oft 3 Daylily: Botany, Propagation, Breeding Surinder K. Gulia, Bharat P. Singh, and Johnn y Carter Agriculture Research Station Fort Valley State University Fort Valley, GA 31030 USA Robert I. Giiesbach United States Department of Agriculture Agricultural Research Service Beltsville, MD 20705 USA I. INTRODUCTION II. BOTANY A. History B. Systematics III. ANATOMY AND PHYSIOLOGY A. Roots. Stains, and Leaves B. Inflorescences and Flowers IV. HORTICULTURE A. Propagation B. Pests and Diseases C. Coltivar Registration and Awards V. GENETICS A. Genorne and Ploid y Level B. Flower Color Inheritance C. Biotechnology VI. CONCLUSION VII. LITERATURE CITED I. INTRODUCTION Davlilies (Hernerocallis spp., Hemerocallidaceae) are herbaceous perennials grown extensively as ornamental plants in home gardens Horticultural Reviews. Volume 35 Edited by Jules Janick Copyright L 2009 John Wiley & Sons, Inc. 193 194 S. K. GULIA, B. P. S]NGH. J. CARTER. AND R. J. GRIESBACH and commercial land inflorescences worldwide. Their botanical name, Hernerocallis, is derived from the Greek words hernero ("a day") and callis ("beauty") referring to the fact that each flower lasts only one day (Panavas et al. 1999). However, multiple buds on the inflorescences provide bloom over a number of weeks. Ancient Chinese and Japanese used daylilios for their roots, leaves, and flowers as both food and medicine. Daylily buds contain more protein and vitamin C than green beans and asparagus and vitamin A equivalent to asparagus (Erhardt 1992). All parts of the plant are edible and consumed either dried or fresh (e.g., young shoots are cooked as vegetables in China while flowers and bud are delicacies in the cuisines of several southeast Asian countries). Daylily can be consumed in various preparations, such as chicken with davlily, daylily soup, daylily casserole, deep-fried daylilies, and steamed daylily. Recent sensory evaluation and consumer preference studies (Knight et al. 2004; Pollard et al. 2004) also support the potential food value of davlilies. In addition, daylily roots and crowns are used as a pain reliever, a diuretic, an antidote to arsenic poisoning, and an anticancer agent (American Hemerocallis Society 2007). Daylily flowers are known to possess antioxidant properties (Mao et al. 2005) and cyclooxygenase inhibitory activities (Cichewicz and Nair 2002). Daylilies are easy to grow, have attractive flower colors and shapes, and the plant has an attractive growth habit. They are tolerant to drought, flooding, and heat stress and grow well in most soil types under full sun or light shade. Besides of their esthetic value, they are used to help control soil erosion along highways and water channels (Munson 1989; Garber 2004). Daylilies thrive well over a large climatic range in North America, from southern Florida to northern Canada (Peat and Petit 2004), Daylilies, however, are unsuitable as cut flower or potted plant due to short flower life. Market value of daylilies in United States together with other perennials was estimated at $571 million in 2002 (U.S. Dept. of Agriculture [USDA] 2003). II. BOTANY A. History According to Chinese oral traditions, reference to da ylily (known as Hsuan Ts'ao) dates back to 2697 BCE (Kitchingman 1985), but the first written record appears in the canonical writings of Confucius dating 3. DAYLILY: BOTANY, PROPAGATION, BREEDING 195 back to about 551-479 BCE (Barnes 2004). Hu (1968a) found the first reference of H. fulva in the writing of the Chou dynasty dating back to 112-255 BCE, where it was grown for food and medicine (Kitchingman 1983). About 300 BCE, daylily was brought from the Far East to Europe by the silk and spice traders. By 25 BCE, ii. flava was known to the Greeks, Romans, Egyptians, and Africans (Baker 1937). In 1597, John Gerard was the first English herbalist who used the name daylily to designate the Chinese Hsuan Ts'ao (Hu 1968a). By 1620, H. flava and H. fulva daylilies were cultivated in England (Stout 1934), they found their way to the United States in the 18th and 19th centuries (Garber 2004), The pre-Linnnaean name of da ylil y was Ephemeron from the Greek epi ("upon') and hemera ("day"). In 1753, Linnaeus retained hem era and added cabs ("beauty") and created a new generic name Hemerocalbis (Eddison 1987). Many books describe the early history of daylily including information on species classification, propaga- tion, and cultural practices (Stout 1986: Munson 1989; Erhardt 1992). Schabell (1990) has reviewed the history of daylily cultivation in detail. B. Systematics Hemerocallis is native to Asia throughout China, northern India, Japan, and Korea. The first extensive taxonomical study of Henleroca ills was carried out by Stout (1941); however, he died before his complete monograph could be published. Using Stout's draft manuscript, Shiu- Ying Hu (1968b) published the first monograph with a key to 23 species separated into three groups. In 1969, Hu recognized two additional species: H. tazaifu (Hu 1969a) and H. darrowiana (Hu 1969b). Erhardt (1992) developed a more elaborate classification of daylily species separating them into five groups: fulva, citrina, middendorfli, nana, and multiflora (Table 3.1). Erhardt recognized only 20 species (Table 3.2). He did not recognize H. gramiflea, H. luteola, or H. littorea. Since 1992, two additional species have been recognized: I-I. hongdoensis (Chung and Kang 1994) and H. taeanensis (Kang and Chung 1997). In 1985, Dahlgren et al. separated Heinerocallis from the Liliaceae and placed them within their own family, the Hemerocallidaceae. Homer- ocallidace'ae differ from Liliaceae in the shape of their seeds, placement of their nectarines, and type of their roots. Hemerocallidaceae seeds are black and round shaped while Liliaceae seeds are brown and flat. Nectaries are located in the walls of the ovary in Hernerocallidaceae but 196 S. K. GULIA. B. P. SINGH. J. CARTER. AND R. J. GRIESBACH Table 3.1. Classification of Hemerocollis species and common characteristics of each group. Species group Species Common characteristics Citrina H. oltissima. H. citrina, Inflorescences are multiple branched, H. coreano, H. lilioasph ode/us. flowers mostly yellow, nocturnal H. minor, H. pedicellata. habit, fragrant with long perianth H. thunbergii, H. yezoensis tubes. Fulva H. x aurantiaca, ii. fulva Inflorescences are branched, flowers brownish-red (fulvous d ye) color, diurnal habit, roots have spindle- shaped swellings. Middendorffii H. dumoi'tieri. H. esculcnto, Inflorescences are noobranched, i-I. exoltata, I-I. hakuunensis, flowers orange color, diurnal habit. II. middendorffii bracts short, broad and overlapping. Nana H. forrestii, H. nano Inflorescences are nonbranched, inflorescences max. 50 cm long, flowers reddish-orange color, diurnal habit, perianth tube shorter than I cm; not winter-hardy. Multiflora H. micron thu. H. in ultiflom. Inflorescences have man y branches, H. plicata orange to orange-yellow color, diurnal habit, flowers on short stalks smaller than 7 cm. tubes less than 2 cm long. Source: Erhardt 1992. at the base of the perigonial leaves in Liliaceae, Unlike Liliaceae, Hemerocallidaceae do not grow from true bulbs. Molecular approaches are helping to more accurately define Hemerocallis taxa (Noguchi and De-Yuan 2004; Noguchi et al. 2004). For example, it appears that H. citrina var. vespertina originated from at least three different lineages that invaded the Japanese archipelagoes separately through different routes (Noguchi and De-yuan 2004). Juerg Plodeck and Jianping Zhuang Plodeck (2003) have a Web site that describes Hemerocallis systematics in detail (www.hemerocallis-species .coin/). III. ANATOMY AND PHYSIOLOGY The anatomy and physiology of daylily plants was reviewed in detail by Voth et al. (1968). Daylily plants are composed of rammets, commonly called fans, that consist of an underground thickened stern, roots, rhizomes, leaves, and flowering inflorescences. The underground stern, commonly called a crown, contains the apical meristem. The crown is 3. DAYLILY: BOTANY. PROPAGATION. BREEDING 197 Table 3.2. List of Hemerocallis species with an overview of their traits description. Name of species Description of traits H. aitissima M—La: nor.: nbc., fr.; flowers on inflorescence 120-200cm tall: Pale yellow flower; >30 flowers per inflorescence; flower diani. 7.5 cm: tall; fading in hot son I-I. a wan tiaca EM: cv.: din.; flowers on inflorescence 60-90 cm tall; orange with red tinge flower; 6-8 flowers per inflorescence; flower diameter > 12 cm II. auvantioca Major' EM; cv.; dio.; sI. fr.; ext.: Re.; flowers on inflorescence 60-90 cm tall; yellow-orange; 5-10 flowers per inflorescence; flower diameter >12cm IL citrina M—MLa; dor.; nor..; flowers on inflorescence 100-115 cm tall; pale yellow flower; 30-70 flowers per inflorescence; flower diameter > 12cm I-I. citrina var. M—MLa; dor.; nbc., sl.fr .; flowers on inflorescence 180 cm tall: vespertina light yellow flower: 30-70 flowers per inflorescence: fading in full sun H. coreana EM—M; dor.: din.; fr.; flowers on inflorescence 50-80 cm tall: yellow flower: 50-80 flowers per inflorescence II. darrowiana M—MLa: dor.; diu.; yellow flower: 2 flowers per inflorescence H. duioortjeii EE ; dor.; dio.; flowers on inflorescence 15-60 cm II: it flower; sepal outside brownish red: 2-4 flowers i inflorescence I-I. esciileota EM; dor.; diii.; flowers on inflorescence 60-90 cm I:! flower; 5-6 flowers per inflorescence H. exaltata EM—M; dor.; din.: flowers on inflorescence 120-150 cin tall: orange flower: branching