Introduction

Cymbidium, or boat orchid, is a genus of 52 evergreen species in the orchid family Orchidaceae. This genus is distributed in tropical and subtropical Asia (such as Northern India, China, Japan, Malaysia, Philippines, and Borneo) and Northern Australia. The larger flowered species from which the large flowered hybrids are derived grow at high altitudes (Du Puy and Cribb, 2007).

Most of Cymbidium species native to temperate regions, such as C. kanran and C. ensifolium have strong fascinating scents. On the other hand, most of the species that are native to subtropical regions have very weak or no scent, except for the C. eburneum, C. canaliculatum, C. hookeerianum, C. suavissimum, and C. tracyanum species which have strong scents (Du Puy and Cribb, 2007).

The classic hybrids are divided into two groups, called the standards and the miniatures. The standards are large- flowered and usually less fragrance, while the miniatures are small-flowered, and some of them have light fragrance.

The fragrant Cymbidium hybrids are obtained from crossing classic types with species which are native to temperate regions. Some good examples of these hybrids are Peter Pan ‘Greensleeves’ (C. ensifolium × C. Miretta), Maureen Carter (C. sinense × C. Sleeping Beauty), and Golden Elf ‘Sundust’ (C. ensifolium × C. Enid Haupt). Also these hybrids are more manageable in size and more free-blooming than the classic hybrids. The commercially well-known C. Golden Elf ‘Sundust’, having a parentage, C. ensifolium (50%) and C. eburneum (6.25%), has a strong fragrance. Recently, Cymbidium export has become a promising business compared with other flower crops in Korea. Cymbidium produced in Korea is exported to China during the Chinese New Year season, and export earnings amounted to about US$ 15.2 M in 2011 (MFAFF, 2012). To establish a continuous and stable export system and domestic market, the supply of domestically produced seedlings and breeding of new fragrant cultivars are essential. Since 2003, thirty-three hybrids have been bred by the National Institute of Horti-cultural & Herbal Science (NIHHS) of the Rural Development Administration (Kim et al., 2006, 2010, 2011, 2012).

The most popular oriental, C. kanran has strong scented greenish flowers and blooms from the beginning of December. It produces about 10 sprays of beautiful flowers.

In some reports, in order to develop fragrant floricultural crops, the electronic nose was used to analyze patterns of scents (Been and Kim, 2003; Lee et al., 2003; Park et al., 2011). Mother plant, C. kanran has fragrance and attractive flowers, but grows slowly from 4 to 5 years from plantlets to flowering and has short flower longevity. The aim of this breeding program was to produce flowers with long base life, various colors, fragrance, and vigorous variety. This new hybrid combined the characteristics of C. kanran with strong fragrant flowers and spreading shape, and C. Jack Frost with light pink flower color and long vase life and vigorous growth to obtain a fragrant variety with bright colored, round flower, vigorous growth and flower longevity of more than 20 days.

Origin

The new cultivar, C. Snow Bell, is a cross bred between C. kanran, a small-sized fragrant plant, and C. Jack Frost, a small to medium sized plant with light pink petals and light red lip developed at the NIHHS in 2011. Fifty-five seedlings were obtained after planting and acclimatization was done in the greenhouse. Varietal evaluation, selection and breeding were done for nine years (1999-2010).

The characteristics were evaluated based on the manual for agricultural investigation and guidelines for the conduct of tests for distinctness, uniformity and stability for Cymbidium (UPOV, 1999).

Analysis of Fragrance Pattern

Samples were collected through the solid phase micro extraction (SPME) method and analyzed using αFOX 2000 (Alpha-MOS, France) electronic nose with six (6) metal oxide semi-conductors. Each sample was analyzed three times. Principal component analysis (PCA) was used to distinguish the fragrance patterns obtained from the combination of responses of the six sensors. The Alpha Soft Version 12.0 statistical program was used for analysis.

Description

The cultivar named ‘Snow Bell’ (Fig. 1) was finally selected for its distinguishing characteristics such as flower color and shape, length of flower stalk, leaf attitude, and vigorous growth. This hybrid was bred with the objective of combining good qualities such as C. kanran fragrance and C. Jack Frost flower shape, bright color, vigorous growth and flower longevity of more than 20 days.

C. kanran, a mother plant with greenish colored flowers, some spreading flower shape, and small sized plant with relatively strong scent, was similar to the fragrance and small-sized plant of ‘Snow Bell’. In 2010, a consumer preference survey was conducted during the Cymbidium show in NIHHS to determine a new variety. By 2015, the orchid farmers will be supplied with ‘Snow Bell’ variety after producing more plantlets.

Performance

Plant

The C. Snow Bell is a sturdy, small sized plant with along straight leaf shape and a semi-upright flower spikes arising from pseudobulbs above the ground at approximately 35 mm. When mature, the plant displays multispiking characteristics in an 18 cm diameter pot. Plant height is approximately 47.5 cm from the base of the pseudobulb to the tip of the leaf. The leaf width is wider than the mother plant and leaf shape resembles that of the pollen parent (Table 1). This variety can withstand low temperature (5-7°C) during the winter season in Korea without damage or loss of flower buds.

Flower

The light pink colored flower of ‘Snow Bell’ was mixed with C. kanran, as a female parent with greenish colored flowers and C. Jack Frost, as a male plant with light pink flowers. The type of flower and leaf was similar with female parent with some incurve and spreading shape.

The basal color of the flower is light pink (RHS, R56D close to white) with light red line (R56A) on the sepal and same colored (R56A) spotting on lip when it is fully opened. This flower color is brilliant compared with pollen plant. The ‘Snow Bell’ has small bright pink fragrant flowers that are arranged bilaterally on the raceme. The petals and sepals show some incurve and spreading shape. The flowering season is mid-winter (December to February), under optimal cultural conditions (Sakamoto, 1996). Inflorescences that are uncut typically exceed 30 days in a wide range of environmental conditions. Spike habit is strong and erect without any arching (Table 2).

The flowers of ‘Snow Bell’ (Fig. 2) have a natural horizontal spread of 6.2 cm and a vertical spread of 5.1 cm, which are larger than those of C. kanran 5.6 cm and 4.5 cm, respectively. The flower size is reduced as compared with the pollen plant, but is much larger than the species.

The number of flowers per flower stalk is 13.8 when the plant is 36 months from in vitro deflasking and increased compared with the mother plant.

The length of flower stalk is about 50.7 cm and it produces 2.6 spikes per mature pseudobulb. The ‘Snow Bell’ is a middle-of-winter-season pot Cymbidium.

Also, the flower longevity of this new hybrid is about 20-25 days, extended to more than 10 days compared with the mother plant.

From these results, the hybrid was improved in more round flower shape and extended longevity compared with the mother plant. It can also be distinguished by its superior flower quality combined with good arrangement, flower shape and color.

To investigate the fragrance intensity of ‘Snow Bell’ variety, fragrance pattern was analyzed using the electronic nose (Fig. 3). In the sensory evaluation of growers and consumers who participated in the evaluation meeting of new varieties of ‘Snow Bell’ variety was judged on the degree of scent to be weaker than the C. kanran (Table 3).

Fragrance components of Orchid using the Chromatography (GC) were first evaluated by Dodson and Hills (1966). Most of the flavor components are belonged to the three groups, such as phenyl-propanoids, fatty acid derivatives, and terpenoid systems (Croteau et al., 2000). For the investigation of flavor components in ‘Snow Bell’, GC analysis needs to be conducted in the future.

In the electronic nose analysis, the degree of fragrance of ‘Snow Bell’ was similar with the C. kanran and both of them showed mild or strong scent although they had different fragrance patterns (Fig. 3).

To objectively distinguish scent patterns of each Cymbidium hybrid, the value of principal component (PC) 1 and 2 was obtained using the response value of the metal oxide sensor of the electronic nose. As shown in Fig. 3, the value of PC1 and PC2 was 97.542 and 2.251, respectively and this value was used for analyzing scent patterns.

From these results, the distribution value of C. kanran, mother plant and ‘Snow Bell’ was distinguished from the control (air). Also, results showed that the C. kanran and ‘Snow Bell’ have similar scents. Therefore, it was possible to confirm the scents of two varieties using the electronic nose. The gas chromatography (G/C) analysis will be done later to identify accurate aroma compounds.

With the impressive characteristics of ‘Snow Bell’, this study envisions to increase the income of farmers, as the result of the preference survey (Table 3). Also, a useful germplasm for fragrant Cymbidium breeding and increased consumption are expected.

Notes for Production

This new variety C. Snow Bell is relatively easy to grow by standard cultivating method of Cymbidium. It is possible to produce in early winter season (the end of November) by high land culture, though this variety belongs to a typical middle winter-blooming group (Table 2). Basal flower color of ‘Snow Bell’ is a light pink (Fig. 2), but if it is cultured under the 50% shade net, its color may be light greenish color. Therefore, it is necessary to remove the shade net in blooming season for expression of the brilliant pink colored petal.

Availability

An application for plant variety protection was filed for C. Snow Bell at the Korea Seed & Variety Service (Grant Number 4164). The variety will be available for production at the onset of 2014.