CROP SYSTEMS BIOLOGY and SEEKING SYNERGY WITH SOCIAL SCIENCES
Paul has a track record in grassland science, agronomy and crop physiology. Over the last decade the main focus of his research activities were on the following topics:
- Seed systems, both of vegetatively and generatively reproduced crops. Currently the focus is on developing quality declared seed systems of potato in Eastern Africa.
- Agrobiodiversity, including the anthropological aspects of the use of diversity in staple crops and the global conservation of genetic resources and crop wild relatives.
- Linking ecophysiology and genetics of complex traits through modelling with a focus on the efficiency of resource use efficiency (especially of micro and macro nutrients).
- Modelling of C3 and C4 photosynthesis, with an increasing emphasis on dynamics of photosynthesis under fluctuating light and on photosynthesis under stress.
Research on the impact of positive selection on quality of seed potatoes has greatly contributed to the livelihoods of small scale farmers in Eastern Africa. The mechanisms why positive selection works and how to enhance its positive effects over a number of generations is currently under investigation. In some countries, however, positive election is frustrated by the abundance of bacterial wilt and needs to be replaced by a community-based containment of the disease, through negative selection, farm hygiene, crop rotation, strictly enforced seed inspection, etc.
Research in collaboration with many foreign universities and knowledge institutions and led by a team based at CIAT showed that over 70% of crop wild relative species essential for future food security are under-represented in genebanks worldwide. A global atlas was produced that illustrates which crop wild relatives should be collected and where. High priority should be given to crop wild relatives of sugarcane, maize, banana, cassava, sweet potato and millet. Important regions for collection include the Mediterranean and Near East, but also areas in southern Europe, Asia and South America.
Considerable progress has been made in identifying key traits for crop performance, quantifying genetic variation in such traits, identifying quantitative trait loci for these traits and quantifying their relative importance in boosting yields. For example PhD candidate Junfei Gu has evaluated genetic variation in photosynthesis parameters in rice, has identified major QTLs for these parameters and has scaled up this genetic variation from the leaf level to the canopy level using modelling approaches. Cesar Ospina Nieto has done association mapping of basic above-ground and below-ground crop physiological traits in potato, including nitrogen use efficiency.
Through the ground-breaking work of Xinyou Yin, inspired by the models of Farquhar et al., a large programme - through a combination of experimentation and modelling - on the quantitative analysis of the constraints to the efficiency of both the biophysical and the biochemical aspects of C3 and C4 photosynthesis, under variable conditions, has been developed. If finding can be guaranteed, this programme will develop into the direction of C4 photosynthesis under cool conditions.