Seed Priming Treatments to Improve Heat Stress Tolerance of Garden Pea (Pisum sativum L.)

Heat stress seriously affects the production of cool-season food legume crops such as garden peas. Seed priming is a widely used technique that increases germination and improves plant growth and development, resulting in better field performance and higher yield of crops. In the current study, we investigated three seed priming treatments-hydropriming (dH(2)O), osmopriming (2.2% w/v CaCl2), and hormopriming (50 mg L-1 salicylic acid-SA)-and their effect on germination, initial seedling development, and physiological traits of two novel garden pea cultivars, under optimal conditions and heat stress. Seed priming with H2O, CaCl2, and SA enhanced garden pea performance under both optimal and stress conditions via significant improvements in germination energy, final germination, mean germination time, mean germination rate, seedling vigor index, shoot length, root length, fresh seedling weight, dry seedling weight, shoot elongation rate, root elongation rate, relative water content, chlorophyll content, and membrane stability index, as compared to control. The highest effect on the examined parameters was achieved by osmopriming and hormopriming in both cultivars, suggesting that these treatments could be used to improve the heat stress tolerance of garden pea, after extensive field trials.