Early field performance of fine flavor cocoa clones for agronomic traits and tolerance to cocoa swollen shoot virus disease

Fine flavor cocoa generates substantial revenue and provides livelihood for millions of people in both Latin America and Africa. Cultivars of fine flavor cocoa were recently introduced into Ghana for breeding purposes. These cultivars were evaluated in two sets of experiments. Experiment 1. involved field evaluation of 30 clones for vigor, precocity, survival potential and heritability of the agronomic traits. Experiment 2. involved evaluation of the 30 clones for tolerance to the cocoa swollen shoot virus disease (CSSD) upon inoculation with the New Juabeng strain of Togo B virus. Results of experiment 1 showed significant (p<0.05) variability among the clones for vigor, precocity and percentage survival. Top five stable and precocious clones identified included CRG9006, SCA9, T63/967, GEBP565AF and PA107. Broad-sense heritability estimate ranged from 0.16 for percentage survival to 0.72 for pod number. Pod number had significant and positive correlation (p<0.01, r=0.40) with stem diameter increment. Similarly, flower intensity correlated positively with pod number (p<0.01, r=0.43). In the second experiment, the results showed significant differences in the levels of tolerance to CSSD among the 30 clones inoculated. The tolerance score ranged from 1.63 (SCA6) to -1.52 (PA188). Further observations suggested the importance of genetic factors in the management of the disease. Five outstanding clones identified as tolerant to the cocoa swollen shoot virus disease included PA188, MAN15/60, ICS1, CRG9006 and MAN15-2. It is important that most productive and CSSD tolerant clones identified are considered for future germplasm enhancement.