Germination under High Temperatures of Maize Adapted to the Cerrado of Tocantins

Abstract

The purpose of this study was to evaluate the response of germination and vigor in maize seeds in laboratory conditions, exposure to high temperatures, in order to highlight the most adaptable genotypes at these temperatures. Were supplied three cultivars of the PIONEIRA LTDA. (PIONEIRA HS-9, PIONEIRA HS-14i, PIONEIRA ROBUSTO), to perform the experiment, in addition to the commercial cultivar BRS 3040. After the selection of superior genotypes, were performed at temperatures of 25 reviews, 30, 35 and 40ºC, these being: germination, first count, seedling dry mass and speed index of the emergence of seedlings. At the temperature of 25°C were made the cold test and seedling length, shoot and root axis. The results were submitted to analysis of variance, comparison of averages by Tukey test, to three genotypes and regression analysis to high school, to three genotypes and the witness commercial. Whereas the maximum temperature of 35°C tested, one could observe that the PIONEIRA HS-6 genotype presented the best adaptation to high temperatures. The PIONEIRA ROBUSTO genotype was more adapted to high temperatures whereas as the highest temperature of 40°C. The BRS 3040 was not adapted to the high temperatures in relation to genotypes produced under conditions of high temperatures of the Cerrado.