Effects of essential oils on potato tuber sprouting at room temperature storage in Ethiopia

Abstract

This study was conducted with the objective of finding alternative management options for potato tuber sprouting during storage. Essential oils from <i>Croton macrostachyus</i>, <i>Eucalyptus globulus</i>, <i>Allium sativum</i>, <i>Cymbopogon citratus</i>, <i>Cymbopogon martini</i>, <i>Rosmarinus officinalis</i> and <i>Thymus schimperi</i> were applied in completely randomized design using two quantities (1 and 2 ml) and three frequencies (1, 2, 3). Essential oils from <i>Cymbopogon citratus</i> and <i>Thymus schimperi</i> showed the lowest percentage of weight loss relative to control tubers for varieties <i>Gudene</i> (8.07%) and <i>Jalene</i> (13.34%), respectively. Essential oils were applied in the form of vapour inside wooden box for 24 h without direct contact with tubers. For both varieties, the potato tuber weight loss found to be minimized using 2 ml essential oils. Similarly, lowest percentage of weight loss at one, two and three applications were found for variety <i>Jalene</i> from <i>Cymbopogon martini</i>, <i>Eucalyptus globulus</i> and <i>Croton macrostachyus,</i> respectively<i>.</i> On the other hand, lowest percentage of weight loss was maintained using <i>Eucalyptus globulus</i> for variety <i>Gudene</i>. The number and length of sprouts did not vary with quantities. Therefore, for variety <i>Gudene</i>, lower number of sprouts relative to control tuber (3 sprouts/tuber) was found on potato tuber treated with essential oils from <i>Cymbopogon martini</i> and <i>Thymus schimperi</i> (2.7 sprouts/tuber) whereas for variety <i>Jalene</i>, lower number of sprouts relative to control tuber (8.7 sprouts/tubers) was found on potato tubers treated with essential oils from <i>Allium sativum</i> and <i>Rosmarinus officinalis</i> (5.7 sprouts/tuber). The length of the longest sprouts on control tubers was 11.7 mm and 20 mm for varieties <i>Gudene</i> and <i>Jalene</i>, respectively. Longest and shortest length of sprout was found on potato tubers treated with <i>Eucalyptus globulus</i> and <i>Rosmarinus officinalis</i>, respectively, for both varieties. Therefore, essential oils used in the current study are promising alternatives to control potato sprouting during storage. However, seedlings of these species and other potential species must be made available to farmers with training on how to make extracts and apply them.