Resistance of ‘Laverda’ to powdery mildew and its presence in some winter barley cultivars

In the last two decades, powdery mildew resistance has been investigated in a large number of barleys grown in the Czech Republic. However, only 14 winter barley cultivars were resistant to all used isolates. In this paper, new tests on these cultivars and also on ‘Verena’ are presented. Thirty-two reference isolates of Blumeria graminis f. sp. hordei, including some isolates collected in 2009, were used. One of the latter was virulent on ‘Laverda’ and ten other six-rowed cultivars. It is recommended that this resistance be designated Lv. Another six-rowed cultivar ‘Dubai’ showed a different resistance to which virulent isolates were also found in 2009. Thus, four resistances were found among the 15 cultivars and only three two-rowed cultivars ‘Himalaya’, ‘Venezia’ and Br4190a1 showing two different resistance spectra remain fully resistant to all used isolates