Effect Of Priming On Seed Germination, Seedling Growth And Field Establishment Of Alfalfa

Seed priming has been proved to be an effective pre-sowing treatment techniqiue which not only improved seed germination speed and percentage, but also enhanced seed vigor and production. This study determined the effect of priming on seed germination, seedling growth, establishment and storage of Medicago sativa. The main results were as following:1)Hydropriming significantly increased germination speed and seedling growth, but showed no effect on germination. At 10 ℃ germination condition, the optimal response to hydropriming was achieved at 10 ℃ for 36 h with 90% water of original seed weight, while at 20 ℃ germination condition, the optimal response to hydropriming was achieved at 10 ℃ for 24 h with 120% water of original seed weight.2)All priming treatments significantly increased germination at low water potential but not under the other conditions except for a significant increase at severe salt stress condition by KNO3 priming;Hydropriming and GA3 priming significantly reduced the time of 50% germination(T50) of alfalfa at each temperature and low salt stress. In addition to intermiate water potential, priming significantly reduced the T50. Hydropriming significantly increased root and seedling growth at 10 ℃ as well as shoot growth at severe salt stress condition.In addition to hydropriming, all priming treatments significantly promoted seedling growth of alfalfa under low water potential, among which KNO3 priming exhibited the optimal effect.3)Compared to control, PEG priming significantly increased seedling emergence by 72.5%. hydropriming priming significantly increased plant height of Gannong 3 by 94.8%. PEG and KNO3 priming with redring seed significantly increased biomass of Longdong alfalfa and Gannong 3 by 153% and 157% respectively.4)Storage duration had no effect on germination and T50 of hydropriming and PEG primed seed except for at-0.9 MPa water potential. However, root and shoot length declined at-0.3MPa as storage time extened. The root and shoot length of “Longdong” cultivar after hydropriming decreased significantly at-0.3MPa water potential with the increase of storage time. At 0~-0.6 MPa water potential, the root length of “Longdong” after PEG priming and the root and shoot length of Gannong 3 after hydropriming, was significantly higher after storage 1 month than 3 and 6 months. The shoot length of Gannong 3 after PEG priming was significantly higher after storage 1 and 3 months than 6 months.