The response of safflower genotypes to drought stress induced at the rosette stage

Abstract

Drought stress impact fuelled by climate change is becoming a global concern as it threatens food security in many arid and semi-arid lands (ASALs). However, planting drought-tolerant crops such as safflower (Carthamus tinctorius L.), in the ASALs can help ensure food security and sustainability. Greenhouse and field experiments were conducted during the 2021/2022 planting season to evaluate the response of safflower genotypes to drought stress. Factors under study were stress conditions and five safflower genotypes. The results revealed that drought stress reduced the chlorophyll content, leaf relative water content (LRWC), and plant height while the activities of ascorbate peroxidase (APX) and proline content increased. This trend was observed at different stress durations under both experiments with the effects being more noticeable when stress duration increases from 10 to 30 days. To rank genotypes based on their overall superiority, the genotype by trait (GT) biplot analysis was employed based on the mean values of all studied traits for five safflower genotypes stressed for 30 days. The results showed that genotype Kenya9819 was overall superior (drought tolerant) while Gila and Turkey ranked poorly (drought sensitive). This suggested that different safflower genotypes have different degrees of tolerance to drought stress depending on the duration of stress.