ahmad zare; maede malekpoor; maryam arabizadeh
Abstract
Regression models are a tool to quantify the weeds seed germination in response to temperature. In order to determinate the cardinal temperature of four weeds Brassicaceae family (Eruca sativa, Hirschfeldia incana, Sinapis arvensis, and Erysimum repandum), four separate experiments have been conducted ...
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Regression models are a tool to quantify the weeds seed germination in response to temperature. In order to determinate the cardinal temperature of four weeds Brassicaceae family (Eruca sativa, Hirschfeldia incana, Sinapis arvensis, and Erysimum repandum), four separate experiments have been conducted at nine temperatures (5, 10, 15, 20, 25, 30, 35, 40, and 45°C) as factorial, based on a complete randomized design (CRD) with three replications in Agricultural Science and Natural Resources University of Khuzestan during 2019. The First factor includes four weeds, and the second factor, weeds’ response to temperature. These have been different at 40°C only. H. incana displays some germination (38%), whereas the germination of other weeds has been completely inhibited. Based on the used models, the best models to determine cardinal temperature for E. sativa has been Beta, five parameter; for E. repandum, Beta, four parameter; and for S. arvensis, and H. incana, Dent-like model. The optimum temperature for germination of E. sativa and E. repandum are predicted to be 19.43 and 16.01 °C (Beta four and five parameter models), respectively. Moreover, the lower and upper optimum temperatures for germination of H. incana and Sinapis arvensis have been achieved at 27.22, 29.26, 23.23, and 27.86 °C, respectively (at Dent-like model). The maximum emergence of Eruca sativa, Hirschfeldia incana, and Sinapis arvensis is expected in November and from December to February for Erysimum repandum. Modeling germination in response to temperature can be considered in weed management, especially when determining the control time of weeds.
Behnam Kamkar; Ommolbanin Gorzin; nafiseh khalili; mohammadhosein ghorbani
Abstract
Almolookhiyeh (Corchorus olitorius L.) known in the world as a valuable medicinal plant that was produced for the first time in Iran in 2011. This study was aimed to quantify germination response of Almolookhiyeh to temperature. For this purpose, seeds were exposed to different constant temperatures ...
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Almolookhiyeh (Corchorus olitorius L.) known in the world as a valuable medicinal plant that was produced for the first time in Iran in 2011. This study was aimed to quantify germination response of Almolookhiyeh to temperature. For this purpose, seeds were exposed to different constant temperatures (10 ,15, 20, 25, 30, 35, 40, 45 and 50°C) in Seed Research Lab, Gorgan University of Agricultural Sciences and Natural Resources in 2011. Results showed that the effect of temperature on the maximum germination percentage (MGP), germination rate (R50), germination uniformity (GU), and time to 10, 50 and 90 percent germination as (D10), (D50) and (D90), the percentage of normal seedlings (NS%) and seedling length (LS) was highly significant. Assessment of three nonlinear regression models including segmented, dent-like and beta models based on 10, 50 and 90 percent germination revealed that beta model was superior to other models. Based on the superior model (Beta), base, optimum and ceiling temperatures were estimated as 10.18, 37.31 and 50°C, respectively. Biological hours also were calculated as 13.56 hours. Using beta model to regress seedling length against temperature and normal seedling percentage versus temperature showed that seedling emergence, the maximum seedling length and the highest normal seedling percentage were occurred at 11 to 44, 35.34 and 31°C, respectively.
amirhasan khodabakhshi; Behnam Kamkar; nafiseh khalili
Abstract
This study was conducted to quantify germination response of annual savory (Satureja hortensis L.) to temperature and water potential. For this purpose, seeds were exposed to different temperature (12, 15, 20, 25, 30, 35, 37 and 40°C) and water potential (zero, -0.1, -0.3, -0.5 and -0.7 MPa) treatments ...
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This study was conducted to quantify germination response of annual savory (Satureja hortensis L.) to temperature and water potential. For this purpose, seeds were exposed to different temperature (12, 15, 20, 25, 30, 35, 37 and 40°C) and water potential (zero, -0.1, -0.3, -0.5 and -0.7 MPa) treatments in Seed Research Lab., Gorgan University of Agricultural Sciences and Natural Resources in 2013. Results indicated that temperature and water potential and interacted effects had significant effect on maximum germination percentage, germination rate (reciprocal time to 50 percent germination), and time to 10, 50 and 90 percent germination. Along with water potential decrement, both germination percentage and rate decreased. With temperature increasing to optimum temperature, both germination percentage and rate increased, while it decreased from optimum temperature onward. Assessment of three nonlinear regression models including segmented, dent-like and beta models revealed that the last one was selected as the superior model. Based on the superior model (Beta), base, optimum and ceiling temperatures were estimated as 7.56, 23.98 and 40°C, respectively. Biological hours for control treatment (zero potential water) was calculated as 91.17 hours. Cardinal temperatures were not affected by water potential, but biological hours for germination was delayed as 17.64 hours per each unit water potential increment.