MAS Breeding T. cacao for disease suppressive soils with focus in mycorrhizae.

Agriculture is in need for new sustainable approaches that, next to produce food, care for the environment and human health. Sustainable practices are also required in the cacao plantations in Panama, part of Central America where cacao was first domesticated. Cacao is required to be grown organically if cacao farmers want premium prices due to the Fairtrade certifications. Still, due to the lack of adequate agricultural technology, around 30% of the yield is currently lost due to diseases. Therefore, cocoa farmers require new practices and technologies to increase yield and deter diseases. One of the most common organic practices is to improve soil fertility and plant nutrient acquisition by using beneficial soil microorganisms. Arbuscular mycorrhizal fungi (AMF) are such beneficial soil microorganisms that improve plant nutrient acquisition, and the question is how the beneficial impact of AMF on cocoa production can be increased. Therefore, I aim to unravel the root traits and genetics that facilitate mycorrhizal symbiosis in cacao. Firstly, we will quantify the root traits and genetic composition of currently growing cacao populations on plantations in the cacao regions of Panamá. Secondly, I will perform experiments with contrasting cacao genotypes to investigate the effect of different AMF communities. Thirdly, I will develop a mapping population to identify quantitative trait loci for improved growth with AMF. Identifying markers is an essential contribution to fundamental understanding that will benefit the breeding of crops with increased mycorrhizal benefit and hence sustainably increased productivity.