Responses of Apple Plants to Drought Stress

In order to screen apple rootstocks for drought tolerance, two different drought levels moderate and severe stress, and a control were applied to apple cultivar Red Chief grafted onto M9 and MM106 rootstocks. Apple plants were subjected to drought stress by withholding water for 15 and 19 days in the greenhouse conditions, while the control treatment was continued watering. Data were recorded 15 (moderate drought stress) and 19 days (severe drought stress) after application of drought stress. At the end of the experiment, both rootstocks were significantly affected under drought conditions. Severe drought stress caused decrease in SPAD value in Red Chief grafted onto M9 and MM106 by 15.7 % and 11.1 %, respectively. Severe drought stress declined anthocyanin content in M9 and MM106 by 7.8 % and 28.4 %, respectively. Stomatal conductance was remarkably affected by drought stress. Effects of drought stress on plants depended on rootstocks, severity and duration of drought stress. As a result, the more invigorating rootstock MM106 was found more drought-tolerant when compared to M9 that is needed to be evaluated with more parameters.