Sugar Beet Breeding Research Articles

Performance potential of sugar beets with improved beetroot shape in breeding for heterosis

Purpose. To increase the performance of sugar beet hybrids using integrated approaches to the creation, identification and selection of combination-valuable parents; to evaluate the performance potential of experimental hybrids derived from parents with improved beetroot shape.
 Materials and methods. The study was conducted in the Laboratory of Sugar Beet Breeding of the Tobacco Experimental Station of the National Research Center “Institute of Agriculture of NAAS” in 2018–2020. Sixty-six experimental diploid sugar beet hybrids originating from parents of different genetic origin were tested in the field.
 New starting material of sugar beets was created using classical breeding methods and traditional techniques. The experimental CMS-based sugar beet hybrids were evaluated for several economically valuable traits in accordance with the variety trial method developed by scientists of the Institute of Bioenergy Crops and Sugar Beets NAAS.
 Results and discussion. Analysis of the performance of the sugar beet hybrids originating from the parents with improved beetroot shape (oval-conical) indicates that the beetroot yields, sugar collection and output were significantly higher than those in the group check accession. The sugar content in their beetroots was lower than or similar to that in the group check accession. In general, the yielding type (E) of performance is intrinsic to the hybrids. As to beetroot yield, they exceeded the group check accession by 16.5–23.4%; the sugar collection was higher by 15.1–21.1%; and the sugar output – by 15.0–22.0%.
 Analysis of the beetroot in these hybrids shows that they had oval-conical beetroots. Their shape index varied 1.11 to 1.24. The beetroots of these hybrids were embedded into the soil by 3/4 of their length, had a smooth surface and shallow grooves (orthostichy).
 In the experimental sugar beet hybrids derived from the parents with improved beetroot shape (oval-conical), beetroots were longer (L) by 9.5%, larger in the diameter (D) by 2.2%, and the distance from the maximum diameter plane to the beetroot top (B) increased by 61.5% compared to the group check accession. In parallel with changes of the beetroot shape, the beetroot weight (m) increased by 25.0%. The transition from conical beetroots to oval-conical ones was proven to increase the performance of the sugar beet hybrids by 15–21%.
 Conclusions. We have created 14 high-yielding sugar beet CMS-based hybrids with improved beetroot shape, suitable for energy and environmentally friendly cultivation technologies. Their beetroot yields, sugar collection and sugar output exceed those in the group check accession by 16.5–23.4%, 15.1–21.1% and 15.0–22.0%, respectively

Screening of sugar beet pre-breeding populations and breeding lines for resistance to Ditylenchus dipsaci penetration and reproduction

Ditylenchus dipsaci is an economically important plant-parasitic nematode affecting European sugar beets. To date, no sugar beet cultivars carrying resistance against D. dipsaci are available to farmers. To find potentially resistant sugar beet lines restricting reproduction and penetration of D. dipsaci, three consecutive in vivo bioassays were carried out. The first experiment determined the penetration rate of D. dipsaci in 79 breeding lines and 14 pre-breeding populations. Based on these results, D. dipsaci penetration and reproduction resistance of eight genotypes was intensively investigated. It could be demonstrated that none of the genotypes showed resistance towards D. dipsaci. However, a high variation of the penetration rate by D. dipsaci was observed among the genotypes. The breeding line ‘DIT_119’ effectively reduced D. dipsaci penetration (34.4 ± 8.8 nematodes/plant at 22 days post-planting) compared to the susceptible control (109.0 ± 16.9) while ensuring a yield comparable to non-inoculated plants. However, the breeding line ‘DIT_119’ did not reduce D. dipsaci reproduction. The paternal line of the cultivar BERETTA KWS, demonstrating a high tolerance to D. dipsaci crown rot symptoms, did not reduce penetration and reproduction. Thus, no correlation can be established between reduced penetration rates, reproduction, and tolerance to D. dipsaci. This study provides an essential basis for the development of resistant sugar beet cultivars to D. dipsaci. The variations observed among genotypes now need to be confirmed with larger-scale screenings.

Complex Evaluation and Selection of Domestic Sugar Beet Breeding Material by Productivity and Technological Quality

Complex Evaluation and Selection of Domestic Sugar Beet Breeding Material by Productivity and Technological Quality

Production of Doubled Haploid Sugar Beet (Beta vulgaris L.) Plants Through Gynogenesis.

Haploid and doubled haploid plant production through unpollinated ovule culture, with diverse benefits and applications, is considered among the most effective and advantageous breeding method for sugar beet (Beta vulgaris L.). It is known that sugar beet is not responsive to androgenesis, which is widely used for most plant species. Sugar beet is a recalcitrant plant in vitro due to the very low spontaneous chromosome doubling and low gynogenesis rate. Thus, a steadily increasing gynogenesis efficiency has always been an important target for an efficient sugar beet breeding program. Given the scarcity of published papers focusing on gynogenesis in sugar beet, this chapter describes haploid and doubled haploid production through ovule culture of unfertilized flowers as a practical method.

The molecular basis for allelic differences suggests Restorer-of-fertility 1 is a complex locus in sugar beet (Beta vulgaris L.)

BackgroundCytoplasmic male sterility (CMS) is a widely used trait for hybrid seed production in many crops. Sugar beet CMS is associated with a unique mitochondrial protein named preSATP6 that forms a 250-kDa complex. Restorer-of-fertility 1 (Rf1) is a nuclear gene that suppresses CMS and is, hence, one of the targets of sugar beet breeding. Rf1 has dominant, semi-dominant and recessive alleles, suggesting that it may be a multi-allelic locus; however, the molecular basis for differences in genetic action is obscure. Molecular cloning of Rf1 revealed a gene (orf20) whose protein products produced in transgenics can bind with preSATP6 to generate a novel 200-kDa complex. The complex is also detected in fertility-restored anthers concomitant with a decrease in the amount of the 250-kDa complex. Molecular diversity of the Rf1 locus involves organizational diversity of a gene cluster composed of orf20-like genes (RF-Oma1s). We examined the possibility that members of the clustered RF-Oma1 in this locus could be associated with fertility restoration.ResultsSix yet uncharacterized RF-Oma1s from dominant and recessive alleles were examined to determine whether they could generate the 200-kDa complex. Analyses of transgenic calli revealed that three RF-Oma1s from a dominant allele could generate the 200-kDa complex, suggesting that clustered RF-Oma1s in the dominant allele can participate in fertility restoration. None of the three copies from two recessive alleles was 200-kDa generative. The absence of this ability was confirmed by analyzing mitochondrial complexes in anthers of plants having these recessive alleles. Together with our previous data, we designed a set of PCR primers specific to the 200-kDa generative RF-Oma1s. The amount of mRNA measured by this primer set inversely correlated with the amount of the 250-kDa complex in anthers and positively correlated with the strength of the Rf1 alleles.ConclusionsFertility restoration by sugar beet Rf1 can involve multiple RF-Oma1s clustered in the locus, implying that stacking 200-kDa generative copies in the locus strengthens the efficacy, whereas the absence of 200-kDa generative copies in the locus makes the allele recessive irrespective of the copy number. We propose that sugar beet Rf1 is a complex locus.

Investigation of Changes in Qualitative Characteristics of Sugar Beet Breeding Lines under Drought Stress and Normal Conditions

Investigation of Changes in Qualitative Characteristics of Sugar Beet Breeding Lines under Drought Stress and Normal Conditions

Reasons for slow genetic improvement in sugarcane relative to other crops

The rate of improvement in sugarcane commercial yields in recent decades has been low relative to sugar beet and some other major crops. This is due in part to a relatively slower rate of genetic improvement in sugarcane. Sugarcane breeding programs worldwide have long used a general breeding system which no longer appears well suited to achieving fast inter-generational genetic gains (parental improvement) in modern breeding germplasm. Examples of major innovations in breeding system design being tested are not clearly apparent. From an institutional perspective, sugarcane breeding is conducted by greater than 40 national level programs, owned and directed by local sugar industry clients and/or governments. By contrast, breeding of sugar beet and some other major crops is by companies or organisations whose core business or expertise is crop improvement, often multi-national and large in scale, and often operating in a competitive environment; and these arrangements collectively are perhaps more conducive to major and effective innovation than in sugarcane. Sugarcane is less attractive to companies specialising in crop breeding and genetics because protecting plant variety intellectual property rights and ensuring ongoing sales of top varieties would be challenging in most sugarcane industries. It seems likely that current conditions in relation to sugarcane breeding and recent trends in productivity gains may persist, and therefore that sugar beet may become increasingly competitive with sugarcane in future in terms of sugar production cost.

The effect of heat stress on sugar beet recombination

Meiotic recombination plays a crucial role in plant breeding through the creation of new allelic combinations. Therefore, lack of recombination in some genomic regions constitutes a constraint for breeding programmes. In sugar beet, one of the major crops in Europe, recombination occurs mainly in the distal portions of the chromosomes, and so the development of simple approaches to change this pattern is of considerable interest for future breeding and genetics. In the present study, the effect of heat stress on recombination in sugar beet was studied by treating F1 plants at 28 °C/25 °C (day/night) and genotyping the progeny. F1 plants were reciprocally backcrossed allowing the study of male and female meiosis separately. Genotypic data indicated an overall increase in crossover frequency of approximately one extra crossover per meiosis, with an associated increase in pericentromeric recombination under heat treatment. Our data indicate that the changes were mainly induced by alterations in female meiosis only, showing that heterochiasmy in sugar beet is reduced under heat stress. Overall, despite the associated decrease in fertility, these data support the potential use of heat stress to foster recombination in sugar beet breeding programmes.

Differentiation of Sugar Beet Varieties Using SSR Markers: A Tool to Create Promising Hybrids

The goal of this study was a molecular genetic passportization of the initial breeding material of sugar beet (male sterile lines, synanthous pollinators, and their hybrids). The following SSR primers were used: Unigene 24 552, Unigene 2305, Unigene 17 623, Unigene 14 805, and Unigene 62 524. The length range of the obtained DNA fragments varied within 100–3000 bp, and up to 11 polymorphic bands per genotype were amplified. The maximum Polymorphic Information Content (PIC) value was revealed for the Unigene 17 623 (PIC = 0.88), Unigene 2305 (PIC = 0.84), and Unigene 14 805 (PIC = 0.85) loci that provided a possibility to differentiate sugar beet breeding material. Using five of the tested SSR markers, the molecular genetic passportization of 26 genotypes of valuable breeding samples of this crop was carried out that allowed their identification and certification for further use in a marker-assisted selection. The calculated genetic distances between male sterile forms and synanthous pollinators varied from 2.236 to 4.796. Parent samples located at considerable genetic distances from each other were recommended for use in creating heterotic hybrids.

English

Three pollination control tents (PCTs) made from novel nonwoven synthetic fabrics with more open pore structure (DWB10, DWB23 and DWB24) were compared with the standard DWB01 fabric for pollen proofing in sugar beet (Beta vulgaris L.) at the research station of Lion Seed Ltd Essex, UK in 2019. PCTs of 63.5 x 63.5 cm footprint accommodated single potted plants. A completely randomised trial with five replications including an open pollinated control was conducted using cytoplasmic male sterile line 1TM37. Analysis was computed for (a) full data and (b) excluding three DWB23 defective tents. Differences among treatments were non-significant for all morphological traits except for number of secondary branches in (a) only. There was thus no micro-climatic difference among treatments for morphological traits of the 1TM37 CMS line. Among the seed related traits, 1000-seed weight and 10-day germination (%) were significant between treatments in (a) but only 1000-seed weight in (b). The mean 1000-seed weight was significantly higher for the open control than all other PCT treatment means which did not differ significantly from zero. Therefore, all four fabrics of PCTs were equally pollen proof in preventing pollen contamination. It is concluded for the first time that mini-tents of these novel nonwoven fabrics, engineered for both larger pores for air permeability and fibre architecture to prevent pollen transmission, adequately eliminated cross-pollination while maintaining ambient environmental conditions and are effective for sugar beet breeding. The PCT technology may be equally usefully deployed in other traditional, commercial and fibre crops for hybrid seed production. Key words: Sugar beet, nonwoven synthetic fabric, pollination control tent, male sterility. &nbsp

Genetic diversity of sugar beet under heat stress and deficit irrigation

AbstractIn the light of climate changes and global warming, as well as the rapid expansion in sugar beet (Beta vulgaris L.) cultivation in Egypt, the development of sugar beet varieties with improved tolerance to high temperature and deficit irrigation is of great importance. The objective of this study was to evaluate sugar beet genotypes under high temperatures and deficit irrigation conditions for further identification and selection of heat and drought tolerant genotypes. In the current study, a panel of 18 sugar beet breeding lines produced at the USDA–ARS–NWISRL, Kimberly, ID, and the commercial sugar beet cultivar Kawimera were evaluated for yield and quality under high temperature. Six promising lines in terms of yield and quality were further evaluated under both high temperature and deficit irrigation for two growing seasons.All lines performed differently under deficit irrigation, indicating a high degree of genetic variability in the evaluated lines. Additionally, yield traits showed negative effect due to deficit irrigation. A significant positive correlation was observed between stress tolerance index (STI), and average root and sugar yields under stressed and non‐stressed conditions. A linear relationship between STI and average root and sugar yields indicates that STI is a reliable stress index to select high yielding genotypes under both optimum‐ and deficit‐irrigation conditions. USKPS25 and USC944‐6‐68 breeding lines are most likely adapted to deficit irrigation and high temperature and suitable to be utilized in the proposed sugar beet breeding programs in Egypt.

Evaluation and Grouping of Sugar Beet Breeding Genotypes Under Normal and Drought Stress Conditions Using Multivariate Statistical Methods

Evaluation and Grouping of Sugar Beet Breeding Genotypes Under Normal and Drought Stress Conditions Using Multivariate Statistical Methods

Comparative transcriptome analysis reveals an ABA-responsive regulation network associated with cell wall organization and oxidation reduction in sugar beet

Abscisic acid (ABA) is an essential phytohormone and plays a key role in root architecture and plant stress responses. However, the ABA signalling pathway and its regulatory network in sugar beet roots remain unclear. Here, we carried out a time course experiment and performed global transcriptome profiling via strand-specific RNA sequencing (ssRNA-seq) to evaluate the response of sugar beet plants to exogenous ABA. According to the expression patterns of 5625 differentially expressed transcription units (TUs), the ABA-responsive stages within 24 h were divided into the early (1 h), intermediate (6 h and 12 h) and late (24 h) stages. Gene Ontology (GO) analysis revealed that oxidation reduction (GO: 0055114) and cell wall organization (GO: 0071555) were enriched in all ABA-responsive stages. For oxidation reduction, genes encoding cytochromes, peroxidases (PODs) and 2-oxoglutarate and Fe(II)-dependent oxygenases (2OG-Fe(II)s) constituted the largest proportion. ABA-responsive xyloglucan endotransglucosylase/hydrolase (XTH), expansin A (EXPA), pectinesterase (PME), pectate lyase (PL) and cellulose synthase (CES) were also detected in terms of cell wall organization. By performing regulation prediction and co-expression analysis, we determined that three genes, one encoding an AP2 domain-containing transcription factor (TF) and two encoding Dof domain-containing TFs (BVRB_4g074790, BVRB_8g180860 and BVRB_9g211370, respectively) may play an important role in the regulation of oxidation reduction and cell wall organization. Our profiling of ABA-responsive genes provides valuable information for understanding the molecular functions of regulatory genes and will aid in the future molecular breeding of sugar beet.

Biotechnological methods as a tool for efficient sugar beet breeding.

Here we consider aspects of the application of biotechnological methods to rapid creation, propagation, and maintenance of plants with improved or new traits in sugar beet breeding. The results of the works carried out in these fields by the Federal State Budgetary Scientific Institution “The A.L. Mazlumov All-Russia Research Institute of Sugar Beet” are reviewed. A close association between morphological and physiological changes in in vitro cultured organs and tissues, on the one hand, and breeding traits, on the other hand, which allows the development of experimental systems for non-amphimictic plant reconstruction is shown. The influence of in vitro growth conditions on haploid cells of unfertilized sugar beet ovules in the course of obtaining doubled haploid lines with high degree of homozygosity and maintenance of valuable breeding properties is considered. As compared to common inbreeding, this method shortens the time for development of homozygous material from 10–12 to 3–5 years, which is of great importance for speeding-up the breeding process. The results of studies on the culturing of mature sugar beet zygotic embryos based on in vitro selective systems have made it possible to improve the adaptive potential of plants and to provide complex resistance to environmental stress factors. Strict selection under abiotic stress conditions allowed creation of sugar beet isogenic lines with tolerance of drought, salinity, and soil acidity. It is shown that the proposed original design of mass-scale microclonal in vitro reproduction and deposition of elite plants as components of highly productive hybrids can be used to obtain seeds of uniform high-quality breeding material. The technologies developed by biotechnological methods are a topical and innovative direction of inquiry, since the application of these techniques to sugar beet breeding will promote obtaining of competitive hybrids with a set of commercially valuable traits. The combination of biotechnology methods, including tissue culture, and traditional breeding techniques is expected to provide an opportunity to obtain a new starting material to develop domestic varieties and hybrids of new generation with heterosis effect and a wide resistance spectrum persisting across generations.

Image-Based Dynamic Quantification of Aboveground Structure of Sugar Beet in Field

Sugar beet is one of the main crops for sugar production in the world. With the increasing demand for sugar, more desirable sugar beet genotypes need to be cultivated through plant breeding programs. Precise plant phenotyping in the field still remains challenge. In this study, structure from motion (SFM) approach was used to reconstruct a three-dimensional (3D) model for sugar beets from 20 genotypes at three growth stages in the field. An automatic data processing pipeline was developed to process point clouds of sugar beet including preprocessing, coordinates correction, filtering and segmentation of point cloud of individual plant. Phenotypic traits were also automatically extracted regarding plant height, maximum canopy area, convex hull volume, total leaf area and individual leaf length. Total leaf area and convex hull volume were adopted to explore the relationship with biomass. The results showed that high correlations between measured and estimated values with R2 > 0.8. Statistical analyses between biomass and extracted traits proved that both convex hull volume and total leaf area can predict biomass well. The proposed pipeline can estimate sugar beet traits precisely in the field and provide a basis for sugar beet breeding.

Mechanisms of Sugar Beet Response to Biotic and Abiotic Stresses.

Sugar beet is used not only in the sugar production, but also in a wide range of industries including the production of bioethanol as a source of renewable energy, extraction of pectin and production of molasses. The red beetroot has attracted much attention as health-promoting and disease-preventing functional food. The negative effects of environmental stresses, including abiotic and biotic ones, significantly decrease the cash crop sugar beet productivity. In this paper, we outline the mechanisms of sugar beet response to biotic and abiotic stresses at the levels of physiological change, the genes' functions, transcription and translation. Regarding the physiological changes, most research has been carried out on salt and drought stress. The functions of genes from sugar beet in response to salt, cold and heavy metal stresses were mainly investigated by transgenic technologies. At the transcriptional level, the transcriptome analysis of sugar beet in response to salt, cold and biotic stresses were conducted by RNA-Seq or SSH methods. At the translational level, more than 800 differentially expressed proteins in response to salt, K+/Na+ ratio, iron deficiency and resupply and heavy metal (zinc) stress were identified by quantitative proteomics techniques. Understanding how sugar beet respond and tolerate biotic and abiotic stresses is important for boosting sugar beet productivity under these challenging conditions. In order to minimize the negative impact of these stresses, studying how the sugar beet has evolved stress coping mechanisms will provide new insights and lead to novel strategies for improving the breeding of stress-resistant sugar beet and other crops.

Molecular genetic study of Beta vulgaris L

The results of molecular genetic studies are considered as a basis for the accelerated breeding of sugar beet. By PCR analysis (SSR, IRAP, RAPD), sugar beet parental lines were identified. Polymorphisms of DNA loci for each line were genotyped. The research was demonstrate a number of informative molecular ma (SSR) markers as the most informative to reveal heterogeneity of starting material and effective to forecast heterosis.

Evaluation of the hybridization potential of sugar beet cмs-lines and multi-shoot pollinators bred in uman within the program the «Betaintercross» program

The purpose was to study the hybridization potential of sugar beet CМS-lines and multi-shoot pollinators and to develop, on the basis of the best of them, high-yielding hybrids of various genomic levels. Materials and methods. The study included sugar beet CМS-lines and multi-shoot pollinators bred by us as well as CМS-lines of other research institutions co-executing the “Betaintercross” program. Different designs of top-crosses were used to create test hybrids and to study the general and specific combining abilities of the hybridization components. Results and discussion. In the study years (2014–2018), 25 CМS-lines, which were involved in top-cross hybridization designs with di- and tetraploid pollinators bred at different research institutions, were transferred to the “Betaintercross” program by the Laboratory of Sugar Beet Breeding of the Tobacco Experimental Station of the National Research Center “Institute of Agriculture of NAAS”. The results of the environmental variety trials of sugar beet hybrids distinguished the best hybrid combinations, the parents of which were CMS-lines and multi-shoot pollinators bred at the ТES of NRC “ІA NAAS”. It was established that Uman CMS-lines were the most effectively combined with multi-shoot pollinators of Bila Tserkva and Verkhniachka ЕВSs, and multi-shoot pollinators - with CМS-lines of Ivanivka, Bila Tserkva and Uladivka ЕВSs. The best hybrids’ performance far exceeds the group standard, providing a guaranteed gain of 5–12 % for the sugar collection and of 6–15 % for the sugar yield per hectare. A present, co-developed with Verkhniachka ЕВS mono-shoot diploid hybrid based on Heroi CMS has been entered in the Register of Plant Varieties of Ukraine. Conclusions. The analysis of the performance of the test sugar beet hybrids attests to a significant genetic potential of the CMS-lines and multi-shoot pollinators bred at the ТES of NRC “ІA NAAS”. This breeding material is characterized by high general and specific combining abilities, basic performance, technological quality of raw materials and resistance to diseases.

Fodder beet is a reservoir of drought tolerance alleles for sugar beet breeding

Drought leads to serious yield losses and followed by increasing food prices. Thereby, drought tolerance is one of most important, pivotal issues for plant breeding and is determined by the very complex genetic architecture, which involves a lot of genes engaged in many cell processes. Within genomes of currently cultivated sugar beet forms, the number of favourable allelic variants is limited. However, there is a potential to identify genes related to drought tolerance deposited in genomes of wild or fodder relatives. Therefore, the goal of our study, was to identify the source of allelic variants involved in drought tolerance using a large spectrum of sugar or fodder beets and their wild relatives for analyses. Based on the drought tolerance index, calculated for morphophysiological traits, it was demonstrated that some of selected fodder beets showed the highest level of drought tolerance. The most drought tolerant fodder beet genotype did not show differences in the level of expression of genes engaged in osmoprotection and the antioxidative system, between control and drought condition, compared to sugar and wild beets. The genetic distance between selected beet forms was broad and ranged from 18 to 87%, however the most drought tolerant sugar, fodder and wild beets showed high genetic similarity and formed the common clade. Based on obtained results we propose that an adequate broad source of genes related to drought tolerance occurs in fodder beets, the crossing with which is easier, less time-consuming and more cost-effective than with wild forms of beets.

DETERMINATION OF DETAILED MORPHOLOGICAL FEATURES FOR PHENOTYPING OF SUGAR BEET PLANTS USING 3D-STEREOSCOPIC DATA

Abstract. The sugar beet is the primary source of sugar in Europe and large parts of the world. Tools to determine plant traits with high precision and high throughput are required for the breeding process to quantify the effects of genetic and environmental factors on plant development and yield. In this work, we propose a method to gain a limited yet significant set of descriptive parameters for sugar beet plants. Using optical methods, a 3D representation of each plant is generated and subsequently segmented manually. A customized leaf model developed specifically for sugar beet plants then models the leaves, yielding a vector of descriptive parameters for each leaf. The resulting data is then compared to plant assessments of the same plants performed by sugar beet experts in order to evaluate the viability of automatic plant assessment in the sugar beet breeding process.