Optimizing germination of seven Mediterranean crops

Optimizing the establishment of bean and maize varieties in tropical environments

“…The daily and annual thermal fluctuations make it more practical to identify a thermal range that maximizes either germination or emergence, rather than to calculate a single optimum temperature [32]. Furthermore, a model that gives more importance to the rate than to the optimum temperature and directly optimizes both germination and emergence (i.e., without the need to subsequently resort to the prior imposition of a minimum rate) is consistent with farmers practical needs [26]. In this context, both germination and emergence speed were evaluated by using the Piper et al model ([41]), successfully applied in the relationship between RG [18,32] or RE [23,42] (in day −1 ) and temperature (T), which is a three-segment continuous piecewise-linear function.…”

“…High Gf and Ef values depend essentially on temperature, if water is not a limiting factor [16]. Values of Gf tend to be high and more or less constant along a fairly broad thermal range, but are significantly lower at both lower and higher extreme temperatures [17,26,39]. The variation of Ef with temperature follows a similar pattern to that of Gf [5,40].…”

“…The variation of Ef with temperature follows a similar pattern to that of Gf [5,40]. A kernel function of the type f k (x)= e − x 2 k was proposed in [26] to model Gf as a function of temperature and was used here to model both SzG and SzE. The positive integer k is a shape parameter.…”

“…The size, speed and dispersion of both germination and emergence were modelled separately, applying the models that were discussed in greater detail and successfully fitted to Mediterranean crops in [26]. The results will be discussed jointly, so as to highlight a successful establishment in terms of both germination or emergence.…”

“…Garcia-Huidobro et al [17] optimized the germination of pearl millet considering not only the optimal temperature estimated by using a triangular-shaped model to simulate its speed, but also a thermal range (included in the thermal-tolerance interval) for high germination (final counts). A broader concept of successful germination based on maximizing size and speed and minimizing dispersion was suggested by [26]. These authors optimized the germination temperatures of seven Mediterranean crops by overlapping three thermal bands along which high, fast and concentrated germinations are achieved.…”