Screening The High Nutrition Color Wheat Germplasm Resources And Genome-wide Association Analysis Of Zinc And Iron In Wheat

Wheat(Triticum aestivum L.)is not only an important food crop,but also the main source of nutrient intake.Due to the lack of attention to the genetic improvement of micronutrient elements,the content of micronutrient elements in existing varieties decreases,so that it cannot meet the needs of human health,resulting in health problems caused by micronutrient deficiency in people with wheat as the staple food.therefore,it is particularly important to screen high nutrient wheat varieties through germplasm resources.In this study,cluster analysis was carried out based on the basic agronomic characters of 572 color wheat accessions and wheat 16 K chip genotype data,241 representative accessions were selected for zinc,iron and anthocyanin content determination,and high nutrition color wheat germplasm were selected to provide excellent germplasm resources for industrial development and breeding of color wheat.At the same time,the key sites of zinc and iron accumulation in color wheat grains were identified by association analysis,which provided a theoretical basis for the cloning zinc and iron related key genes of wheat and molecular marker-assisted breeding.The main results were as follows:(1)The relationship between iron,zinc and other agronomic traits.There was a significant negative correlation between the zinc content in the grains of color wheat and the thousand grain weight(TKW).The arsenic content in the grains had a significant positive correlation with plant height,and a significant negative correlation with grain length.The selenium content in the grains had a significant positive correlation with the ratio of grain length to width.Color wheat varieties with high grain iron,zinc,and selenium content and low harmful heavy metal content can be cultivated by simultaneously considering the micronutrient and agronomic traits.Meanwhile,there was a significant positive correlation between zinc content in color wheat grains and crude protein and wet gluten,indicating that while increasing zinc content in grains,grain quality would also be improved.Zinc and iron content are also positive correlated with anthocyanin content.The content of anthocyanin can be improved with increasing the content of zinc and iron in wheat.(2)The content of anthocyanin can be quickly measured by colorimeter.The content of anthocyanin in grain was positively correlated with L* value,and negatively correlated with a*,b*,ΔE*ab value.The color wheat varieties with high L* value and low a*,b* and ΔE*ab value can be selected for rapid detection of anthocyanins in grain by colorimeter.Colorimeter can be used as a quickly and non-destructively auxiliary tool to measure the content of anthocyanin in seeds and screen the high-anthocyanin wheat germplasms.(3)Screening the high nutrient germplasm resources of color wheat.Sixteen high-nutrient color wheat varieties were selected by measuring the agronomic characters,contents of zinc,iron,selenium,cadmium,arsenic,anthocyanin,grain color and grain quality in two years.These sixteen varieties had high content of iron and zinc and the variation degree of both iron and zinc content was small in the two environments.The anthocyanin content of seven wheat materials was high and stable,which provided germplasm resources for cultivating high nutrition color wheat in the future.The contents of zinc,iron,arsenic,selenium and cadmium in Heibaomai 3 and anthocyanin in Jiziheimai 9 increased under organic planting conditions,which indicating that organic cultivation could improve the contents of trace elements in some color wheat.(4)The SNP 1D＿15042348 was a stable site,which is correlated with iron content by genome-wide association analysis in two years.Meanwhile,there are two stable loci related to zinc and iron content on chromosome 3A,namely 3A＿19085855 and 3A＿19085948.These three loci of 1D＿15042348,3A＿19085855 and 3A＿19085948 can be used for the development of molecular markers related to zinc and iron accumulation in wheat.(5)The interval of 0.5Mb upstream and downstream from significant SNP site were divided into a QTL.84 genes within the QTL range were considered as the candidate gene according to the annotation information of Chinese spring wheat genome.These candidate genes mainly included zinc finger protein,metallothionein,heavy metal transporter/binding protein,calcium-dependent protein kinase,F-box protein,calcium-binding protein,seleniumbinding protein,sodium channel protein,transmembrane protein,E3 ubiquitin-protein ligase,glutathione S-transferase T3,ABC transporter,Myb family transcription factor family proteins,and nicotinamide-nucleotide adenylyl transferase,NAC domain protein and so on.These genes could be used as the candidate genes to improve the content of zinc and iron,which laid a foundation for further analysis of the accumulation mechanism of zinc and iron content in wheat grains.