Grain weight is an important factor contributing to grain yield in wheat. Markers closely linked to grain weight could be used in marker-assisted selection (MAS) to accelerate the wheat breeding process. In this paper, a second backcross recombinant inbred line (BC2F4) population, a recombinant inbred line (RIL) population, and one natural population were used to study the relationship between allelic variants of the grain weight gene TaGW2-6A and grain weight, width, and length with the goal of verifying the feasibility using the functional marker Hap-6A-P1/P2 in MAS. The differences in average grain weight, width, and length between haplotypes Hap-6A-G and Hap-6A-A were 8.09 g, 0.22 mm, and 0.38 mm, respectively, in the BC2F4 population; 4.01 g, 0.11 mm, and 0.10 mm in the RIL population; and 3.95 g, 0.10 mm, and 0.20 mm in the natural population. All the differences were significant. Sequencing results of the products of second round PCR indicated that a 167 bp TaqI restriction fragment had been generated from small-grain-size materials because of three TaqI restriction sites (TCGA). However, the large-grain-size variant generated a 218 bp fragment due to a single-nucleotide mutation (SNP) (TCGA → TCGG) at the third site. TaGW2-6A expression levels were negative with respect to grain width, length, and weight. For this reason, Hap-6A-G was considered a superior allele. These results contradict those of a previous study, which showed Hap-6A-A to be significantly associated with wider grain and higher grain weight.

The glutenin and waxy loci of wheat are important determinants of dough quality. This study was conducted to evaluate the effects of high-molecular-weight glutenin (HMW-GS) and waxy alleles on dough-mixing properties. Molecular mapping was used to investigate these effects on Mixograph properties in a population of 290 (Nuomai1 × Gaocheng8901) recombinant inbred lines (RILs) from three environments in the harvest years 2008, 2009 and 2011. The results indicated the following: (i) the Glu-A1 and Glu-D1 loci have greater impacts on Mixograph properties compared to the Wx-1 loci and the effects of Glu-D1d and Glu-D1h on dough mixing are better than those of Glu-D1f and Glu-D1new1 in this population; (ii) the interactions between the Glu-1 and Wx-1 loci affected some traits, especially the midline peak value (MPV), and the lack of Wx-B1 or Wx-D1 led to increased MPV for all types of Glu-1 loci; and (iii) 30 quantitative-trait loci (QTL) over nine wheat chromosomes were identified with ICIM analysis based on the genetic map of 498 loci. Eight major QTL and 16 QTL in the Glu-1 loci from the three environments were found. The major QTL clusters were associated with the Glu-1 loci, and also were found in two regions on chromosome 3B and one region on chromosome 6A, which is one of the novel chromosome regions influencing dough-mixing strength. The two QTL for MPV are located around Wx-B1 on chromosome 4A. QMPT-1D.1, QMPI-1D.1 and Q8MW-1D.1 were stable in different environments and could potentially be used in molecular marker-assisted breeding.

In order to establish an efficient tissue culture and regeneration system for genetic transformation of wheat varieties,mature embryos of 12 wheat cultivars were used as explants to study the induction and differentiation of callus,and the effect of three induction medium and one differentiation media(including three ratios of hormone) on mature embryo in vitro culture.The results showed that the L32 medium were better than MS2 and N64 for callus induction,and all of the average induction rate were more than 85%,of which the N64 medium was the highest.All three hormone ratios could induce the differentiation of callus from wheat mature embryo,but there was great difference of differentiation frequency among different treatments.L3 as the basic differentiating medium containing 0.5 mg·L-1 IAA and 1 mg·L-1 KT,had the highest differentiation rate of 55.68%,and the medium of root formation containing 0.2 mg·L-1 IAA and 0.5 mg·L-1 MET,had the highest rooting rate of 37.02%.Wheat genotypes is an important factor to the formation and differentiation of mature embryo callus.The induction rate of callus,plumule rate,differentiation rate and rooting rate of different genotype were remarkably different.Lumai 14,liangxin 99,jimai 21,shannong20,liangxin66 were screened as the suitable material for genetic transformation among the 12 varieties,and their culture systems had been set up.

Flour color is one of the key factors influencing the quality of flour.In this study,whiteness and color of flour were determined using wheat RIL population from Gaocheng 8901 with strong gluten and Nuomai 1 with three Wx protein subunits deleted,and effects of HMW-GS and Wx protein subunits on them were also analyzed.The results showed that the mean value of whiteness was 79.20,ranging from 71.00 to 84.30;the mean value of b* was 7.38,ranging from 5.31 to 9.95;protein content ranged from 8.81% to 16.50% with the mean value 12.41%.Whiteness was significantly positively correlated with L* values,but was significantly negatively correlated with the b* value,so did L* value.Flour whiteness was significantly negatively correlated with protein content.The whiteness of flour at Glu-A1 locus showed better than that of null,so did protein content.Protein content at Wx-B1 deleted was higher that at Wx-A1 and Wx-D1,respectively.When both Wx-A1 and Wx-B1 protein deleted,grain protein content appeared increased,but flour protein content decreased.The materials with three protein loci deleted showed lower a* value.

In order to establish an efficient regeneration system of tissue culture for genetic transformation of improved varieties,the mature embryos of 3 wheat cultivars(Jimai19,Liangxing 99,Lumai 14) planted in Shandong Province and model variety Bobwhite were used as explants to study the callus induction and differentiation;and the effects of 3 induction media(including 3 concentrations of 2,4-D) and 1 differentiation medium(including 4 ratios of hormone)on mature embryos in vitro culture were investigated.The results showed that N6 medium were better than MS and MSB5 for callus induction.Its average induction rate was more than 80%.When the 2,4-D concentration was 4 mg/L,the induction effect was the best.All 4 ratios of hormone could induce the callus differentiation from wheat mature embryos,but the differentiation rate was low and great different.The MS medium supplemented with 0.5 mg/L IAA and 2 mg/L ZT had the highest differentiation rate of 22.58%.The wheat genotype mainly influenced the differentiation rate,while little affected the induction rate.Lumai 14 was the optimum variety for genetic transformation among 3 varieties.

小麦品种花培3号和豫麦57构建的DH群体的168个株系及亲本为材料,在正常发芽和20%PEG-6000模拟水分胁迫处理条件下测定小麦幼苗的胚芽鞘长、根长.利用完备区间作图法分析幼苗胚芽鞘长、幼根长的QTL.两种处理条件下共定位了8个控制胚芽鞘长加性QTL,其中位于染色体2A、4B和4D上的QCl2A、QCl4B和QCl4D在两种处理条件下均被检测到,可解释6.10%～16.31%的表型变异.两种条件下共定位了10个控制幼根长加性QTL,其中位于染色体6A上Xgwm82和Xwmc553区间的QRl6A在两种处理下均被检测到,可分别解释8.26%和9.74%的表型变异.在检测到的18对控制胚芽鞘长、根长的上位性互作位点中,大多数互作属于非等位QTL间的非加性QTL位点之间互作.因此在小麦材料的早期抗旱性筛选、分子育种时要同时考虑加性QTL和非加性QTL位点间的上位性互作.