Ploidy Level and Reproductive Trait Analysis in Three Matricaria recutita Cultivars

In continuation of past trials to develop a triploid chamomile cultivar, flow cytometer investigations to determine spontaneous ploidy variation in established cultivars of Matricaria recutita were carried out. The screening of a total of 120 plants of three cultivars included general analysis of ploidy level and specific differentiation of aneuploids. Microscopic counts of mitotic chromosome numbers in some reference individuals and comparison of flowering and seed characters between cultivars and ploidy levels were included. Results showed ploidy level-deviants in two of three cultivars and a clear segregation of a uniform diploid unit of plants against a dispersive tetraploid unit with numerous hyper- and hypotetraploid aneuploids, but no triploids. The tendency to flower was significantly higher in diploid plants (vs. tetraploids), whereas the flowering duration of plants and the flowering duration of single capitula rose slightly with increasing ploidy level. Matricaria recutita seems not to produce triploids easily, as none were observed; they neither occurred through spontaneous formation nor after controlled crossing. However, autotetraploid aneuploids with varying number of chromosomes emerged frequently.