Further studies on the slant test as a measure of the vigour of crisp lettuce seedlot

Measurements of seed vigour, emergence and maturity characters were made on six seedlots of crisp lettuce cvs Pennlake and Saladin, vigour being determined by the measurement of root length in a slant test. There were significant differences between the root length and transplant weight of different seedlots of each cultivar. Root length was significantly rank-correlated with transplant dry weight in both cultivars (cv. Pennlake r_s= 0·94, N = 6; cv. Saladin r_s= 0·83, N = 6) but not with head weight at maturity. Percentage germination was significantly correlated with seed weight and root length. It is suggested that the slant test can be reliably used to indicate early plant vigour.