Coffee Science
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3355
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Item Colletotrichum on coffee trees in south of Minas Gerais - Brazil: physiological, molecular and pathogenic description(Editora UFLA, 2016-10) Armesto, Cecilia; Maia, Fernanda Gonçalves Martins; Monteiro, Fernando Pereira; Abreu, Mário Sobral deFungi of the genus Colletotrichum spp. are cosmopolitan and are responsible for disease in many plants of agronomic importance. In coffee crops, three species have been described: Colletotrichum acutatum, Colletotrichum kahawae and Colletotrichum gloeosporioides. In Brazil were only reported the species C. acutatum and C. gloeosporioides, which symptoms are attributed as antracnoses, dieback and blister spot. This study evaluates the population of Colletotrichum spp. through morpho-physiological, genetic and pathogenic characteristics, in several coffee plantations in the southern of Minas Gerais. All isolates showed similar morphological and physiological characteristics, being identified as C. gloeosporioides. The best medium for mycelial growth was agar-malt extract with pH 5.5 and for spore production oat-agar medium with pH 6.5. When inoculated on berries, all isolates were pathogenic with variable levels of aggressiveness, but only 57% of these were pathogenic for hypocotyls. Three isolates, I-9, I-24 and I-26, were identified featuring the highest rates of aggressiveness in berries and hypocotyls.Item Pigments, total soluble phenols and lignin levels of coffee seedlings inoculated with Colletotrichum gloeosporioides(Editora UFLA, 2012-05) Maia, Fernanda Gonçalves Martins; Ogoshi, Cláudio; Vieira, Jucilayne Fernandes; Pierre, Rosana Oliveira; Maia, Jader Braga; Ribeiro Júnior, Pedro Martins; Abreu, Mário Sobral deThe objective of this work was to study the effects of different isolates of Colletotrichum gloeosporioides, as to pigment level (chlorophyll a, b and total), total soluble phenols and soluble lignin in coffee seedlings obtained by artificially inoculated tissue culture. The experiment was carried out in randomized block design in a 2 x 3 factorial scheme (2 genetic materials), 3 isolates (an isolate from mango fruits and another one from coffee plants), with 5 replicates and control (plants without inoculation). The plants were inoculated with a suspension of 2 x 10 6 conidia.ml -1 . The conidial suspension was sprayed on previously injured leaves. Leaves of inoculated plants were collected at 3 and 7 days after inoculation, except for leaves on the lower part of the plants. Afterwards, samples were prepared for the evaluation of chlorophyll, total soluble phenols and soluble lignin. The results showed that the presence of the pathogen in healthy and diseased plants significantly reduced the amount of chlorophyll. At 7 days after inoculation of healthy and diseased coffee plants higher total soluble phenol and soluble lignin levels were observed in response to the attack by Colletotrichum gloeosporioides.