Fertility and seed set in chrysanthemum
The Netherlands is the top exporter of cut flowers and Chrysanthemum represents the second most important cut flower in the world. This position is threatened by low-cost countries that are lurking to take over the market, urging Dutch breeders to search for even more efficient breeding methods. The most important problem that Chrysanthemum breeders are currently facing is the ever decreasing seed set of popular ornamental varieties, resulting in a very low seed yield after crosses. Therefore, in this project we are aiming at:
I. Obtaining fundamental knowledge about the genes and processes involved in formation of the reproductive organs and determining seed set in chrysanthemum.
II. Identification of the genetic basis of severely reduced seed set in ornamental chrysanthemum varieties.
III. Training and education, at PhD level, of an employee of the private partner in this project.
The knowledge generated in this project can be implemented to improve the breeding process of chrysanthemum and probably, other ornamentals. In order to breed for ornamental value and resilience traits, good seed set is a first priority.
In ornamentals, such as chrysanthemum, commercial success and profitability depends on beauty (ornamental value) of the final product, the flowers. For years, breeders have successfully breed for the associated traits, but often these have a trade-off effect on seed number and quality. The need to improve ornamental value remains continuously and additionally, there is a strong demand for the introduction of new traits (resilience, pathogen resistance, etc.) that are essential for a more sustainable production. Unfortunately, breeders do not have the tools and knowledge to improve seed set while maintaining ornamental value, endorsing the necessity of this project.
1. Detailed insight in the development of ray and disc florets in the chrysanthemum inflorescence (capitulum) and insight in potential morphological causes of reduced fertility and seed set (Y1).
2. Identify physiological measures, such as hormone, temperature or light treatments that can improve fertility of decorative varieties (Y1-2).
3. Identification of potential candidate genes controlling fertility and seed set in chrysanthemum based on genome-wide expression studies by RNAseq (Y2-3).
4. Identification of genomic regions associated to reduced seed set by a classical QTL approach (Y2-3).
5. Functional analyses of identified candidate genes by: (I) detailed expression studies (qRT-PCR and/or in-situ hybridization) in different tissues and at different time points during capitulum development; (II) Stable or transient overexpression or silencing/knock-out; (III) Investigation of expression and/or presence of SNPs in existing genetic material (populations, lines). (Y3-4).
6. Performing additional perturbations (as described in point 2 above) based on the outcomes of the RNAseq and/or QTL analysis, aiming at improved fertility and seed set (Y4).
7. Organization of semi-annual progress meetings (Y1-4).
8. PhD thesis (Y4).