Genetic Diversity At Gliadin Loci Of Some Wheat Cultivars

Genetic diversity study of wheat is the prerequisite for wheat breeding. It will strengthen the assessment and utilization of germplasms, and accelerate the breeding process. By analysis of the wheat gliadin, the genetic diversity studies were done for some germplasm resources. The research on genetic diversity experienced the following stages:agronomic character morphological markers,comparative analysis of quality character ,biochemical maker(isozyme and seed store protein),and latest research on DNA molecular marker in the field of molecular biology ,that indicates difference of internal germplasm.Gliadin is one of the main components of wheat storage proteins. It accounts for about 40% protein of endosperm protein .Its content and composition determines the ductility and viscosity of wheat dough. The baking quality of wheat flour is also closely related to it.In this paper, genetic diversity of 213 materials were studied in gliadin, the result is as follows :1. The genetic diversity at gliadin loci of 109 common wheat cultivars or lines was studied by A-PAGE. A total of 1793 bands were identified in the examined wheat accessions. 8 to 21 gliadin bands were identified in each accession, with an average of 16.5. 88 gliadin bands with different relative mobility were observed by electrophoresis. Bands No. 2 and No. 4 had the highest present frequencies of 46.79% and 51.38% respectively. The other bands showed very high polymorphisms. The mean genetic distance (GD) was 0.49, ranging from 0.16 to 0.82. All of the tested materials could be classified into 5 clusters at the level of GD 0.76. The result indicated that the wheat cultivars or lines examined in this study had a rich genetic diversity at the gliadin loci. This paper provides some useful information for wheat breeding with these wheat germplasms. Rely on the results of clustering, the wheat from the same region did not completely come together, we can see the relations of gliadin and geographical are not close.2. A-PAGE electrophoresis results showed that 56 different species of plant height of wheat gliadin-type appeared a strong polymorphism. There are 56 gliadin patterns in the 56 material,among which 847 gliadin bands are separated. The number of bands within an accession ranged from 9 to 21. The No. 2 and No. 4 protein bands had the highest present frequencies of 44.64% and 50.00%. The material above 105 cm in height isolated with 435 bands. It Brings the total number of 51.36%. They have no common bands. The material less than 75 cm in height isolated with 412 bands. It brings the total number of 48.64%.They have no same bands.The other bands showed very high polymorphisms. The genetic distance (GD) of the tested germplasm accessions varied from 0.39 to 0.86, with an average of 0.63. Cluster analysis divided the germplasm accessions into 3 major classes at the level of GD 0.82. The results showed that the tested germplasms had a rich gliadin variation, suggesting a wide genetic diversity. The number of gliadin which height are not different did not change significantly.It indicats that the height has a little impact on gliadin.Clustering result shows that the material height greater than 105cm gathered together and the material less than 75cm gathered together.It shows that wheat height and gliadin gene has some linkage.3. The genetic diversity at gliadin loci in 48 wheat gemplasms of different panicle length was analyzed by acid polyacrylamide gel electrophoresis. the results showed that the gliadin band patterns of the 48 wheat germplasms were significantly different. Each material had its unique pattern.A Total of 744 bands were detected from the tested germplasms. There were 85 different mobility protein bands. The No. 3 and No.4 protein bands had the highest present frequencies of 45.83% and 43.75%. The other 46 protein bands showed higher polymorphism.,and most accessions had 14 to 16 bands.the material above 12 cm in panicle length isolated with 377 bands. It brings the total number of 50.67%.They have no common bands. the material less than 8.5 cm in panicle length isolated with 367 bands. It brings the total number of 49.33%.They have no same bands.The genetic distance (GD) of the tested germplasm accessions varied from 0.45 to 0.86, with an average of 0.66. Genetic variation was wide. Cluster analysis divided the germplasm accessions into 3 major classes at the level of GD 0.82. The results showed that the tested germplasms had a rich gliadin variation. The number of gliadin which spike length are not different did not change significantly. It show s that the spike length has a little effect on gliadin.Clustering result shows that the material spike length greater than 12cm gathered together and the material spike length less than 8.5cm gathered together.It shows that wheat height and gliadin gene has some linkage.