Studies on the Variations in Leaf Characters and DNA Sequences of Tea Germplasm in Taiwan
Date Issued
2004
Date
2004
Author(s)
Hu, Chih-Yi
DOI
zh-TW
Abstract
The main purposes of this study were: (1) to evaluate variation in leaf traits for variety identification, (2) to establish DNA fingerprints and a process for variety identification of tea, (3) to analyze the genetic diversity and/or parentage among germplasm of tea, and (4) to evaluate the feasibility of molecular identification for processed tea and tea mixtures from different varieties.
According to the leaf traits investigated from 132 tea germplasm, the distribution of 7 qualitative traits, including bud color, leaf color, leaf shape, apex shape, base shape, bud hair and morphology of leaf teeth, except for leaf shape, were subjected to specific phenotypes. The quantitative traits, including leaf length, leaf width, leaf thickness, internode length, leaf area, length/width ratio, number of leaf teeth and angle of vein, leaf thickness, and length/ width ratio of mature leaf exhibited relatively low variation. By using UPGMA method, the cluster diagram based on 15 quantitative and qualitative leaf traits showed that the tea varieties could be divided into three groups according to the leaf shape and apex shape.
Sixty-seven polymorphic bands with strong signal were amplified from 12 ISSR primers, which were prescreened from 100 primers. Furthermore, these 67 ISSR markers were used to develop the DNA fingerprints and analyze genetic diversity of tea germplasm. According to UPGMA method, the tea gerplasm could be divided into 6 groups: including C. tenuifolia group, Chyh Ya Sun Cha group, wild tea plants group, var. assamica and var. sinensis group, var. assamica with var. sinensis and their hybrid group and var. sinensis group. Some germplasm had high similarity in ISSR markers to other one, including Shiang Yuan and Shiang Eel, Dah Nan Wan Bair Mau Hour and Heh Mau Hour, Chin Shin Oolong and Wu Jin, Tzao joong and Chin Shin Tzao joong, Bair Yeh and Dah Pan, Jy Lan and Wen Sun Jy Lan, Chuh Du Bair Joong and Feng Tzy Lin.
Similar grouping result was found in the principal coordination components analysis and the cluster diagram. Furthermore, the ISSR analysis revealed that there is quite large genetic diversity among tea germplasm in Taiwan (58%). Despite the high genetic diversity among germplasm, high percentage of it was contributed by the wild tea plants, and most important cultivars had high degree of similarity. The most important 22 cultivars and 3 newly bred varieties could be efficiently identified with ten ISSR markers amplified by three primers (818, 864 and 866).
In the chloroplast DNA sequence analysis, 4 out of 5 primers could generate amplification products. There were 23 sites detected with DNA sequence variation in a total length of 4415 bp, including 17 single nucleotide polymorphism(SNPs) and 6 nucleotide insertion or deletion(Indels). The total variation length is 47 bp and the rate of variation is 1.06% in the survey of 15 tea germplasm. Therefore, the variation of chloroplast DNA sequences among germplasm is mainly SNPs , and it could be used to identify cultivars and to trace their female parents. In the mitochondria DNA sequence analysis, 6 of 8 primers could generate amplification products. There were 24 sites detected with DNA sequence variation in a total of 4415 bp length, including 9 SNPs and 15 Indels. The total variation length is 87 bp and the rate of variation is 1.21% in the comparison of 15 tea cultivars (similar to chloroplast). Therefore, the variation of mitochondrial DNA sequences among germplasm is mainly Indels. Similar result of cluster analysis was observed in chloroplast and mitochondria DNA sequences. Fifteen tea germplasm were classified into three groups, only Taiwan Sun Cha was done differently. According to the cytosomic sequences analysis, the sequence of TTES No. 18, resembled Shan instead of its female parent, Burma. Based on the leaf trait, ISSR DNA and cytosomic sequences analysis, Shiang Yuan, Shiang Eel and Gau Lu were identified as var. sinensis. And their larger leaf size was due to triploid. Besides, Chyh Ya Sun Cha might not be the same with Camellia sinensis.
Different levels of fermented tea were investigated on the isolated DNA quality. The result indicated that high temperature (250℃) was the most devastating step to the DNA in processed tea. The bands of amplified ISSR DNA under 1000 bp had stable signals, and they could be used in cultivar identification. On the other hand, stable and specific bands with higher molecular weight were obtained by using cytosomic primers for all. It suggestes that applying DNA techniques in cultivar identification of processed tea is feasible. Furthermore, the tea mixtures from different varieties could be identified by cytosomic DNA sequences because the cytoplasmic genome is haploid with unique sequence.
Subjects
茶樹
葉部性狀
葉綠體DNA序列
ISSR分子標誌
粒線體DNA序列
成茶品種鑑定
Tea
mitochondria DNA sequence
ISSR
chloroplast DNA sequence
variety identification of processed tea
leaf character
Type
thesis