Breeding rootstock varieties with complete phylloxera resistance

Since its first appearance in Europe in 1863 phylloxera has been a major threat to European viticulture. Phylloxera tolerant rootstock varieties are since then used to control this pest. During recent years phylloxera damages occurred even in grafted vineyards in California and Germany. The rootstock variety 'Borner' (Na 5153-54) appears to be able to overcome these problems. It is a cross between Vitis riparia and the completely phylloxera resistant Vitis cinerea Arnold. So far it has demonstrated a high resistance against all strains of phylloxera, available for testing. It has a grafting affinity similar to commonly used Berlandieri x Riparia rootstocks and shows a good adaptation to a wide range of soil types. The performance of Riesling as scion grafted on 'Borner' is similar or better than that of commonly used rootstocks in Germany and in particular under dry conditions. The only problems encountered so far are iron chlorosis on extremely wet, heavy, water logged soils and moderate rooting under certain conditions.