Effects of kaolin and seaweed (Ascophyllum nodosum) applications on the physiological and vegetative development of Spil Karası table grape cultivar grafted on different rootstocks in a soilless culture under deficit irrigation conditions

Greenhouse gases, which began to increase rapidly with the industrial revolution, triggered global warming, causing changes in the earth's climate that have become a global problem. These changes have had effects at different levels in many parts of the world and have affected viticulture as well as other branches of agriculture. It is predicted that especially the decreasing amount of precipitation and changing precipitation distribution will affect viticulture in many ways. Since the world's vineyard regions are generally in arid ecologies, it is reported that water is the main factor limiting productivity in vines, especially in arid and semi-arid agricultural areas. In order to reduce these negativities, researchers have focused on finding a suitable solution to alleviate the effects of drought in recent years. For this purpose, the physiological and vegetative responses of the 'Spil Karasi' grape cultivar, grafted to different rootstocks (1103 P, 5 BB and 41 B) and grown on its own root, under full and limited irrigation conditions, to kaolin and seaweed applications were investigated. In order to limit the effects of environmental factors and to understand the effects of the applications more accurately, the study was carried out in a soilless culture environment (equal volume of peat and perlite mixture) under greenhouse conditions. According to the physiological findings obtained, chlorophyll values, leaf relative water content and stomatal conductance decreased, while leaf temperature, malondialdehyde amount and cell membrane permeability increased in grafted and ungrafted grapevines in the restricted irrigation environment. Considering the vegetative parameters, it was determined that the number of leaves, area, fresh and dry weights, shoot length, shoot diameter and woody shoot length decreased in all vines in the limited irrigation environment. It has been understood that kaolin and seaweed applications under limited irrigation conditions, with some exceptions, have positive effects on efficient photosynthesis in vines, better management of the physiological process and therefore reducing the effect of stress on vines. In all parameters, kaolin and seaweed increased the photosynthetic efficiency in grapevines and positively affected grapevine physiology and vegetative development.