Effect of physical priming on phenology, some of physiological traits and yield components of wheat (Triticum aestivum) under delayed sowing date

Background and objectives
Some of farmers in Iran cultivate soybean as a secondary crop after wheat harvesting in early summer. In this case, on-time planting of soybean will be important in its productivity. For better land use, exploitation of new technologies could be help to earlier maturing of wheat and finally prepare better growth period and good yield production of secondary crop. Good crop establishment is a major challenge in crop production, a fact recognized by farmers as well as researchers. Seed priming is a feasible technology to enhance rapid and uniform emergence, high vigor and better yields in crop species. Ultrasonic waves can be a major role in earlier seedling emergence and maturing (5-10 days). Therefore, the present study was carried out to investigate the effects of physical treatments and sowing date on emergence and production of wheat crop.
Materials and methods
The experiments were conducted in greenhouse and research field of Islamic Azad University of Tabriz, Iran during 2013-2014. The wheat seeds were treated by ultrasonic, laser, magnetic field, gamma and beta irradiations for 3.5 and 5 min. and were sown on dates of 27th September and 17th October. Data statistical analysis was performed by MSTAT-C software. Also, analysis of variance and LSD test (P 0.05) were used for statistically test of sources of variation and means comparison respectively.
Results
All the seed priming treatments improved coefficient of uniformity of emergence compared with non-primed seeds. Seedling vigor index responded positively and significantly to seed priming agents. There was no significant difference among laser, gamma and beta irradiations with a view to time from sowing to harvesting. Wheat seeds primed by magnetic fields, ultrasonic waves and lower exposure time of gamma had high chlorophyll in leaves. Gamma irradiation with exposure time of 3.5 min, as well as magnetic field and ultrasonic wave lead to producing heavier seeds with thousand seed weight of 50.5 g, but only 40.5 g from those seeds treated under other agents and non-treated one. There is no significant difference between seed yields from sowing dates of 27th September and 17th October, and the yield ranged from 334 g.m-2 in average of control; laser and beta irradiations and higher exposure time of gamma up to 480.1 g.m-2 in other treatments.
Conclusion
It is concluded from the study that wheat seed priming by magnetic fields, ultrasonic waves and lower exposure time of gamma irradiation can be effectively used to improve the crop performance and yield especially in late sown plants.