Influence of hydropriming on seed germination behavior of canola cultivars as affected by saline and drought stresses

In order to determine the impact of hydropriming on germination characteristics of three canola cultiv ars under drought and salinity stresses, an experiment was co nducted in 2012 at research laboratory in Bu-Ali Si na University as a factorial experiment in CRD with 3 replication s. In this experiment, three factors were examined including canola cultivars (Hayola 401, Hayola 308 and RGS 00 3), seed hydropriming and similar osmotic potential levels by PEG-6000 and NaCl (-2, -4,-6, -8 and -10 bars) plus zero osmotic potential using by distilled water as third factor. Results revealed that in both stress, all measured traits except allometric coefficient (root:shoot le ngth ratio) were decreased by reducing osmotic potential. Also at -8 and -10 bars of PEG all traits except germination percentage and germination index were zero. Hydropriming incre ased germination percentage especially under drough t stress. The Hayola 401 displayed highest increase in germin ation percentage by hydropriming as compared with i ts noprimed treatment (24.6 % vs 11.5 and 11.18 % in RG S003 and Hayola 308 respectively). In all cultivars and osmotic potentials, hydropriming increased coeffici ent of velocity of germination about 6.5 and decrea sed mean germination time by 5.5 %. Highest mean germination time was achived in Hayola 308 at -10 bars in PEG (3.06 days). Germination index fluctuations by drought st ress were more than salinity stress that indicate d rought stress in lower potentials had been more harm to germinabi lity than salinity stress. Also root and shoot length were reduced more in PEG than NaCl solution. However hyd ropriming in RGS003 and Hayola 308 at -6 bars in PE G caused increase in root length by 148 and 102 % res pectively. Allometric coefficient of primed seeds o f all cultivars in both stress medium increased up to -4 bars. Vigo r index was better in NaCl than in PEG at the equiv alent osmotic potentials and in Hayola 401 at -10 bars of NaCl th e vigor index was increased about 231% compared wit h its noprimed.