02967nam a2200325 a 450000100080000000500110000800800410001910000220006024501200008226000160020230000100021850000800022852020630030865000130237165000100238465000220239465000150241665000190243165000250245065000120247565000210248765000120250865300200252065300170254065300200255765300210257765300110259865300130260965300190262214892582023-10-19       1977    bl uuuu  m   00u1 u    #d1 aANDRADE, R. V. de  aEvaluation of firm seed in Pensacola bahiagrass (Paspalum notatum Flugge) and browntop millet (Panicum ramosum L.).  a1977.c1977  a43 f.  aDissertação (Mestrado) - Mississippi State University, Mississippi State.  aSeeds of Pensacola bahiagrass, (Paspalum notatum Flugge) and browntop millet (Panicum ramosum L.) are dormant after harvest and dormancy often persist for several months, or in some cases for a few years. The dormancy of these grasses is characterized by gaseous impermeability and recognized as firm seed. The general objectives of this study were: (1) to determine the effectiveness and convenience of acid scarification for overcomirg seed dormancy in Pensacola bahiagrass and browntop millet, and (2) to evaluate the planting value of firm seed in these crops. The experiment was conducted in both the laboratory and the field. Ten lots each of bahiagrass and browntop millet seed were evaluated by the standard germination test and by a 20-minute acid scarification treatment. Bahiagrass seed lots showed an average increase of 17.4% in germination in the laboratory after acid scarification. However, non-treated seed germinated, on the average, higher than acid-scarified seed 38 days after planting. A 20-minute acid scarification treatment almost overcame dormancy in bahiagrass. At the end of the 28-day germination test period, firm seeds were subjected to the tetrazolium test. Results showed that not all seeds were viable. Total viability of the seeds was not affected by the acid scarification treatment but the number of abnormal seedlings increased. The acid scarification method shortened the time required for germination by about nine days. The 20-minute sulfuric acid treatment in browntop millet gave no improvement in the germination percentage. Browntop millet seeds, when treated with sulfuric acid, were more susceptible to fungal attack and as a consequence, there was an increase in the number of abnormal seedlings. The number of abnormal seedlings and degree of fungal attack were closely related to the time of sulfuric acid treatment; as the time increased, abnormality increased. Based on the results of this study, there appears to be no immediate planting value in the firm seeds of Pensacola bahiagrass or browntop millet.  adormancy  aseeds  aÁcido Sulfúrico  aDormência  aGrama Batatais  aGramínea Forrageira  aMilheto  aPaspalum Notatum  aSemente  aForage graminea  aForage grass  aPanicum ramosum  aPaspalum matatum  aQuebra  aSementes  aSulphuric acid