Identification of wild citrus from Tongluo using morphological characteristics and RAPD markers

• Main Authors: Shu-Yen Lin, 林書妍
• Other Authors: Iou-Zen Chen
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/47332039791255976394

碩士 === 國立臺灣大學 === 園藝學研究所 === 92 === Citrus taiwanica Tan. & Shim., of which relevant researches are few, is one of the endemic Citrus in Taiwan. It is also the world endangered plant because of the severely scarce population. On the basis of keeping genetic diversity and developing the potential in endemic plant, we carry on the conservation and studied of C. taiwanica. Thirteen suspected individuals of C. taiwanica were found at the Chang-Shu-Lin region, in Tongluo township, Miaoli county in 1999. After numbering respectively and orienting each position with the global positioning satellite (GPS), 13 suspected individuals of C. taiwanica were compared with the specimen (in TAI) and description in related references. We supposed the wild population might be C. taiwanica. This study was based on the morphological characteristics and DNA level analysis with RAPD. Species which have close relationship to C. taiwanica, or which are universal cultivated in Taiwan were used in morphological investigation, including C. taiwanica, C. aurantium L., C. sinensis (L.) Osbeck, C. grandis (L.) Osbeck, C. paradisi Macf., C. reticulate Blanco, and C. tankan Hayata. All of them were planted in Citrus germplasm of Chiayi Agriculture Experiment Station (CAES). Investigational items are leaf shape, leaf margin, leaf texture, length of leaf, width of leaf, length of wing, width of wing, color of flower, petal number, filament number, length of petal, length of filament, length of stylus, coherence of filament, color of fruit rind, skin of fruit, coherence of rind, color of pulp, height of fruit, cross section diameter, seed shape, color of chalaza, color of embryo, and number of embryo. The results revealed suspected individual No.1 is different from others, so it is excluded the suspects of C. taiwanica. The rest of the suspects are very similar intra-population, and are different from all major cultivated species in Taiwan. They are the most related to C. aurantium and C. taiwanica from CEAS, whether these three were certainly separated. The same results are suggested in clustering analysis and principle component analysis. Species using in RAPD analysis include the three basic species (C. medica L., C. grandis, and C. reticulata). Besides samples in morphological investigation, C. aurantifolia Swingle and C. medica were added. Fifty-one primers produced 277 polymorphic bands. Among the suspected individuals, polymorphism was revealed on No.1, as well as several specific bands of no.1 were shared with C. grandis. Grouping resulted from dendrogram and principle coordinate analysis matches taxonomic definition both in Swingle system and Tanaka system. The suspected clone No. 1 was more similar with C. grandis, but away from orange-group or C. taiwanica from CAES. The genetic similarity distance was lower than 50%. The rest of the suspected clones, clustered in orange-group, were 90% similar with C. aurantium, but they indeed spilt into two groups with bootstrap value 100. C. taiwanica from CAES was 60% similar with C. aurantium. The suspects had narrow genetic base. The suspects of No.12, No. 13, and No.11 were the most similar with C. taiwanica. Both the results in morphological investigation and DNA markers showed the suspects of C. taiwanica in Tongluo township were very related to C. aurantium and C. taiwanica from CAES, especially to C. aurantium. As a result of clear differences on width and size of wings between the suspected clones and C. aurantium, combining geographical distribution and local history, we suggested the suspects should be C. taiwanica or a new variety of C. aurantium.