Garcinia kola: diversity, utilisation and domestication in Cameroon

Ing. Anna Maňourová

Disertační práce

Abstract:

Garcinia kola Heckel (Clusiaceae) is an important multipurpose medicinal species and one of West and Central Africa's most traded non-timber forest products. Despite its undeniable local significance, most current research focuses on G. kola therapeutic effects, omitting topics that could lead to the species' improvement and advancement in domestication. Therefore, our study aimed to provide a comprehensive understanding of G. kola phenotypical and genetic variation, its biochemical potential, and utilisation and management by local communities. In total, 122 farmers were interviewed and 227 trees along with 1,040 leaves, 1,727 fruits and 4,559 seeds were evaluated in Cameroon's Southwest, Central, and South regions. Major regional differences in the utilisation, management and commercialisation of G. kola products were discovered related to the plant part that was primarily used. Even though fruit collection was harmless to the tree, bark and root harvesting was discovered to be invasive and unsustainable, threatening the species' existence in wild stands. Kolaviron, the most investigated chemical compound, appeared to be overrated in terms of its therapeutic impact. Clinical study evidence is lacking, while other substances may merit more investigation. G. kola seed hulls were discovered to be a rich source of protein for animal feed, although the protein quality must first be evaluated. The main production factor of fruit seed mass and the harvesting factors of crown diameter and trunk height were used to identify G. kola ideotype and elite trees. Most of these trees originated in the South region, which exhibited higher genetic diversity than the rest of the study sites. However, no significant differences in genotype or phenotype were found between wild and cultivated trees, and most variation was found within rather than between populations. This suggests that the domestication of G. kola is still in its early stages. If market access is supported, promoting the species' therapeutic potential among farmers could be a successful strategy for shifting their focus from the bark to the seeds. Selecting trees with above-average fruit seed mass is recommended to improve marketable seeds' quality and consistency. Future cultivar development can be approached in two ways: by fruit seed mass - big fruits with large/many kernels; and by fruit seed mass ratio - smaller fruits with high seed mass. However, field experiments acknowledging the Participatory Domestication Approach must first be established to test, monitor, and propagate potential cultivars of elite trees and ideotypes.

Keywords

agroforestry, Cameroon, indigenous fruit trees, kolaviron, neglected crops, underutilised species

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 26. 9. 2023

Obhajoba závěrečné práce

• Vedoucí: prof. Ing. Bohdan Lojka, Ph.D.
• Oponent: Petr Maděra, externi, Roger RB Leakey, externi, Jean Yong, externi

Česká zemědělská univerzita v Praze

Fakulta tropického zemědělství

Doktorský studijní program / obor:
Zemědělská specializace / Tropical Agrobiology and Bioresource Management