Genetic Regularity And Gene Mapping Of Purple Seed Character Of Guizhou Purple Wheat No.1

Purple seed wheat is a special wheat germplasm resource,which has attracted more and more attention because of the seed is not only rich in anthocyanin,but also rich in nutrients compared with common wheat.Previous studies on purple seed wheat variety Guizhou purple wheat No.1 have been carried out on comprehensive quality evaluation,dynamic deposition of anthocyanin pigments and transcriptome sequencing of purple seed character.However,the inheritance and control genes of purple seed character are still unclear.Therefore,this paper used the purple wheat variety?guizhou purple wheat No.1?was crossed with white wheat varieties?Guinong No.19 and Guinong No.30?to construct genetic research populations of different hybrid generations?F₁,F₂,F₃ and BC₁F₁?.Based on the statistical analysis of purple seed traits of different hybrid generations,the genetic regularity of purple seed traits of guizhou purple wheat No.1 was explored and the positioning of purple seed genes was studied by cluster segregation analysis?BSA?and 660K gene chip detection technology.The follow main research results were obtained:1.This paper used the purple wheat variety?guizhou purple wheat No.1?and white wheat varieties?Guinong No.19 and Guinong No.30?were reciprocal crosses and backcross respectively.The seed color of reciprocal cross F₁ generation were the same as that of female parent.The seed color of reciprocal cross F₂ generation were light purple.The segregation of seed color occurred of reciprocal cross F₃ generation and purple seed character showed delayed inheritance.The separation ratio of purple and white seeds of reciprocal cross F₃ generation were 9:7.The seed color of offspring crossed between the reciprocal cross F₁ and purple parents was purple.The seed color of the offspring crossed between the reciprocal cross F₁ and white parent was separated and the ratio of purple and white was 1:3.The results showed that the purple seed character of guizhou purple wheat No.1 was determined by two completely dominant genes and delayed inheritance was caused by maternal genotype.2.The 231 individual plants of F₂ population were obtained by crossing Guinong No.30 with Guizhou purple wheat No.1 variety.Using bulked segregant analysis?BSA?strategy select 30 individual plants with the darkest and lightest seeds were constructed the purple and white seed pools.The whole genome of purple pool,white pool and their parents were detected by 660K gene microarray of wheat.The results showed that the purple seed gene of Guizhou purple wheat No.1 probably existed in 716-759 Mb of 2A chromosome and 611-661 Mb of 4B chromosome.A total of 17571 SNPs with different performance between two mixed pools and two parents were obtained based on quality control.According to the genetic integration map information of 660K microarray were integrated into 21 chromosomes of SNPs with different performance.Among the 5551differential SNPs were distributed on 1A chromosome,the 1873 differential SNPs were distributed on 1B chromosome,the 1851 differential SNPs were distributed on 4A chromosome,the 1436 differential SNPs were distributed on 6A chromosome,the 815differential SNPs were distributed on 4B chromosome and the 770 differential SNPs were distributed on 2A chromosome.The distribution of differential SNPs on chromosomes 2A and 4B were the most concentrated,whereas the distribution of chromosomes 1A,1B,4A and 6A were more diffuse.The differential SNPs on 2A chromosome were concentrated in 716-759 Mb,while those on 4B chromosome were concentrated in 611-661 Mb.3.Two parents and two mixed pools were screened for SSR polymorphism by using the 500 SSR markers published on 6 candidate chromosomes and the 100 SSR markers designed based on transcriptome data obtained earlier.The SSR markers with the polymorphism between two parents and two mixed pools will be used for population validation.Finally,the 11 SSR markers linked to purple seed character were screened.They were Xwmc296,Xgwm122,Xcfd6,GZPp1 and GZPp2 on chromosome 2A and Xwmc826,Xgwm368,Xwmc254,GZP3,GZP4 and GZP5 on chromosome 4B respectively.The results showed that the two complementary dominant genes controlling purple seed character of guizhou purple wheat No.1 were located on chromosomes 2A and 4B respectively.In this study,the two genes were named GZMPp1 and GZMPp2 respectively.The genetic distances between Xcfd6 and GZPp2SSR markers adjacent to GZMPp1 are 20.2 cM and 18.5 cM respectively.The genetic distances between Xgwm368 and GZPp3 SSR markers adjacent to GZMPp2 are 37.4cM and 32.8 cM respectively.The left and right primer sequences of Xcfd6,GZPp2,Xgwm368 and GZPp3 comparing with the Chinese Spring 1.0 version of the wheat reference genome.The physical distance between Xcfd6 and GZPp2 on 2A chromosome overlaps with 716-759 Mb,while that between Xgwm368 and GZPp3 on4B chromosome overlaps with 611-661 Mb.Therefore,the purple seed genes GZMPp1and GZMPp2 of Guizhou purple wheat No.1 were located in 716-759 Mb of 2A chromosome and 611-661 Mb of 4B chromosome respectively.To sum up,this paper used the purple wheat variety was crossed with white wheat varieties to construct genetic research populations of different hybrid generations.Through statistical analysis of purple seed traits in different hybrid generations,it was found that purple seed traits of guizhou purple wheat No.1 were controlled by two pairs of dominant complementary genes.Two genes controlling purple seed trait of Guizhou purple wheat No.1 were successfully located in the intervals of 716-759 Mb and 611-661 Mb of 2A chromosome and 4B chromosome by BSA strategy combined with gene chip and SSR marker technology,which laid a theoretical foundation for fine mapping of purple grain genes and expression analysis of candidate genes in subsequent wheat.