Diagnostic method for predicting tomato seedling emergence

Abstract

This research was conducted to determine the usefulness of laboratory vigour tests as predictors of seedling emergence in tomato. Three seed lots of cvs. 'CXD 254', 'CXD 255', 'CXD 267', 'CXD 179', 'CXD 224' and 'CXD 222' were subjected to the standard germination, seedling emergence, saturated salt accelerated ageing (SSAA), controlled deterioration (CD), tetrazolium (TZ) viability and vigour, 3-day (3D), 4-day (4D), 5-day (5D) and 7-day (7D) germination tests. Moreover, seedling vigour index was determined. The standard germination of seed lots ranged from 70.0% to 97.0%, while the seedling emergence ranged from 80.50% to 99.50%. Vigour assessment tests, seedling emergence and seedling vigour index of 'CXD 179' were significantly higher than in other cultivars. Standard germination and SSAA test results did not vary among lots. The CD test predicted seedling emergence more accurately than standard germination. However, we observed significant differences (P<0.05) in 3D germination and seedling emergence among the lots. 3D germination demonstrated its ability to detect differences in seed quality. Results indicated that 3D and 4D germination tests were the most efficient in predicting seedling emergence. However, the TZ vigour and 5D germination tests were superior to standard germination for predicting seedling emergence, the use of such predictors as absolute determinants of emergence is less than desirable. The regression values obtained for SSAA (R-2 = 0.361) and standard germination (R-2 = 0.370) were much lower than for 3D (R-2 = 0.785) germination. Results indicated that 3D germination was more efficient for evaluating tomato seedling emergence, allowing the identification of different levels of seed quality.