Sanitary aspects and results of the Hungarian grape breeding

In Hungary the detection of virus and virus-like diseases of grapevine began in 1960's at the Research Institute for Viticulture and Enology by János Lehoczky and his colleagues. At present sixteen virus and virus-like diseases of Vitis vinifera are known to occur in Hungary. Some of these viruses, for example fanleaf and leafroll cause significant yield loss and/or lower fruit quality. Other virus diseases, for example, Rugose wood complex can provoke untimely death of grapevine stocks. A few viruses are latent. Little is known about their effects on grapevine, however occurrence of these diseases is quite frequent, so they may have high economic importance. Regular virological screening of grapevine varieties started in 1972. The present system of screening (visual selection, indexing, ELISA) has been established using methods with continuous improvement according to recommendations of international organizations. In the first year symptomless grapevine plants are selected and marked during surveys carried out twice in the vegetation period: at about flowering and in the second half of September. At the first selection time plants are sampled for ELISA. In the spring of the second year, overwintered canes are checked by woody indexing on 8 indicator species in the field. In the third and fourth years the nursery is evaluated twice again. At the end, the marked grapevine plants, giving negative results on all indicators in every case, are considered virus-free. In autumn of the fourth year, the virus-free material is planted out under screenhouse and also in a special mother block (nuclear stock) for maintenance and propagation. During these propagation steps, visual observation and random tests by ELISA are done to monitor the virus status of the plants. The propagation is performed under strict official control by the National Plant Protection Service. Trueness to type is also monitored by the inspectors of National Institute for Agricultural Quality Control. Mother blocks of virus-free scion varieties have been established on 2 ha and those of rootstock varieties on 0,5 ha planted with the following number of varieties included in the national list: 71 European scion - and 12 rootstock varieties or variety candidates/clones. Number of other virus-free varieties and clones: 42. There are 167,8 ha of virus-free Pre-base, Base and Certified stocks from 71 European scion varieties and 98,4 ha from 12 rootstock varieties. So it is necessary to increase the area of Pre-base, Base and Certified stocks exclusively with tested virus-free (clean) material. It can be said that the sanitary and clone selection, maintenance and propagation of the vine meets EU standards in Hungary.