Institute of Sugar Beet Research

Göttingen, Germany

Institute of Sugar Beet Research

Göttingen, Germany
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Hoffmann C.M.,Institute of Sugar Beet Research
Journal of Agronomy and Crop Science | Year: 2010

Drought stress may affect sucrose accumulation of sugar beet by restricting leaf development and storage root growth. The objective of this study was to identify changes occurring in the storage root of Beta beets in growth characteristics and ions and compatible solutes accumulation under drought with regard to sucrose accumulation. Two pot experiments were conducted: (1) sugar beet well supplied with water (100 % water capacity), under continuous moderate (50 %) and severe drought stress (30 %), (2) sugar beet and fodder beet well supplied with water (100 %) and under continuous severe drought stress (30 %). Under drought stress, the ratio of storage root to leaf dry matter of sugar beet decreased indicating a different partitioning of the assimilates. The sucrose concentration of the storage root was reduced. In the root, the number of cambium rings was only slightly affected, although drought stress was implemented already 6 weeks after sowing. In contrast, the distance between adjacent rings and the cell size was considerably restricted, which points to a reduced expansion of existing sink tissues. The daily rate of sucrose accumulation in the root showed a maximum between 16 and 20 weeks after sowing in well-watered plants, but it was considerably reduced under drought stress. The concentration of compatible solutes (K, Na, amino acids, glycine betaine, glucose and fructose) decreased during growth, while it was enhanced because of drought. However, when sucrose concentration was added, a constant sum of all examined solutes was found throughout the vegetation period. It was similar in sugar beet and in fodder beet despite different concentrations of single solutes, and the total sum was not affected by water supply. A close negative relationship between the concentration of compatible solutes and sucrose occurred. It is therefore concluded that the accumulation of compatible solutes in the storage root of Beta beets under drought might be a physiological constraint limiting sucrose accumulation. © 2010 Blackwell Verlag GmbH.

Bornemann K.,Institute of Sugar Beet Research | Varrelmann M.,Institute of Sugar Beet Research
Phytopathology | Year: 2011

The genome of most Beet necrotic yellow vein virus (BNYVV) isolates is comprised of four RNAs. The ability of certain isolates to overcome Rz1-mediated resistance in sugar beet grown in the United States and Europe is associated with point mutations in the pathogenicity factor P25. When the virus is inoculated mechanically into sugar beet roots at high density, the ability depends on an alanine to valine substitution at P25 position 67. Increased aggressiveness is shown by BNYVV P type isolates, which carry an additional RNA species that encodes a second pathogenicity factor, P26. Direct comparison of aggressive isolates transmitted by the vector, Polymyxa betae, has been impossible due to varying population densities of the vector and other soilborne pathogens that interfere with BNYVV infection. Mechanical root inoculation and subsequent cultivation in soil that carried a virus-free P. betae population was used to load P. betae with three BNYVV isolates: A European A type isolate, an American A type isolate, and a P type isolate. Resistance tests demonstrated that changes in viral aggressiveness towards Rz1 cultivars were independent of the vector population. This method can be applied to the study of the synergism of BNYVV with other P. betae-transmitted viruses. © 2011 The American Phytopathological Society.

Hoffmann C.M.,Institute of Sugar Beet Research | Kluge-Severin S.,Institute of Sugar Beet Research
European Journal of Agronomy | Year: 2011

Slow leaf formation in spring is regarded as the main factor limiting sugar beet yield. It is therefore expected that yield can be enhanced when plants develop leaves earlier resulting in an extended growing period. The aim of this study was to analyse leaf and storage root growth of sugar beet plants sown in autumn or very early in spring with regard to possible yield increases. In 2005/06 and 2006/07, field trials were conducted at 4 sites with 6 sowing dates: August, beginning and mid of September, and in February, March and April. Sequential harvests were conducted to follow yield formation.Field emergence of autumn sown sugar beets was fast and reached 90% whereas in early spring it was severely restricted due to low temperature. Leaf and root yield formation of autumn and spring sown sugar beets could well be described with thermal time confirming that sugar beet growth is temperature driven and day length insensitive. Despite longer growing periods autumn sown beets did not form more cambium rings in the storage root than spring sown beets. That might be partly due to the bolting process after winter. However, early spring sown beets as well did not achieve more cambium rings than plants sown in April pointing to a presumably limited ability to adapt cambium ring formation. Because of the shift to reproductive growth, autumn sown beets formed high amounts of shoot dry matter, but not much root dry matter. Furthermore, the root dry matter consisted of a lower sugar and a higher marc content and would therefore not be suitable for sugar recovery. Earlier sowing in spring did not result in a significant yield increase because the benefit from early sowing diminished throughout the season as also obvious from the distance between the cambium rings.For bolting resistant sugar beet varieties, which are expected to be available in near future, the presented data form a basis to predict yield with models. However, it has to be investigated to what extent sugar beet growth and yield formation benefits from early sowing and extended growing periods. © 2010 Elsevier B.V.

Loel J.,Institute of Sugar Beet Research | Hoffmann C.M.,Institute of Sugar Beet Research
Field Crops Research | Year: 2014

The cultivation of sugar beet as a winter crop harvested in autumn of the next year is expected to contribute to a marked yield increase. Sown in autumn the plants have to survive frost during the winter. The study thus aimed to characterize the optimal growth stage, in which maximum winter hardiness is reached, and to determine the lowest temperature sugar beet plants can survive in this optimal growth stage. Furthermore, the importance of weather conditions (temperature, snow) in relation to the growth stage of the plants was assessed with a PCA (principle component analysis).From 2009 to 2012 field trials with 5 genotypes at 3 locations in Germany were conducted, which were accompanied by greenhouse experiments with controlled frost experiments. The survival rate after winter was mainly affected by the environment (year. ×. location, 93%), while the genotype effect (1%) was rather low. An optimal growth stage for maximum survival was determined at a thermal time after sowing of 600-900. °Cd (base temperature 3. °C). The greenhouse experiments revealed that in this optimal growth stage the plants survived a minimum temperature of -7. °C (-6. °C to -8. °C). In the field trials, the impact of the growth stage reached before frost (46%) on the survival rate after winter was considerably higher than the actual weather conditions during winter (17%). In particular too much advanced growth (dry matter yield of root and leaves, root diameter) resulted in a high susceptibility for frost damage. Regarding the weather conditions, the number of frost days with snow and the minimum temperature during winter without snow had the highest importance for survival.The knowledge of the required thermal time to reach maximum winter hardiness can be used to optimize the sowing date of autumn sown beets in different environments. However, a conflict may occur between the aim to obtain optimal winter hardiness and to reach maximum yield in the next year. © 2014 Elsevier B.V.

BACKGROUND: Resistance of Chenopodium album to triazinones and triazines can be caused by two amino acid exchanges, serine-264-glycine (Ser264Gly) and alanine-251-valine (Ala251Val), in the chloroplast D1 protein. This paper describes the identification of a biotype with a leucine-218-valine (Leu218Val) switch found in German sugar beet fields with unsatisfactory weed control. A greenhouse experiment has been performed to compare the resistance profile of the newly identified biotype with biotypes that carry the Ser264Gly and Ala251Val mutations. RESULTS: Application rate-response curves obtained from the greenhouse experiment showed that the Leu218Val exchange induced significant resistance against the triazinones but not against terbuthylazine. The level of resistance against the triazinones was higher in the Ser264Gly and Ala251Val biotypes compared with the Leu218Val biotype. All biotypes tested were more resistant to metribuzin than to metamitron. Following terbuthylazine treatment, Ser264Gly displayed a high level of resistance, Ala251Val showed moderate resistance. A PCR-RFLP assay for Ser264Gly has been extended to include detection of Ala251Val and Leu218Val mutations. CONCLUSION: The D1 Leu218Val substitution in C. album confers significant resistance to triazinones. This suggests that Leu218Val is involved in the binding of triazinones. First establishment of the resistance profiles of the three psbA mutations suggests that these mutations have been independently selected. © 2013 Society of Chemical Industry.

Bornemann K.,Institute of Sugar Beet Research | Varrelmann M.,Institute of Sugar Beet Research
Molecular Plant Pathology | Year: 2013

Beet necrotic yellow vein virus (BNYVV), vectored by Polymyxa betae, causes rhizomania in sugar beet. For disease control, the cultivation of hybrids carrying Rz1 resistance is crucial, but is compromised by resistance-breaking (RB) strains with specific mutations in the P25 protein at amino acids 67-70 (tetrad). To obtain evidence for P25 variability from soil-borne populations, where the virus persists for decades, populations with wild-type (WT) and RB properties were analysed by P25 deep sequencing. The level of P25 variation in the populations analysed did not correlate with RB properties. Remarkably, one WT population contained P25 with RB mutations at a frequency of 11%. To demonstrate selection by Rz1 and the influence of RB mutations on relative fitness, competition experiments between strains were performed. Following a mixture of strains with four RNAs, a shift in tetrad variants was observed, suggesting that strains did not mix or transreplicate. The plant genotype exerted a clear influence on the frequency of RB tetrads. In Rz1 plants, the RB variants outcompeted the WT variants, and mostly vice versa in susceptible plants, demonstrating a relative fitness penalty of RB mutations. The strong genotype effect supports the hypothesized Rz1RB strain selection with four RNAs, suggesting that a certain tetrad needs to become dominant in a population to influence its properties. Tetrad selection was not observed when an RB strain, with an additional P26 protein encoded by a fifth RNA, competed with a WT strain, supporting its role as a second BNYVV pathogenicity factor and suggesting the reassortment of both types. © 2013 BSPP AND BLACKWELL PUBLISHING LTD.

Gajic A.,Institute of Sugar Beet Research | Koch H.-J.,Institute of Sugar Beet Research
Journal of Environmental Quality | Year: 2012

Hydrothermal carbonization allows rapid conversion of biomass into a carbon-rich, lignite-like product (hydrochar). It is assumed to have benefi cial eff ects on soil properties and plant growth, but detailed studies are lacking, especially in the fi eld. Th e objective of our study was to investigate the eff ect of hydrochar incorporated into arable soils on soil mineral nitrogen (Nmin) content and sugar beet growth. In 2010-2011, a fi eld and a pot trial were conducted. Hydrochars (fi eld: 10 Mg ha-1; pot: equivalent to 30 Mg ha-1) processed from sugar beet pulp (HSP) and beer draff (HBD) were tested against an untreated control. As a second factor, mineral nitrogen (N) fertilizer level (fi eld: 0, 50, 100, 150 kg N ha-1; pot: 0, 100, 200 mg N kg-1 soil) was varied. In both trials, hydrochars reduced initial sugar beet growth, especially when hydrochar with a high C/N ratio (38, HSP) was combined with a low N fertilizer level; high N supply partly compensated for the reduced seedling growth. Without N fertilization, no extractable Nmin was present at the end of the pot trial in the HSP treatment, whereas in HBD even more Nmin was extracted than in the control. Th is suggests remineralization of previously immobilized N when hydrochar with a low C/N ratio was applied (16, HBD). In the fi eld, beet yield was equal at the high N fertilizer level in HSP and at all N levels in HBD treatment. Our results suggest that hydrochar can decrease plant-available N due to N immobilization. Other potential causes for the observed early growth reduction need to be studied more in detail. © 2012 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

Hoffmann C.M.,Institute of Sugar Beet Research | Kluge-Severin S.,Institute of Sugar Beet Research
Field Crops Research | Year: 2010

The cultivation of autumn sown sugar beets is expected to result in large yield increases due to more light absorption. The objective of this study was thus to analyse growth of autumn sown sugar beets with regard to (a) leaf development and light absorption and, (b) radiation use efficiency, the conversion of the absorbed light into dry matter. In 2005/06 and 2006/07, field trials were conducted at 4 sites with 3 sowing dates in autumn and 3 sowing dates in spring. The results show that the formation of leaf dry matter of autumn sown beets followed thermal time. A leaf area index of 3.5, and thereby canopy closure, was reached 3-4 weeks earlier than in spring sown beets resulting in extra absorption of light, in particular in April and May. Autumn sown beets produced 1.2 g dry matter per MJ solar radiation absorbed and thus, did not differ from spring sown beets in the radiation use efficiency. From light absorption and radiation use efficiency the possible yield of autumn sown sugar beets was estimated, provided these beets would not bolt after winter. Autumn sown beets could capture 2338. MJ solar radiation between sowing and harvest during October in the following year. Taking into account the improved light absorption, a theoretical yield increase of 26% compared to spring sown beets was calculated. It is discussed that yield formation of autumn sown beets would most likely be limited by the sink capacity and changes in the composition of the storage root. The data of these experiments will form a good basis for modelling yield formation of autumn sown sugar beets. © 2010 Elsevier B.V.

Reinsdorf E.,Institute of Sugar Beet Research | Koch H.-J.,Institute of Sugar Beet Research
Agricultural and Forest Meteorology | Year: 2013

The cultivation of sugar beet as a winter crop in Central Europe will require tolerance of severe frost. Due to the large variation of survival rates in different environments it is necessary to quantify the risk of frost killing for potential growing regions. The objectives of our study were, (i) to determine the lethal temperature of sugar beet taproot crown tissue as an indicator of frost damage, (ii) the development of a regression model that properly estimates the temperature of crown tissue from standard weather data, and (iii) a risk assessment for frost killing in four beet cultivation regions, representing different climatic conditions in Central Europe. In field trials at six environments, temperatures were measured above the beet canopy (0.3-0.5. m height), at the soil surface, 5. cm deep in the soil, and in the taproot crown. Survival rates were determined after winter.The survival rates of sugar beets were highly dependant on the maximum taproot diameter (optimal size: 1-2.5. cm) and the environmental conditions. A crown tissue temperature below -6. °C was a reliable indicator for frost killing, even though the exact lethal temperature of optimal sized sugar beets could not be identified. The crown temperature was accurately predicted from available weather data using multiple linear regression models. It was estimated best by combining the parameters 'daily mean air temperature', 'daily mean soil temperature at 5. cm depth' (closest correlation to crown temperature) and 'daily snow depth'. The prediction was further improved by adding the air and soil temperatures of the previous day and the 2-fold interactions of regressors to the model.Risk assessment for frost killing in Central European beet growing areas was based on weather data of the past 20 years provided by Germany's National Meteorological Service (Deutscher Wetterdienst, DWD). Our approach showed that at locations with mild winters, such as Cologne, the successful cultivation of winter sugar beet is possible with little risk of frost killing. On the contrary, growing winter sugar beet at places like Göttingen and Regensburg holds a high risk for frost killing. Finally, the presented approach needs to be improved with more accurate estimates of crown tissue temperature, and more precise determination of the lethal temperature of winter beets with the optimal taproot diameter. © 2013 Elsevier B.V.

Kluth C.,Institute of Sugar Beet Research | Varrelmann M.,Institute of Sugar Beet Research
Crop Protection | Year: 2010

Root and crown rot is the major soil-borne fungal disease in sugar beet. In Europe, the disease is mainly caused by the anastomosis group (AG) 2-2IIIB of the basidiomycete Rhizoctonia solani (Kühn). No chemical fungicide to control the disease has been registered in Europe. Therefore, agronomic measures must be optimized to keep the disease severity below an economic damage threshold and to minimize white sugar yield losses. R. solani AG 2-2IIIB infects many other crops besides sugar beet, including maize, where it causes root rot. Sugar beet and maize are frequently grown in the same crop rotation. The proportion of cultivated maize in several European sugar beet growing areas is expected to rise due to a projected increase in demand for renewable resources over the next few years. Although the susceptibility to and tolerance of the disease varies among cultivars in both crops, little is known about the effects of cultivar susceptibility in the pre-crop on a subsequent susceptible crop. The cultivation of R. solani-resistant maize genotypes in rotation with resistant sugar beet might therefore be a useful tool in an integrated control strategy against R. solani, eliminating the need to restrict the desired crop rotation for phytosanitary reasons. A crop rotation experiment with artificially inoculated R. solani was conducted in the field to investigate the pre-crop effects of maize cultivars which differed in their susceptibility to R. solani on a susceptible sugar beet cultivar. We hypothesized that the maize genotype would influence the inoculum potential and performance of a susceptible sugar beet genotype grown after a maize pre-crop, and that this would correlate with the susceptibility of the maize genotype. The results demonstrate that the susceptibility of maize genotypes is consistent over a period of years and that cultivated maize genotypes influenced the inoculum potential measured as disease severity in sugar beet. However, disease severity in sugar beet did not correlate with the disease susceptibility of the genotype of the maize pre-crop. Possible reasons for this missing relationship might be differences in the quality of maize residues for the saprophytic survival of the pathogen or a genotype-specific alteration of the antagonistic microbial community. However, our findings showed that in the presence of maize- and sugar beet-pathogenic R. solani, the most favourable maize cultivar for a crop rotation cannot be determined solely on the basis of its resistance level against Rhizoctonia root rot. © 2009.

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