Some expression of heterosis in F1-hybrid barley

Small and large scale trials of F₁ barley hybrids were done in a glasshouse in the United Kingdom and in the field in the United Kingdom and Europe in 1970, 1971 and 1972. The results showed that there were few instances of significant positive heterosis in yield with either the small or field scale experiments. The hybrids studied were all derived from American varieties as male-sterile parents and therefore the hybrids were not adapted to European countries, thus the case for or against F₁-hybrids cannot be assessed solely on this material.