Influence of external factors on growth and development of sugar-beet (Beta vulgaris L.)

Several trials on the quantitative influence of photophase, chilling (vernalization) and high temperature (devernalization) on bolting of sugar-beet were analysed on the basis of a simple physiological model, in which bolting is considered as the final event of dynamic, momentary and quantitative processes in the plant. Trials in the field and in growth chambers examined factors in chilling and in light response. The inhibitory effect on bolting of high temperatures and the role of photophase in this process was investigated for several periods after vernalization.<p/>Growth and bolting seem to be correlated, as plants with just visible bolting were usually heavier.<p/>A possible relation between bolting resistance and vigour was investigated. Also the influence of photophase and cold treatment on growth was measured in a trial.<p/>Some ways are shown of using a climatic factor like temperature to predict bolting in the field. Finally some recommendations for sugar-beet breeders are drawn up.