PhD defence by Sara Miller

Sorghum under a beautiful blue sky, presumably in Africa

Sorghum as a crop for the future - Investigating nitrogen recycling from the cyanogenic glucoside dhurrin and developing new technologies for sorghum improvement

Sorghum is a cereal crop originally from Africa with many useful qualities such as heat and drought tolerance, high nitrogen use efficiency and protein content. It is mostly grown on marginal soils where almost no other crops can be grown and therefore considered underutilized. Furthermore, it produces big amounts of the toxic nitrogen containing compound dhurrin that can cause livestock poisoning.

Nitrogen is one of the most important macro nutrients for plants and is essential to form proteins or DNA. To ensure good crop yields big a mounts of artificial nitrogen fertilizer are used worldwide. The production of nitrogen fertilizer causes a big part of agriculture's CO2 emissions and if plants cannot take up all the fertilizer applied on a field this leads to more environmental problems such as the emission of N2O, a greenhouse gas 300 times more potent than CO2.

In this thesis we investigate how sorghum can recycle nitrogen from dhurrin and use it to grow. This will hopefully provide insight into why sorghum is so efficient at using nitrogen which can help improving other crops and also make sorghum even more efficient at using nitrogen. Additionally, we investigate new ways to study genes from sorghum, so we can build a platform for sorghum research in Europe. So far only very little sorghum is grown in Europe, but this might change with climate warming and increasing weather extremes which will make sorghum a very attractive crop.

Associate Professor Nanna Bjarnholt, PBIO, PLEN

Assessment committee
Professor Robert Edwards, Newcastle University, UK
Senior Researcher Nancy Terrier, INRAE, Montpellier, France
Professor Søren Bak, PLEN (chair)

Section secretary
Jette Højgaard,


Reception after the defence at 16:00 in H117