Next generation breeding tools for chamomile: Evaluating genetic diversity, ploidy variation, and identifying marker-trait associations

Abstract

Chamomile (Matricaria recutita L.) has a long history of use in herbal medicine with various applications, and the flower heads contain numerous medicinally active compounds. Next generation sequencing (NGS) approaches are applied to exploit genetic resources in the major crop plants to develop genomic resources, and to enhance breeding. Genotyping-by-sequencing (GBS) has been used to evaluate the genetic structure of cultivated populations in the non-model crop chamomile using 6495 SNP markers, and to perform a genome wide association study (GWAS) identifying sequences significantly associated with the medicinally important alpha-bisabolol content. Ploidy variation in chamomile was investigated by high-throughput flow-cytometry. Di-, tri- and tetraploid plants were identified, and in field trials characterized. Since seeds are not needed in the harvested product of chamomile, triploidy could be a way to obtain a sterile chamomile variety, omitting the problems of chamomile seeds lying up to 15 years dormant in the soil and facilitating crop rotation in the fields.