Maize Research Institute, 5835 Kneja, Bulgaria
Abstract. During two-year field trials (2012 –2013) 11 inbred maize lines were studied on two contrasting conditions: under irrigation and without irrigation (water stress simulation). Screening was carried out of the tolerance to drought of the traits describing the biometrics of the stalk and affecting the photosynthesis and the water regime in normal conditions and under stress. The relative stress tolerance and sensitivity of the studied lines to drought stress was studied. The results showed that water deficit was reduced and the plant turgor was improved in the lines: XM 94507, CHK 4382, 2378B and 26A having higher drought tolerance. The plant height of the lines AС 9434, ХM 94507, CHK 4382, 2378B and KB 11 was the least affected by the negative stress impact and they had relative resistance for that trait, while concerning the ear leaf area the inbred lines: ХM 4418, 2378B, KB 11, 26A and AС 9434 were resistant. Under drought stress all studied inbred lines reacted by decreasing the total pigment content of the leaf tissues. The differentiation of the studied inbred lines in drought tolerance could be used in the source units of adaptability selection of maize.