Avaliação da qualidade fisiológica de sementes de milho por meio da atividade respiratória

Abstract

Rapid and reliable methods for evaluating the physiological quality are increasingly needed for the imminent decision-making during all the stages of seed production. Therefore, the objective is through the research reported in this study to evaluate the efficiency of the Pettenkofer´s physico-chemical method of determining the respiratory activity and differentiation of lots of corn seeds, by the vigor. The tests were performed in the Central Laboratory of Seeds at Universidade Federal de Lavras (UFLA). Sixteen lots were used with varied physiological quality. The following tests were applied, for reference: moisture content, germination, germination first count, seedling emergence, rate of emergence, mean emergence time, electrical conductivity, cold test, length of shoot and root and dry mass of shoot and root. The design used for statistical analysis of data was ramdomized. Analysis of isozymes alcohol dehydrogenase, malate dehydrogenase, esterase and α-amylase, were also made. The tests were examined individually and collectively by the sum of the performance of the lot in each test. It was seen low correlation between the Pettenkofer and other tests, both by simple correlation analysis (r) and by analysis of relative performance. Isoenzyme analysis was related to the physiology, but with limitations. With these results, the conclusion is that the time of two hours inside the unit and 24 hours pre-soaking is not efficient for the corn crop. But the Pettenkofer´s method is promising for having good theoretical fundamentals and high capacity of distinction by the vigor, requiring some adjustments.