Grapevine leafroll disease causes poor color development in red grape varieties and non-uniform maturation of fruit in Vitis vinifera. It also has been reported to cause delay in fruit maturation from 3 weeks to a month and crop losses of as much as 20-40%. To date 11different viruses, named Grapevine leafroll associated virus (GLRaV) types -1 to -7, -9, -10, -11 and a newly discovered virus from a Carnelian clone which tentatively has been named GLRaV-Car are proven to be associated with leafroll disease. This project was planned to study the effects of GLRaV types -1 and -2 (2 isolates each), -3 (3 isolates), -4, -5, -7 and -9 (one isolate each) and a combination of two of types -1, -2, -3, -5 and -7 on Cabernet Franc grafted on 9 different rootstocks. Rootstocks used are AXR #1, Mgt 101-14, 110R, 3309C, 5BB, 420A, Freedom, St. George 15 and St. George 18. In this experiment 15 replicates for each treatment in three different blocks (5 replicate per treatment per block) were used. The data collected from the experiment in 2011 showed that the virus isolate LR132 (a mixed infection of GLRaV-1 and Grapevine virus A) had unfavorable reaction on Cabernet Franc plants propagated on 420A, Freedom, 3309C and 101-14 rootstocks and many of these plants died few months after inoculation. It is not clear whether a certain strain of GLRaV-1 is the cause of poor vine performance or the presence of GVA creates a synergistic effect and kills the plants. It was also found that the presence of GLRaV-2 had harmful reactions on vines propagated on Freedom and 5BB. These vines were week and exhibited red leaf symptoms, short internodes and almost dying. Furthermore, it was shown that different GLRaV types produce leaf symptoms with different severity, for example, it was observed that leaf symptoms produced by GLRaV-3 was more severe than by GLRaV-4.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF2011-10-15 14:46:582019-01-22 18:46:57Grapevine Leafroll Disease, a General Detail Study and Evaluation