Controlled deterioration and paper-piercing tests predict seedling emergence potential in okra seed lots

The present study was conducted to evaluate some of the available seed vigour tests to predict field emergence in okra (Abelmoschus esculentus L. Moench) seed lots. Twenty-one commercial seed lots of okra were evaluated by the following laboratory vigour tests: germination, speed of germination, vigour index, brick gravel test, paper-piercing test, accelerated ageing, controlled deterioration, dehydrogenase activity and electrical conductivity. The vigour tests were able to assess vigour differences among the seed lots. The seedling emergence percentage in the field ranged from 35% to 63% for these seed lots. The correlation coefficient of following laboratory vigour tests viz., standard germination, speed of germination, brick gravel test, paper-piercing test and controlled deterioration were significantly and positively correlated with field emergence. The vigour index I, vigour index II and dehydrogenase activity test were not significant with field emergence. Determination coefficient of seed lots for standard germination, speed of germination, brick gravel test, paper-piercing test and controlled deterioration were found significant and explains 49%, 50%, 52%, 83% and 87% of variation in field emergence, respectively. The regression analysis result for vigour indices (I and II), dehydrogenase activity test and cold test explains 4%, 9%, 2% and 7% of the variation in field emergence, respectively. The correlation coefficient and determination coefficient of controlled deterioration test and paper-piercing test were found highly significant among all other vigour tests in predicting seedling emergence of okra seed lots. The results suggest that controlled deterioration and paper-piercing test can be successfully used to predict seedling emergence in okra seed lots. (C) 2014 Elsevier B.V. All rights reserved.