This project is part of an interdisciplinary study into the influence of one of the most devastating viral diseases of grapevines, namely grapevine leafroll disease (GLD), on vine performance, and the integration of the resulting information into decision management tools for growers. In 2009 we evaluated plant water status, leaf gas exchange, and cold hardiness of Merlot grapevines with and without GLD. The vines are grown in a commercial vineyard and drip-irrigated using regulated deficit irrigation. We found no differences in gas exchange and plant water status before veraison, but GLD was associated with lower photosynthesis during fruit ripening. This, in turn, led to partial closure of the stomata and decreased water loss by transpiration. This response, in combination with reduced shoot vigor, improved plant water status of GLD-affected vines late in the season. Thus far we have found no differences between healthy and infected vines in the cold hardiness of buds and cane bark (phloem) and wood (xylem), but we are only in the middle of the first winter season. Although they are, of course, still preliminary, the results from the first of three field seasons seem to confirm our expectation that GLD might improve drought tolerance of grapevines and that the virus may at least not have a detrimental effect on cold hardiness. We would like to caution growers not to draw any premature conclusions, before additional data confirm or otherwise these results.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF2009-10-16 07:27:582017-10-16 07:28:47Effect of leafroll disease on grapevine drought tolerance and cold hardiness