MORPHOLOGICAL DIVERSITY OF TEA GROWN IN LAM DONG PROVINCE (VIET NAM)

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1 MORPHOLOGICAL DIVERSITY OF TEA GROWN IN LAM DONG PROVINCE (VIET NAM) Thai Dan Vo, Heiko C. Becker Institute of Agronomy and Plant Breeding, Georg-August-Universität Göttingen, Germany Abstract Assessing the diversity in tea provides the basic information for tea breeding aiming to build up a set of regionally adapted tea populations and clones. All tea taxa freely interbreed and therefore tea plants with many overlapping morphological, biochemical and physiological attributes are highly diverse and consequently their populations are very heterogeneous. Because of the high out crossing rate, existence of the pure archetypes of tea is doubtful. Thirty-one tea types belonging to Chinese tea, Indian tea, Shan tea and hybrid tea, which are either commercially planted or new promising in tea germplasm, were morphologically described at four locations in 2004 at Lam Dong province (Viet Nam) and assessed for their morphological diversity. Thirty-four morphological characteristics of stem, the 4 th leaf, young shoot and flower were investigated qualitatively and quantitatively based on the IPGRI s guidelines. The investigated teas were grouped by hierarchical cluster analysis to construct a dendrogram representing the relationship among cultivars and clones. Results strongly proved the high diversity of investigated teas of Lam Dong province based on the morphological characteristics; within each known taxa, all teas planted commercially were morphologically similar. Keywords: Camellia sinensis, diversity, morphology, tea Contact Address: Thai Dan Vo, Georg-August-Universität Göttingen, Institute of Agronomy and Plant Breeding, Von-Siebold-Str. 8, Göttingen, Germany. tvo@gwdg.de 1 Introduction Tea (Camellia sinensis (L.) O. Kuntze), which yields a non-alcoholic, healthy beverage with worldwide significance, is an eco-socially important cash crop, widely cultivated in tropical and subtropical regions. Viet Nam is one of the main tea producers of the world; its tea area, tea production and tea export quantity of the 2004 was placed the sixth, the seventh and the sixth position world wide, respectively; while its tea yield and tea export value only keeps the thirteenth and the eighth position, respectively (FAO, 2005). Lam Dong province, located in the Southern part of the West plateau, is one of Vietnam's main tea producing area. Since the early time of its tea industry (reputed around 1927) until the end of 1990s, there have been many tea types spontaneously cultivated there in various ways. Unwisely using cultivars for a long time has been believed as the main reason of low productivity and quality. At present, in the same trend of Vietnam and World tea production, Lam Dong tea industry tends to stabilize its area and continually increases productivity as well as quality by improving tea plant breeding and intensive farming techniques (Lam Dong Center for Research and Transfer technology in Industrial crops and Fruit tree Production, 2004). Therefore building up the sets of suitably adapted tea cultivars for each specific area becomes an urgent requirement for sustainable tea production. Tea is an allogamous plant and all tea taxa freely interbreed; therefore tea plants, with many overlapping morphological, biochemical and physiological attributes, are highly diverse and heterozygous (Willson and Clifford, 1992). Indeed, because of the extreme hybridization, existence of the pure archetypes of tea is doubtful (Willson and Clifford, 1992). In addition, its primary recommended propagation method asexual propagation would be over time expected to be the cause of further reduction in genetic diversity due to the accumulation of systemic pests and the spread of a few, vigorous, well-adapted clones with a capacity to produce high yield and good quality tea. For these reasons, assessing the diversity in tea provides the basic information for tea plant breeding and consequently teas planted widespread and new promising tea germplasm of Lam Dong

2 Table 1. List of evaluated Camellia species and the number of samples. The taxonomic classification used was based on Cohen-Stuart (1919) (cited by Yamamoto et al., 1997) Taxa Local name of tested cultivars/clones No. of sample C. sinensis var. bohea (Small-leaved China tea) C. sinensis var. shan (Shan tea) C. sinensis var. assamica (India tea) Hybrid between India and China teas Unknown (new promising clones) Yabukita (Yabu), Kim Tuyen (KT), Ngoc Thuy (NT) and Tu Quy (TQ) LD97, TB14, TBCD, TB11 and St PH1 LDP1 and LDP2 No. 1 to No Total 31 province were described and assessed for the morphological diversity. 2 Materials and Methods Thirty-one tea samples (Table 1), which are either cultivars commonly planted commercially or new promising clones at Lam Dong province, were morphologically described. Thirty-three important characteristics of stem, the 4 th leaf, young (P+2) 1 shoot and flower were investigated qualitatively and quantitatively following IPGRI s guidelines (IPGRI, 1997). Tannins content in (P+2) shoots was analyzed at Center for Technology and Management of Resources and Environment, Nong Lam University. Most of investigated teas were cared and harvested following the official procedure of Lam Dong Center for Research and Transfer Techniques on Industrial Crops and Fruit Tree Production (socalled Lam Dong Center), except for the cultivars of Kim Tuyen, Ngoc Thuy and Tu Quy which were planted according to the specific techniques of Taiwanese; besides these cultivars, St (Shan Tuyet) clone at Cau Dat recently grown freely without pruning and plucking. In this paper, due to the rather homogeneity of the local climatic conditions and the similarity of farming techniques applied, the effect of those factors on the morphological characteristic was not considered and interpreted. With NTSYS 2.1 (Rohlf, 2000), the investigated cultivars and clones were grouped by hierarchical 1 Furled leaf + 2 next two leaves cluster analysis using the Unweighted Pair Group Method Analysis (UPGMA) based on the similarity matrix of Euclidean distances of the investigated quantitative morphological data. To construct a dendrogram representing the relationship among cultivars and clones, data were standardized before clustering. 3 Results and discussions Data on morphological characteristics of investigated tea at Lam Dong presented in Table 2 clearly demonstrated the high diversity of investigated teas at Lam Dong. Stem Year of cultivation and the way of pruning obviously influenced the stem circumference as well as stem height, thus these variables were not included in the analysis. St was planted in 1927 and recently grown freely; hence its values of stem circumference and height were the highest among the whole investigated tea cultivars and clones. Data on the length and breadth of plucking surface indicated an example for the effect of farming techniques on morphological characteristics. Those variables were strongly influenced and/or limited by plant density: most of investigated teas had the length of plucking surface smaller than the bread except for tea germplasm planted with low density at Bao Loc High school. Leaf Leaf morphology is traditionally of important basic for tea taxa. Leaf sizes of most described teas were medium (data not shown), only that of clone 21 was

3 Table 2. Variability in vegetative and reproductive characteristics of investigated teas at Lam Dong province Characteristics Stem Stem circumference (cm) Height of the first branching position (cm) Branch angle to stem (degree) Height of plucking surface (cm) Length of plucking surface (cm) Breadth of plucking surface (cm) Leaf Leaf length (cm) Leaf breadth (cm) Leaf length/breadth ratio Leaf shape Leaf angle to branch (degree) Leaf pose Leaf color Number of pair of main vein on leaf surface Number of pair of serratulation on leaf margin Serrulated form Length of leaf pedicle (cm) Length from leaf pedicle to first serration (cm) Posture of leaf base Shoot Pubescence density on bud Pubescence density on lower surface of 1 st leaf Shoot color Shoot length (cm) Fresh shoot weight (g) Dry shoot weight (g) Fresh/Dry ratio Tannins content (% DW) Flower Flower color Number of petal Style Flowering ability large. Among cultivars and clones planted commonly, all Shan tested teas had medium leaf size while microphylla imported teas in the study were characterized by rather small leaf size. Data on the leaf shape divided investigated teas into 4 groups: ovate leaf (only clone 13); oblong leaf (11 cultivars and clones); elliptic leaf (12 cultivars and clones) and lancelate leaf (7 cultivars and clones). Purplish leaves were only found in clone 15 while all the rest had light or dark green leaves. Most of investigated teas were characterized by semi-erect leaf pose except for TB11, clone 11, Range of variation (with standard deviation) 18.8 (1.9) (3.7) 4.8 (0.8) (2.0) 70.6 (3.8) 68.6 (2.6) (2.7) (7.9) (0.6) 13.3 (0.6) 2.6 (0.2) 5.7 (0.3) ovate lancelate 47.6 (3.2) 84.3 (2.2) semi-erect horizontal light green purplish 5.6 (0.5) 12.1 (1.0) 23.9 (1.5) 64.7 (2.4) regularly acute irregularly blunt 0.18 (0.03) 0.57 (0.08) 1.4 (0.1) 2.7 (0.2) attenuate rounded nil - dense glabrous leaves with only hair on the mid-rib leaves where pubescence forms a dense indumentums light green purplish 5.6 (0.4) 13.1 (0.6) white equal splitting styles 3-unequal splitting styles few many clone 12, clone 17 and TB14 that had horizontal one. Data of other variables such as numbers of pair of main vein on leaf surface; numbers of pair of serratulation on leaf margin, serrulated form; length of leaf pedicle; length from leaf pedicle to first serration show a continuous variation as reported in Table 2. Shoot Depending on the cultivation techniques Pubescence density on buds and the lower surface of the 1 st leaves were estimated perceptually. In theory, only Shan teas are characterized by dense pubescence on their buds and lower surface of the

1 st leaves. However, due to the free crossing among tea taxa, nowadays many tea clones and cultivars also have pubescence at various levels on buds and lower leaf surface.

4 1 st leaves. However, due to the free crossing among tea taxa, nowadays many tea clones and cultivars also have pubescence at various levels on buds and lower leaf surface. Similar to leaf color, most shoot color were light and dark green, except for clone 15, Yabukita, LDP2, Ngoc Thuy and Tu Quy which were purplish green to purplish. Shoot length (cm) and shoot weight (g) of observed teas also varied continuously (Table 2). Tannins content (% DW) was analyzed and in general tannins content of investigated teas were rather low ( %) because samples were taken at the end of the year when the tannins content in young shoots were low physiologically. Observed data of fourteen quantitative characteristics were standardized for cluster analyses which were created on the similarity matrix of Euclidean distances with UPGMA as the clustering algorithm (Fig. 1). Assessing the morphological diversity of investigated teas at Lam Dong According to Fig. 1, the morphological differences between known taxa were clear; Shan, China and India teas belonged to clearly separated clusters in the dendrogram. All taxonomically known teas formed their own groups, except for TB11 and LDP2. Among Shan observed teas, LD97, TBCD, TB14 and St, but not TB11, formed a group; similarly all small-leaved China teas formed another group. PH1 is the mother of LDP1 and father of LDP2, but PH1 was morphologically similar with LDP1, but not with LDP2. The commercially cultivated tea cultivars/clones tended to form groups because until now selection in tea breeding is still mainly based on the morphological characteristics. The vegetative characteristics overlap and show a continuous variation. Figure 1. UPGMA-derived dendrogram illustrating the relationship among 31 observed teas. Commercial teas with the similar morphological characteristics were indicated by interrupted boxes.

5 4 Conclusions Investigated teas at Lam Dong showed high diversity based on their morphological characteristics. China, India and Shan teas were clearly separated by cluster analysis and within each known taxa, all teas planted commercially were morphologically similar. A larger diversity was observed in new promising clones which broaden the diversity observed in the established groups. Acknowledgement Many thanks to Vietnamese government and DAAD/IPAG for financial support to the fieldwork. Deep gratitude is also expressed to Nguyen Trung Kien and Lam Dong Center for Research and Transfer technology in Industrial crops and Fruit tree Production for their all useful collaboration and support. References FAO, Internet resources ( Rohlf F.J., NTSYS-pc. Numerical taxonomy and multivariate analysis system. Exeter Software, New York. IPGRI, Descriptors for tea (Camellia sinensis). International Plant Genetic Resources Institute, Rome, Italy. Lam Dong Center for Research and Transfer technology in Industrial crops and Fruit tree Production, Yearly report. Willson K.C. and Clifford M.N. (editors), Tea: Cultivation to Consumption. Chapman & Hall. Yamamoto T., Juneja L.R, Chu D.C. and Kim M., Chemistry and application of green tea. CRC Press.

Chapter V SUMMARY AND CONCLUSION

Chapter V SUMMARY AND CONCLUSION Coffea is economically the most important genus of the family Rubiaceae, producing the coffee of commerce. Coffee of commerce is obtained mainly from Coffea arabica and