| Nanjiang large-leaf tea is one of the representative tea varieties in local Si chuan,enjoying equal popularitywith Chongzhou loquat tea,ancient Lin bovine tea,as well as Yingjing loquat tea.After field research of it's main tree-cover areas,Nanjiang large-leaf teawas divided into 8 populations according to natur al distribution of different communities.To provide theoretical basis for breeding ways of itand excavating specific resources fromit,from which we screened o ut some outstanding external-ones materials form tea tree,totally 52 copies,d oing experimental study on the given 52 's morphology,biochemistry and geneti c diversity.Results shows:(1)Nanjiang large leaf tea is mainly distributed in 887?1240m elevate d-area,N32°00'91"?N32° 27'79",E107° 06'24"?E107°45'72".On ext ernal morphological features,Nanjiang large-leaf tea shows from various parts t he following characteristics,tree shape,belonging to shrub,mainly open-scrub o nes with mid-dense foliage cover;leaves,mostly large,oval-shaped with acumi nate tip;shoots,major green and yellow-green buds,upper-level slight hair,relati vely densegermination;flower,medium pattern with lesspetals fruit,mostly sph erical and reniform with brown seed peel,Among the wild populations,only on e of them seeped the major traitsof large wild tea-tree,large flower,full length stylus and so on,while another four groups kept cultivated one's characters lik e shrub traits,3 crack stigma,thinpeel and so on.The results showed that the variation range of the numerical traits was bet ween 0.06 and 42.00,with an average of 7;the coefficient of variation was b etween 7.00%and 18.18%,with an average of 10.94%;diversity index H' w as between 0.23 and 1.94,with an average of 1.34;and significant genetic diff erences in leaf length,width and peel thickness were observed.The diversity i ndex of the Nanjiang large-leaf tea's dominant traits was between 0 and 1.09,with an average of 0.73.It was quite high of the diversity index of lea's bla de,body and edge,around or even higher than 1(the average valueH' of dom estic tea tree is 0.96),which indicates how rich the phenotypic diversity is of Nanjiang large-leaf tea.(2)The results of 2016 spring,summer shoots' biochemical composition c ontent test showed that the content of water extracts in the eight populations was 39.61 ± 0.42?54.77 ± 0.79,and the content of tea polyphenols was 15.78 ± 0.58%?22.30 ± 0.23%,amino acid content of 1.90 ± 0.15%?6.87 ±0.35%,caffeine content of 2.65 ± 0.17?3.71 ± 0.24,catechins content of 110.08 ± 0.62?185.6 ± 3.12mg/g,phenolic ammonia ratio(TP/A)Was 2.38 ± 0.12?.41 ± 0.86.In combination with the main biochemical compositi on of each population,population D and H can be used as high amino acid b reeding materials,and the ratio of H phenol to ammonia is low,the proportion of non-ester catechins is higher.So preliminary inference,it is suitable for green tea.The diversity index of the main biochemical components of spring and su mmer shoots was between 0.91?1.81,with an average of 1.59,showing a ri ch genetic diversity.The coefficient of variation was between 6.27%and 41.50%,with an average of 18.23%Large range.The average variation coefficient of amino acid content in the main biochemical components was the highest,re aching the point of 37.87%,with large variation range and was great potential of genetic transformation.Setting euro-distance 17 as the threshold,we divide d 8 populations and references into two groups.Results showed that only the difference of tea polyphenols and catechins of the two groups was significant a mong all Ingredients.(3)In this study,10 pairs of SSR primers were used to characterize the ge netic diversity of 52 large-leaf tea trees in Nanjiang large-leaf tea.The results showed that the average Ne's genetic diversity(H)was 0.3315,and the averag e Shannon's genetic information index(?)0.4929.The polymorphism informatio n(PIC)of the Nanjiang large-leaf tea was between 0.3730 and 0.5006,with an average of 0.4454,showing moderate polymorphism.(4)In this research,the genetic diversities of eight different populations u nder two different growth states were studied.The results showed that the aver age H value of wild tea group was 0.3442,the I value 0.5114,the PPL 93.54%;While the average H value of the cultivated population was 0.3105,the I value 0.4620,the PPL 85.29%,which indicated that the genotype and geneti c diversity of the wild tea was more abundant than the cultivated one.From t he genetic structure,the genetic differentiation index(Gst)of the tested tea po pulation was 0.1233,and the gene flow(Nm)among the populations was 3.5549,showing a moderate gene flow among populations.So it showed that the v ariation degree in the same population is quite high,while it is relatively low among different regional populations.(5)In this experiment,52 copies were clustered into four categories by U PGMA method through NTSYS software.The average genetic distance of 8 te a populations was 0.0398,and the variation range was 0.0003?0.1229.The g enetic distance between population C and population G is the smallest one,wh ich is 0.0003,showing the closest genetic relationship.While genetic distance between population D and population G is the largest,which is 0.1229,showin g the relatively distant relationship of genetic relationship. |
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