Molecular Characterization Of Vernalization And Photoperiod Genes In Partial Landraces And Historical Wheat Cultivars Of China

The vernalization gene and photoperiod gene of wheat are major factors that influence wheat heading and flowering,and reflect the adaptation of wheat under different environmental conditions.This thesis tested and identified vernalization and photoperiod genes in 254 wheat Landraces and Historical genotypes from Collection of wheat molecular breeding research group of Henan Agricultural University.Comprehend the regularities distribution of the vernalization and photoperiod gene genotype,and detailed the effects of vernalization and photoperiod gene loci on wheat heading and flowering.The main results are as follows:1.Allelic variations of wheat vernalization relate gene Vrn-A1,Vrn-B1,Vrn-D1 and Vrn-B3 were identified in 254 landraces.The identification results showed that in the locus Vrn-A1,all the tested cultivars were recessive alleles;while 3 alleles,Vrn-B1,Vrn-B1 a and Vrn-B1 b in Vrn-B1 locus were discovered,and the frequencies were 89%,10% and 1% respectively.At the Vrn-D1 locus,we discovered 3 alleles,Vrn-D1,Vrn-D1 a and Vrn-D1 b,and the corresponding frequencies were 35%,47% and 18% respectively.At the Vrn-B3 locus,2 alleles Vrn-B3,Vrn-B3 b were discovered,which with allele frequency of 95% and5% respectively.Ten allelic combinations of different vernalization genes were found in 254 wheat landraces: vrn-A1/vrn-B1/Vrn-D1a/vrn-B3,vrn-A1/vrn-B1/vrn-D1/vrn-B3,vrn-A1/vrn-B1/Vrn-D1b/vrn-B3,vrn-A1/Vrn-B1a/vrn-D1/vrn-B3,vrnA1/Vrn-B1/Vrn-D1a/vrn-B3 b,vrn-A1/Vrn-B1a/Vrn-D1a/vrn-B3,vrn-A1/Vrn-B1a/Vrn-D1b/vrn-B3,vrn-A1/vrn-B1b/Vrn-D1a/Vrn-B3,vrn-A1/vrn-B1/Vrn-D1/vrn-B3 b,vrn-A1/vrn-B1/Vrn-D1b/Vrn-B3 b.and the corresponding allele frequencies were 39%,28%,16%,6%,3%,3%,2%,1%,1% and 1% respectively.Among the ten g enotype combinations,vrn-A1/vrn-B1/Vrn-D1a/vrn-B3 and vrn-A1/vrn-B1/vrn-D1/vrn-B3 were the 2 most prevalent genotypes in the studied wheat population which with the highest frequency distribution.2.The research results of different photoperiod genes confirmed that,at the Ppd-D1 locus there were 2 alleles,Ppd-D1 a and Ppd-D1 b which with allele frequency of 76% and 24% respectively.Our results of the major photoperiod gene Ppd-D1 confirmed that most of wheat landraces in this study were insensitive to photoperiod,which indicated that the great majority of wheat landraces have a good adaptability.Through identification of the allelic combinations of photoperiod genes,8 different kinds of Ppd-D1 sequence polymorphism combinations were found,Hapl-I,Hapl-II,Hapl-III,Hapl-IV,Hapl-V,Hapl-VI,Hapl-VII and Hapl-VIII,and the frequency were 55.0%,31.5%,4.0%,4.0%,2.0%,1.6%,1.6% and 0.3% respectively.three copy number variants,Sonora64 type,Truncated Chinese Spring type and Intacted Chinese Spring type at the Ppd-B1 locus were detected,and the corresponding allele frequency were 18%,28% and16%,respectively.3.Analysis of the relationship between different genotypes of vernalization and photoperiod combined with wheat heading and flowering stages.vrn-A1/vrn-B1/Vrn-D1a/vrn-B3,vrn-A1/vrn-B1/vrn-D1/vrn-B3,vrn-A1/vrn-B1/Vrn-D1b/vrn-B3,vrn-A1/Vrn-B1a/vrn-D1/vrn-B3 were the four common genotype combinations.Analysis with the heading and flowering days date showed that cultivars with vrn-A1/vrn-B1/Vrn-D1a/vrn-B3 and vrn-A1/vrn-B1/Vrn-D1b/vrn-B3 genotypes demonstrated the latest heading and flowering times among the four common allelic combinations in two cropping seasons.The function of photoperiod Ppd-B1 gene is affected by the variations of its copy number,wheat without the Intacted “Chinese Spring” Ppd-B1 a allele,Truncated “Chinese Spring” Ppd-B1 a allele and Intacted “Sonora64” allele showed the longest heading and flowering times.However,cultivars with the Intacted “Chinese Spring” Ppd-B1 a allele,Truncated “Chinese Spring” Ppd-B1 a allele and Intacted “Sonora64” allele showed the shortest heading and flowering times.Cultivars with Ppd-D1 Hapl-VIII and Ppd-D1 Hapl-III demonstrated the latest and earliest heading and flowering times respectively in two planting years among all the eight different Ppd-D1 polymo rphisms.