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 soilmoisture and reduced nitrogen supply was found amongthe wild Hordeum spontaneum accessions and thelandraces and modern cultivars of H. vulgare ofdifferent geographic origin. Measurements at the endof vegetative growth in plants grown in soil culturesrevealed genotypically specific responses to the usedenvironmental factors. Cultivars and breeding linesfrom Syria and Ethiopian landraces combined bothdrought resistance and tolerance to low nitrogen. TheSyrian barleys were also distinguished by a highnitrogen utilization efficiency (NUE) under low Nnutrition. European cultivars indicated a pooradaptation to N shortage, but some of them wereresistant to soil drought. No stress resistant barleyswere found among the wild accessions and Sardinianlandraces. Genotypic differences in the relativevalues of NUE and water use efficiency were associatedwith low N-tolerance. Some Syrian selections,Ethiopian landraces and the modern German cv. Maresiwere found to be most drought resistant. Maintenanceof a relatively high photosynthetic activity of theuppermost leaves was associated with droughtresistance. As far as concerning with the vegetativegrowth phase, the modern Syrian germplasm andEthiopian landraces may be recommended as donors ofadaptative characters for local barley breeding.