128 Literature cited Another example that yellow [1] Cao, J. Y. et al. ed. 2005. Collected Species flowered hybrids produced of the Genus an Illustrated Outline. from cross-combination with Chekiang Sci. Tech. Press, Hangzhou. non-yellow Camellia species [2] Chang, H. T. 1981. A of the Genus Camellia. Act. Sci. Nat. Univ. Sunyatseni. LIU Xin-Kai ZHONG Nai-Sheng FENG Gui‑Mei YAN Dan-Feng GAO Ji-Yin* [3] Hakoda, N., Kirino Sh, Tran Ninh, 2007. New species of genus Camellia in Viet Nam. The Academy of Landscape, Palm Landscape International Camellia Journ. N 39:54-57. Architecture Co. Ltd., China 510627 *Author for correspondence: [4] Ming, T. L. ed. 2000. Monograph of the Gao Ji-Yin, Professor, [email protected] Genus Camellia. Yunnan Sci. Tech. Press, Kunming. Abstract: Through the cross-combination, C. japonica cultivar, ‘Tama Beauty’ x C. amplexicaulis, [5] Ninh, T. 2003. Biodiversity of Camellia genus two pale-yellow hybrids were obtained. This of Viet Nam. Intern. Camellia Journ., 2002 is another example that demonstrates that the [6] Ninh, T. 2003. Results of study on yellow hybrids of non-yellow Camellia species can also of Viet Nam. Intern. Camellia be used to breed yellow ones, following results Journ. from previous work. The flower characteristics of the hybrids were described in details and the leaf [7] Ninh, Tr. 2005. Bảo tồn nguồn gen một số characteristics, growth vigor and resistances were loài động thực vật quý hiếm ở VQG Tam Đảo also compared between the hybrids and their cross- nhằm phục vụ cho công tác nghiên cứu, giảng parents. The first hybrid, H-No.1 is pale yellow and dạy và du lịch sinh thái. Đề tài QG – 03-08, the second hybrid is pale-yellow with light-pink ĐHQG Hà Nội. tone on flowers. Their growth vigor is 2-5 times [8] Ninh, Tr.; Hakoda N., 1998. Three new that of their cross-parents and their resistances are species of the genus Camellia from Viet Nam. stronger. Also, the reasons that yellow hybrids can International Camellia Journal, No.30, pp. 76 be obtained from the hybridizations of non-yellow –79. Camellia species and the gardening value of the [9] Ninh, T.; Hakoda N. 1998. Camellia petelotii: hybrids were discussed. a new species of yellow Camellia from Viet Keywords: Breeding; Hybrids; Non-yellow nam. International Camellia Journal, No. 30, Camellia species; Yellow camellias pp. 81 –83. Background [10] Ninh, Tr.; Hakoda N., 2010. Các loài trà ở vườn Quốc gia Tam Đảo. GTZ. The dream of obtaining yellow flowered camellia cultivars began with the discovery of yellow [11] Ninh, Tr.; Ninh, L.N.H. 2007 Diversity of Camellia species, especially C. nitidissima. wild Camellia species of Tam Dao National Although the road to the development of yellow Park. Journal of Science – Natural Sciences camellia cultivars was long and hard [1], some and Technology, 23, pp. 152-154. light-yellow flowered cultivars have been created [12] Sealy, J. R., 1958. A Revision of the Genus with different breeding approaches [2]. It was the Camellia. Roy. Hort. Soc., London. yellow flowers of yellow Camellia species that made camellia breeders first attempt to move [13] Bộ KHCN & MT, 2007. Sách đỏ Việt Nam the yellow genes into their projected hybrids, tập 2: Thực vật. NXB KHTN& CN.. and so a lot of hybridizations have been done [14] Hội các VQG & Khu bảo tồn thiên nhiên Việt by camellia breeders around the world, using C. Nam, 2001. Vườn Quốc gia Tam Đảo, Nhà nitidissima, which has the brightest yellow flower XBNN. colour, as a cross-parent. [3] It is estimated that mistake on the description about the back-cross. Red new growth on a backcrossed seedling of C. azalea x (C. azalea x a cultivar of C. japonica) I added () in the cross-combination, C. azalea x (C. azalea x a cultivar of C. japonica) Sincerely, Gao Jiyin CHINA

129 Mr. Kazuo Yoshikawa and Mr. Tadao Yamaguchi, ‘Witman Yellow’ X [seedling x (‘Elizabeth who were the representatives of yellow flowered Boardman’ x ‘Colonial Dame’)], by W.F. Homeyer camellia breeding enthusiasts in Japan, got about Jr., U.S.A [11]. 20 hybrids whose flowers were yellow or yellow From above, we must think seriously about toned. Of these hybrids, ‘Shoko’, ‘Kicho’, ‘Ki- using non-yellow Camellia species as cross- no-moto 95’ and ‘Kagirohi’ became famous in the parents，while also using yellow Camellia camellia world because of their yellow flowers, species as cross-parents when crossing, in order to multi-petals and high ornamental value. [4] In the get yellow camellia cultivars. In the course of our United States，Nuccio’s Nurseries Inc., very camellia breeding work, we found an example that famous for camellias, made many crosses between demonstrates that you can get yellow hybrids in C. nitidissima and other camellia cultivars and a cross-combination without any yellow Camellia obtained four first generation hybrids, of which the species being involved. We report it below: most outstanding hybrids were ‘Golden Glow’, a semi-double with light-yellow flowers and 1 Materials and methods ‘Honeymoon’ with creamy yellow flowers[5]. Dr. Cross-combination: ‘Tama Beauty’(A cultivar of Gene Phillips from Georgia also raised a hybrid C. japonica) x C. amplexicaulis named ‘Alice B. du Pont’ that was bred from a cultivar of C. japonica crossed with C. nitidissima. Cross method: It was done in the spring, 2006. Ten Professor Clifford Parks, the most famous yellow flower buds which were just open were selected camellia hybridizer, got a yellow toned hybrid on a of ‘Tama Beauty’: we took off all of named ‘Solstice’ bred from C. flava crossed with the stamens from the buds, put fresh pollen from a cultivar of C. japonica. Mr. Huang Liandong C. amplexicaulis onto the stigmas, covered each in Nanning Yellow Camellia Garden of Guangxi, of the buds with a paper bag and labeled them. China has been making crosses of yellow Camellia Only two of the pollinated flowers fruited. The species in recent years and has raised many hybrid hybrid capsules were taken off after maturing in seedlings. He published two new varieties named September of 2006, 11 seeds were obtained from as ‘Jinbei Danxin’, a light red but with yellow the two capsules and then sown into a suitable color on back surfaces of its petals [6] and the medium immediately. Seven seeds germinated yellow-flowered ‘Dongyue’ [7]. and when the seedlings grew up to over 20 cm Does a yellow Camellia species have to be used high, they were moved into a plant bed, containing as a cross-parent for getting yellow flowered fertile soil. Two of the seven hybrid seedlings hybrids? The answer is negative. The chance first bloomed in the spring of 2010 and were C. japonica seedlings or hybrids whose parents labeled as H-No.1 and H-No.2 respectively. The show no hint of yellow in their petals, in fact, characteristics of their flowers, and growth also can produce yellow-flowered or yellow- were measured in detail. Also, the hybrid plants tone flowered cultivars. Mr. W.F. Homeyer Jr., were cultivated in eastern China so could be U.S.A., for example, selected a yellowish cultivar measured for their cold hardiness in winter. named ‘Witman Yellow’, which is the first yellow 2 Results cultivar in the world, from C. japonica seedlings in 1963[8]. The second yellow camellia cultivar Both H-No.1and H-No.2 are pale-yellow in was named ‘Gwenneth Morey’ with cream-yellow flower color, but the former has soft branches and and anemone form was selected from ‘Edith a spreading growth habit and the latter is pale- Linton’, a C. japonica cultivar, by Dr B.R. Morey, yellow with some light pink in the flower color and Australia in 1965[9]. The third yellow camellia is upright in its growth habit. cultivar named ‘Brushfield’s Yellow’ with light- 2.1 Flower characteristics yellow color and anemone form was selected from C. japonica seedlings by Mr. Keith Brushfield, H-No.1: Flower buds dense, ball-like, sepals 10, Australia in 1970[10]. The fourth yellow one named yellow-green, back surface white-pubescent. ‘Dahlonega’, a canary yellow formal double, was Flowers pale-yellow, semi-double, petals 32, obtained from a C. japonica cross-combination, arranged in order, elliptic, round and slightly 130 outward-inclined at the tip, medium in size 8.5- flower buds are light pink during the extension 10.5 cm in diameter, stamens about 150,1.9-2.1 phase and petals are very light pink at the edges cm long, densely arranged, united at the base, when flower is fully open. filaments light-yellow, anthers yellow, pistil 1 It should be pointed out that the two hybrids are cm long, 7-9 splits at the tip. Blooming period is different from their cross-parents in both flower from winter to the following spring. The flowers color and shape. See Table 1. of H-No.2 are nearly the same as H-No.1, but the Table 1. Comparisons of flower characteristics in hybrids and their cross-parents

Hybrids and their Flower Flower Flower Blooming Flower photo cross-parents color form size period

Winter to H-No.1 Pale-yellow Semi-double Medium following spring

Pale-yellow Winter to Medium to H-No.2 with light- Semi-double following large pink tone spring

Winter to Female parent Red with Medium to Semi-double following (Tama Beauty) white edges large spring

Autumn to Male parent (C. Light-red to Small to Single following amplexicaulis) red medium summer 131 2.2 Leaf characteristics it can safely grow in winter in eastern China. The leaves of the two hybrids all tend to their male Meanwhile, the male parent, C. amplexicaulis, is parent in leaf size, but the leaves are much thicker not cold hardy and cannot resist the cold weather [12] than the female parent and much thinner than the of eastern China . With cultivation experiments male parent. Please see Table 2. in different areas, the hybrids showed high summer heat resistance and strong winter cold hardiness. 2.3 Growth vigor They can normally grow well in temperatures up The hybrids have obvious growth vigor by to 40℃ in summer and temperatures down to -5℃ comparison with their cross-parents on average in winter (Table 3.). annual growth. Based on the measurements, the 3 Discussions annual growth of the hybrids was 3-4 times the average and the total annual growth was about 80 Some very famous pale-yellow camellia cultivars, cm in length, i.e. the growth of the hybrids is five which do not have any blood relationship to times that of the female parent, ‘Tama Beauty’ and yellow Camellia species, were obtained in the twice that of male parent, C. amplexicaulis. This United States and Australia, during the selection growth habit of the hybrids indicates the possibility of chance seedlings from C. japonica cultivars in. that they could be used for as garden plants. This shows that using yellow Camellia species as cross-parents is not the only way to produce yellow 2.4 Resistances camellias and to arrive at the yellow goal. The two It has been shown that the female parent of the hybrids we produced were obtained using non- hybrids, ‘Tama Beauty’, belongs to C. japonica yellow Camellia species that had no relationship and has a high degree of cold-hardiness; therefore with yellow Camellia species but had pale-yellow

Table 2. Comparisons of leaf characteristics in hybrids and their cross-parents

Hybrids and their Leaf photo Leaf length (cm) Leaf width (cm) Thickness (mm) cross-parents

H-No.1 12.0 ± 0.9 5.1 ± 0.1 0.88 ± 0.05

H-No.2 11.6 ± 1.3 4.8 ± 0.4 0.93 ± 0.08

Female parent 6.4 ± 0.3 3.4 ± 0.3 0.75 ± 0.05 (Tama Beauty)

Male parent (C. 23.8 ± 1.5 8.6 ± 0.9 1.90 ± 0.10 amplexicaulis) 132 flowers. It has been shown before that yellow Also，our two hybrids grow very strongly, have camellias can be obtained from the hybridizations high resistances and can be cultivated in the areas that are done with camellias other than those of the of southern China and eastern China. Therefore, yellow Camellia species. Our hybrids are another they are good camellia hybrids for garden purposes. true example that yellow flowered hybrids can be Literature cited produced from cross-combinations without any yellow Camellia species. [1] Chen Junyu. 1987. Forty Years for Breeding New Yellow Camellia Varieties. Journal of Beijing Forestry University, The cross-parents do not have yellow flowers but 9(5):315-319 their hybrids can show yellow flowers, why? [2] Wu Hormish. Yang Jiangfan. Zhan Zijin. 2004. Advance of Yellow Camellias on Cultivation and Breeding. Jour of Fujian With the cross-combinations that we did, we Forestry Sci and Tech, 31 (3):147-150 inferred that the possible reasons for yellow color [3] Clifford R. Parks. 2000. Breeding Progress with Yellow Camellias. American Camellia Yearbook, 9-10 appearing in the F1 are that: a) both female, ‘Tama Beauty’ and male, C. amplexicaulis, all contain [4] Saburo Yokoyama, Kirino Shuho. Camellias of Japan. yellow genes which they have not yet expressed Tankosha Publishing Co., Ltd. 2005 out, b) only one of the cross-parents contains [5] Bradford King. 2011. The Wonderful Hybrid Camellias. American Camellia Yearbook, 76-87 yellow genes which they have not yet expressed [6] Huang Liandong. Jiang Changjie. Li Zhihui. 2011. An Inter- out and c) both of the two cross-parents do not species Hybrid bred with C. nitidissima as Cross-parent, contain any yellow genes, but their genetic re- proceedings of the stWenzhou Cross-Strait Symposium on combinations changed in a particular way during Conservation and Exploitation of Camellias Annual Chinese Camellia Breeding Meeting, 125-127 the process of crossing between them, which led [7] Huang Liandong. Li Zhihui. 2012. An excellent cultivar to the yellow color expressions in the F hybrids. 1 derived from F2 hybrid of .2012 Of course, these inferences would need to be Proceedings of The International Camellia Congress, 169-171 researched further in the future. [8] Southern California Camellia Society. 1999. Camellia Nomenclature, edited by Arthur A. Gonos, 122, 164-165 According to the successful results obtained from [9] Tom Durrant. 1982. The Camellia Story, Heinemann the crosses among yellow camellia cultivars from Publishers, 121-122 non-yellow Camellia species, the two hybrids [10] Don Ellison. 1997. Camellias, A Photo Dictionary. Flora we obtained can also be used for crossing with Publications International Pty, Ltd. 26 other yellow camellias. It can be expected that [11] Gao Jiyin. Su Yuhua. Hu Xiancong. 2007. The Identification the hybrids as cross-parents will, in some degree, and Appreciation of The World’s Outstanding Camellias, Zhejiang Science & Technology Publishing House, 69 have the potential to create new yellow camellia [12] Gao Jiyin. 2002. Talking about Camellia amplexicaulis. hybrids. American Camellia Yearbook, 22-24

Table 3. Comparisons of the leaf resistances of the hybrids and their parents under extreme temperatures

Summer extreme H-No.1 H-No.2 Female Male highest temperature 35℃ Normal Normal Normal Normal 38℃ Normal Normal Normal Normal 39℃ Normal Normal Normal Normal 40℃ Normal Normal Some leaves burnt Normal Winter extreme H-No.1 H-No.2 Female Male lowest temperature 5℃ Normal Normal Normal Normal 0℃ Normal Normal Normal Leaves cold injury Leaves cold injury -5℃ Normal Normal Normal and fall off Leaves cold injury Leaves cold injury Leaves slightly cold Leaves and branches Below -5 ℃ or fall off or fall off injury dried and plant die