Some enzyme changes in chicory (Cichorium intybus) during forcing

Differences in beet weight and sugar concentration of four commercial varieties grown on two types of soil and at different planting density were related to changes in the numbers, sizes and sugar storage capacities of the storage root cells. Much of the variation in beet weight between varieties and soil type was attributable to differences in cell size, less to differences in their number. Differences in weight of beet grown at different densities were caused equally by changes in number of cells and their size. Variation in sugar concentration of the beet was, in all cases, determined more by differences in cell size than in their capacity tostore sugar, but the two factors were not wholly independent of each other.     

Gehalt an Beet Necrotic Yellow Vein Virus (BNYVV) in der Hauptwurzel von Zuckerrübenpflanzen verschiedener Sorten und deren Leistung unter Rizomaniabefall im Feld

BNYVV concentration in the tap roots of sugar beet varieties grown in rhizomania-infested fields During plant development, the BNYVV concentration in several commercially available rhizomania-tolerant sugar beet varieties and one susceptible variety was examined as an index of the intensity of infection. The root weight, sugar content and sugar yield of the same varieties in fields naturally infested with rhizomania were also measured. Significant negative correlations were found between the average virus concentration in the tap root and yield parameters in infested fields. These were largely independent of the growth stage of beet plants used for virological investigations. However, the negative correlations between virus concentration and yield were not significant if rhizomania-tolerant varieties only were compared. The possibility that virus concentration might be used as a criterion for selection in addition to yield performance is discussed. This may lead to selection that is targeted more directly at rhizomania resistance and thereby accelerate breeding work.     

Influence of phloem transport, N-fertilization and ion accumulation on sucrose storage in the taproots of fodder beet and sugar beet

To investigate the factors governing the accumulation of sucroseand amino acids in the taproots of sugar beet, their contentswere measured in the leaves, phloem sap and the taproots ofsugar beet, fodder beet and a hybrid between both, grown oneither 3.0 or 0.5 mM nitrate. In the taproots the contents ofmalate, citrate and inorganic ions were also determined. Forthe high sucrose accumulation in sugar beet as compared to theother varieties three factors were found. (a) In sugar beet,less amino acids and more sucrose are taken up into the phloemthan in fodder beet. (b) In sugar beet, the sucrose and aminoacid syntheses are less sensitive to the nitrate concentrationsthat are required for optimal plant growth than in other varieties.In fodder beet, upon raising the nitrate concentration from0.5 mM to 3 mM, the synthesis and storage of sucrose is decreasedand that of amino acids increased. The corresponding valuesin sugar beet (0.5 mM) are similar to those in fodder beet andare not much affected by an increase of nitrate. (c) The sucroseaccumulation is limited by the accumulation of inorganic ionsin the taproots. The sucrose content in the taproots is negativelycorrelated to the total ion content. Whereas sucrose representstwo-third of all solutes in the taproots of sugar beet, it amountsto only one-third of the solutes in fodder beet taproots. Key words: Amino acids, Beta vulgans L, phloem sap, potassium, sucrose storage, sugar beet, taproots, transport     

Genotypic Variation for Drought Tolerance in Beta vulgaris

Insufficient soil moisture during summer months is now the majorcause of sugar beet yield losses in the UK. However, selectionfor increased drought tolerance has not been a breeding priorityuntil recently. Genetic variation for drought tolerance is anessential prerequisite for the development of more stress-tolerantvarieties, but commercial sugar beet varieties seem to havesimilar yield responses to drought. The objective of this studywas to assess the degree of genotypic variation for droughttolerance within a wide range of sugar beet germplasm and genebankaccessions within Beta. Thirty sugar beet genotypes were screenedunder field drought conditions, and putative drought tolerantand sensitive lines (in terms of yield reduction in polythene-coveredvs. irrigated plots) were identified. Significant genotype xwater treatment interactions were found for dry matter yieldand relative leaf expansion rate. Genotypic differences fordrought susceptibility index were also significant. Differentialsensitivity of seedling shoot growth to water deficit was examinedby comparing 350 genebank accessions in a simple growth chamberscreen. Methods of data management were devised to highlightlines for entry into subsequent field tests. The results ofthe field and seedling screens indicate that there is variationfor tolerance to water deficits within sugar beet and relatedtypes, and that there are lines that show greater drought tolerancethan selected commercial varieties. Divergent lines showingcontrasting behaviour should aid in the identification of keymorpho-physiological traits that confer drought tolerance.     

An analysis of the variation in crown size in sugar-beet (Beta vulgaris) grown in England

The processed part of the sugar-beet plant, the beet, consists of secondary storage tissues developed from the root and hypocotyl and the crown which, botanically, is the compressed stem. Crowns contain less sugar than roots and higher concentrations of melassigenic substances (such as amino-nitrogen compounds, sodium, potassium and invert sugars) which impair the crystallisation of white sugar during processing and make beets with high proportions of crown costly to process. Two factors influence the amount of crown material in beet delivered to factories: the original size of the whole crown in intact beet (subsequently referred to as the biological crown), and the fraction removed by the topping mechanisms of beet harvesters when the crop is lifted. The residue left on the delivered beet, for which growers in the UK are not paid, is measured as crown tare at the factory. To understand the causes of variation in crown tare, an analysis was made of the trend and variation in the size of the biological crown of sugar beet varieties introduced in the UK during the last 25 yr using information from past variety trials and new trials done in 1993, 1997 and 1998. Except for a few diploids, the biological crown was generally as large and variable in recently-introduced varieties as in those grown 15–20 yr ago. Its size was strongly influenced by locational and seasonal factors which changed the plant's shoot:root ratio primarily, it is suggested, through differences in amounts of available nitrogen. There was no evidence of changes in beet anatomy in recently-introduced varieties that would result in root material being removed with the crown when samples of delivered, machine-topped beet are contractually de-crowned to estimate crown tares in the factory tarehouse. Variable amounts of crown are removed by harvesting machines. Experiments showed that a greater proportion of beet were over-topped and more root material was removed with the crown when the biological crown was small and when harvester knives were set low to deliver a minimal crown tare. In these situations, significant amounts of root material, for which growers would be paid if delivered to the factory, were left in the field. Data from differential machine-topping trials on commercial sugar beet crops at four locations in 1996 and 1997 were used to relate yield loss through over-topping to crown tare. A crown tare of at least 8% was needed to ensure that no economic yield was left in the field; below this level the losses in delivered yield and grower's income increased exponentially through over-topping. It was estimated from the factory records of individual contracts that deliveries of beet with crown tares below 8% decreased the national adjusted yield of clean beet by 58 400 t in 1997, equivalent to 0.34 t ha^-1 and 0.56% of the total delivered tonnage.     

Thidiazuron-induced organogenesis and somatic embryogenesis in sugar beet (Beta vulgaris L.)

Summary Improved in vitro tissue culture systems are needed to facilitate the application of recombinant DNA technology to the improvement of sugar beet germplasm. The effects of N ⁶-benzyladenine (BA) and thidiazuron (TDZ) pretreatment on adventitious shoot and somatic embryogenesis regeneration were evaluated in a range of sugar beet breeding lines and commercial varieties. Petiole explants showed higher frequencies of direct adventitious shoot formation and produced more shoots per explant than leaf lamina explants. TDZ was more effective than BA for the promotion of shoot formation. The optimal TDZ concentrations were 2.3–4.6 μM for the induction of adventitious shoot regeneration. Direct somatic embryogenesis from intact seedlings could be induced by either BA or TDZ. TDZ-induced somatic embryogenesis occurred on the lower surface of cotyledons at concentrations of 0.5–2μM and was less genotype-dependent than with Ba. A high frequency of callus induction could be obtained from seedlings and leaf explants, but only a few of the calluses derived from leaf explants could regenerate to plants via indirect somatic embryogenesis. These results demonstrated that TDZ could prove to be a more effective cytokinin for in vitro culture of sugar beet than BA. Rapid and efficient regeneration of plants using TDZ may provide a route for the production of transgenic sugar beet following Agrobacterium-mediated transformation.     

Phytosulfokine stimulates cell divisions in sugar beet (Beta vulgaris L.) mesophyll protoplast cultures

The aim of this work was to improve plating efficiency of sugar beet mesophyll protoplast cultures. Preliminary experiments showed that cultures of good quality, viable protoplasts were obtained in rich media based on the Kao and Michayluk formulation and with the calcium alginate as an embedding matrix. Nevertheless, in these cultures cell divisions were either not observed or very seldom confirming earlier reported recalcitrance of sugar beet protoplasts. The recalcitrant status of these cultures was reversed upon application of exogenous phytosulfokine (PSK)—a peptidyl plant growth factor. The highest effectiveness of PSK was observed at 100 nM concentration. Plating efficiencies obtained in the presence of PSK reached approximately 20% of the total cultured cells. The stimulatory effect of phytosulfokine was observed for all tested breeding stocks of sugar beet. Our data indicate that PSK is a powerful agent able to overcome recalcitrance of plant protoplast cultures.     

甜菜耐盐性筛选及其幼苗对盐胁迫的响应

为了探讨甜菜耐盐机理、不同耐盐等级甜菜盐耐性机制差异,对40份甜菜品种（系）用300mmol·L-1NaCl胁迫处理,通过芽期相对盐害率和苗期盐害指数确定不同品种耐盐等级,将不同耐盐等级材料进行NaCl浓度梯度（150、300mmol·L-1）处理,测定植株鲜重、超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量和叶片质膜透性。试验结果如下：40份甜菜材料经过芽期和苗期耐盐性筛选最终确定耐盐等级极强的品种（系）1份（‘KWS0143’）,耐盐等级强的品种（系）6份（‘ACERO’等）,耐盐等级中等的品种（系）14份（‘HI0183’等）,耐盐等级弱的品种（系）5份（‘OVITO’等）;在同一盐胁迫时间下,不同耐盐等级材料的植株鲜重随盐浓度的增加呈下降趋势,品种‘KWS0143’和‘ACERO’变化幅度较小,品种‘OVATIO’下降幅度最大;不同耐盐等级材料随盐浓度增加和胁迫时间延长超氧化物歧化酶（SOD）活性呈现先上升而后下降的趋势,耐盐性极强的品种酶活性显著高于其他耐盐等级材料;不同耐盐等级材料随盐浓度增加和胁迫时间延长丙二醛（MDA）含量和叶片质膜透性均呈上升趋势,耐盐等级弱的品种（系）明显高于其他各个材料。     

Genetic approaches to sustainable pest management in sugar beet (Beta vulgaris)

Sugar beet (Beta vulgaris) is an important arable crop, traditionally used for sugar extraction, but more recently, for biofuel production. A wide range of pests, including beet cyst nematode (Heterodera schachtii), root‐knot nematodes (Meloidogyne spp.), green peach aphids (Myzus persicae) and beet root maggot (Tetanops myopaeformis), infest the roots or leaves of sugar beet, which leads to yield loss directly or through transmission of beet pathogens such as viruses. Conventional pest control approaches based on chemical application have led to high economic costs. Development of pest‐resistant sugar beet varieties could play an important role towards sustainable crop production while minimising environmental impact. Intensive Beta germplasm screening has been fruitful, and genetic lines resistant to nematodes, aphids and root maggot have been identified and integrated into sugar beet breeding programmes. A small number of genes responding to pest attack have been cloned from sugar beet and wild Beta species. This trend will continue towards a detailed understanding of the molecular mechanism of insect–host plant interactions and host resistance. Molecular biotechnological techniques have shown promise in developing transgenic pest resistance varieties at an accelerated speed with high accuracy. The use of transgenic technology is discussed with regard to biodiversity and food safety.     

Intraspecific variation of Myzus persicae on sugar beet (Beta vulgaris)

Differences in inherited resistance among seven sugar-beet stocks had similar effects on Myzus persicae clones representing the range of variation in aphid response to resistant and susceptible sugar beet observed in fifty-eight clones collected between 1969 and 1971. Three sugar-beet stocks were consistently resistant. Statistically significant interactions between beet stocks and aphid clones did not indicate the existence of biotypes with specific abilities to overcome resistance. M. persicae clones differed in their vigour of colonizing sugar beet, irrespective of the differences between beet stocks. The readiness of adult aphids to settle determined the size of aphid population produced and included a component related to the response of the aphid clone to sugar beet as a host, and a component related to the resistance ranking of the beet stock. Breeding sugar beet with resistance to aphids will be simplified, as the results indicate that, at present, differences between aphid biotypes need not be considered a problem.     

Morpho-physiological responses of sugar beet (Beta vulgaris L.) genotypes to drought stress

The identification of morpho-physiological traits related to drought tolerance and high yield potential is a challenge when selecting sugar beet genotypes with greater tolerance to water stress. In this paper, root morphological parameters, antioxidant systems, leaf relative water content (RWC) and H⁺-ATPase activity as key morpho-physiological traits involved in drought tolerance/susceptibility of sugar beet were studied. Genotypes showing a different drought tolerance index (DTI) but a similar yield potential, under moderate (?0.6 Mpa) and severe (?1.2 MPa) water stress, were selected and their morpho-physiological traits were investigated. The results showed a wide genetic variation in morpho-physiological parameters which demonstrated the different adaptive strategies under moderate and severe drought conditions in sugar beet. In particular, an efficient antioxidant system and redox signalling made some sugar beet genotypes more tolerant to drought stress. The alternative strategy of other genotypes was the reduction of root tissue density, which produced a less dense root system improving the axial hydraulic conductivity. These results could be considered as interesting challenge for a better understanding of the drought tolerance mechanisms in sugar beet.     

Growth and nutrition of three Salix clones in low conductivity solutions

The effect of replacing 50% or 95% of the potassium by sodium on growth and on potassium and sodium levels in three genotypes of sugar beet (MONOHILL; ADA; FIA) has been studied in water culture over a period from 2 to 9 weeks.
In all three genotypes there was a preferential uptake of potassium compared to sodium. Nevertheless, at high sodium supply most of the potassium was replaced by sodium, particularly in the leaves. At the same supply the accumulation of sodium in the leaves increased in the following order: ADA < MONOHILL < FIA. Even with high dominance of sodium in the medium, the youngest leaves of FIA held about 0.5 mmol potassium per g dry matter, and potassium was evidently translocated from old leaves to the new growth.
Effects of sodium on growth became more important with time. After 9 weeks, 50% replacement of potassium by sodium increased growth of all plant organs of the three genotypes. Replacing 95% of potassium by sodium depressed growth of the storage root in MONOHILL and particularly in ADA, with simultaneous enhancement of leaf growth in the latter. In FIA, however, this treatment further stimulated both leaf and, particularly, storage root growth. Sodium in comparison with potassium increased the sucrose concentration in leaves and storage roots. The highest sucrose concentration in the storage roots of ADA and FIA was obtained in the treatment with 95% sodium.
The results demonstrate pronounced genotypic differences in sugar beet with respect to the response to sodium. FIA has the most natrophilic behaviour and might be a promising genotype for breeding programmes for adaptation of sugar beet plants to soils high in sodium.     

Widespread distribution of Beet necrotic yellow vein virus in Iranian sugar beet industry

Beet necrotic yellow vein virus (BNYVV) is the most devastating pathogen of sugar beet worldwide. This virus has been reported in the majority of sugar beet growing regions of Iran as well. For the present study, we collected samples from different sugar beet varieties with suspected symptoms of BNYVV from the main important sugar beet growing regions in eight provinces of Iran. Infection of collected samples to BNYVV was tested by ELISA and RT-PCR. Upon testing of 167 collected samples of BNYVV suspected through ELISA and RT-PCR, 115 (68.9%) were infected. Different incidences of BNYVV through surveyed provinces may represent the presence of diverse infective viral sources or resistance genes in tested sugar beet varieties which need further attempts to develop control strategies. Results also showed that BNYVV has been recently distributed throughout some surveyed regions. Otherwise, trace infection or resistance to BNYVV infection in some varieties of distinct regions may represent proper sources of resistance to BNYVV.     

Variation in a natural population of Schizophyllum commune. Variation within the extreme isolates for growth rate.

Two extreme dikaryotic idolates chosen from a large sample of a localised population of Schizophyllum commune exhibited a considerable amount of genetical variation for growth rate at the near ambient temperature of 20 degrees C and at the higher temperature of 30 degrees C. The potential variation within these extreme isolates were greater than the variation observed in the whole sample. Regression analysis of the variation in growth rate of the dikaryotic progeny of the extreme isolates on that of their component monokaryons showed that the nature of gene action was not the same in these two stages of the life cycle. The simple additive-dominance model of gene action was adequate to explain the variation in growth rate in both of the extreme isolates at both of the temperatures. The small deviations from this model could be accounted for by unequal gene frequencies due to small sample size although a low incidence of non-allelic interactions could not be rule out. Directional dominance for growth rate was detected in both isolates at the more normal temperature and it was opposing in direction in the two isolates. In the slow growing isolate the dominance was for faster growth and in the fast growing isolate it was for slower growth. This is expected for a character which displays overall ambi-directional dominance if isolates with more extreme growth rates than those recovered in the population sample are eliminated by stabilising selection. The dominance is temperature dependent being ambi-directional in both isolates at the higher temperature. Environmental heterogeneity, the buffering effects of directional dominance and genotype-environment interactions and opposing selective forces operating on the monokaryotic and dikaryotic stages of the life cycle are possible contributory factors to the considerable free and potential variability displayed in this small, localised population.     

利用SPSS与AFLP方法对双丰甜菜品种（系）间亲缘关系与系谱分析比较

作物育种必须调查植物学性状和生物学特征指标数据,来建立种质资源库,利用SPSS多元分析方法克服了传统植物学性状和生物学特征指标难以综合评价的缺陷,探讨利用SPSS统计分析软件对双丰系列甜菜品种（系）间亲缘关系与系谱进行准确性分析,除双丰2号品种块根产量、产糖量和株高三个主成分具有极值影响外,结果基本与亲本分析一致,可以作为亲缘关系与系谱分析的一种辅助工具;通过AFLP获得不同基因型品种的特征带和特征缺失带,表明AFLP技术在甜菜品种鉴定上的应用潜力。但AFLP也具有缺点,主要是标记是共显性的,不能完全区分某一位点是杂合体和纯合体,因而不能更好地估算种群遗传的变异,对种群遗传结构的分析不能提供更多的统计信息,相信随着AFLP分子标记技术的不断完善与发展,将与SPSS统计分析软件一起越来越广泛地利用在种群遗传和系谱分析中。     

Phenotypic plasticity for life-history traits in Drosophila melanogaster. III. Effect of the environment on genetic parameters.

We estimated genetic and environmental variance components for developmental time and dry weight at eclosion in Drosophila melanogaster raised in ten different environments (all combinations of 22, 25 and 28 degrees C and 0.5, 1 and 4% yeast concentration, and 0.25% yeast at 25 degrees C). We used six homozygous lines derived from a natural population for complete diallel crosses in each environment. Additive genetic variances were consistently low for both traits (h2 around 10%). The additive genetic variance of developmental time was larger at lower yeast concentrations, but the heritability did not increase because other components were also larger. The additive genetic effects of the six parental lines changed ranks across environments, suggesting a mechanism for the maintenance of genetic variation in heterogenous environments. The variance due to non-directional dominance was small in most environments. However, there was directional dominance in the form of inbreeding depression for both traits. It was pronounced at high yeast levels and temperatures but disappeared when yeast or temperature were decreased. This meant that the heterozygous flies were more sensitive to environmental differences than homozygous flies. Because dominance effects are not heritable, this suggests that the evolution of plasticity can be constrained when dominance effects are important as a mechanism for plasticity.     

The identification of allergen proteins in sugar beet (Beta vulgaris) pollen causing occupational allergy in greenhouses

Background

During production of sugar beet (Beta vulgaris) seeds in greenhouses, workers frequently develop allergic symptoms. The aim of this study was to identify and characterize possible allergens in sugar beet pollen.

Methods

Sera from individuals at a local sugar beet seed producing company, having positive SPT and specific IgE to sugar beet pollen extract, were used for immunoblotting. Proteins in sugar beet pollen extracts were separated by 1- and 2-dimensional electrophoresis, and IgE-reactive proteins analyzed by liquid chromatography tandem mass spectrometry.

Results

A 14 kDa protein was identified as an allergen, since IgE-binding was inhibited by the well-characterized allergen Che a 2, profilin, from the related species Chenopodium album. The presence of 17 kDa and 14 kDa protein homologues to both the allergens Che a 1 and Che a 2 were detected in an extract from sugar beet pollen, and partial amino acid sequences were determined, using inclusion lists for tandem mass spectrometry based on homologous sequences.

Conclusion

Two occupational allergens were identified in sugar beet pollen showing sequence similarity with Chenopodium allergens. Sequence data were obtained by mass spectrometry (70 and 25%, respectively for Beta v 1 and Beta v 2), and can be used for cloning and recombinant expression of the allergens. As for treatment of Chenopodium pollinosis, immunotherapy with sugar beet pollen extracts may be feasible.     

Field performance of chitinase transgenic silver birches (<Emphasis Type="Italic">Betula pendula</Emphasis>): resistance to fungal diseases

A field trial of 15 transgenic birch lines expressing a sugar beet chitinase IV gene and the corresponding controls was established in southern Finland to study the effects of the level of sugar beet chitinase IV expression on birch resistance to fungal diseases. The symptoms caused by natural infections of two fungal pathogens, Pyrenopeziza betulicola (leaf spot disease) and Melampsoridium betulinum (birch rust), were analysed in the field during a period of 3 years. The lines that had shown a high level of sugar beet chitinase IV mRNA accumulation in the greenhouse also showed high sugar beet chitinase IV expression after 3 years in the field. The level of sugar beet chitinase IV expression did not significantly improve the resistance of transgenic birches to leaf spot disease. Instead, some transgenic lines were significantly more susceptible to leaf spot than the controls. The level of sugar beet chitinase IV expression did have an improving effect on most parameters of birch rust; the groups of lines showing high or intermediate transgene expression were more resistant to birch rust than those showing low expression. This result indicates that the tested transformation may provide a tool for increasing the resistance of silver birch to birch rust.     

Cross prediction studies on spring barley

Summary The genetical and environmental control of three height characters, two maturity characters and neck length in five barley pair crosses was studied using both F₂ triple test cross and model fitting analysis.Significant additive and dominance effects were found for all six characters with some evidence of epistasis for each character. Generally, dominance was incomplete for the height characters but was significantly directional for increased height in those crosses where dwarfing genes were segregating. Variable dominance effects were found for both the maturity characters. Complete dominance was found in three cases, otherwise incomplete dominance was found. Significant directional dominance for earliness was found for both maturity characters in one cross but this was attributed to the presence of a daylength insensitivity factor in one of the parents. Most of the genetic variation for neck length was additive, though some evidence of dominance was found.Broad sense and narrow sense heritability estimates generally were found to be high for the height and maturity characters but low for neck length. It was concluded that early generation selection for height at ear emergence, for final height and for awn emergence was worthwhile. Early generation selection for neck length was not recommended from the results of this study.     

Effects of beet cryptic virus infection on sugar beet in field trials

The effects of beet cryptic virus (BCV) infection on sugar beet crops were investigated in field trials in 1990. Two sugar beet breeding stock lines were screened for infection by BCV. Seed lots containing different proportions of seed infected with BCV1 & 2 were obtained by crossing the stock lines and used in field trials at five different sites. Five characteristics of the infected plants were assessed. BCV infection appeared to have no significant effects on the sugar beet crop at four locations which suffered from drought stress but significant effects were found at one site where the crop was grown on grade 1 land with good moisture retention properties. Root yield and sugar yield were reduced by up to 17% and 20%, respectively, by BCV infection.