Abstract

Irrigated wheat in cold regions of Iran is faced with the end drought stress. Humic substances, as natural biological origin fertilizers have mitigation activity on plants facing the biotic and abiotic stresses. This experiment was conducted by a split plot on the basis of completely randomized block design (RB) in Ardabil in 2008 to 2009 farmer year. Main factor was stressed and non stressed conditions; and sub factor was genotypes. Gascogne, Toos, 4057 and 4041 were the most tolerant genotypes against stress from mean productivity (MP), geometric mean productivity (GMP) and stress susceptibility index (STI) indices; and had highest yield in this research. Gascogen, Sabalan and 4057 genotypes had the low susceptibility against stress by stress susceptibility index (SSI). On the basis of stress tolerance (TOL), genotypes 4041 and Toos had a high tolerance to drought stress. In non-stress condition, there were significantly positive correlations between yield and MP, GMP, STI and TOL. And, in the stress condition, correlation of yield with GMP and STI were significantly positive. Correlation of yield with SSI was negative and significant for stress condition. Cluster analysis was placed 4041 and Toos genotypes in a group which were the best genotypes of this research. These two genotypes had the high yield relative to others in the both conditions of stress and non stress. Principle components analysis showed that yield component was justified 64% of the changes; tolerance indices component 30% of the changes.

Key words: Wheat, stress, humic fertilizer, tolerance indices.

Abbreviation

RB, Randomized block design; MP, mean productivity; GMP, geometric mean productivity; STI, stress susceptibility index; TOL, stress tolerance; SSI, stress susceptibility index.