ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 102, No. 4 (2015), p. 403–410
DOI 10.13080/z-a.2015.102.051

Effect of post-harvest flame-defoliation on strawberry (Fragaria × ananassa Duch.) growth and fruit biochemical composition

Reelika RÄTSEP, Ulvi MOOR, Ele VOOL, Kadri KARP


The experiment with strawberry (Fragaria × ananassa Duch.) cultivar ‘Darselect’ was carried out at the Research Centre of Organic Farming of Estonian University of Life Sciences (58º21′ N, 26º40′ E). The objective of the present research was to determine the influence of post-harvest defoliation with a directed propane flamer and the combination of flaming and additional application of humic substances on strawberry growth and fruit biochemical composition in two successive years. Defoliation decreased the number of leaves and inflorescences, and crown and root mass. Post-harvest flame-defoliation of two-year-old plants increased the yield in the next year (in 2012), but the succeeding flame-defoliation decreased the yield in the following year (in 2013). The effect of defoliation on fruit biochemical composition was significant, but differed between years and fruit orders. The defoliation treatment increased soluble solids content in primary fruits from 8.9 to 9.3 °Brix, but decreased anthocyanins content in all fruit orders in 2012. Flaming treatment increased the content of phenolics from 181 to 206 mg 100 g-1 in primary, but decreased from 268 to 254 mg 100 g-1 in tertiary fruits in 2013. Application of humic substance to the defoliated plants increased the number of leaves in 2012, and crown and root mass in 2013, but decreased the yield in both years. The influence of the treatment differed yearly for soluble solids – decreasing the content in 2012, but increasing in 2013. Humic substances had positive influence on the total phenolics and anthocyanins content in both years.

Keywords: anthocyanins, ascorbic acid, humic acids, soluble solids, titratable acids, total phenolics.

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