Inheritance And Evolution Analysis Of Wheat Cultivars In Shanxi Province

Wheat(Triticum aestivum L.)is the third major cereal crops in China and the primary staple food in Shanxi province.Wheat cultivation in Shanxi has a long history and produce plentiful germplasm resources with strong drought-resistance and good quality,which have contributed enormously to wheat improvement.The lack of systematic research,especially the genetic diversity and pedigree analysis in these resources,has become a major limiting factor for the utilization.Phenotypes of wheat varieties registered since the founding of China were tested both in the field and indoor experiments.16 agronomic characters such as spike length,spikelet number,Grains per spike,Plant height,Neck length of spike,Internode length below the spike,Flag leaf length,Flag leaf width and 1000-grain weight were analyzed.The results showed that the Neck length of spike had the highest coefficient of variation,while Spikelet number had the lowest.The agronomic characters of wheat varieties display regularity changes with breeding eras.The mean plant height decreased from110-20 cm to 75-90 cm,which indicated that the plant type is evolved from high stalk-horizontal type towards dwarf-erect type.The main yield components,1000-grain weight,grains per spike and spikelet number continued to increase stably.There was no significant correlation among the three y ield factors,while the grains per spike correlated significantly with spikelet number,indicating a together improvement with the two characters during the development of wheat breeding in Shanxi.102 SSR markers were used to analyze the genetic diversity of wheat modern varieties in Shanxi.The average allelic variation richness of 102 markers was 3.94,the polymorphic information content(PIC)was between0-0.810,and the average polymorphism information content was0.446,indicating that the genetic diversity of wheat cultivars in Shanxi province was rich.Among the varieties analyzed,those registered during2000-2005 have the highest genetic diversity.Cluster analysis based on the Nei's genetic distance separated the varieties into eight groups,group classification is mainly related to breds and geographical distribution,the third ?fourth?fifth?sixth?seventh and eighth groups have the largest genetic difference.By analyzing the markers related to grain numbers,thousand grain weight and chlorophyll content,it was found that the frequency of favorable allelic variation gradually increased with years,indicating the potential in improving yield traits of wheat varieties in Shanxi.Wheat cultivars HMW-GS subunits composition and quality traits were detected.Results showed that the medium-strong gluten wheat varieties dominate in Shanxi,with the hardness index decrease annually,and other quality traits increase first,and then decrease.Wheat cultivars of Shanxi have rich alleles in Glu-1 locus which code HMW-GS.There had three types of subunit(Null,1 and 2*)at the Glu-A1,seven types of subunit(7+8?7+9?6+8?13+16?14+15?17+18?20)at Glu-B1 locus,and six types of subunits(2+12?2+10?5+12?5+10?4+12 and 2.2+12)at Glu-D1 locus.The change trend of the quality subunits was consistent with the trend of quality traits evolution.It was discovered that Glu-D1 locus has the greatest effect on protein content,hardness,Test weight,wet gluten content,extensibility and absorption,which4+12 and 2+10 have positive effect on protein content and wet gluten content,Glu-B1 locus has the greatest effect on Zeleny sedimentation,development time,stability time,Stretch area and Max Resistance,which 7+8 and 7+9subunits have positive effect on stretch area.2* of Glu-A1 locus has positive effect on Zeleny sedimentation,development time,stability time,Stretch area and Max Resistance.And Thirty-two different subunit combination were discovered,and “Null,7+8,2+12”had the highest frequency.“2*,7+8,4+12”and“1,7+9,2+10”had a greater positive effect on quality traits.