Improved Mg nutrition of grapevine due to a comprehensive analysis

Magnesium is an essential component of chlorophyll for plant physiology. Low Mg content in the leaves of grapevines reduces photosynthesis and, thus, glucose production and, consequently, lower wine quality. The right choice of rootstock is essential to alleviate this deficiency. However, the necessary Mg efficiency restricts the selection of the rootstocks, and in particular, the rootstocks that have been tried and tested in this country are less suitable. The deficiency can also be remedied by fertilizing the leaves, at least in the short term. But, the most sustainable solution would be to plant clones with an unproblematic Mg metabolism. An important grape variety for Austrian viticulture is mainly affected by Mag deficiency, namely Welschriesling (WR). The WR clones that are available for domestic viticulture all show more or less a weak Mg uptake. The variety has been used in viticulture for several centuries and was intensively cultivated and therefore exists in different genetic types. Since the old descriptions do not report this Mg deficiency, it is entirely conceivable that there is genomics in old genotypes that show average Mg utilization. Therefore, it would be necessary to look for genotypes that offer a better uptake and research it genetically. It is well known that crop phenotypic variation is shaped by their ancestors’ genetic variation and the selection and maintenance of collections of mutations. Moreo ver, most of this varia ti on is quan ti ta ti ve. Therefore, more than ever, an essential goal of genetics is to identify and use appropriate bio-markers for selection. In this way, appropriate biomarkers could be developed for the selection of WR, which enables a distinction between Mg-efficient and inefficient, which is very important for winegrowers. New clones with Mg efficiency would strengthen the local vine nurseries and viticulture and could also mean that vine material can be delivered to the neighbouring countries Hungary, Croa tia, Slovenia and Slovakia because the problem also exists there. Furthermore, this would result in a competitive advantage for domestic planting stock companies.