Determination of Cardinal Temperatures and Respons of Securigera securidaca L. to Different Temperatures of Germination

In order to determinate the cardinal temperatures and investigate the effect of temperature on seed germination and seedling growth of Securigera securidaca, a study was conducted in a completely randomized design with 8 temperature treatments (5, 10, 15, 20, 25, 30, 35 and 40oC) and four replications in research laboratory of faculty of agriculture at the Birjand University in 2013. Two-segmented linear regression model was fitted between germination rate and temperatures to determine cardinal temperatures for germination. Cardinal (minimum, optimum and maximum) temperatures of germination were determined as -1, 22.5 and 40.2oC respectively. Maximum rate and percentage of germination obtained in the range of 20-25oC. Maximum of radical length and dry weight, maximum of caulicle length and dry weight and maximum of vigor seedling were obtained in 20oC,10-20oC and 5-30oC respectively. Maximum and minimum germination uniformity (GU) was obtained in 25 and 5oC.