| In this study,we investigated the wild tea plants located in Leibo County,Sichuan Province.Fifty representative wild tea plants were selected for morphological,biological characteristics,and genetic diversity analyses.Biochemical samples were collected in spring of 2019 and their main biochemical components were determined.Genomic DNA was extracted from the 50 tea trees for genetic diversity analysis using SSR markers.The diversity and genetic relationship of Leibo wild tea plants and other wild tea populations were discussed.In addition,this study preliminarily analyzed the quality characteristics of black tea made from the spring fresh leaves of those wild Leibo tea plants.The results were as follows:(1)A large number of wild tea plants distributed in over 100 hm2 in the southwest of Yinchanggou Village,Luoshanxi Town,Leibo County,Sichuan Province(28°28’10 "N～28°30’49" N,103°28’07 "E～103°29’52" E,altitude 1200-1350 m)was found.The tree type is mainly arbor and small arbor types,but shrub type also existed;the tree posture is mainly upright or semi-open.The leaves are mainly large leaves and extra-large leaves;the leaf length is 10.1～17.2 cm,the leaf width is 4.2～7.6 cm,and the leaf shape is mainly narrow ellipse;petals are all white,corolla diameter is 3.5～4.2 cm,style is mainly 3-lobed;low flowering and seed setting rate,seed coat is brown.The seed shell is thick and hard,and the fruit shape is mostly spherical and triangular.The seeds are mostly spherical and hemispherical,with a diameter of 0.9～1.4 cm.(2)The content of free amino acids,tea polyphenols,caffeine,catechins and water extracts of the 50 Leibo wild tea germplasms were 1.64%～4.29%,13.97%～20.82%,3.75%～5.30%,8.76%～16.12% and 35.10%～48.60%,respectively,with the average values of2.58%,16.99%,4.62%,12.06% and 41.39%.The coefficient variation(CV)based on biochemical components was 7.54%～28.58%,and the genetic diversity index(H’)was 1.94～2.03.Cluster analysis could divide 50 wild tea plants into 4 groups with different biochemical characteristics.In general,the biochemical composition of Leibo wild tea plants varies greatly,and the caffeine content is high compared with other tea germplasms.Nine plants with a caffeine content >5% were obtained.(3)Fifteen fluorescently labeled SSR primers were used to amplify alleles from 108 tea plant materials,including the above-mentioned 50 Leibo tea plants.A total of 89 alleles and 221 genotypes were detected.Among them,76 alleles and 143 genotypes were detected in the 50 Leibo tea plants,and 29 alleles were were only detected in the Leibo population.The number of alleles(76),genetic diversity(H = 0.598),and polymorphism information content(PIC = 0.546)in the Leibo population were the higher when compared with six other wild or cultivated tea populations.However,the average heterozygosity of Leibo population was lower(He = 0.4511).The genetic distances between different tea populations varied from 0.0818 to 0.2552.The Leibo wild tea population has cloest distance with Sichuan Dayi wild tea population,and farest genetic distance with Yunnan Fengqing wild tea population.(4)The black tea made from the fresh spring leaves of Leibo wild tea has orange-red and bright soup,long lasting sweet aroma with caramel flavor,sweet taste and outstanding characteristics.The black tea has its advantages and market competitiveness compared with other black tea on the market.These results are valuable to understand Leibo wild tea germplasm,and provide important clues for resource protection,screening of high-caffeine tea materials and direct commercial utilization. |
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