PhD defense: Adama Korbo – Københavns Universitet

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PhD defense: Adama Korbo

Adama Korbo defends his thesis: 

Genetic variation in food potential and adaptation of baobab (Adansonia digitata L)

Principal supervisor

Professor Erik Dahl Kjær
Department of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen, DK

Co-supervisor

Senior Researcher Jon Kehlet Hansen
Department of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen, DK

Assessment Committee

Senior Researcher Ulrik Bräuner Nielsen (chair)
Department of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen, DK

Professor Roeland Samson
Department of Bioscience Engineering, University of Antwerp, Belgium

Researcher Gunnar Jansson
Skogforsk, Uppsala Science Park, Sweden

Summary

The baobab is one of the most important African multipurpose tree species providing food, medicine, fodder, and income to the people living in the South of African Sahara. Because of the important role and the increasing international interest, the species has been proposed for future domestication programme. However the quantitative genetic related to the species has not been investigated sufficiently. Therefore the present research aimed to generate knowledge to support domestication and conservation of baobab.

The genetic analyses have focused on traits as: survival and growth with and without water stress, leaf productivity (total and distributed over the year), and leaf quality (sliminess/taste and provitamin A). The water stress test is based on an approach to change the length of the raining season rather than simply stress the plants. This part of the study has involved ecophysiological methods. The analysis of the leaf quality is based on cooperation with food science creating a cross disciplinary research angle.

Results reveal an interesting difference between West and East African provenances for early growth in nursery, but less geographic structure in leaf morphological traits. From the hedge system (where baobab is cultivated for fresh leaf production mainly during the dry period) despite the plants being irrigated, lowered leaf productivity during the dry season was found. For total leaf production, the existence of large genetic variations within and among provenances, suggests the possibility of improvements in productivity. However to increase the production during the dry season, it seems necessary to look more specifically for “evergreen” provenances (and select trees within provenances). The provitamin A potential and the sliminess estimated were substantial and the observed levels of provitamin A is very high for some families. But the two properties were not always associated. However selection of superior genotypes and/or families can increase the regularity and the productivity of the system with nutritive values and attractive taste. With regards to the drought stress, the baobab trees from various origins reveal relative high resistance to reduced growth length but the growth rate is influenced. In addition provitamin A in the leaves varied substantially according to origin with highest levels of provitamin A in some of the provenances from dry areas.

After the PhD defense there will be a reception at Rolighedsvej 23, in the canteen (common area) on ground floor in the new building.