The program continues to develop and evaluate new perennial plants for introduction to the horticulture industry and gardeners. The program ended the year with 1,974 plants in the ground representing 278 accessions. The Chicago Botanic Garden’s Production Department is holding another 971 plants for the program that will be planted in 2014. Most of these plants are advanced generation hybrids developed at the Garden and are under evaluation as potential further breeding stock or as introductions. Of the 34 crosses attempted this year, 15 were successful, producing a total of 921 seeds. Much of this seed was turned over to the Production Department for germination and subsequent planting in 2014. Backup seed was transferred to the seed vault for longer-term storage. Seven hybrid plants were selected for propagation for initial evaluation in-house at the Garden as potential future introductions (Ault).
About the Program
Botanic gardens and arboreta around the country are often living repositories of not only the finest, but also the most unusual and rare, ornamental plants for garden cultivation and display. Yet few botanic gardens utilize their plant collections for breeding and development of new garden plants, although the public interest in gardening and in new garden plants has never been greater. Drawing on one of the Midwest's and one of the country's finest plant collections, the plant breeding program at the Chicago Botanic Garden aims to develop beautiful new perennials that thrive in midwestern soils and climates.
In this era of advanced technologies such as gene splicing and DNA fingerprinting, the Garden finds traditional plant breeding methods still invaluable for developing new ornamental plants. These methods include controlled hand pollination of flowers, collecting and germinating seeds, growing out thousands of plants for evaluation, and then selecting the best plants for further breeding and evaluation.
The process begins by selecting two related plants, each with a set of desirable traits—such as attractively colored flowers, compact height, drought tolerance, or resistance to a plant disease. The plant that is to produce the seed may need to be emasculated (removal of the anthers from the flowers) to prevent self-pollination. Also, the flowers may need to be placed behind barriers such as mesh bags or screens to prevent insects from pollinating the flowers with undesirable pollen.
After determining when to collect pollen and when a flower is ready to be pollinated, the crosses are made. Each cross is carefully labeled, and the plants are monitored for seed ripening. The hybrid seed is collected and germinated to grow new plants, and the process begins all over again, until the right combination is found of desirable traits without the less desirable traits from the original parent plants.
Most of the priority genera in the breeding program are taxa indigenous to North America. There is a wealth of naturally occurring plant taxa largely unexplored as subjects for garden cultivation. The ecological and plant taxonomic literature is surveyed for genera that produce interspecific hybrids in nature. Garden scientists then attempt to reproduce these hybrids under controlled conditions. Advanced generation breeding and selection can produce unique genotypes with novel ornamental attributes of flower color and fragrance, plant habit, better cold and heat tolerances, and improved adaptability to the stressors encountered in urban landscapes, such as compacted and alkaline soils.
The major taxa under current study include coneflowers (Echinacea), false indigos (Baptisia), phlox (Phlox), and speedwells (Veronica). Individual plants are selected and clonally propagated for evaluation by the Garden's Plant Evaluation Program, as well as by other cooperative evaluators. Those plants that get the highest marks are introduced to the horticultural trade and home gardeners through the Garden's Plant Introduction Program, Chicagoland Grows® Plant Introduction Program.