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Sugar beet (Beta vulgaris L.) is a biennial herb belonging to the Amaranthaceae family. It contributes to approximately 30% of the world's total sucrose production and is an economically important crop. In this study, we analyzed the genetic diversity and population structure of 132 exotic sugar beet varieties using three molecular makers: four pairs of simple sequence repeat (SSR) primers, three pairs of insertion–deletion sequence (InDel) primers, and 20 cis-element amplification polymorphism (CEAP) primers. The results indicated that the number of alleles (Na) was 298, among which the number of effective alleles (Ne) was 182.426 (accounting for approximately 61.2%). The mean value of the genetic diversity index was 0.836. The polymorphic information content (PIC) was 0.639–0.907 (mean = 0.819), indicating a high level of polymorphism. These sugar beet varieties were classified into six clusters using the UPGMA method of cluster analysis. Population structure analysis revealed that the most ideal K value was 6. This indicated that the test materials could be divided into six categories, consistent with the clustering results. The clustering results indicated that most sugar beet varieties from the same breeding company clustered together, and the genetic distance between them was small, indicating that they may share the same male and/or female parent. Some varieties from different companies clustered together, indicating a narrow genetic base and potential exchange of germplasm resources between breeding companies. This study revealed the genetic differences among exotic sugar beet varieties and characteristics of the population structure. It provided a scientific basis for the identification of sugar beet varieties and markers-assisted breeding in China in the future. [ABSTRACT FROM AUTHOR]

Sugar beet is an economically significant crop, and the homozygosity of paired monogerm cytoplasmic male sterile (CMS) and maintainer lines directly influences the number of hybrid combinations that can be created. This study aimed to evaluate the genetic variation within monogerm sugar beet germplasm resources to establish a foundation for advancements in sugar beet breeding and the development of hybrid female parent lines. This study analyzed the genetic diversity of 86 distinct monogerm germplasm resources, including 38 paired monogerm CMS and maintainer lines, 5 individual maintainer lines, and 5 externally introduced sterile lines. The analysis employed 26 pairs of SSR primers and 35 pairs of InDel primers across nine sugar beet chromosomes. Several genetic parameters, and analyses such as structural analysis, genetic diversity analysis, and principal coordinate analysis, were used to evaluate the samples. The results indicated that these strains could be classified into two groups: Group I and Group II. Group I was further divided into three subgroups. Further, 18 pairs of original CMS and maintainer lines were successfully clustered, confirming that their nuclei had achieved homozygosity, making them suitable for use in the development of binary sterile lines. However, 20 other pairs still require further backcrossing to achieve homozygosity. The analysis of molecular variance (AMOVA) revealed that most of the genetic variation occurred within individuals, with relatively low genetic differentiation between groups. Significant genetic differentiation was observed between Subgroups 2 and 3, and between Subgroups 1 and 3. The results suggest that additional monogerm sterile and maintainer lines from these subgroups should be selected to configure binary sterile lines. This study offers a theoretical foundation for developing new sugar beet germplasm resources and cultivating hybrid mother plants. [ABSTRACT FROM AUTHOR]

By using 14 SSR primer pairs, we here analyzed and compared the amplification results of 534 DNA samples from six red sugar beet germplasm resources under three treatments. These data were used to explore the sampling strategy for the aforementioned resources. Based on the sampling strategy results, 21 SSR primer pairs were used to evaluate the genetic diversity of 47 red sugar beet germplasm resources. The six population genetic parameters used for exploring the sampling strategy unveiled that individual plants within the population had a relatively large genetic distance. The genetic parameters Ne, I, and Nei's of the randomly mixed sampling samples increased rapidly between 10 and 30 plants before decreasing. Therefore, when SSR technology was used to analyze the genetic diversity of the red sugar beet germplasm resources, the optimal sampling gradient for each population was the adoption of a random single-plant mixed sampling sample of no less than 10 plants and no more than 30 plants. The 21 SSR primer pairs were used to detect genetic diversity in 30 random mixed samples of 47 resources. The average polymorphic information content (PIC) was 0.5738, the average number of observed alleles (Na) was 4.1905, the average number of effective alleles (Ne) was 2.8962, the average Shannon's information index (I) was 1.1299, the average expected heterozygosity (Nei's) was 0.6127, and the average expected heterozygosity (He) was 0.6127. The genetic distance of the 47 germplasm resources ranged from 0.0225 to 0.551 (average: 0.316). According to the population structure analysis, the most suitable K value was six, which indicated the presence of six populations. Based on the clustering analysis results, the 47 germplasm resources were segregated into six groups, with obvious clustering and some germplasm resources noted for having groups with close genetic relationships. We here established a more accurate and scientific sampling strategy for analyzing the genetic diversity of red sugar beet germplasm resources by using SSR molecular markers. The findings provide a reference for collecting and preserving red sugar beet germplasms and protecting their genetic diversity. [ABSTRACT FROM AUTHOR]

This study analyzed the genetic diversity, population structure, and cluster analysis of 129 sugar beet germplasm resources to screen superior germplasms for breeding using the 27 simple sequence repeat (SSR) and 33 pairs of insertion–deletion (InDel) molecular markers. After integrating the phenotypic variation of 16 descriptive and 4 qualitative phenotypic variables, the genetic variation levels of the 129 sugar beet germplasms' phenotypic traits were analyzed using the principal component analysis (PCA), correlation analysis, and analysis of variance methods. The genetic diversity examination of molecular markers showed a polymorphism information content (PIC) of 0.419–0.773 (mean = 0.610). Moreover, the mean number of effective alleles detected via the SSR and InDel markers was 3.054 and 2.298, respectively. Meanwhile, the PIC ranged from 0.130 to 0.602 (mean = 0.462). The population structure analysis revealed the most appropriate K-value, indicating three populations (K = 3). The genetic distances of the 129 germplasm resources ranged from 0.099 to 0.466 (mean = 0.283). The cluster analysis results demonstrated that the germplasms were grouped into three primary classes. Based on the analysis of variance, the two qualitative features with the highest coefficients of variation were petiole width (16.64%) and length (17.11%). The descriptive trait root length index (1.395) exhibited the greatest genetic diversity. The PCA reduced the 20 phenotypic traits into five principal components, contributing 51.151%. The results of this study provide a theoretical foundation for the future selection and breeding of superior sugar beet germplasm resources. [ABSTRACT FROM AUTHOR]

At the entry of the pickling and tandem cold strip mill (PL-TCM), the unreasonable cut length of the head and tail of the strip often causes a thickness difference between the weld surfaces of the front and back strip, resulting in a weld seam with thickness difference after welding. This can easily lead to strip breaking at the weld seam in the cold rolling process. In this paper, a finite element model of roll and strip with weld seam is established to investigate the mechanism of strip breaking at weld seam due to thickness difference. By simulating the working conditions in the rolling process for weld seam with different thickness differences, the evolution of the stress state of the weld seam in the rolling process under each working condition is analyzed. The influence of thickness difference in the rolling process of the weld seam is revealed, and the effect of thickness difference on the risk of strip breaking at weld seam during the rolling process is further discussed. According to the research results, the optimization method of strip head and tail shear length was designed and applied to the industrial site. After application, the accident rate of strip breaking is reduced and the effect is as expected. [ABSTRACT FROM AUTHOR]

To understand the relationship between vernalization and endogenous phytohormones on bolting, phytohormone levels and transcriptome changes were measured by LC-MS/MS and RNA sequencing before vernalization (CK), at the end of 16 weeks of vernalization (Vel) and at 5 days after vernalization (Re). A total of 32 phytohormone compounds significantly changed after vernalization; especially, the content of abscisic acid (ABA) and jasmonic acid (JA) was dramatically decreased more than sixteen and three times in the Vel and Re samples. In addition, GA19 accumulated after vernalization, while the content of GA53 and GA20 decreased. A total of 7471 differentially expressed genes (DEGs) were identified in response to vernalization. These DEGs were enriched with GO terms including response to stimulus (GO:0050896), response to hormone (GO:0009725) and shoot system development (GO:0048367). KEGG mapping indicated that 16, 13 and 11 DEGs were involved in gibberellic acid (GA), ABA and JA biosynthesis, suggesting a negative role of vernalization in phytohormone biosynthesis. Vernalization also repressed the expression of BvABFs and BvMYC2s, implying the inhibition of ABA and JA signalling. Additionally, vernalization plays a positive role in GA signalling, owing to the down-regulation of BvDELLAs. We also found that GA3-induced bolting could be retarded by exogenous ABA and methyl jasmonate (MeJA). In total, our results suggest that vernalization can promote GA-induced bolting by decreasing BvDELLA repressors of GA signalling and eliminating the antagonistic effects of ABA and JA. [ABSTRACT FROM AUTHOR]