of foliar application of phosphorus fertilisers (MKP, Phostrade Ca) on the colour of 'Pinova' apples without adversely affecting the quantity or quality of the crop. We were also interested in the effect of harvest date on colour intensity, soluble solids content, starch value, firmness and the content of sugars, organic acids and phenolics. For the ripeness tests, 20 apples from each treatment were used, as well as for the laboratory tests. The results of the experiment show that there are no statistically significant differences in sugar and organic acid content between the treatments. Higher levels of phenolic groups in the flesh and skin were observed in the Phostrade Ca fertilised fruit. Measurements of fruit quality in terms of size, weight, firmness, soluble solids and colour showed no statistically significant differences between treatments. Regarding harvest date, foliary fertilised apples from first harvest had higher firmness while fruits from second harvest showed higher soluble solids content as comapred to nontreated control. The effect of phosphorus foliar fertiliser application on the improvement of the colour of 'Pinova' apples was not confirmed, nor were there any statistically significant effects on the other quality parameters.
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