| Wheat(Triticum aestivum L.)germplasm resources are the foundational materials for wheat breeding.Genetic diversity study will strengthen the assessment and utilization of germplasms,and accelerate the breeding process.By analysis of the high molecular weight glutenin subunit composition,wheat gliadin,ISSR markers polymorphism,and agronomic traits,the genetic diversity studies were done for some Germplasm Resources in Huanghuai Wheat zone.The results are as follows:The HMW-GS compositions of 100 common wheat germplasms in Huanghuai wheat zone were analyzed by SDS-PAGE.The results showed that in analyzed cultivars or lines there were 2 kinds of subunit alleles at locus of Glu-A1(Null,1),5 allele combinations(7+8,7+9,14+15, 6+8,17+18)at Glu-B1 and 3 allele combinations(2+12,5+10,5+12)at Glu-D1.The frequency of bread making positively associated subunit combination of 14+15 was 16%,that of 5+10 was 33%,and that of 5+12 was 7%.The frequencies of subunit combinations of "1,14+15,5+12","1, 7+9,5+10",and "1,14+15,5+12" were very low,these had a positive effect on bread making quality.The result indicated that these wheat lines with ideal HMW-GS compositions could be used as a good quality subunit provider for wheat quality breeding.The genetic diversity at gliadin loci in 100 wheat gemplasms was analyzed by acid polyacrylamide gel electrophoresis(A-PAGE).The results showed that the gliadin band patterns of the 100 wheat germplasms were significantly different.Total 1 608 bands had achieved from the tested germplasms.There were 116 different mobility protein bands.The No.10 and No.14 protein bands had the highest present frequencies of 64%and 96%.The other 114 protein bands showed higher polymorphism.Each germplasm accessions had 10 to 24 gliadin bands,and most accessions had 13 to 19 bands.The genetic distance(GD)of the tested germplasm accessions varied from 0.24 to 0.83,with an average of 0.54.Genetic variation was wide.Cluster analysis divided the germplasm accessions into six major classes.The results showed that the tested germplasms had a rich gliadin variation,suggesting a wide genetic diversity.In order to detect the polymorphism revealed by five ISSR primers synthesized in our laboratory,20 wheat varieties in Henna were analyzed.The results showed that 2 of the 5 ISSR primers revealed the maximum polymorphism among the 20 wheat varieties.100 wheat germplasms in Huanghuai wheat zone were studied with the 2 ISSR primers.Total 6 296 bands had achieved from the tested germplasms by the 2 ISSR primers.There were 127 different mobility bands.ISSR showed high ability to distinguish wheat germplasms,suggesting ISSR molecular marker was one of the effective molecular marker techniques to detect genetic diversity in wheat Germplasms.Cluster analysis divided the germplasm accessions into 11 major classes, 14 subclasses according to the genetic distance(GD).However,not all of the wheat germplasms came from the same ecological areas were divided into the same major class.The reason may be these germplasmes were exchanged frequently,resulting in reduction of the region characters. Therefore,this study showed the current situation of the wheat germplasms in breeding program. The genetic distances(GD)of the tested germplasm accessions varied from 0.22～0.73,with an average of 0.50.The tested germplasms had a rich variation,suggesting a wide genetic diversity.14 important agronomic traits were investigated and recorded in detail,including plant height,lodging,powdery mildew,seeding habit,tiller,cold damage,ear length,length of the stem under the ear,awn length,the flag leaf characteristics,milking speed and the mature appearance. The results showed a rich genetic diversity of agronomic traits in Huanghuai wheat zone.Which also provide rich wheat germplasms for wheat breeding.We found out the best combination of agronomic traits in Huanghuai wheat zone for high yield.
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