Experimental and simulated production of inulin by chicory and Jerusalem artichoke

Abstract

Chicory and Jerusalem artichoke are candidate crops for inulin production. Their yield level and yearly stability of inulin yields are important criteria when deciding between them. A concise crop simulation model was used to estimate the yield potential of the two species and to quantify the effects on yields of some variations in characteristics found in the available cultivars and of some hypothetical improvements in the critical crop characteristics. In chicory the model attains at similar root yields as found in experiments. In Jerusalem artichoke the model properly describes the seasonal pattern of tuber growth, but the simulated yields show larger deviations from experimental results. Simulations of the root and tuber yields under the weather conditions of a rage of years indicate that the attainable yields in chicory are much higher than in Jerusalem artichoke. According to the simulations Jerusalem artichoke tuber yields are strongly affected by the temperature-related senescence of the leaves and by the ratio between structural stem dry matter and inulin stored temporarily in the stem. Chicory root yields are strongly related to early leaf expansion and to the shoot-root ratio. It is suggested that chicory breeders should concentrate on improving the assimilate supply to the first leaves in order to reduce the early lag phase in leaf area growth, rather than increasing the growth rate during the temperature related exponential phase of leaf expansion.