Radicle emergence (RE) test identifies differences in normal germination percentages (NG) of watermelon, lettuce and carrot seed lots

This study was conducted to test the potential of the radicle emergence (RE) test to predict normal germination percentage (NG) in seed lots of watermelon, lettuce and carrot. One seed lot of each species was aged at 100% RH and 45 degrees C for different times to produce 14 aged sub-samples. The RE (>= 2 mm radicle) was counted during a germination test (ISTA Rules) and NG was assessed at the end of the test. RE counts after 74 (watermelon), 40 (lettuce) and 120 hours (carrot) were significantly (P < 0.001) related to NG (watermelon, R2 = 0.81; lettuce, R2 = 0.74; carrot, R2 = 0.81). RE counts at the same times were significantly related to NG in ten commercial seed lots of watermelon (R2 = 0.66, P < 0.01), nine lots of lettuce (R2 = 0.94, P < 0.001) and eight lots of carrot (R2 = 0.64, P < 0.05). The potential of the RE test to predict NG of both different lots within the same cultivar (watermelon, carrot) and lots from different cultivars (lettuce) is discussed.