Adaptation of barley (Hordeum vulgare L.) to harsh Mediterranean environments III. Plant ideotype and grain yield

Abstract

Barley adapted to the combined stresses of low winter temperatures and terminal drought requires a medium carly heading date, little affected by environmental fluctuations. Two plant ideotypes that are adapted to terminal drought in Mediterranean environments can be distinguished. The first combines early heading with good early vigour, erect winter growth habit, light plant colour, and ability to recover from cold damage. The second combines medium early heading, prostrate winter growth habit, dark winter plant colour which changes to pale green in spring, and cold tolerance. This study was conducted to determine the relationship between consistency in heading date and plant ideotype, and to identify the usefulness of earliness and plant ideotype as criteria for indirect selection for grain yield under drought. Thirty-six two-rowed entries of barley (Hordeum vulgare L.) were sown at 15 environments in northern Syria. Average grain yields ranged from 7 to 331 g/m2; the range in average heading date was 20 days. Consistency in date of heading was related to the second ideotype through vernalization requirement. Early heading was positively correlated with grain yield in most of the environments, but especially in low-yielding environments. After eliminating the effect of heading date, the second plant ideotype was advantageous only under harsh conditions. In early generations, selection under favourable conditions for earliness, prostrate winter growth habit, dark winter plant colour, and cold tolerance is a useful alternative for yield testing, to identify material well adapted to environments experiencing low winter temperatures and terminal drought stress. Selection for the first plant ideotype is proposed for Mediterranean environments with mild winters.