Efeitos das concentrações e tipos de sais na germinação e vigor de sementes de sorgo granífero (Sorghum bicolor (L.) Moench).

Abstract

The objectives of this work were to study the effects of different concentrations and types of salts on the germination and vigor of different cultivars of sorghum sorghum (Sorghum bicolor (L) Moench). The work was developed in the laboratory under controlled conditions of temperature and relative humidity, using as substrate germitest paper. The experimental design was completely randomized, in the factorial scheme 11 x 2 x 6 with four replications, each containing 50 seeds in the case of germination and 10 seeds for vigor. The studied factors were eleven sorghum cultivars (IPA 7300007, 7300017, 7300201, 7300265, 7300281, 7300780, 7300940, 7300958, 7300988 and 7301011), two types of salts (NaCl and Na2SO4) and six concentration levels , 50, 100, 150, 200 and 250 meq / l). Analyzes of variance showed significant effects, at the 0.01 probability level, for cultivars, concentrations and salt types, for both germination and for the index of vigor. Among the salts studied, it is verified that NaCl was more toxic than Na2SO4. The results indicate that the percentage of germination and the vigor index decreased as the concentration increased, regardless of the salt type, it was observed that the effects were more drastic from the cultivars (IPA 7300007, 7300029, 7300265, 7300281 , 7300780, 7300958, 7300988 and 7301011), it was found that low concentrations (<100 meq / l), especially Na2SO4, provided a beneficial effect on seed germination. Analyzes of variance for the isolated effects of the salts on germination showed significant effects at the 0.01 probability level for the cultivars and the concentrations. It was observed that the cultivar x concentration levels interaction was significant only for NaCl. In the case of Na2S04, cultivars IPA 7300958 and 7301011 presented the highest and lowest germination percentage respectively, and differed from each other at the 0.05 probability level, while for NaCl the cultivars IPA 7300017, 7300281, 7300780, 7300029 and 7300958 showed a higher germination percentage and did not show significant differences among them, by the Tukey test at the 0.05 probability level. The analysis of variance regarding the effect of NaCl and Na2SO4 on seed vigor index also showed significant effects at the 0.01 level of probability between cultivars and concentrations. The cultivars IPA 7300029 and 7300007 for NaCl, 7300958 and 7300201 for Na2SO presented respectively a maximum and minimum percentage of germination, whereas for the vigor of the cultivars 7300281 for the NaCl and 7300017 in the case of Na2S04 were the most outstanding. The evaluation through the relative reduction showed that the cultivars IPA 7300281 and 7301011 in the case of NaCl, and 7300029 and 7300958 for Na2SO4 were the ones that presented the lowest decrease in the percentage of germination in relation to the control. For the studied cultivars, the effect of the concentration of the salts on the germination and vigor of sorghum seeds can be represented by linear or quadratic equations, significant at the 0.01 level of probability.