Seed Priming Induced High Temperature Tolerance in Wheat by Regulating Germination Metabolism and Physio-biochemical Properties

High temperature is one of the major limiting factors in wheat (Triticum aestivum L.) production in arid and semiarid regions of world. The crop experiences moderate to severe high temperature during most of its reproductive growth stages. In this pot study, the efficacy of seed priming treatments to improve the performance of wheat genotype (NIA-Amber) under optimal and late sowing was evaluated. Wheat seeds were subjected to hormonal priming with salicylic acid (SA), osmopriming with calcium chloride (CaCl2), sorgaab (Sor) and moringa leaf extract (MLE) for 12 h. Results revealed that priming treatments significantly improved seed emergence and seedling establishment under both sowing dates. However, seedlings raised from SA priming, showed least time taken to 50% emergence (E-50) while osmopriming with MLE exhibited lesser mean emergence time and maximum emergence rate, coefficient of uniformity index and final emergence percentage over control. Furthermore, flag leaf area, spike length, 100 grain weight, grain yield per plant and chlorophyll content were improved in plants raised from seeds primed with SA, MLE and Sor. Contrarily, utmost relative water contents, glycine betaine and total phenolics were observed in osmopriming with CaCl2 while maximum cell membrane thermo-stability exhibited by osmopriming with MLE, thus SA treatment illustrated maximum proline and total soluble sugars under high temperature stress. In crux, seed priming improves wheat performance under optimal as well as late sown conditions through improved germination metabolism and augmented accrual of osmoprotectants, resulting in accelerated growth and development even under high temperature. (C) 2018 Friends Science Publishers