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Journal 2014

In this paper, we focused on taxonomic systems, geographic distribution and preservation status of yellow camellia germplasm resources in Guangxi, and have putted forward some ideas and suggestions for further preservation in situ and conservation ex situ, scientific research, exploitation and utilization of yellow camellia germplasm resources in this region.

Since 1982, the breeding work in the Golden Camellia Park has been conducted on an arduous path. The paper introduces the main technique and achievements in past three decades, and concludes the breeding goals, main approaches and technological measures, and discussion of current effecting factors and prospects for further breeding.

Tam Dao is one of the famous places of Vietnam. 8 yellow Camellias have been recorded here and are all described in this article.

In this paper the characteristics of Golden Camellias, which were also called as the Panda of Plant Kingdom, were briefly introduced, as well as the collection of these plants including tropical camellia resources in the conservation glasshouse in Kunming Botanical Garden (KBG). Viet Nam is one of important native places of yellow camellias. Due to the international co-operation, 5 Camellia species native to Viet Nam were also introduced into KBG which has 36 tropical camellia species. KBG has now become an important institution with great international influence in the conservation of yellow camellias.

The floral volatile compounds emitting at different stages of flower development and different parts of Camellia azalea Wei were studied by solid phase micro-extraction and gas chromatography-mass spectrometry(GC-MS). The result showed that 8 volatile compounds were identified in bud stage, 20 in first flowering, 21 in full flowering and 17 in declining flowering stage. The main releasing stages were first flowering and full flowering stage. With the development of flowerof C. azalea, the relative content of alcohols increased gradually. Alkenes, esters and alkanes increased at first and then decreased, and aldehydes and ketones decreased on the whole. 20 compounds were identified in sepals, 22 in petals, 21 in stamens and 13 in pistils. The main flower parts of volatile releasing were petals and stamens. The relative content of alkanes was the highest in sepals, stamens and petals, accounting for 49.86%, 51.59% and 44.66% of total volatile compounds respectively. The content of aldehydes and ketones was the highest in pistils, accounting for 83.87%.

Six new, yellow flowering species of Camellia (Theaceae), endemic to the southern provinces of Vietnam, were compared to one another and to nine Camellia species from Viet Nam and China. Morphological evidence indicates the dissimilarity of the majority of the newly discovered Camellia species to other yellow flowering Camellia taxa. Available data supports the assertion that: 1. the morphological differences are reflected in the respective genomes; 2. the morphological dissimilarities indicate modified primitive traits; 3. southern Viet Nam is an important centre of genetic diversity and the possible area of origin for genus Camellia.

A field survey was conducted at Long Liu Depot, Ma’An village, one of the habitats of Camellia chuangtsoensis. A comparative study was made among C.chuangtsoensis, C.ptilosperma and C. longzhouensis. The species scions were successfully grafted for propagation purpose under continuous observation. The successful rate of grafting was all over 90%. Part of leaf mutations on a graft was observed. We found that successful pollination could be made between Camellia chuangtsoensis and C. azalea as well as between C.chuangtsoensis and C. reticulata hybrid. We successfully obtain first four seedlings in cultivation with C. chuangtsoensis as parent plant.

The genetic variations among parents and their hybrids of Camellia nitidissima were analyzed using ISSR molecular marker. Camellia nitidissima was used as one of their common parents, while Camellia sasanqua, Camellia japonica and Camellia tunghinensis were their other parents. Eleven stable and polymorphic primers were from twenty ISSR primers, which could receive 199 amplification loci and 195 polymorphic loci with 97.99% in polymorphism. The genetic similarity coefficients were high (0.618-0.769) between every hybrids and their common parent (Camellia nitidissima), and also higher between their and another parents than unrelated plants. The results of clustering analysis were consistent with that of the genetic similarity coefficients. These results implied that four plants really were the hybirds between Camellia nitidissima and Camellia sasanqua, Camellia japonica, Camellia tunghinensis. Furthermore, we found the hybrids inclined to the other Camellia parents but not Camellia nitidissima in the genetic similarity coefficients and the clustering analysis. We thought the hybrids were difficult to inherit the genetic material of Camellia nitidissima, and their characters were resembled to another parents. It interpreted the reason why the new varieties with golden flowers were difficult to obtain in hybridization of Camellia nitidissima. Meanwhile, the alleles, expected alleles, expected heterozygosities and Shannon diversity indexes of hybrids were higher than their parents respectively. This shows that the hybrids of Camellia nitidissima had more genetic variations and more genetic diversity in DNA level.

29 Samples of yellow camellias were analyzed by inter-simple sequence repeat (ISSR) markers to detect their genetic diversity and relationship. 133 discernible loci were obtained from all the samples by using 14 primers and 126 bands were polymorphic. The average percentage of polymorphic bands was 94.74%, Nei’s gene diversity and Shannon’s information index was 0.3606 and 0.5314 respectively, indicating that the genetic diversity of yellow camellias was relatively high. According to the dendrogram, 29 materials could be divided into 3 groups. Camellia achrysantha formed the first group, C. pingguoensis var. terminalis and C. lungzhouensis were classified into the third group, and the others into the second group. The pair of C. xiashiensis and C. micrantha was classified into one group at very early stage, indicating two taxa are very similar. The pair of C.tunghinensis and C.leptopetala was much similar. The two pairs of C.tianeensis and C.flavisa, C.wumingensis and C. parvipetala were similar, respectively. There are certain relationship between C.pinguoensis and the ‘hybrid’ sample, but low relationship between C.nitidissima and C.chrysantha. C.chuongtsoensis is a separated species.

Camellia japonica (L.) is an important horticultural and economically-important species, distributing naturally in China (Zhejiang and Shandong provinces), Japan (Honshu, Shikoku, and Kyushu Islands) and along the southern and western coast of the Korean Peninsula. Inter-simple sequence repeat (ISSR) markers were used to investigate its genetic diversity within and among thirteen natural populations of C.japonica in East China and Japan.

The induction and differentiation experiments of adventitious buds were conducted with somatic embryos derived from cotyledons of Camellia azalea, cultured on Murashige and Skoog’s basal medium with various combinations of 2,4-D, NAA and 6-BA. On MS medium with NAA 0.2 mg·L-1+6-BA 1.0 mg·L-1+50 mL·L-1 CW, nearly61% of the cotyledons successfully developed the embryos. Embryogenic capacity has been maintained for over 90 days by subculture on MS medium supplemented with NAA 0.1 mg·L-1+6-BA 1.0 mg·L-1+100 mL·L-1 CW at 7- to 8-week intervals. Adventitious buds were obtained after 22 days on the medium supplemented with NAA 0.125 mg∙L-1+6-BA 10.0 mg∙L-1+50 mL·L-1 CW. The differentiation rate was 63.83%.

There are 62 Yellow Camellia species have been described in the world and only growth restricted from southern Guangxi to northern Vietnam area. However, habitat destruction serious threatens Yellow Camellia population in the field. Thus, the conservation of Yellow Camellia becomes an important issue. Here we propose that Yellow Camellia is well growth in artificial environment in Cecilia Koo Botanic Conservation Center (KBCC) in Taiwan.

My purpose of camellia breeding is to develop new camellias to have yellow or creamy color flower. By utilizing Camellia nitidissima and very pale color flowers of C. reticulata hybrids as the parentage plants, many F1 hybrids were produced.  The flowers of F1 hybrid seedlings demonstrate very pale petal color with obvious creamy color in center portion of the flower. By means of back crossing, nine seedlings of F2 hybrids were produced and five seedlings start to bloom. The F2 flowers are generally found in pale creamy color. Yet the yellow color intensity is not enough.  The size of F2 hybrid flower is smaller, between miniatures to small in size. The result indicates C. reticulata posses the domination to suppress the yellow coloration transferred to the flower of their off spring. On the other hand, a few new camellia seedlings of C. japonica were produced with rather attractive flowers flared with yellow color.  My continuous task is to use other yellow flower C. species to breed new yellow camellias.

Camellia sasanqua is one of the loveliest autumn and winter blooming shrubs for its elegant plant appearance, colorful and graceful scented flowers, long blooming period, evergreen foliage. There are about 500 cultivars in the world. In China, horticulturists introduced sasanquas since 1980s. Prof. Xu Biyu listed 122 sasanquas in book C.sasanqua (Xu Biyu, 2007). 10 sasanqua cultivars were commonly cultivated in China. Hangzhou Flower Nursery, Hangzhou Botanic Garden and Shanghai Agrobiological Gene Center(SAGC)  also established field genebank for sasanquas.

Through the cross-combination, C. japonica cultivar, ‘Tama Beauty’ x C. amplexicaulis, two pale-yellow hybrids were obtained. This is another example to demonstrate that the hybrids among non-yellow camellia species also can get yellow ones, after the previous work. The flower characteristics of the hybrids were described in details and the leaf characteristics, growth vigor and resistances were also compared in the hybrids and their cross-parents. The first hybrid, H-No.1 is pale yellow and the second hybrid is pale-yellow with light-pink tone on flowers. Their growth vigor is 2-5 times of their cross-parents and their resistances are stronger. Also, the reasons that yellow hybrids can be gotten from the hybridizations of non-yellow camellia species and the gardening value of the hybrids were discussed.

Novel flower color is an attractive character for ornamentals. In order to generate new flower colors for camellias, a number of genes related flavonoids biosynthesis have been expressed by researchers. 

 

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