Research on the genus Guizotia at SLU with particular emphasis on G. abyssinica
Although Ethiopia and India are the major niger producing countries, the crop is cultivated in small scale in several African and Asian countries and in the USA. Niger seed oil is being used as edible oil, for various industrial purposes such as soaps, paints, illuminants and lubricants. Its potential as a source of biodiesel is also encouraging. In addition to its oil, the crop offers an important source of seed protein that significantly contributes to the human dietary protein intake.
Until recently, niger has received little attention from the scientific community and consequently suffers from a lack of improvement through modern breeding efforts despite its great potential.
The major objective of our research on niger is to have a significant contribution towards the improvement of niger in order to make it a competitive oil crop worldwide. We started research on niger and its wild relatives with the cytogenetic analyses followed by the molecular marker (RAPD, AFLP and ISSR) based analyses of genetic diversity, which revealed a high genetic variation both in niger and in most of its wild relatives.
Through the phylogenetic analyses of the genus Guizotia, using DNA sequence data from various regions of the chloroplast genome, the closest wild relative of niger was identified, two new populations were identified as distinct Guizotia species, and the subtribal position of the genus in the Tribe Helianthae was determined. We developed a niger EST-library and sequenced its chloroplast genome through a collaborative research project between SLU, University of British Columbia (UBC, Canada), Indiana University (IU, USA), Bioversity International (Bioversity, Italy) and Addis Ababa University (AAU, Ethiopia).
The EST-library consists of 25,711 Sanger reads that are assembled into 17,538 contigs and singletons, of which 4781 were functionally annotated using the Arabidopsis Information Resource (TAIR). From the EST library, we developed 43 microsatellites and then designed and tested primers for their amplification.
Niger is a strict self-incompatible crop species with a sporophytic self-incompatibility (SI) mechanism. SI has been one of the problems that complicate breeding efforts in niger. We verified several aspects of SI in niger and developed self-compatible genotypes for the first time in the cultivation history of the crop.
Developing self-compatible strains in niger has several advantages including the opportunity to develop everlasting mapping populations that facilitates genetic linkage mapping and QTL analysis and developing pure lines for various economically important traits. Currently, we are developing an EST-library from these pure lines and F2-mapping populations based on these inbred lines will soon be used for SNP discovery and genotyping.
Niger is sensitive to long photoperiods and flowering is either very much delayed or does not happen at all at a photoperiod of more than 12 hours. This photoperiod sensitivity is of one of the main factors that limit the cultivation of niger in Europe.
We have identified genotypes less sensitive to the long photoperiod and further studies is underway, as they have a potential to be grown in Europe and other countries with a long-day summer.
List of publications on the genus Guizotia from SLU |