Teste de envelhecimento acelerado em sementes de café

Abstract

Coffee is commonly propagated by seedlings produced by seeds, which present slow and nonuniform germination. Thus, seedlings production with desirable quality standards at the ideal time of planting is of great importance. The official tests required for marketing provide little information on the quality of the seeds. In this sense, the accelerated aging test has shown to be an important tool used in the internal quality control by the sowing companies, because it is a sensitive method for vigor evaluation. It provides reliable information on the physiological potential, ensuring more assertive decision-making about the fate of lots. However, for coffee seeds, there is little information regarding its use and efficiency as a vigor test. In this context, the objective of this study was to investigate appropriate methods of the accelerated aging test to evaluate the vigor of Coffea arabica seeds. Two studies were performed. Firstly, different temperatures and exposure times were investigated to perform the accelerated aging test in seeds of Coffea arabica. In the second study, the best combinations of temperature and exposure times were tested in different batches of different cultivars in the evaluation of the vigor of seed lots of Coffea arabica. For the first study, two seed lots of Coffea arabica L., cultivar Catucaí Yellow IAC/62, three incubation temperatures in BOD (42, 44 and 46 °C) and nine exposure times (0, 24, 48, 72, 96, 120, 144, 168 and 192 hours) were used. For the second study, seven seed lots of seven different cultivars of Coffea Arabica L.: cultivar Catucaí Yellow 2 SL, Catucai, Asa Branca, Acauã, Arara, Guará and Topázio, as well as two incubation temperatures in BOD (44 and 46 ° C) and four exposure times (24, 48, 72 and 96 hours) were evaluated. The Gerbox method was used for both studies. An initial characterization of the batches was carried out to compare with the results obtained in the accelerated aging test. After each aging period, the seed water content was determined and the physiological quality was evaluated in the germination test by the percentage of normal seedlings at 30 days. In the first study, it was concluded that the temperature of 42 °C promoted a slow deterioration of the seeds, not being indicated for the evaluation of seed vigor of Coffea arabica. The temperature of 44 ºC is promising for the evaluation of vigor after 72 hours of exposure. The temperature of 46 ºC is sensitive to evaluate the deterioration between the periods of 48 to 96 hours of exposure. In the second study, it was concluded that the accelerated aging test performed at 46 ºC for 48 hours was the most appropriate combination to compare lots of seeds of Coffea arabica with different vigor levels.