Implementation of molecular techniques (RAPDs, AFLPs) on camomile (Chamomilla recutita (L.) Rausch.) for genotyping and marker development

Camomile varieties of different provenience can be distinguished by morphological and physiological traits. However, these traits vary under different environmental conditions leading to difficulties in the discrimination of genotypes. PCR-based molecular techniques like RAPDs and AFLPs are useful tools to characterise genotypes rapidly and reliably on the DNA-level independently from ecological factors. Besides this, these techniques facilitate the development of molecular markers for ingredients of camomile oil, e.g. (-)-alpha-bisabolol, thereby enabling pre-flowering selection. Therefore, attempts were carried out to establish these molecular techniques on camomile. In a first step genetic similarity (Jaccard, 1908) was estimated in a set of released cultivars, breeding populations and twice self-pollinated lines. Based on data obtained by 20 RAPD primers and 16 AFLP EcoRI+3/MseI+3 primer combinations genetic similarity was estimated between 0.52 and 0.91 (RAPDs) and 0.58 to 0.79 (AFLPs). By cluster analysis as well as by principle co-ordinate analysis genotypes were grouped according to their different proveniences. Regarding the self-pollinated lines which differ in their (-)-alpha-bisabolol content a high degree of homogeneity within lines (0.81-0.94) and a relatively low genetic similarity between them (0.46-0.56) was determined by RAPDs. By crosses between these lines a segregating F-2-Population was created for developing molecular markers corresponding to the (-)-alpha-bisabolol content. Using bulked segregant analysis (Michelmore et al., 1991) a set of 200 RAPD-primers and 256 AFLP-primer combinations were tested up to now and two AFLP-markers linked to the (-)-alpha-bisabolol content were detected. Future work will aim at the development of additional more closely linked markers.