| Genus Linum L. was one of crops used by human firstly, and it comprises more than 200 species, there are abundant genetic resources. The cultivated species comprises two types, one is fibre flax, the other is linseed(oil flax). Fibre flax had important economic value in textile industry, materials, paper industry,and so on, so was the linseed in business for its abundant insaturated fatty acid and lignan content, which resist against cardiovascular and cerebrovascular diseases. Although has a long cultivated history, the research to Genus Linum L. was at initial phase. The little understanding was knewn to Genus Linum L., and there are many different views to origin, evolution of cultivated flax and relationship within Genus Linum L.Genetic diversity within part of Genus Linum L.and the evolution of cultivated flax(Linum usitatissimum L.) were analysised from phenotypes, peroxidase polymorphism and DNA polymorphism of SRAP markers in the study. Evolutionary pathway of the cultivated flax was disscussed by analysising homologous sequence of gene CesA CDS section and gene Sad2. Otherwise, local wild flax(Linum stelleroides) was taken as sample to understand the genetic diversity and gene flow(Nm) of population, and it could supply theoretical basis for evolutionary pathway of cultivated flax and wild flax utilization reasonable. The results was as follows from the study:1. the optimal SRAP-PCR reaction system in flax were made certain as follows: 1×buffer, 2.5mmol/L Mg2+, 0.3mmol/L each dNTP, 0.2μmol/L primer, 0.08U/μl Taq DNA polymerase, and 1.2ng/μl flax DNA template in a final volume of 25μl, and the optimal amplification protocol was: 94℃3min, (94℃10s,35℃20s,72℃1min)×4,(94℃10s,54.5℃20s,72℃1min)×38, 72℃7min,held at 4℃.2. Genus Linum L.had abundant genetic variation, the average mean of variation coefficient based on 21 phenotype characters from 65 accesions within 17 species was at 0.47, the range was at 0.12-1.36, in which, variation coefficient value of several characters >0.5, the order was: branching habit>corolla color, anther color> seed color>the number of vascular cells in main nervation>growing habit>shape of leaf. The variation of observed characters was higher than that of measured characters. The range of variation coefficient in species was at 0.02-0.25, and the variation among species was higher than that of in the species.3. Similarity index range among 65 accessions was at 0.577-0.993, and among wild species was at 0.583-0.950, and among cultivated varieties was at 0.841-0.993, in which, that of fibre flax was at 0.897-0.993, the linseed was at 0.841-0.987. From above, the highest variation was among wild species, fibre flax had narrower genetic basis than linseed. 4. Wild flax had closer relationship with linseed than fibre flax from the evidence of phenotypecharacters, isozyme polymorphism and DNA polymorphism amplified by SRAP marker. Linseed not only had its own clustering group, but also existed in fibre flax clustering group.5. It was found that differentiation was strong between the local wild flax species population(Linum stelleroides) and cultivated species population(Linum usitatissimum L), there was little gene flow and big gene dirrerentiation coefficient between two species population.6. Linum grandiflorum,Linum bienne,Linum angustifolium,Linum tenuifolium were close to cultivated flax in similarity, in which, Linum grandiflorum was close to cultivated flax at phenotype, Linum bienne,Linum angustifolium was at isozyme, and Linum angustifolium,Linum tenuifolium,Linum bienne was at DNA polymorphism amplified by SRAP marker.7. It supported the view that cultivated flax had many origins, and didin't support the only origin from Linum bienne, and Linum bienne was considered that contributed to envolvement of cultivated flax...
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