Abstract

Cross-pollination of suitable genotypes and earlier selection of elite offspring using adequate plants-associated defence markers in plantlets leaves are decisive for development of T. cacao genotypes tolerant to black pods disease (BPD). T. cacao plantlets from manual cross-pollination of ♀SNK64 × ♂UPA143 were analyzed for their susceptibility to BPD using leaf disc test. Subsequently, leaves (healthy, wounded and wound+infected) of selected E9 (tolerant), E13 (moderate susceptible) and E32 (most susceptible) young hybrid genotypes from ♀SNK64 × ♂UPA143 were used for flavones analysis using a HPLC/LC/MS system. Leaf disc test showed 62.5% of the progeny with disease score rates lower than the mean value of both parents. About 79.17% and 20.83% of the progeny were lesser susceptible than the most susceptible parent (UPA143) and the tolerant parent (SNK64) respectively. Total flavones contents were abiotic and biotic stresses dependant. Under infection, tolerant hybrid genotype (E9) displayed the highest flavones contents, which might control tolerance to BPD. Individual flavones analysis revealed differential patterns depending on flavones, treatment and hybrid genotype. Luteolin rutinoside isomer (tR=12.5), isoorientin (tR=12.0) and apigenin-pentosyl-hexoside (tR=10.9) appeared to be characteristic of tolerant hybrid genotype (E9) during infection. Reversely, high content of Apigenin-hexoside (tR=10.1) and apigenin-hexoside (tR=11.6) might be associated to the susceptible hybrid genotypes (E13) and(E32). Hence, ♀SNK64 × ♂UPA143 could be used to develop hybrid genotypes tolerant to BPD. Pools of above flavones, reported here for the first time in T. cacao defence, might be useful markers to develop T. cacao hybrid genotypes tolerant to BPD.

Authors (7)