The level of deterioration of nine lots of maize, determined by germination after accelerated ageing (AA) was significantly related to the mean germination time (MGT), the average lag period to radicle emergence, at 20°C (R2 = 0.61; P < 0.01) and 13°C (R2 = 0.62; P < 0.01). The greater the deterioration, the longer was the average delay. The MGTs of the lots were closely related (R2 = 0.88) at the two temperatures, the relative ranking being maintained. However, the delay for the more deteriorated lots was markedly greater at the lower temperature. The delay to radicle emergence is discussed in terms of a need for metabolic repair during early germination. MGT was predicted by single counts of germination at 66h at 20°C (R2 = 0.95) and 6d at 13°C (R2 = 0.95). Both MGT and single counts were significantly related to the rate and level of emergence in a field sowing, as was the count of normal seedlings in a cold test. The same low emerging lots were identified by both tests. Germination after AA was positively, but not significantly, related to emergence. One count of radicle emergence at 66h is proposed as a routine vigour test, that is quicker than the cold test and indicative of relative emergence and could be included in a standard germination test.

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