Drought stress effect on the leaf relative water content and proline content of safflower genotypes

Drought stress reduces the productivity of many crops especially in arid and semi-arid areas. In such areas the use of tolerant genotypes becomes ideal for increased growth and yield. A greenhouse experiment was conducted to study the effects of drought stress on the leaf relative water content (LRWC) and proline accumulation of various safflower genotypes. Factors under study were drought (stressed and non-stressed plants), three developmental stages, and five safflower genotypes. The results showed that drought stress significantly reduced LRWC and increased accumulation of leaf proline content. However, there were no genotypic differences regarding leaf proline accumulation with increase in stress level. The genotype ‘Turkey’ was the earliest to experience the highest level of water loss and accumulation of leaf proline content, irrespective of phenological stage. On the contrary, the genotypes ‘Gila’ and ‘Kenya-9819’ had the lowest percentage of leaf water loss and no signs of proline accumulation during the early stages of stress induction. These results suggested that the genotype ‘Turkey’ was more likely to be drought sensitive compared to the genotypes ‘Gila’ and ‘Kenya-9819’ which were the most drought tolerant. Key words: Botswana, drought tolerance, proline accumulation, safflower