عنوان مقاله [English]
Safflower (Carthamus tinctorius L.) is a member of the family Compositae cultivated for its seed, which is used as edible oil. This crop was also grown for its flowers, used for coloring and flavoring foods and making dyes. It is a rich source of oil (35-40 %) and linoleic acid content (75-86 %). Safflower flowers are known to have many medicinal properties for curing several chronic diseases. This annual Compositae plant native in Iran, India, the Middle East, and East Africa and it has recently received much attention due to its adaptation to arid and dry areas in terms of oil production (Poordad, 2003). It has also been proved that the growth and performance of crops in many parts of the world are affected by biotic and non-biological stresses; therefore, there is a large difference between the real and potential yields. Considering Iran's climatic features, the selection of plants with low water demand and high value-added is essential to ensure food security and promote development.
This plant is a multifunctional crop due to its wide adaptation to different climates and its high tolerance to adverse environmental conditions; therefore, conducting extensive breeding and agronomic studies and striving to develop cultivation and improvement is essential (Khajehpour, 2012). In plants, leaves are the main source of light absorption and conversion of light energy to photosynthetic material for growth, development and filling of seeds, so any reduction in leaf surface areas like diseases, weeds or mechanical damage (hail) can cause malfunction and decreased absorption and utilization of Co2 in plant (Ashly et al., 2002). Improvement in crop yield was the result of greater dry matter allocation to grains, so approaches to improve grain yield include increased seeding, delayed leaf aging, and increased seed filling duration (Imam and Thaqi al-Islami, 2005). However, in the first place, crop yield improvement requires seed germination and proper seedling establishment because it exposes plants to a variety of biological and non-biological stresses, especially drought stress. Priming is one of the cheapest ways to improve seedling establishment (Ashraf and foolad, 2005). Effects of priming on seed stability for better germination have been thoroughly described under suboptimal studied by (Vahid et al., 2007) and the effect of temperature and humidity by (Dual and Tuong, 2008) different methods of priming was completely discussed. It has been reported that the pretreated seeds had high resistance to stresses and seed priming improves the quality and quantity of crop produced under appropriate and stressful conditions