Genetic analysis of resistance in barley to barley yellow dwarf virus

The inheritance of resistance to barley yellow dwarf virus (BYDV) was studi ed in the selected 24 spring and winter barley cultivars that showed a high or intermediate resistance level in 1994-97 field infection tests. The pol ymerase chain reaction diagnostic markers YLM and Y1p were used to identify the resistance gene Yd2. The presence of the Yd2 gene was detected with bo th markers in all the resistant spring barley cultivars and lines from the CIMMYT/ICARDA BYDV nurseries. The results of field tests and genetic analys es in winter barley corresponded with marker analyses only when the Y1p mar ker was used. Genes nonallelic with Yd2 were detected by genetic analyses a nd the Y1p marker in moderately resistant spring barley cultivars 'Malvaz' 'Atribut' and 'Madras' and in the winter barley cultivars 'Perry' and 'Sigr a'. Significant levels of resistance to BYDV were obtained by combining the resistance gene Yd2 with genes detected in moderately resistant cultivars. The utilization of analysed resistance sources in barley breeding is discu ssed.