VIRUS DISEASES SCREENING IN CLONAL SELECTION OF CROATIAN GRAPEVINE CULTIVARS

Abstract

There is a large number of grapevine cultivars grown in Croatia. Most of them are considered to be autochthonous. Unfortunately, clonal selection of these cultivars has never been done and there is no planting material of adequate quality standards. As a first step in clonal selection, mass positive selection together with sanitary selection of 15 economically important cultivars has been started. In rpoceeding of genetic selection visual symptoms of the viruses have also been observed. Samples of dormant canes have been taken from vines with positive agronomic traits and no visible symptoms of virus infection. The presence of four economically important viruses was evaluated using ELISA (enzyme linked immunosorbent assay): two nepoviruses, Grapevine fanleaf virus (GFLV) and Arabis mosaic virus (ArMV) and two closteroviruses Grapevine leafroll-associated virus 1 (GLRaV-1) and Grapevine leafroll-associated virus 3 (GLRaV-3). Survey of virus deseases in production vineyards of different vine-growing region of Croatia has disclosed the widespread presence of viruses and the number of non infected vines was rather low. This is true especially for the coastal region where it was not possible to find any healthy plant of certain cultivars. Although no visible symptoms were observed , it was not rear to detect multiple infections with two or even three viruses. Mostly spread virus in Dalmatia was GFLaV-3 with approximately 80% of vines infected. The situation is much better in northern region, where almost half analysed plants were healthy and most represented virus is GLRaV-1. The presence of both nepoviruses is rather low, especially ArMV (only 1% of vines infected) and somewhat higher of GFLV in Dalmatia.