Variation in utilization efficiency and tolerance to reduced water and nitrogen supply among wild and cultivated barleys

Broad genotypic variation in the response to low soil moisture and reduced nitrogen supply was found among the wild Hordeum spontaneum accessions and the landraces and modern cultivars of H. vulgare of different geographic origin. Measurements at the end of vegetative growth in plants grown in soil cultures revealed genotypically specific responses to the used environmental factors. Cultivars and breeding lines from Syria and Ethiopian landraces combined both drought resistance and tolerance to low nitrogen. The Syrian barleys were also distinguished by a high nitrogen utilization efficiency (NUE) under low N nutrition. European cultivars indicated a poor adaptation to N shortage, but some of them were resistant to soil drought. No stress resistant barleys were found among the wild accessions and Sardinian landraces. Genotypic differences in the relative values of NUE and water use efficiency were associated with low N-tolerance. Some Syrian selections, Ethiopian landraces and the modern German cv. Maresi were found to be most drought resistant. Maintenance of a relatively high photosynthetic activity of the uppermost leaves was associated with drought resistance. As far as concerning with the vegetative growth phase, the modern Syrian germplasm and Ethiopian landraces may be recommended as donors of adaptative characters for local barley breeding.