Improving yield and essential oil content in annual caraway accompanied by utilization of molecular-genetic methods

von Daniel Baron von Maydell

75 Seiten, Taschenbuch

Kurzbeschreibung des Verlags

Caraway (Carum carvi) is a species of the Apiaceae family with a long history of usage and cultivation. Fruits or extracted components are used as spice, in pharmaceuticals and for sprout inhibition in potato. Caraway cultivation in Europe was based on biennial varieties until annual varieties were introduced in the 1990s. Annual cultivation promises a reduction of production costs and better integration into crop rotation. However, current annual varieties do not gain satisfying yields and essential oil contents. Moreover, caraway cultivation in Germany becomes riskier due to ongoing climatic changes.

Therefore, a breeding project was started to increase yield potential and essential oil content in annual caraway and to develop material adapted to changing climatic conditions. To achieve yield increases, breeding of synthetic varieties should be tested as potential method in caraway breeding. To some extent, this method allows the systematical exploitation of heterosis. Breeders expected to find strong heterosis due to the assumed outcrossing nature of caraway. However, neither heterosis nor predominant outcrossing in open pollination had been experimentally verified for caraway. Hence, gathering first insights into heterosis and into the outcrossing rate of caraway were major scientific goals of this thesis. Moreover, breeding of caraway is hampered by a small amount of phenotypic and genotypic data on available germplasm. To lay a sound foundation for new breeding programs, a broad phenotypic and genotypic evaluation of available germplasm should be conducted within the project. This thesis is focused on the genotypic evaluation.

For phenotypic and genotypic evaluation, a set of 137 accessions consisting of 67 annual and 70 biennial accessions was composed (chapter 1, von Maydell et al. 2021a). A GBS was chosen for genotyping and led to the generation of a set of 13,155 SNP markers. This approach was unique in its breadth and depth for caraway breeding research. Population structure was investigated by using a PCoA, a Bayesian clustering analysis, phylogenetic trees and a neighbor network. Across all analyses a separation of accessions into two subpopulations was supported, which was associated with the flowering type. AMOVA indicated a rather low genetic variation between the two subpopulations of 7.84%. In addition, flow cytometry was conducted for 35 accessions to determine the genome size of caraway. An average genome size of 4.282 pg/2C was estimated, which is about half the size indicated in literature. In general, it was corroborated that GBS can be a robust method to analyze population structure and genetic diversity in minor crops like caraway without a reference genome. With further downstream applications, GBS should turn out to be highly cost-efficient and sustainable. In a subsequent study, generated SNP markers were already successfully be converted to diagnostic markers.

• Reihe: Dissertationen aus dem Julius Kühn-Institut
• ISBN: 9783955471255
• Sprache: Englisch
• Erscheinungsdatum: 02.12.2022
• Genre: Biologie/Landwirtschaft, Gartenbau, Forstwirtschaft, Fischerei, Ernährung
• Verlag: Bundesforschungsinstitut für Kulturpflanzen (JKI)