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GENETIC PARAMETERS AND RESISTANCE OF CACAO PROGENIES TO CERATOCYSTIS WILT UNDER NATURAL INFECTION

2015; Volume: 27; Issue: 3 Linguagem: Inglês

10.21757/0103-3816.2015v27n3p215-218

0103-3816

Milton Macoto Yamada, Fábio Gelape Faleiro, Uilson Vanderlei Lopes, José Luís Pires,

Cocoa and Sweet Potato Agronomy

O objetivo deste trabalho foi avaliar a resistencia do fungo Ceratocystis cacaofunesta, que causa a murcha de ceratocystis, doenca letal do cacaueiro. Em marco de 2005, na Estacao Experimental Joaquim Bahiana do Centro de Pesquisas do Cacau (Cepec), situada no municipio de Itajuipe, Bahia, Brasil foi instalado no campo um experimento com progenies de 27 cruzamentos dispostos em blocos ao acaso no espacamento de 3x3 metros com parcelas de 30 plantas e 4 repeticoes, totalizando 120 plantas/cruzamento. As plantas das progenies dos 27 cruzamentos foram avaliadas em relacao a doenca, e, em outubro de 2012, os dados da incidencia de plantas mortas foram submetidos a analise de variância e da herdabilidade. As medias de incidencia da doenca variaram de 0,83 a 51,66%, enquanto que a media geral do experimento foi 16,19% de plantas mortas. As progenies mostraram diferencas significativas de resistencia e incidencia a murcha de ceratocystis. A selecao natural realizada nas condicoes deste experimento para resistencia a Ceratocystis cacaofunesta foi eficiente, considerando a alta herdabilidade (h2 =0,92) e o valor da relacao CVg/CVe = 1,71. Abstract: The objective of this study was to evaluate the resistance to the fungus Ceratocystis cacaofunesta, causing Ceratocystis wilt, a lethal disease of cacao. In March 2005, in the Joaquim Bahiana Experimental Station (ESJOB) of the Cocoa Research Center (Cepec) located in the municipality of Itajuipe, Bahia, Brazil was an experiment installed in the field with progenies of 27 crosses arranged in randomized blocks with spacing of 3x3 meters with plots of 30plants and four repetitions, with a total of 120 plants /crosses. The plants of progenies from 27 crosses were evaluated in relation to disease, and, in October 2012, data of the incidence of dead plants were subjected to analysis of variance and heritability. The mean disease incidence ranged from 0.83 to 51.66%, while the overall mean was 16.19% of dead plants. Progenies showed significant differences in incidence and resistance to Ceratocystis wilt. Natural selection performed in this experiment for resistance to Ceratocystis cacaofunesta was efficient considering the high heritability (h2 = 0.92) and the value of the relationship CVg / CVe = 1.71.