Cardinal temperatures for germination of Kochia scoparia (L.)

In order to examine seed germination responses of kochia (Kochia scoparia L. Schrad) to temperature regimes, an experiment was performed in a completely randomized design with two replications. The trial was conducted at 8, and 5 degrees C intervals from 10 to 40 degrees C. From 8 to 35 degrees C, average germination percentage was 85%, but when temperature increased to 40 degrees C, germination percentage decreased to 31%. At 25 degrees C, 50% germination was achieved within the first 24h, but when temperature increased or decreased from this level, germination was slower. On the basis of these results, kochia can adjust its germination over a wide range of temperatures, from 3.5 degrees C (T-b) to 50 degrees C (T-max), with an optimum germination temperature of 24 degrees C. This extended temperature range for germination and the ability to germinate rapidly suggest the high potential of kochia to establish in most areas of Iran as a new forage crop. (c) 2006 Elsevier Ltd. All rights reserved.