| Breeding goals |
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The sugar beet breeder must consider all the breeding goals that should be met in order to fulfil both the requirements of the grower and the industry. The most common and important characters are described in the following pages. In addition to these requirements, the breeder also has to take into account a number of different characters that are also important from a breeding point of view, such as seed multiplication characters, seed harvest, seed size and monogermity.
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| High sugar yield |
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 Sugar yield will be evaluated in repeated yield trials at several locations within the appropriate region. Sugar yield is influenced mainly by the root weight and the sugar content of the root. These two components are negatively correlated. Sugar content in the U.K. normally varies between 16 and 19% and root yield between 35 and 65 tonness/ha.
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| Extractability |
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The sugar must be easy to extract from the sugar beet. Extractability is mainly influenced by the sugar content and the juice quality. This character is measured through a brei sample taken from the roots at the time of analysis of the trial beets. Good juice quality is dependent on a low amino nitrogen content in the root. Both sugar content and juice quality are strongly variety related.
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| Clean beets |
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 Harvested roots should be clean, in other words with a low dirt tare. To achieve this, the breeder chooses beet with a good root shape. These are then used in the continued breeding programme. It is important that the root groove is as flat as possible or even non-existent. The root should also be smooth with as few adventitious roots as possible. The crown of the beet should be above the surface of the ground and the tops should be gathered neatly and closely to the central growth point.
The cleanliness of the beet (dirt tare) is found by weighing the harvested roots before and after washing.
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Field emergence |
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A quick, even emergence is important in creating the best potential for high yields. The speed and evenness of different varietal material is judged in special emergence trials. A high field emergence is one of the fundamental conditions for continued breeding. In general, diploid varieties are somewhat better than triploids for these characters.
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| Stability |
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 The yield of a sugar beet hybrid should be even and stable under a wide range of growing conditions. Ideally, a good variety should have a low genotype - environment reaction, and should be able to cope with stress conditions, such as too much or too little water, as well as both a cold and warm climate. This character can be studied by comparing all of the Hilleshög trials placed in different countries.
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| Early row covering |
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Varieties should develop strong foliage at an early stage to cover the rows. The beet can then compete more quickly with weeds, which can reduce the need for chemical and mechanical weed control. Generally in the breeding material there is a genetic difference between diploid and triploid varieties for this character. Diploid varieties grow with their tops somewhat more turned upwards (erectoid habit), while triploids grow with a little more horizontal spread (prostrate habit). However, what can be an advantage early in the season might be a disadvantage later at the time of lifting. Diploid varieties tend to have a neater crown, which facilitates clean topping at harvest.
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| Bolting |
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That beet can bolt is fundamental for breeding and seed multiplication. The sugar beet plant is biennial and therefore normally bolts during the second year after a longer cold period. In general, the bolting mechanism is triggered when the average day and night temperature is 4-12 degrees Celsius. The length of the cold period (vernalisation) required to trigger bolting is dependent on the genetics of a variety. Some breeding material is only suitable for southern Europe, while other varieties will not bolt even when drilled very early in Scandinavia. Bolting resistance is tested in special trials, drilled very early in spring. Sensitive material, which could be triggered by even a cold spring, can thus be discarded or used only on markets where this risk is not present.
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| Ramularia leaf spot |
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Resistance against Ramularia is available in a range of sugar beet material. Resistant varieties are selected through field trials undertaken in Sweden, where breeding lines and hybrids are inoculated with a water solution containing Ramularia spores.
Read more about the Ramularia leaf spot disease.
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| Powdery Mildew |
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 Resistance against powdery mildew is tested in glasshouse trials. Selection of material is made by placing sugar beet plants infected by powdery mildew in the glasshouse, where they in turn infect the sugar beet hybrids and lines grown there. Sensitive material can be detected and as necessary rejected. Resistance genes to Powdery Mildew are naturally present in some sugar beet material.
Read more about the leaf disease Powdery Mildew.
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| Cercospora leaf spot |
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Resistance genes to the leaf spot disease Cercospora have been transferred from sea beet plants (Beta vulgaris ssp. Maritima) originating in Italy to commercial germplasm. . More than 80 years of repeated crossings, alternated with selection, have contributed to the current high levels of resistance of our varieties. This is vital for southern and central European varieties in order for them to cope with the high infection pressure there.
New varieties are tested in special field trials in Germany, the Czech Republic and Italy, where the breeding material can be infected naturally or inoculated artificially.
Read more about the leaf spot disease Cercospora.
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| Aphanomyces |
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Resistance against Aphanomyces is present both in a range of sugar beet material and in species related to sugar beet. The selection of resistant material can be made in the glasshouse or in the field. The disease can appear at different stages of the development of sugar beet. Therefore resistance is aimed at both damping-off at the seedling stage and later attacks, which may cause root rot.
Read more about Aphanomyces.
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| Rhizoctonia |
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Rhizoctonia resistance originates above all from sea beet (Beta vulgaris ssp. Maritima), from which it has been transferred to sugar beet through breeding programmes in the USA where the disease is commonly present. In Europe the problem is increasing and breeding material is selected both in the field and in the glasshouse through natural or artificial inoculation of the fungus.
Read more about Rhizoctonia.
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| Rhizomania |
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Resistance to Rhizomania is a vital character in major parts of Europe where the disease is present and development of resistant varieties is one of our highest priorities. Resistance has been found in sugar beet germplasm as well as in wild beet species and crossed into sugar beet lines via extensive breeding programmes. The presence of resistance genes in new varieties can be detected in part by laboratory tests at a molecular level, but also by means of glasshouse or field trials.
Read more about Rhizomania
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| Nematodes |
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Severe nematode attacks are often caused by a problem with the crop rotation. In a tight crop rotation, which contains both sugar beet and oilseed rape, nematode populations can build up.
Nematode resistant material is generally selected in glasshouse trials. Young plants are infected by beet cyst nematode larvae from Heterodera schachtii. After a certain time the beets can be scored by counting the number of cysts on the roots of the plants. Sugar beet has no natural resistance, but it is present in the wild beets, Beta procumbens and Beta vulgaris ssp. Maritima.
Read more about Nematodes.
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