Drought Resistance and Limited Water Treatments

of Standard Apple Cultivars Grafted on Different Rootstocks II.
Nilüfer KAYNAÞ1, Kenan KAYNAÞ1,Fahrettin ÖZ1, Masum BURAK1

SUMMARY

 

This study was conducted in the non-heated green house at Yalova-Atatürk Central Horticultural Research Institute in 1995. At the studies Amasya and Granny Smith cultivars grafted on seedling, M9 and MM106 clonal rootstocks were used. The potted one year old plant kept in the green house were watered at available capacity until the beginning of July. When the outside temperature was the highest then the watering levels were changed by giving 100 %, 50 % and 25 % of available soil water. In the Limited Water Treatments (Test I): The drought resistance ability of the rootstocks and cultivars under different levels of watering were investigated until the end of the experiment. The physiological and morphological changes of the plants were determined by periodically observations and measurements. In the Drought Resistance (Test II): When the available water capacity reached up to 100 %, 50 % and 25 % levels the watering stopped. The drought resistance ability duration’s were determined until 75 % of the leaves wilted and fell down.

The results obtained in the limited water treatment as follows: In two cultivars grafted on seedling, M9 and MM106 rootstocks, a linear correlation was obtained between the amount of water given to the plants and leaf relative water content (RWC). The highest leaf RWC in the drought conditions were obtained from plants grafted on M9 and seedling rootstocks of Amasya cultivar and on M9 rootstock of Granny Smith cultivar. In all plants leaf water potential (LWP) was measured seasonally at noon time, it decreased to wards to the end of the experimental period. The amount of water given at 25 % level caused a dramatically decrease in LWP in all plants. The cultivars grafted on M9 and seedling showed slower decrease in LWP when watered at 50 % level. In the case of limited watering the growth of shoots and trunk diameters were inhibited in all plants on all rootstocks. The best growth and trunk diameter in the drought conditions were observed in all plants on M9 rootstock. During growth and development, fading of leaving due to senescence was further enhanced by limited watering regime. At the end of experiments, leaves of Amasya cultivars grafted on M9 and seedling cultivars and leaves of Granny Smith grafted on M9 cultivars were darkest. There were not any differences between numbers of stomata in the leaves of Amasya and Granny Smith cultivars. The drought resistance duration’s of all variety/rootstock combinations decreased as the water soil decreases. The drought resistance duration was longest for Amasya cultivars grafted seedling rootstock and for Granny Smith cultivars grafted M9 rootstocks.

Keywords: Apple, Rootstock, Variety, Drought Resistance