European Journal of Sustainable Agroecosystems

Context: Although the safflower (Carthamus tinctorius L.) is known as a highly significant oilseed crop and its potential as a crop may not have been fully explored but it is still significant due to its high tolerance to drought, its adaptability to saline soil, and its robust root system. However, it is important to point out that global warming has caused the safflower plant to face threats to its growth with a possible decline in yield to as high as 53% under terminal heat stress. Although safflower has a reputation of being a climate-resilient crop, there are not many studies that have focused on safflower’s heat vulnerability in comparison with other oilseed crops such as soybeans, sunflower, or canola.
Purpose: This paper’s goal is to analyze the present diverse methods of growing safflower, such as changing sowing date, choosing appropriate genotype, or using biostimulants and antioxidants, and analyze their effect on the growth of safflower and its yield during a terminal heat stress period.
Literary sources: The analysis was based on results of literature search in databases such as Scopus, Web of Science, PubMed/PMC, ScienceDirect, SpringerLink, Frontiers, and PeerJ, and at the same time, it included reports issued by agricultural research institutes in different parts of the world, as well as combinations of words, such as “safflower,” “Carthamus tinctorius,” “heat stress,” “terminal heat stress,” “sowing date,” and “agronomic management” etc.
Research results: Results indicated that the best time to sow safflower is the best and least costly means of overcoming heat stress during flowering and grain filling, where ill-timed sowing can reduce the yield by almost half. Discovery of the most heat resistant cultivar indicated that high genotypic variation was registered for heat resistance, which was associated with osmolyte accumulation and some other traits. The application of salicylic acid, selenium, and potassium biostimulants led to the improvement of physiological resilience and biological yield of safflower by 12%–13%, while the combination of safflower with chickpea under rainfed growing conditions significantly increased the microclimatic stability and the level of yield. Finally, irrigation policy and canopy temperature depression were suggested to be effective indicators of heat and drought resistant genotypes.
Research gaps: There is a paucity of multi-site and multi-season validation of biostimulants and cropping systems that are particular to end-of-season heat stress, the integration of genotype-environment-management tests, and evaluations of the economic viability of interventions for poor farmers.
Conclusion: The use of phenology-based sowing adjustment in combination with heat-resistant variety adoption and suitable physiological solutions creates a feasible approach to maintain safflower productivity under more heat stress, although it is important to perform further calibration and validation in particular regions.