Identification Of Genotypes And Development Of Molecular Markers Related To Grain And Flour Colour In Wheat

Polyphenol oxidase (PPO) activity、yellow pigment content and grain color areimportant indicators of color traits affecting flour products in wheat grain. Polyphenoloxidase is the main reason resulting in enzymatic browning in the process of wheatproducts. The highly yellow pigment content will result in yellow flour increased, atthe same time reduces the whiteness of the flour. Red wheat grain in the grindingpowder will cause the rising of flour yield of bran flour mixed color variation. Thesethree factors leading to flour color and luster are not popular with Chinese consumers.Therefore, the highly white flour wheat varieties bred by the way of geneticimprovement will become one of the priorities of the current quality breeding.This study uses molecular marker detection, homology cloning and sequencingmethods, carried on the activity of polyphenol oxidase, yellow pigment content, graincolor related allelic variation type identification and gene sequence analysis ofmaterials, which come from China’s winter wheat, spring wheat, landraces, historicalvarieties of cultivars and Aegilops. PPO activity was measured to determine thecorrespondence between genotype and phenotype, variety of unknown gene typeusing homology cloning methods, in order to find new alleles. The main conclusionsof the study are as follows:1. In the444tested materials, the genotype distribution frequency of PPO-A1b(low PPO activity) and PPO-D1b (high PPO activity) are58.60%and54.50%,respectively. Activities of PPO gene distribution between the different types ofvarieties are quite different. High PPO activity characteristic PPO-A1a genotype andthe PPO-D1b genotype distribution in the Chinese Spring higher frequency were59.68%and67.74%, respectively, have the characteristics of low PPO activity of thePPO-A1b genotype and PPO-D1a genotype frequency distribution of local varieties ofChinese and Chinese winter wheat high as69.19%and61.40%, respectively. Indifferent PPO genotype combinations, the survey showed intermediate type PPOgenotype combination accounted for the highest proportion, thus in quality breedingof wheat color traits as the main target, we should focus on the impact of differentPPO genotypes. 2.Through the material different Psy-A1/Psy-B1genotype, allele identificationresults found in all of the444tested materials, polymeric material of a variety ofhigh-quality allele less in the yellow pigment content genes associated with lowyellow pigment content allele Psy-A1b/Psy-B1b gene composition containing bothless material, only57parts, the frequency is12.84%, the combination of genesassociated with high yellow pigment content Psy-A1a/Psy-B1a and Psy-A1a/Psy-B1cproportion of66.89%, a larger proportion of the remaining combinations of genes areheterozygote space of variation, influencing factors. Therefore, marking theidentification and analysis can understand the distribution of alleles of the genes ofthe wheat varieties in China, which provide theoretical reference for future breedingresearch.3.In Tamyb10-A1, Tamyb10-B1and Tamyb10-D1locus, three recessive allelesTamyb10-A1a (56.41%), Tamyb10-B1a (96.46%) and Tamyb10-D1a (76.31%)participating the frequency distribution of material were greater than three dominantalleles Tamyb10-A1b (43.59%), Tamyb10-B1b (3.54%) and the frequency distributionof Tamyb10-D1b (23.69%), which led to the white grain genotype combinationTamyb10-A1a/Tamyb10-B1a/Tamyb10-D1a (50.31%) in the tested materialdistribution frequency significantly higher than that of the other seven red graingenotype combinations, so in the future breeding work we should consider the impactof Tamyb10-A1a, Tamyb10-B1a and Tamyb10-D1A alleles. In addition, the whitegrain wheat genotype combination has one combination genotype, whereas red grainwheat has seven, and those seven kinds of combination genotypes showed differentcolor depth. Therefore, this study identified the material with different genotypes ofwheat grain color as the traits target improvement to provide certain information.4. There are three new alleles cloned in Ae.tauschii a named Tamyb10-D1c,Tamyb10-D1d and Tamyb10-D1e, based on the difference among the three allelessequences designed two pairs of common significant of functional marker DD3andDD5. Using he DD3and DD5Molecular identify tested Ae.tauschii material, showingthat Tamyb10-D1c, Tamyb10-D1d and Tamyb10-D1e three genotypes, whosedistribution of frequencies were36.36%,55.46%and8.18%, respectively.Understanding genotype Tamyb10in distribution of Ae.tauschii, which provide moreinformation for the effective use of these materials, provide certain information formodern varieties of Chinese grain color improvement, and build the foundation forthe Chinese wheat molecular breeding.