The influence of temperature on germination of taree Irani (Allium ampeloprasum L. spp iranicum W.)

Experiments were carried out to determine the effects of various constant (6, 10, 15, 20, 25, 30 and 35 degrees C) and alternating temperatures (15/5, 20/10 and 30/20 degrees C) on germination in two cvs of taree (Allium ompeloprasurn L. spp. iranicum W.) namely, Shadegani and Isfahani. Linear relationships were demonstrated between reciprocal of time taken to 50% germination (G(50)) and temperatures. There was a good linear relationship (P < 0.001, r(2) = 0.99) between temperature and rate of germination for each case. Three cardinal temperatures for germination established by extrapolation of regression lines relating rate of 50% germination to temperature. These three cardinal temperatures: base (T(b)), optimum (T(o)) and maximum (T(m)) were 0.82, 19.4 and 40.43 degrees C respectively in cv Shadegani. In cv Isfahani, cardinal temperatures were then calculated and they were 0.5, 19.52 and 40.52 degrees C. The thermal times required for 50% germination were 62.5 and 61.5 degrees Cd in cvs Shadegani and Isfahani, respectively. Thermal time for final germination were 200.1 degrees Cd in cv Shadegani and 188.1 degrees Cd in cv Isfahani. No significant differences were found in thermal time required for germination between two cultivars (P > 0.05). Differences in the rate and thermal times for (G(50)) were not statistically significant under both constant or alternating temperatures (P > 0.05).