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The purpose of the experiment was to investigate the relationship between the accumulation of polyamines during the filling period of wheat grain with yield and grain protein under dryland and supplemental irrigation (SI) conditions and also the effect of foliar spraying of urea on the amount of polyamines in grain a factorial experiment was conducted based on randomized complete block design with three replications during two cropping seasons. The examined treatments included water availability (dryland and SI), wheat cultivars (Homa, Sardari, Rijaw, Ouhadi, and Azar2), and foliar application of urea (control and 4% urea foliar application). The results demonstrated that SI (10%) reduced and urea foliar (12%) application increased the percent of grain protein. SI reduced the contents of three PAs by 24%: spermine, spermidine, and putrescine. But urea foliar application increased the three PAs in the first and second years by 31% and 27% in dryland conditions and 12% and 4% in SI conditions, respectively. These results indicated that there is less need for PAs in SI conditions, and they thus exhibit poorer accumulation in the grain; in dryland conditions, however, their content increases with greater access to foliar nitrogen. Older cultivars Sardari and Azar 2 had more polyamines. According to the observed positive correlation between 1000-grain weight and the three PAs under stress conditions, PAs are probably involved in the improvement of grain filling, and urea foliar application can affect drought tolerance by increasing PA accumulation. Moreover, cadaverine exhibited a different function from the other PAs. [ABSTRACT FROM AUTHOR]

Drought is a major obstacle for wheat production around the world. Seed priming and foliar nutrition spray at various stages of growth have both been shown to be beneficial in lowering stress and improving wheat grain production. For this reason, this experiment was conducted in the form of split plots in a randomized complete block design with two factors including seed priming (Main factor) and foliar application (Sub-factor), and 3 replications during the 2018–2019 and 2019–2020 cropping seasons. Eight seed priming treatments including control (without seed priming), water (hydro-priming), urea (2%), zinc sulfate (0.6%), potassium chloride (1%), calcium chloride (1.4%), vitaspirin (1 g L−1), and cytokinin (50 mg L−1) were randomized on the main plot, and 3 foliar application treatments including control (without foliar application), urea (4%), and vitaspirin (0.1%) were randomized on a sub-plot. The results showed that the thousand kernel weight had not had much effect on grain yield in this experiment. Furthermore, treatments that increased the number of grains had a positive impact on enhancing grain yield. In the 2020–2019 cropping season, none of the seed priming treatments enhanced grain yield because of temperature and rainfall constraints. This demonstrated the role of early growth conditions in the effectiveness of seed priming treatments. As a result, seed priming treatments without foliar application under dryland conditions cannot be recommended due to the unpredictability of weather conditions. In both cropping seasons, seed priming with calcium chloride + foliar application of vitaspirin was one of the top three treatments in terms of grain yield. [ABSTRACT FROM AUTHOR]