Crossability barriers between barley ( Hordeum vulgare L.) and Hordeum bulbosum L. Genetical studies of the partial incompatibility mechanism in the barley cultivars ‘Vada’ and ‘Vogelsanger Gold’

The crossability with Hordeum bulbosum was investigated in the barley cultivars ‘Vada’, two‐rowed spring barley, and ‘Vogelsanger Gold’, sis‐rowed winter barley and their F 1 ‐ and F 2 ‐combinations with the barley line VK 16032, which shows high crossabilily with H. bulbosum . The low seed set of ‘Vada’, 4.5 %. was reflected in its F 1 with VK 16032, 6.1 % seed set. ‘Vogelsanger Gold’ showed considerably lower seed set than the F 1 , VK 16032 בVogelsanger Gold’, 9.5 % and 29.7 % respectively. Both F 2 ‐populations revealed a 3:1 segregation between partially incompatible and compatible plants although the variation between individual plants was greater in the VK 16032 בVogelsanger Gold’ group. The partial incompatibilities in both ‘Vada’ and ‘Vogelsanger Gold’ are governed by dominant genes but may be further influenced by environmental and additional genetic factors especially in ‘Vogelsanger Gold’, and it was also assumed that more than one gene for incompatility with H. bulbosum is present in the barley genome. A linkage study showed no linkage of incompatibility to either the winter or six‐rowed character and accordingly it was concluded that low crossability in certain European six rowed winter barley genotypes could easily be overcome.