The Qualification of Germination Response of Zygophyllum (Zygophyllum eurypterum L.) and Hemp(Cannabis sativa L.) to Temperature

Germination is probably the most important event for the success of plant and plays a major role in crop production. Appropriate temperature control of seeds leads to uniform germination and efficient management of the production of seedling, which are required for successful cultural practices. For studying of response of germination in Zygophyllum and Hemp, a CRD experiment performed in seed research laboratory of Islamic Azad University, Mahabad Branch with four replication which temperature treatment were twelve levels as: 1, 3, 5, 7, 10, 15, 20, 25, 30, 35, 40, 45, 50 0C for Hemp and eight levels as: 5, 7, 10, 15, 20, 25, 30, 35 0C for Zygophyllum. Describing of reaction of germination to temperature and determination of cardinal temperatures tested by Nonlinear regression model as segmented model. Results revealed that temperature had a significant effects on rate and germination percent in two plants. In Zygophyllum , the lowest germination percent occurred in 70C and temperatures lower tha it, and so in the higher temperatures. Also, the highest germination percent in this plant observed in 15-20 0C. Similar to effect of temperature on germination percent, the lowest germination rate obtained in temperature 7 0C and lower than it and the higher temperature than 30 0C. Also, in Hemp the maximum germination percent observed in range 15-20 0C. As it expected, the highest germination rate occurred in this temperature range. Although, the minimum percent and rate of germination were related to temperature 3 and 50 0C and The most germination percent occurred in 15- 20 0C in two plants and the highest value of rate germination were 20 and 25 0C in Zygophyllum and Hemp respectively. The Segmented model had the less RMSE, CV and the more R2 and good correlation coefficients, thus was a well model which cardinal temperature as:base, upper and bottom optimum and ceiling temperatures were 7.2, 21.07 and 30.0 0C respectively in Zygophyllum and in Hemp were 4.74, 23.98 and 45.95 0C, Also, the maximum germination rate (rmax ) was 0.007 and 0.041 in Zygophyllum and Hemp respectively. Overall results revealed that in all of two plants (Hemp and Zygophyllum) but increasing in temperature to 15-20 0C, rate and percent of germination upgraded rapidly but increasing temperature to 30 0C, aging was caused that seed no germinate in Zygophyllum. So, in Hemp this diminish in germination rate followed to 50 0C and generally, result emphasized that segmented model determined cardinal temperature acceptably.