Time, Temperature and Germination of Pearl Millet (<i>Pennisetum typhoides</i>S. &amp; H.)

Abstract

The germination of pearl millet (Pennisetum typhoides S. &amp; H.) seeds was investigated at constant temperatures between 12 �C and 47 �C on a thermal gradient plate. The rate of germination increased linearly with temperature from a base &lt;it&gt;T&lt;/it&gt;&lt;inf&gt;b&lt;/inf&gt; to a sharply defined optimum &lt;it&gt;T&lt;/it&gt;&lt;inf&gt;o&lt;/inf&gt; beyond which the rate decreased linearly with temperature, reaching zero at &lt;it&gt;T&lt;/it&gt;&lt;inf&gt;m&lt;/inf&gt;. The linearity of the response both above and below &lt;it&gt;T&lt;/it&gt;&lt;inf&gt;o&lt;/inf&gt; allowed time and temperature to be combined in a thermal time at which a specified fraction of the seeds germinated. Within the population &lt;it&gt;T&lt;/it&gt;&lt;inf&gt;b&lt;/inf&gt; and &lt;it&gt;T&lt;/it&gt;&lt;inf&gt;m&lt;/inf&gt; were constant.