Test of exudates color hues for evaluating the physiological potential of coffee (Coffea arabica L.) seeds

Abstract

-Coffee seeds have slow and irregular germination, losing fast their viability during storage, and the standard germination test of these seeds requires at least 30 days. Besides, the results may not reflect the actual physiological quality of these seeds. The objective of this work was to develop a fast and practical test for evaluating the viability of coffee seeds, which is based on the interpretation of different color hues of exudates from seeds. Coffee seeds of the cultivar Catuai 44 from six lots were submitted to germination, accelerated aging, and electrical conductivity tests. In the exudates color hue test, coffee seeds without the parchment and the silvery pellicle (four replications of 10 seeds each) were distributed on top of paper towels moistened and then maintained into a germinator, at 25 ºC for 24, 48, 72, 96, and 120 h. Three classes of color hues were established: colorless, light color hue, and dark color hue, assigning the values of 0, 1, and 3, for each class, respectively. The proposed exudates color hue test can be recommended for the fast assessment of viability for coffee seeds. The most promising results were obtained for seeds with 12% moisture content, after imbibition periods of 72, 96, and 120 h; and with 30% moisture content, after imbibition periods of 72 and 120 h.

pH do Exsudato na Avaliação da Viabilidade de Sementes de Araucaria angustifolia

“…Em sementes que apresentam germinação lenta e desuniforme, os resultados do teste de germinação podem não refletir a real condição fisiológica das sementes, acentuando a predisposição ao ataque de patógenos durante o período de execução do teste, prejudicando seriamente os resultados obtidos pela germinação (Carvalho et al, 2002;Hilst et al, 2012).…”

Exudate coloring test suitability for assessing the viability of coffee seeds ( Coffea arabica L.)

“…The closed boxes were maintained on B.O.D. at 45 °C, for 72 hours, as described by Hilst et al (2012). After this period, four subsamples with 50 seeds were placed to germinate as described above for the germination test (Brasil, 2009), evaluating the mean percentage of normal seedlings obtained 21 days after sowing.…”

“…Exudate coloring test: the methodology described by Hilst et al (2012) was used. Four subsamples of 10 seeds without the parchment were soaked in water for 10 minutes, in order to remove the silver skin (spermoderm).…”

“…Deteriorated or less vigorous seeds usually release a larger amount of exudates due to the disruption of their membranes (Milosevic et al, 2010). Among the quick tests that are based on the integrity of the system of cellular membranes and that have been studied for coffee seeds, some highlights are the electrical conductivity test (Costa and Carvalho, 2006;Soto et al, 1995;Malta et al, 2005), pH exudate (Vieira et al, 1998), Lercafé (Zonta et al, 2008;Reis et al, 2010), and the exudate coloring test (Sera and Miglioranza, 2000;Sera et al, 2006;Hilst et al, 2012).…”

“…This methodology was improved by Hilst et al (2012), classifying the coloration of exudates into three categories: absence of coloring, light and strong coloring, which allowed the distinction of lots of high and low physiological quality 24 hours after the seeds had been imbibed on a paper soaked with water. However, the authors reported that, for a more efficient separation of the lots into quality levels, studies would be necessary in order to adjust the evaluation criteria.…”