The study was conducted to evaluate and correlate the radicle emergence test with other vigour parameters to predict the seed vigour and field emergence potential in ten seed lots of cluster bean with varying vigour. The results showed that the significant differences were observed among the seed lots in terms of physiological parameters viz., speed of germination, germination percentage (GER), root length, shoot length, dry matter production, vigour index, mean just germination time (MJGT), mean germination time (MGT), radicle emergence (RE) and field emergence (FE) and biochemical parameters viz., electrical conductivity of seed leachate (EC) and dehydrogenase activity (DA). Relationship between seed vigour parameters and radicle emergence per cent with 1mm and 2mm radicle length was also evaluated. The highest R2 values were observed in 2 mm length of radicle emergence per cent (R2 values viz., MJGT = 0.8832, MGT = 0.9379, EC = 0.8320, DA = 0.7810, GER = 0.8323 and FE = 0.8796) compared with 1mm length of radicle emergence per cent (R2 values viz., MJGT = 0.8777, MGT = 0.8826, EC = 0.8107, DA = 0.8113, GER = 0.8292 and FE = 0.8699) for most of the seed vigour parameters in ten different seed lots. The study concluded that counting 2 mm radicle emergence at 32 hours could be used for a quick evaluation to assess the seed vigour in terms of field emergence in cluster bean seed lots.
Key words : Radicle emergence, cluster bean, germination, vigour and field emergence