PHYSIOLOGICAL QUALITY OF RICE SEEDS SUBMITTED TO NITROGEN STRESS

The aim of this study was to evaluate the effect of nitrogen fertilization on the physiological quality of upland rice seeds. The experiment was carried out at the "Laboratorio de Analise de Sementes" of the Federal University of Tocantins, "Campus de Gurupi", at 2007/2008 growing season. The cultivars Caiapo, Conai, Bonanca, Sertaneja, Primavera and Curinga were grown under two environmental conditions: with and without nitrogen stress, 20 kg.ha(-1) and 120 kg.ha(-1), respectively. The experiments were carried out in a completely randomized blocks design, factorial 6x2 with four replicates, where six cultivars where evaluated under two cultivation conditions and the results were analyzed using Tukey test at 5% probability. To evaluate the physiological quality the following methods were applied: standard test of germination, first seed counting, accelerated aging and tetrazolium. Results showed that the physiological quality of the seeds was affected by the nitrogen doses applied. When compared to the other cultivars, Caiapo and Sertaneja showed the highest physiological quality.