Chrysanthemums (Chrysanthemum ×grandiflora Ramat.; =Dendranthema × grandiflora Tzvelv.) are popular cut flowers, potted flowering plants, and perennial garden favorites worldwide with thousands of cultivars available (Anderson, 2006). Garden chrysanthemums are the number one herbaceous perennial in the United States, with a wholesale farmgate value of $141.845 million in 2005 (U.S. Dept. Agr, 2006). Numerous factors contribute to the long-term popularity of garden chrysanthemums, including fall flowering (most cultivars are obligate short-day plants), a wide range of flower types and colors, distinct plant habits (upright, cushion, groundcover), and winter hardiness (particularly for northern gardeners; Anderson, 2004; Anderson and Gesick, 2003, 2004; Dole and Wilkins, 2005; Kim and Anderson, 2006). A small number of private and public sector breeding programs across the globe have active chrysanthemum breeding programs (Anderson, 2006). The chrysanthemum breeding program at the University of Minnesota is now the oldest public sector chrysanthemum breeding program in the world and the only public sector chrysanthemum breeding program in the United States (Anderson, et al., 2001). The program's trend-setting breeding endeavors, coupled with its germplasm base and genetic resources, continue to bring a wide range of colors and plant habits in hardy chrysanthemums for northern gardens.
The cushion habit of mums, a genetic discovery of University of Minnesota Agricultural Experiment Station mum breeders, was the basis for the University of Minnesota's first U.S. plant patent for ‘Minngopher’ (U.S. Plant Patent, No. 4,327; Widmer, 1978). Plants are hemispherical in shape with flowers almost completely covering the outside surfaces of each plant, like a pincushion. Previous mums, like most other flowers, bloomed only at the top of long stems (upright plant habit; Anderson, 2006). Shortly thereafter, all U.S. breeding programs were producing garden chrysanthemums with this plant habit (Anderson, 2006). The cushion is now the primary plant phenotype in the market (Anderson, et al., 2001).
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