Response of Virginia (flue-cured) tobacco genotypes to water-deficit stress

The effect of prolonged water deficit on four Virginia (flue-cured) tobacco genotypes, Line 842, Oxford 207, RG11 and Virgin D, was analyzed in whole plants. Drought stress was induced by withholding irrigation and subjecting plants to low, moderate and severe regimes. Some growth indices such as fresh weight, plant growth rate, number, color and area of new developed leaves, as well as proline, hydrogen peroxide (H2O2) and malondialdehyde (MDA) content as a measure of oxidative stress were investigated to examine the role of genotype in water-deficit tolerance. Under stress, the weight of the aboveground parts of plants, plant growth height, number of new developed leaves and leaf area index decreased with the severity of treatment. The stressed plants accumulated more proline, malonildialdehide and hydrogen peroxide than control non-stressed plants under water-deficit conditions. The results showed that among the genotypes, Virgin D (VD) was the most sensitive to drought, while L 842 and Oxford 207 were moderately tolerant; RG11 was drought-tolerant. This suggests that the correlation between the physiological traits and level of antioxidative response exists and therefore it could be used as a rapid screening test to evaluate the drought tolerance of tobacco