Despite the vast cultivated area worldwide of cereal and forage crops such as wheat and alfalfa and their importance in human and animal nutrition their seed vigour testing has not been standardized. The radicle emergence (RE) test has however been applied to maize and may therefore have potential in wheat and alfalfa. Early counts of germination (radicle emergence) were taken at 6 hourly intervals at temperatures of 20, 17, 15 and 13 °C for 18 seed lots of wheat and 14 seed lots of alfalfa, all having standard germination above 85%. Mean germination time (MGT) was also calculated. Field emergence was carried out for both species on 4 replications of 50 seeds from each seed lot in a complete block design and emerged seedlings counted daily to assess mean emergence time (MET) and final emergence. Cell cycle activation and DNA replication during imbibition and germination at a range of temperatures was also studied using flow cytometry for lots showing a range of vigour. In general, in both species as temperature decreased, the rate of germination reflected in MGT and the final germination decreased. The effects of temperature were greater on the germination rate than on the final germination percentage. Many of the early counts of radicle emergence at all germination temperatures were correlated with MET and final emergence in both wheat and alfalfa. However at lower temperatures radicle emergence took place later. RE vigour tests after 48 hours at 15 °C and 24 hours at 20 °C, are proposed as the most convenient timing and temperature for wheat and alfalfa respectively. The relationship between RE and the cell cycle is discussed. Cell cycle activation is proposed as a possible molecular marker for seed vigour testing.

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