Kvasny Prum. 2010; 56(3): 118-122 | DOI: 10.18832/kp2010015

Possibility of evaluation of drought tolerance in barley.Peer-reviewed article

Ludmila HOLKOVÁ, Lucie MELIŠOVÁ, Marta BRADÁČOVÁ, Pavlína MIKULKOVÁ, Jaroslava EHRENBERGEROVÁ

Ústav pěstování, šlechtění rostlin a rostlinolékařství, Mendelova univerzita v Brně, Zemědělská 1, 613 00 Brno

Breeding of drought-tolerant varieties, which is steadily gaining in importance for improving crop yields and health condition of economically important crops, is based on evaluation and efficient selection of tolerant genotypes. The assessment of plant sensitivity to drought is not simple owing to the complex character of this trait. We compared the stress responses of five different barley genotypes with different sensitivity (Tadmor, Malz, Amulet, Bojos and Jersey) exposed to drought stress by using a molecular biological method based on evaluating the activity of two dehydrin genes, Dhn1 and Dhn4. The efficiency of the method was verified in laboratory conditions and also in a pot experiment in which only watering was regulated. More detailed evaluation was done on plants grown hydroponically in a cultivation box under conditions of physiological drought (-0.3 MPa). Transcription activity of both genes, as dependent on stress sensitivity, was evaluated over 14 days in leaf tissue samples. The more tolerant genotypes (Tadmor and Malz) exhibited lower water losses from tissues and higher expression of both genes. Comparable results for individual varieties were obtained also in the pot experiment, which confirmed the relationship between the activity of these genes and drought sensitivity, especially in the phase of earing and grain formation. The activity of the two genes was further evaluated under the action of exogenously applied phytohormone ABA. ABA was found to activate only the expression of the Dhn4 gene and a marked increase in expression was observed only in variety Malz. Comparison of results of all three experiments documented the usefulness of the method as a tool for determining drought tolerance of barley and revealed two different mechanisms of activation of stress protective responses in the two tolerant varieties Tadmor and Malz, which could reflect a different participation of the ABA phytohormone in their regulation.Breeding of drought-tolerant varieties, which is steadily gaining in importance for improving crop yields and health condition of economically important crops, is based on evaluation and efficient selection of tolerant genotypes. The assessment of plant sensitivity to drought is not simple owing to the complex character of this trait. We compared the stress responses of five different barley genotypes with different sensitivity (Tadmor, Malz, Amulet, Bojos and Jersey) exposed to drought stress by using a molecular biological method based on evaluating the activity of two dehydrin genes, Dhn1 and Dhn4. The efficiency of the method was verified in laboratory conditions and also in a pot experiment in which only watering was regulated. More detailed evaluation was done on plants grown hydroponically in a cultivation box under conditions of physiological drought (-0.3 MPa). Transcription activity of both genes, as dependent on stress sensitivity, was evaluated over 14 days in leaf tissue samples. The more tolerant genotypes (Tadmor and Malz) exhibited lower water losses from tissues and higher expression of both genes. Comparable results for individual varieties were obtained also in the pot experiment, which confirmed the relationship between the activity of these genes and drought sensitivity, especially in the phase of earing and grain formation. The activity of the two genes was further evaluated under the action of exogenously applied phytohormone ABA. ABA was found to activate only the expression of the Dhn4 gene and a marked increase in expression was observed only in variety Malz. Comparison of results of all three experiments documented the usefulness of the method as a tool for determining drought tolerance of barley and revealed two different mechanisms of activation of stress protective responses in the two tolerant varieties Tadmor and Malz, which could reflect a different participation of the ABA phytohormone in their regulation.

Keywords: drought tolerance, Dhn genes, ABA, barley

Received: November 15, 2009; Accepted: January 18, 2010; Published: March 1, 2010