Quantitative Assessment of Camelina (Camelina sativa L.) Response to Salinity at Early Growth Stage
2022
Homaee, Mehdi | bayram, mansure | mokhtasibidgoli, ali
Germination plays a vital role in crop establishment and its yield. Most oilseeds are sensitive to salinity at germination, so cannot be irrigated with saline water. Although camelina is considered as a tolerant crop to water stress, but its tolerance to salinity must be investigated. To quantitatively evaluate camelina response to salinity at germination stage, an experiment with a completely randomized design was conducted including 17 water salinity levels of 0.85, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32 dS m-1, each with three replicates. Germination indicators were calculated using the SeedCalc package in R software and MATLAB. The optimization procedure was carried out with frequent changes in the model parameters based on reduced RMSE and minimizing least squares error. Then, parameters of salinity models including Maas-Hoffman, van Genuchten-Hoffman, Dirksen-Augustijn and Homaee et al. were derived and compared. The obtained threshold values of germination rate (GSI), seed vigor (SV), SeedCalc seed vigor (SV-S) were 2, 12 and 12 dS m-1, respectively; The corresponding reduction slope for these variables were 2.4, 7.7 and 1.7%, respectively. Based on the obtained EC* and the slope, it was concluded that camelina is very tolerant to salinity at this growth stage. So that, it can be established quickly and produce strong seedlings at very high salinity levels. Further analyses of model performance statistics indicated that the examined nonlinear models provide better performance. Best performance of fitted models was obtained by HVG and H models, respectively. Germination indices were decreased by increasing the salinity levels, a lower GSI was associated with decreased seeds water uptake. The higher the seed vigor, the higher the GSI and seedling growth, as well as the lower MGT. Overall, camelina can be considered as a suitable alternative for oilseed cultivation in semi-arid regions.
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