The Diversity Of Alleles Within Wheat Landraces In China

Wheat landraces are one important wheat resource in China, which is about 13976 recorded. The wheat landraces have many traits, for example: planted for long history, many kinds, early rapeness, fertility and wide adaptability, which have contributed much to our country and this world. The wheat landraces had ucdergone natural and manual selections for a long time and had abundant genetic variations. Therefore, it is very important to know the genetic structure within and between wheat landraces, in order to wide genetic foundation and develop wheat plant breeding. The objectives of this study were to analyze and evaluate genetic structure within Chinese wheat landrace. To select 50 individuals from each landrace, and eliminate those individuals which were too big and different color, and then with the half-grain way, the wheat landrace of 47 were analyzed at the levels of the gliadin protein and modality. And then on the base of gliadin study, 12 wheat landraces were evaluated through SSR to study their group structures. The major results were that: 1. There existed abuandant genetic varations within wheat landraces in China, which embodied thereinafter: 1.1 Fourty-seven wheat landraces were done by A-PAGE, as a result, 122 kinds of gliadin biotypes were discoveried. The variation of gliadin types was 1~6, twelve of which contained one kind of gliadin biotype with the frequency of 25.5%; thirteen contained 2 kinds of gliadin biotypes with the frequency of 27.7%; ten contained 3 kinds of gliadin biotypes with the frequency of 21.3%; seven contained 4 kinds of gliadin biotypes with the frequency of 14.9%; three contained 5 kinds of gliadin biotypes with the frequency of 6.4%; two contained 6 kinds of gliadin biotypes with the frequency of 4.3%. Therefore, there were abundant variations of alleles within the wheat landraces in our country. 1.2 The UPGMA clustering analysis of 122 kinds of gliadin biotypes indicated that different gliadin biotypes within every wheat landrace were gathered firstly, there existed diversity at the alleles which coded the gliadin. So, the genetic background within the wheatlandrace was very resemble. 1.3 On the basis of the frequencies of gliadin bands, we computed the diversity of index and found that they were not evident between wheat langraces, and the range of disversity index was 0.9231~0.9575, the average was 0.9442. There existed 50 different mobility gliadin bands, 2 of which were common. The variation of frequency distribution and disversity index were 0.22%-100%, and 48 of which were polymorphic with the frequency of 90.0%, and 2 of which were common. 2. There esisted abuandant diversity of alleles on the whole genome, which embodied as follows: 2.1 There were variations of alleles within 12 wheat landraces, but the frequencies of whose polymorphic loci were different very much, and the variation of the variety of ZM001511 was the least ,whose the percentage of polymorphic loci was 11.76%, but the variation of the variety of ZM000080 was the biggest ,whose the percentage of polymorphic loci was 94.12%. 2.2 Totally 99 alleles were revealed with the average of 5.8 alleles per SSR marker. The variation range was 1~11. 2.3 On the basis of the frequencies of alleles on every SSR primer in different wheat landraces, we computed the diversity of index and found that it ranged 0.000~0.699, with the average of 0.213 per primer. And the diversity of index of every wheat landrace ranged 0.044~0.334, with the average of 0.213 . 2.4 The comparison of diversity at the level of gliadin and SSR showed that if one variety had more gliadin types, and then there would exist more alleles in it. The study of correlation between the gliadin types and alleles, polymorphic loci indicated, they were correlative evidently, and the coefficient between the gliadin types and alleles was 0.68, and the coefficient between the gliadin types and polymorphic loci was 0.62. 2.5 At the genetic distance of 1.01, the 12 wheat landraces could be plotted three group, and which was relative to the zone of variety.