Seventeen genotypes of cocoa (Theobroma cacao) were tested for reaction to Ceratocystis wilt caused by Ceratocystis cacaofunesta, using the three most virulent isolates among five isolates tested. In greenhouse conditions, a suspension containing 3.0 x 10(4) CFU/mL of each isolate was inoculated on six-month-old seedlings. The assay was carried out using a randomized complete block with 17 treatments, three replications and five seedlings per experimental unit. Assessments were made at 60 days after the inoculation date, by counting the number of healthy seedlings per plot unit. The data were analyzed by SAS statistical procedure and treatment averages were tested by Dunnett test at 5% significance level, using the cultivar Theobahia as control. From the genotypes analyzed, VB 1159 showed high resistance to the pathotype. The genotypes MUC 43, FL 78, VB 681, FC 101, VB 184, LP 06, ICS1, VB 902, FA 13, NO 34, PS 5784 and Theobahia showed moderate resistance, while CA 1.4, VB 206, LCT 37A and SJ 02 were the most susceptible genotypes. The new resistance source to Ceratocystis wilt identified in this work may be used in cocoa breeding programs and as a source of rootstock selection by farmers.
Ceratocystis wilt; resistance; Theobroma cacao
