Controlling dormancy and sprouting in potato and onion

A number of approaches were taken, exploiting the expertise and resources across the four collaborating institutions; James Hutton Institute, Cranfield University, Imperial Collage, University of Greenwich. These included:

• Phenotypic analysis of a population of potato lines derived from a cross between diploid potato parents, and the use of quantitative trait locus analysis to identify the locations on the genome that control length of dormancy.

• Identification of key controlling genes through sequencing of the gene transcription (RNAseq) at critical stages during dormancy and sprouting for potato lines with contrasting dormancy characteristics, and for onion bulbs with differing dormancy characteristics as influenced by ethylene treatment.

• Analysis of hormones and metabolites for both potato and onion tubers during dormancy and sprouting

Results

• An updated unified model for hormonal dormancy control for potato produced (also relevant to onion)

• Genome locations (QTLs) identified associated with tuber dormancy and sprout growth. This could potentially lead to markers for tuber dormancy/sprouting for use in breeding

• Candidate genes involved in dormancy control were identified. Transgenic lines for functional validation and further expression work were  produced for one gene (TERMINAL FLOWER 1/CENTRORADIALIS)

• Profiles of gene expression, hormone concentrations, key metabolites and respiration through progression of dormancy, dormancy break and sprout growth were obtained for both potato and onion.