Early counts of radicle emergence, counted manually and by image analysis, can reveal differences in the production of normal seedlings and the vigour of seed lots of cauliflower

Abstract

The ability of a single early count of radicle emergence (RE) to predict differences in the production of normal seedlings (NG) and seed vigour was examined in four seed lots from each of three varieties of cauliflower (Brassica oleracea var botrytis). Initial seed quality was assessed in germination and controlled deterioration (CD) vigour tests. RE (first appearance of the radicle) was counted manually after 48 hours in the germination test (RE 48h 20/30°C) and every two hours for 144 hours at 20°C using automated image analysis. Seed vigour was assessed in field and glasshouse trials. A large proportion of the variance in NG was explained by the RE count. The same RE counts at 20/30°C and 20°C predicted seed vigour in the field and glasshouse and revealed the same vigour differences as the validated CD test. Differences in vigour (field and glasshouse emergence) observed between varieties were related to the extent of previously sustained seed ageing revealed by the CD test, although genotypic differences in vigour could not be excluded. We propose that single counts of RE taken manually or by image analysis can be used to reveal differences in the NG and vigour of seed lots of cauliflower.