Behavior of ‘bordô’ grapevine dorment buds in Pinhais, Paraná, Brazil

<p></p><p>ABSTRACT The dormancy of temperate fruit trees is still not totally clarified, and this knowledge is important to better understand the plant behavior in different climates. The objective of this experiment was to characterize the dynamics of ’Bordo’ grapevine budding through biological and tetrazolium tests. Branches of grapevine were collected biweekly from a vineyard located in Pinhais-PR, in May and August of 2013 and 2014. The collected branches were used to install the biological (to obtain the average bud break time, final bud break rate, vigorous buds rate, and velocity of bud break) and the tetrazolium (to verify buds respiratory rate) tests and analyze the moisture and the water contents of the buds. The results were significant in all the parameters evaluated, except for vigorous bud rate. The endodormancy is more intense in May, and the tetrazolium test has a high correlation with biological test data, which shows that tetrazolium test is an alternative for dormancy analysis of temperate fruit trees. The moisture content also varied according to respiratory rate, being higher when the metabolic activity is higher.</p><p>