TEST OF EXUDATE pH IN RICE SEEDS

ABSTRACT The objective of this study was to evaluate the efficiency of a pH test of the exudate (with and without tegument) as an indicator of the physiological quality of rice seeds. The experimental design was completely randomized, with seven lots and four replications. The seven lots were assessed for water content and initial physiological quality by means of germination, first germination count, emergence, emergence speed index and tetrazolium tests. The pH test of the exudate was conducted with 100 seeds of each treatment, with tegument and without tegument. The seeds were individually soaked in 2.0 mL distilled water for different periods (20, 40, and 60 minutes) and three temperatures (20, 25, and 30 °C). The results were submitted to the Scott Knott test at 5% probability. The pH test of the exudate is a promising method to evaluate the physiological quality of rice seeds by detecting differences in vigor between marketable lots. This test should be conducted with rice seed without tegument, at 25 °C, with a soak time of 60 minutes.