Optimal Germination Temperature Assessed by Indices and Models in Field Bean (Vicia faba L. var. minor)

This paper seeks to shed light on the effect of temperature on field bean (Vicia faba L. var. minor) germination and root elongation. Accordingly, the results were as follows: germination was faster at 20°C than at 5, 10, 15, 25 or 30°C. However, temperature had no effect on total germination percentage between 10 and 30°C, although it was reduced by approximately 4% at 5°C and delayed at other temperatures. 50% germination required nine days at 5°C but only three days at 20°C. Seeds required a mean germination time of 12 days for total germination at 5°C but only four days at 20°C. The coefficient of the velocity or rate of germination index reached the highest (23.71%) and lowest (8.24%) value at 20°C and 5°C, respectively. Maximum germination speed (43.26), as assessed by the speed of germination index, was at 20°C. The speed of accumulated germination grew in proportion to the increase in incubation temperature. Th e main root axis length index and root elongation speed peaked at 20°C (five days and 0.72 cm/day, respectively). Prediction of optimal temperature for germination (To) by using the equation D = [a-(b×T) +(c×T2)] showed that 20°C is the optimum To, indicating that the theoretical model was robust. Hence, it could confidently be used to calculate all parameters related to the effect of temperature on faba bean germination