Wild barley: a source of genes for crop improvement in the 21st century?

The development of new barleys tolerant of abiotic and biotic stresses is a n essential part of the continued improvement of the crop. The domesticatio n of barley, as in many crops, resulted in a marked truncation of the genet ical variation present in wild populations. This process is significant to agronomists and scientists because a lack of allelic variation will prevent the development of adapted cultivars and hinder the investigation of the g enetic mechanisms underlying performance. Wild barley would be a useful sou rce of new genetic variation for abiotic stress tolerance if surveys identi fy appropriate genetic variation and the development of marker-assisted sel ection allows efficient manipulation in cultivar development. There are man y wild barley collections from all areas of its natural distribution, but t he largest are derived from the Mediterranean region. The results of a rang e of assays designed to explore abiotic stress tolerance in barley are repo rted in this paper. The assays included; sodium chloride uptake in wild bar ley and a mapping population, effects for delta(13)C and plant dry weight i n wheat aneuploids, effects of photoperiod and vernalization in wild barley , and measurements of root length in wild barley given drought and nitrogen starvation treatments in hydroponic culture. There are examples of the use of wild barley in breeding programmes, for example, as a source of new dis ease resistance genes, but the further exploration of the differences betwe en wild barley and cultivars is hampered by the lack of good genetic maps. In parallel to the need for genetic studies there is also a need for the de velopment of good physiological models of crop responses to the environment . Given these tools, wild barley offers the prospect of a 'goldmine' of unt apped genetic reserves.