Obtenção de classes de vigor e viabilidade em sementes de Urochloa brizantha cv Marandu, através de imagens de teste de tetrazólio

Abstract

The speed and amplitude of tropical pasture expansion in Brazil are associated with the availability of high quality seeds, thus the country is considered the largest producer, consumer and exporter of tropical forage grass seed in the world. The objective of this work was the establishment of vigor classes for seeds of Urochloa brizantha cv Marandu via digitized images made from the tetrazolium test. The project was carried out from March to December 2016 at the University of Oeste Paulista (UNOESTE) Seed Laboratory in Presidente Prudente, SP. The analyzes were carried out in two experiments using six seed lots of Urochloa brizantha cv Marandu, in order to classify the seeds into three distinct classes: viable and vigorous, viable and non - vigorous and non - viable. In the second step besides the differential use of two parts of the seed for the tetrazolium test two concentrations were used 0.1% and 1% of salt 2, 3, 5 triphenyl tetrazolium chloride. The tests carried out were: germination test, tetrazolium test, emergency test, IVE (emergence speed index), shoot length and root and dry matter mass of shoot and root. All the tests performed followed the rules for the Rules for Seed Analysis. The use of scanned images through the two methods (scanner and camera) proved to be efficient for determination of the viability of the seeds of Urochloa brizantha cv Marandu, but the results of seed vigor classification using scanned images using vigor tests did not were promising.