Imagem digital para rápida avaliação do potencial de germinação de sementes de café

Abstract

Coffee is a culture of great expression in the Brazilian agro-industrial scenario contributing strongly to the country’s economy. Its propagation is dependent on the quality seeds to obtain healthy and vigorous seedlings. For this purpose, the analysis of the physiological quality of the seeds is fundamental, being performed through of laboratory test, such as the germination test. Despite being widely used, the germination test in coffee seeds is laborious and time consuming, taking 30 days to obtain the results. Reducing the test evaluation time is an advantageous strategy, as it will favor the processes of the coffee production chain. The image analysis is a promising method, non-destructive, rapid and not subjective when compared to the traditional germination test. Therefore, the objective was to investigate the germination potential of coffee seeds, developing a protocol with the GroundEye®equipment for the reduction of germination test time, using a new evaluation criterion. The germination potential analysis was performed considering a new criterion for evaluation of normal seedlings, defined as seedlings in the arrow stage.The first stage was based on the development of an evaluation protocol through the configuration and training of the GroundEye® S800 image analysis system, for the analysis of coffee seedlings in the arrow and no-arrow phase at 12 and 15 days after of sowing in the germination test. Classifiers and a decision network were used to allow the classification of seedlings into different categories. The efficiency of the equipment was measured by evaluating samples with six different proportions of seedlings in arrow (0%, 20%, 40%, 60%, 80% and 100%) and two times of analysis (12 and 15 days after sowing). For the second stage, a measurement of the developed protocol was performed, using samples from ten commercial lots of coffee seeds. The samples were submitted to the germination test, according to the Rules for Seed Analysis (RAS), and also to the visual evaluation and in the GroundEye® at 12 days (time when the equipment was more efficient in classifying seedlings), quantifying the seedlings in the arrow stage. It’s possible to evaluate the germination potential of coffee seeds through the technique of image analysis, using the criterion of seedlings at the arrow stage, such as in a visual evaluation. According to the parameters of the configuration and efficiency tests, GroundEye® is more efficient for the classification of coffee seedlings in the arrow and non-arrow phase in the evaluations performed at 12 days of sowing in the germination test. The protocol developed for evaluation of coffee seedlings at 12 days underestimates the real percentage of normal seedlings, being of interest the protocol mensuration for the evaluations at 15 days.