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Because of the yield increase of 3.5–15% compared to conventional wheat, hybrid wheat is considered to be one of the main ways to greatly improve the wheat yield in the future. In this study, we performed a principal component analysis (PCA) on two-line hybrids wheat and their parents using the grain weight (GW), the length of spike (LS), the kernel number of spike (KSN), and spike number (SPN) as variables. The results showed that the variables could be classified into three main factors, the weight factor (factor 1), the quantity factor 1 (factor 2) and the quantity factor 2 (factor 3), which accounted for 37.1, 22.6 and 18.5%, respectively of the total variance in different agronomic variables, suggesting that the GW is an important indicator for evaluating hybrid combinations, and the grain weight of restorer line (RGW) could be used as a reference for parents selection. The hybrid combination with a higher score in factor 1 direction and larger mid-parent heterosis (MPH) of the GW and its parents were used to carry out the analysis of grain filling, 1-aminocylopropane-1-carboxylicacid (ACC) and polyamine synthesis related genes. The results suggested that the GW of superior grain was significantly higher than that of inferior grains in BS1453×JS1 (H) and its parents. Both grain types showed a weight of H between BS1453 (M) and JS1(R), and a larger MPH, which may be caused by their differences in the active filling stage and the grain filling rate. The ADP-glucose pyrophosphorylase (AGPase), granule bound starch synthase I (GBSSI), starch synthase III (SSS), and starch branching enzyme-I (SBE-I) expression levels of H were intermediated between M and R, which might be closely related to MPH formation of the GW. Compared with R and H, the GW of M at maturity was the lowest. The expression levels of spermidine synthase 2 (Spd2), ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) had significantly positive correlations with the grain filling rate (r=0.77*, 0.51*, 0.59*), suggesting their major roles in the grain filling and heterosis formation. These provide a theoretical basis for improving the GW of photo-thermo-sensitive male sterile lines (PTSMSL) by changing the endogenous polyamine synthesis in commercial applications.

Additional file 1: Figure S1. (A) and (B): Distribution of two sub-gene families on wheat chromosome. Distribution of two gene families on wheat chromosome. All wheat chromosomes have HKMT gene distribution, which are relatively uniform. However, chromosome 2 and chromosome 3 also tend to cluster. Compared with the HKMT genes, the number of PRMT genes is relatively small, and the distribution of PRMT genes in the whole wheat genome is uneven. In addition, compared with previous research results, most HMT genes have been located in a clear range, and there is only one HKMT gene on the U chromosome, may also indicate that the genome quality of wheat has been greatly improved. Figure S2. Analysis of cis-elements of promoters of TaHMT genes. The 2kb sequence before the CDS of each HMT gene was extracted as the promoter region and submitted to PlantCARE database for cis-regulatory response elements prediction, and the results were visualized by TBtools. Figure S3. Expression analysis all selected TaHMT genes. (A) Expression analysis of 19 genes in spike. (B) Expression analysis of 12 genes in tiller. The relative expression of the female parent of each combination was relative 1, and the expression values for each parent are placed in front of each combination. The horizontal column is the gene name and the vertical column is the name of the samples. Figure S4. The phenotype as well as sampling times at different periods of wheat development. (A) Different periods of wheat spike development and sampling were conducted on this basis at anther separation stage. The length of the red ruler represents 1mm. (B) Tillers from root base to stem about 0.5 cm in length were sampled which contains the apical meristem at about four-leaf stage; P: male parent, M: maternal parent. (C) Phenotypic trait combinations for different tillers at harvest time, from left to right, they were: high parent (HP), middle parent (MP) and low parent (LP). In the picture, the three plants were photographed as a whole. Figure S5. The phylogenetic trees of HKMT (A) and PRMT (B) proteins from wheat, rice, Arabidopsis, Sorghum bicolor, Hordeum vulgare, and Brachypodium distachyon were constructed by MEGA-X using Maximum likelihood method. The HKMT proteins were divided into seven subfamilies and PRMT were divided into four subfamilies based on the previous methods. The members of wheat were marked with red circles in Fig. S5B. Figure S6. Interaction networks of miRNAs and HMT targets. miRNAs were marked as a blue node and HMT targets were marked as a yellow node. The size of the node represents the number of action sites. The black solid line represents that the mismatch expectation is 3.0, the red thick solid line represents that the mismatch expectation is 1.5, and the green thick solid line represents that the mismatch expectation is 2.5.

Background: Known as the prerequisite component for the heterosis breeding system, the male sterile line determined the hybrid yield and seed purity. Therefore, a deep understanding of the mechanism and gene network that leads to male sterility is crucial. BS366, a temperature-sensitive genic male sterile (TGMS) line, were male sterile under cold condition (12℃ with 12 h daylight) but fertile under normal temperature (20℃ with 12 h daylight). Results: During the meiosis, BS366 was defective in forming tetrad and dyad due to the abnormal cell plate. During the pollen development, unusual vacuolated pollen that cannot accumulate starch grains at the binucleate stage was also observed. Transcriptome analysis revealed that genes involved in the meiotic process like sister chromatid segregation and microtubule-based movement were repressed, while genes involved in DNA and histone methylation were induced in BS366 under cold condition. MethylRAD was used for a reduced DNA methylation sequencing for BS366 under both cold and control conditions. The differentially methylated sites (DMSs) located in the gene region were mainly involved in carbohydrate and fatty acid metabolism, lipid metabolism, and transport. Genes differentially and methylated were mainly involved in cell division. Conclusions: These results indicated that methylation of genes involved in carbon metabolism or fatty acid metabolism would contribute to the male sterility in BS366, which will provide a novel insight into the molecular mechanism of wheat male sterility.

Background DNA methyltransferase (DMT) genes contribute to plant stress responses and development by de novo establishment and subsequent maintenance of DNA methylation during replication. The photoperiod and/or temperature-sensitive genic male sterile (P/TGMS) lines play an important role in hybrid seed production of wheat. However, only a few studies have reported on the effect of DMT genes on temperature-sensitive male sterility of wheat. Although DMT genes have been investigated in some plant species, the identification and analysis of DMT genes in wheat (Triticum aestivum L.) based on genome-wide levels have not been reported. Results In this study, a detailed overview of phylogeny of 52 wheat DMT (TaDMT) genes was presented. Homoeolog retention for TaDMT genes was significantly above the average retention rate for whole-wheat genes, indicating the functional importance of many DMT homoeologs. We found that the strikingly high number of TaDMT genes resulted mainly from the significant expansion of the TaDRM subfamily. Intriguingly, all 5 paralogs belonged to the wheat DRM subfamily, and we speculated that tandem duplications might play a crucial role in the TaDRM subfamily expansion. Through the transcriptional analysis of TaDMT genes in a TGMS line BS366 and its hybrids with the other six fertile lines under sterile and fertile conditions, we concluded that TaCMT-D2, TaMET1-B1, and TaDRM-U6 might be involved in male sterility in BS366. Furthermore, a correlation analysis showed that TaMET1-B1 might negatively regulate the expression of TaRAFTIN1A, an important gene for pollen development, so we speculated regarding an epigenetic regulatory mechanism underlying the male sterility of BS366 via the interaction between TaMET1-B1 and TaRAFTIN1A. Conclusions Our findings presented a detailed phylogenic overview of the DMT genes and could provide novel insights into the effects of DMT genes on TGMS wheat.

Dependence on the crystallization behavior, thermal ability and soft magnetic properties of the Fe 84.7 Si x B 10.5-x P 4 Cu 0.5 C 0.3 (x = 0–2.0 at.%) alloys with high Fe content were investigated. The results show that the addition of minor Si significantly weakens the crystallization peaks and increases the amorphous forming ability of the alloys. With the increase of Si content, it improves the second crystallization peak temperature and greatly enlarges the temperature interval between the two crystallization peaks, which broadens the annealing range. When Si content is up to 1.5 at.%, the alloy can effectively inhibit the precipitation of Fe-B compounds during the process of annealing. The addition of Si contributes to the formation of stable nano-structure, leading to a good soft magnetic properties for the amorphous alloy. Through the optimum annealing treatments, the nanocrystalline alloy exhibits the high Ms of 206.5 emu/g (Bs ≈ 1.92 T) and low Hc of 12.5 A/m.

Plate-like Zr 60 Ni 25 Al 15 bulk metallic glasses (BMGs) were prepared under the gaseous mixture of hydrogen and argon. The effects of hydrogen on micro-hardness and wear resistance of the BMGs were researched. The results showed that BMGs fabricated under the gaseous mixture of hydrogen and argon exhibit higher micro-hardness and superior wear resistance, i.e., hydrogen addition can increase the wear resistance of bulk metallic glass dramatically. The enhanced wear resistance of the BMGs is attributed to the increment in micro-hardness and free volume introduced by the addition of hydrogen into the BMG matrix. The findings in present paper demonstrate that rapid solidification methods combining with hydrogenation could be an attractive means to improve the mechanical properties of bulk metallic gasses.

It has been well documented that the plastic deformation of bulk metallic glasses (BMGs) is localized in narrow shear bands, resulting in rapid propagation of these shear bands and catastrophic failures of BMGs subjected to loads. Shear bands in BMGs play a dominant role in their deformation behavior and macroscopic properties. In order to comprehensively understand the deformation mechanism of BMGs, it is necessary to investigate the formation of shear bands and consequent deformation. In present paper, Zr62.55Cu17.55Ni9.9Al10 and Zr64.80Cu14.85Ni10.35Al10 BMGs were prepared and the effect of indentation on the formation of shear bands was studied at room temperature. The results showed that Zr62.55Cu17.55Ni9.9Al10 BMG deforms through formation of radiation-like and circular shear bands, while for Zr64.80Cu14.85Ni10.35Al10 BMG, basically only radiation-like shear bands can be found after indentation deformation. The density of shear bands in the former is larger than that in the latter with a same loading condition. The different indentation deformation behavior in the two BMGs might be attributed to the differences in thermodynamic stabilities and intrinsic natures. The formation mechanism of the shear bands as well as the deformation mechanism of the BMGs were analyzed and discussed.

The Zr62.55Cu17.55Ni9.9Al10 bulk metallic glass (BMG) was prepared by using copper-mold suction-casting. X-ray diffraction and differential scanning calorimetry were utilized to determine its structure and thermal stability. Uniaxial compression and Rockwell indentation tests were adopted to study the plastic deformation behavior at room temperature. The results show that the glass transition temperature and the onset temperature of exothermic reaction of the BMG are 651.5 and 748 K, respectively. During the compression test, the BMGs undergo an engineering strain of about 2.5%, i.e., true strain of 2.8%, and then fracture. The BMGs deform via the formation and propagation of shear bands. Under indentation loading, the BMGs deform through the formation of radiation-like and circular shear bands. The circular shear bands form earlier than the radiation-like ones. The formation mechanism of shear bands in the BMGs was analyzed and discussed.

The bulk metallic glassy (BMG) rods of [(Fe0.5Co0.5)0.72B0.192Si0.048Nb0.04]100−xYx (x=0−6) and [(FexCo1−x)0.72B0.192Si0.048Nb0.04]96Y4 (x=0.5−0.8) were prepared by copper mold casting. The structure, thermal stability, and magnetic properties of the samples were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and vibrating sample magnetometer (VSM). Adding 1at% to 6at% of yttrium, the bulk glassy alloy rods of [(Fe0.5Co0.5)0.72B0.192Si0.048Nb0.04]100−xYx (x=0−6) with the diameter of 3 mm were not formed, and the sample with 4at% of yttrium showed less crystalline phase than others. When the Fe/Co atomic ratio was between 5:5 and 7:3, the bulk glassy alloy rods of [(Fe1−xCox)0.72B0.192Si0.048Nb0.04]96Y4 (x=0.5−0.8) with the diameter of 2 mm were fabricated. In the (Fe, Co)-B-Si-Nb-Y BMGs, when the Fe content increased, the thermal stability, the supercooled liquid region, and the glass-forming ability (GFA) decreased, but the saturation magnetization (Ms) increased.

Commonly, bulk metallic glasses exhibit very limited plastic deformation (

Water shutoff is a commonly used method to mitigate the early breakthrough in horizontal wells. Gel is frequently used as an effective water shutoff agent in mature fields, especially for horizontal wells in recent years. However, the relevant water shutoff prediction model lacks the accurate physical description of the gelation phenomenon. Using the conventional model, which simply accounts for the gelation mechanisms, does not allow us to predict the horizontal wells performance correctly. In this paper, a newly coupled reservoir–wellbore model for horizontal wells gel water shutoff prediction is presented. A conventional gel simulator is used to simulate the gel injection process in the reservoir and then modified to predict the horizontal well performance after the treatment. The time-varying residual resistance factor model and viscosity model is developed to simulate the gel degradation process. Especially, the wellbore pressure drop calculation takes account for the non-Newtonian behavior during and after the gel injection. An explicit modular coupled scheme, which consists of reservoir modular and wellbore modular, is adopted to numerically predict the horizontal wells performance. The newly presented method not only simulates the gel injection process but also predict the water shut off performance in horizontal wells. A field horizontal water shutoff case prediction shows that the coupled modeling method can give satisfactory results to guide the water shutoff treatment.