Resistance to the Barley Yellow Mosaic Virus Complex — Differential Genotypic Reactions and Genetics of BaMMV‐Resistance of Barley (Hordeum vulgareL.)

摘要

AbstractBarley yellow mosaic disease is caused by several viruses, i.e. barley yellow mosaic virus (BaYMV), barley mild mosaic virus (BaMMV) and BaYMV‐2. The reaction of different barley germplasms to the barley mosaic viruses was studied in field and greenhouse experiments. The results show a complex situation; some varieties are resistant to all the viruses, while others are resistant to one or two of them only.Crosses between different barley germplasms were earned out in order to test whether genetic diversity of resistance against mosaic viruses does exist, particularly, BaMMV. A total of 45 foreign barley varieties were crossed to German cultivars carrying the resistance geneym4.In F2of 27 crosses, no segregation could be detected, leading to the conclusion that the resistance genes of the foreign parents are allelic withym4e.g.Ym1(‘Mokusekko 3’) andYm2(‘Mihori Hadaka 3’). A total of 18 crosses segregated in F2indicating that foreign parents, like ‘Chikurin Ibaraki 1’, ‘Iwate Omugi 1’, and “Anson Barley”, carry resistance genes different from the gene of German cultivars, e.g. ‘Asorbia’ or ‘Franka’. By means of statistical evaluation (Chi2‐test), the observed segregation ratios were analyzed in order to obtain significant information on the heredity of resistance. All the resistance genes described here as being different from the geneym4, act recessively. Most of the exotic varieties seem to carry only one resistance gene. In a few cases, mo