Response of different genotypes of safflower (Carthamus tinctoriuos L.) to the foliar spraying of nano-iron oxide at the low irrigation conditions

Among oilseeds that have a good compatibility with the climatic conditions of the Iran, safflower has a special place due to the drought and salinity resistance and also because of having the different spring and autumn varieties. Environmental stresses are the main factors reducing growth and crop yield. Among the environmental stresses, water stress is the main risks for the successful production of crops in Iran and the world. One of the most important applications of nanotechnology in various agricultural fields, especially regarding to the water and soil, is the application of nano-fertilizers to nourish plants. Iron is one the micro elements in plant nutrition. In the condition of iron deficiency, the amount of photosynthetic pigments such as chlorophyll content decreases.
To evaluate the effect of foliar spraying of nano-iron oxide on yield and some important agronomic traits of safflower genotypes at the low water stress conditions, an experiment was carried out in split factorial based on randomized complete block design with three replications in 2016 at the research farm of Imam Khomeini International University. The main factors include irrigation on two levels (full irrigation and water stress in the flowering stage) and nano-iron oxide spraying on two levels (application and non-application of nano-iron oxide) and sub-factor included 10 genotypes of safflower (Golmehr, Padideh, Goldasht, Sofeh, Mexican88, Sina, Mexican11, Isfahan mahali, Faraman and Kuseh).
The effect of irrigation on plant height, seed number in boll, boll number in plant and seed yield were significant. The interactions among all factors were also significant on plant height, main stem diameter, subsidiary branches number, seed number in boll, boll number in plant and seed yield. Mexican88 genotype had the maximum seed yield (499.5 gr. m2) in the conditions of non-stress and foliar application of nano-iron oxide. The highest boll number in plant (22) was observed in the genotype Sina in non-stress conditions and foliar application of nano-iron oxide. In conditions of non-stress and applying nano-iron oxide, genotype Sina had the highest plant height (74.33 cm) and was not significantly different from Kuseh, Sofeh, Golmehr and Isfahan mahali genotypes (73.6, 71.43, 69.2 and 68.5 cm, respectively). The effect of fertilizer was significant only on the subsidiary branches number. Mexican 88 genotype had the greatest subsidiary branches number at the conditions of stress and applying nano-iron oxide.
The study showed that, regarding to the most traits, Mexican 88 and Kuseh genotypes were suitable for planting in both conditions of stress and non-stress.