Genetic Analysis Of Early Heading And Molecular Marker Identification Of Amylose Content Of Hulless Barley

Hulless barley(Hordeum vulgare L.var.nudum Hook.f.),which is the most distinctive crop on the Qinghai-Tibet Plateau,is the typical representative of plant adaptive evolution under extreme environment on the Qinghai-Tibet Plateau.Hulless barley is the first major crop,and also the irreplaceable and the most important food crop on Qinghai-Tibet Plateau.Insufficiently cumulative temperature has been the great factor which will deeply affect normal growth of hulless barley.Therefore,early maturity is the important trait for high yield of hulless barley.The composition of starch,which is an important quality trait of hulless barley,is directly related to the end-use of brewing and food processing.In the current study,the inheritance of early heading trait which is highly correlated to early maturity were analyzed,amylose content were also identified by molecular marker.The main conclusions are listed as followings.1.Taken the F2 and F2:3 populations derived from ?Dazhangzi×Kunlun 10? as the experimental material,the genetic characteristic of early heading in hulless barley were analysed by using major gene plus polygene model.Number of days from emergence to heading was affected by 2 pairs of major genes with additive-dominance-epistasis effects in F2 population of hulless barley.In the F2:3 population,the early maturity was regulated by 1 pair of major gene with additive-dominance and 2 pairs of major genes with equivalence additive-equivalence dominance in the Xining and Haibei of Qinghai province,respectively.Meanwhile,the additive effect of 2 pairs of major genes controlling early maturity should be negative in F2 population,indicating that promote early maturing of hulless barley,and the major genes controlling early maturity postponed the heading of hulless barley in the F2:3 population under two different environments.In addition,the effect of genotype on phenotype was less than that of environment on phenotype in F2:3 population in different environment except for Haibei.These results were conducive to new variety breeding of characters correlated with early maturity in hulless barley.2.In order to better analyze genetic characteristics for early maturity of hulless barley,the F2 and F2:3 populations derived from ?Dazhangzi×Kunlun 10? were taken as the experimental material,SNP markers of the population were developed and Bin marker and SNP marker integration were carried on through applying the simplified genome sequencing technology and related bioinformatics software.High density genetic map of the F2 population has been constructed by JoinMap.The map has contained 1,243 Bin markers,including 2,380 SNP markers,and the total length was 854.929 cM,and the average genetic distance was 0.69 cM between two markers,and the 7 linkage groups were formed and has located on 7 chromosomes of hulless barley.Without considering the interaction between QTL and environment,11 additive-dominant QTLs and 8 pairs of epistatic QTLs were found in the F2 and F2:3 population under three environmental conditions,and the qDfEH-1H-3 on 1H chromosome could be detected in three environments,inferring that Xyloglucan endotransglucosylase/ hydrolase gene was candicated one of this QTL region.Then under considering the interaction relationship between QTL and environment,9 additive QTLs and 15 pairs of epistatic QTLs were detected in the F2:3 population under the two environments,and the epistatic QTLs were dominated by interaction between dominance and dominance.3.GBS-SNP molecular marker combined with BSA have been applied,to look for related genetic loci regulating grain amylose change in F2 population derived from ‘Kunlun12×Nuoqingke'.According to genetic characteristics of two parents,the current research has developed 22,506 polymorphic molecular markers for association analysis of related loci.By using the related multiple regression analysis combined with ?SNP index methods,the major genes regulating grain amylose contents were located in the region of 32.35 Mb at the 7H chromosome.Using 51 samples with large difference in amylose content as template,these samples were amplified by P4(SSR marker),the results indicated that the molecular weight of amplified product increased with increasing amylose content,the Wx gene loci has exhibited the polymorphisms,and significant positive correlation has also been shown between them.The current research has showed that primer P4 could be used as the special marker to assist selection in waxy hulless barley variety breeding.