Effect of surface coating with waxes on the dormancy of potato tubers grown from true potato seed (TPS)

The control of dormancy is of great importance for the long-term storage of potato tubers.
The effect of tuber coating with two waxes (paraffin wax and the edible wax ‘Teycer’, based on shellac and oxidised polyethylene) on the dormancy, weight loss, respiration and soluble sugars (glucose, fructose, sucrose) content of tubers grown from true potato seed (IP88008) was studied, using untreated tubers as controls.
Tubers were stored for 120 days after treatment (DAT) in the dark at three different temperatures (5, 15, 20°C) and 80±5% R.H. Paraffin wax and ‘Teycer’ did not affect tuber dormancy at 5°C. In comparison with the controls, paraffin-treated tubers had a lower number of sprouted buds after the 42^nd (15°C) and the 35^th (20°C) DAT, lower weight loss (5, 15°C) and lower respiration rate up to the 15^th (5°C) and the 5^th (15, 20°C) DAT. However, they presented higher weight loss at 20°C and a higher respiration rate after the 25^th and 10^th DAT at 15 and 20°C, respectively.
In contrast, ‘Teycer’ increased tuber sprouting after the 7^th (20°C) and the 21^st (15°C) DAT, as well as tuber weight loss at 5°C, but it had no effect on tuber weight loss at 15 and 20°C. In addition, ‘Teycer’ caused tuber rotting (18-32%) at all storage temperatures. ‘Teycer’-treated tubers had lower respiration rates than the controls from 5 to 15 DAT (5°C) and up to the 10^th (15°C) and the 5^th (20°C) DAT. However, respiration was higher than the controls after the 40^th (5°C) and the 50^th (15, 20°C) DAT. In comparison with the control, fructose, glucose and sucrose content was higher in both paraffin-treated and ‘Teycer’-treated tubers at all storage temperatures.
These findings suggest that paraffin wax effectively controls tuber dormancy at 15°C, whereas the application of ‘Teycer’ is not satisfactory for the control of tuber dormancy.

III International Symposium on Horticulture in Europe – SHE2016

T. Karanisa, A.A. Alexopoulos, K.A. Akoumianakis, I.C. Karapanos, H.C. Passam

edible wax, fructose, glucose, paraffin, respiration, Solanum tuberosum, sucrose

https://doi.org/10.17660/ActaHortic.2019.1242.105