Dissertation > Agricultural Sciences > Gardening > Fruit trees gardening > Nuts (shell fruit ) > Chestnut

Analysis of Genetic Diversity of Castanea Henryi Populations and Native Varieties Based on Inter Simple Sequence Repeat (ISSR)

Author LiuGuoBin
Tutor LuoZhengRong; GongBangChu
School Huazhong Agricultural University
Course Pomology
Keywords Castanea henryi population Native variety ISSR genetic diversity
CLC S664.2
Type Master's thesis
Year 2009
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Castanea henryi Reld. Et Wils. belongs to Fagaceae, is a endemic species of Castanea spp. in China. It is not only a fruit tree, but also an economic tree. At the same time, C. henryi is a natural gene pool for the cultevars improvement. But until now, there are few reports on the investigation of this germplasm resource, and the genetic diversity and genetic variation is seldom. In this paper, taking the 16 populations and 449 individuals, which sampled from the mail distribution area, as materials, we analyse the genetic diversity and genetic variation among and within populations based on ISSR. At the same time, study on genetic diversity of Some C. henryi cultivars is taking at the same time.The main results are as follow:1.Genomic DNA,which extracted from C. henryi leaves, as the template, By adjusting same mail influencing factors, we established the PCR amplification condition: 25ul reaction system containing 40 or 50ng template DNA, 1.5mmol/L Mg2+, 0.2mmol/L dNTPs, 1U Taq DNA polymerase, 0.3μmol/L primer; with a ABI thermal cycle,the optimal amplification program was an initial denature for 3 min at 94℃, 1 cycle, followed by 32 cycles of 45s at 94℃, 45s at Tm+2-4℃, 2 min at 72℃, and a final extension for 5 min at 72℃, 1 cycle.2 A total number of 20 ISSR primers screened from 60 ISSR primers were used for ISSR analysis. A total of 379 bands were scored from 449 individuals. Among the 379 loci, 378 of which were polymorphic (PPL=99.74%). The Nei’s gene diversity(average expected heterozygosity, He) is 0.2950, Shannon information index is 0.4522. PPL varied from 36.94% to 53.30% per population, the average is 46.09%; the Nei’s gene diversity varied from 0.1202 to 0.1861, the average is 0.1573; Shannon information index varied from 0.1817 to 0.2781, average is 0.2357. AMOVA analysis shows, the genetic variation among populations is 47.49%, and within population is 52.51%. The result shows, (1) C. henryi possess a relatively high level of genetic diversity, and a higher level of genetic differentiation was detected among populations. (2) The genetic diversities varied among different populations, the Xiang Xi population and Jing Zhou population have the highest level of genetic diversity, whereas Nan Ping and Zi Yuan population have the lowest level of genetic diversity. UPGMA clustered analysis indicated 449 individuals clustered in 16 clades based on their populations.3 To investigate the genetic diversity and genetic relationship of 37 C. henryi cultivars, 13 ISSR primers were screened. The result shows: (1) 37 cultivars were distinguished by 13 ISSR primers. (2) The Observed number of alleles is 1.8269, the effective number of alleles is 1.5097, Nei’s gene diversity is 0.2923, Shannon information index is 0.4344. (3) A total of 156 bands were scored from 13 screened primers, 129 of which were polymorphic (PPL=82.69%, 9.9 bands per primer).4 Some conservation measures are suggested based on the observed population genetic information.

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