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Quality has always been the main focus for Belgian endive producers in Flanders to hold its comparative advantage with respect to the mass production in our neighbouring countries. To maintain its position in witloof chicory production, investments in quality improvement are inevitable, judging by the constant decrease of both, the acreage for chicory root production and the trade balance for Belgian endives, which dropped from 11.7 million EUR in 2000 to 2.7 million EUR in 2008. So, the main focus in the doctoral research project was exploring the possibilities for quality improvement in chicory production by focusing on the maturation process at the end of the field phase. In this respect, on line measurements of changes in soil matric potentials in the root zone are related to plant development, maturation and quality of the chicory heads produced. Given that most problems encountered in the forcing period are the consequence of inferior root quality at the start of the forcing period, research emphasis was on correlating postharvest characteristics of chicons with the root quality at harvest, and to use this information to define the most optimal moment for root harvesting. The logic behind this is that the quality and related postharvest characteristics of chicons are mainly determined by the quality of the root at the start of the forcing period and the forcing and storage conditions. More specifically the physiological behavior of the roots during forcing, which ultimately determines the overall quality of the produced chicons, is intrinsically connected with its previous history in the field. The chicory supply chain commences with growing plants from seeds in the field. During the vegetative development, from spring till autumn, tuberized roots are formed and the foundation of high quality chicons is laid. Through field management growers attempt to provide roots with a superior quality containing the optimal amounts of carbohydrates, nitrogen compounds and mineral nutrients. For the growth process and physiological homeostasis, water uptake and hence soil water availability in the root zone are of crucial importance. In this respect changes in soil matric potential at two depths (30 and 60 cm below surface) measured near the tap root were related to the chicory plant development of Cichorium intybus L. throughout the growing season. The soil parameter Δp (diel difference in soil matric potential) was found to be a good estimator of root activity, evolving throughout the growing season in accordance to crop developmental stages. Given that this methodology allows separation of the different stages during plant development non-destructively, makes it an ideal tool for decision making in field and harvest management. Since yield and quality of chicory heads highly depends on the physiological status of the roots at harvest, determination of the optimal root harvesting time is critical. Based on chemical and physical measurements the physiological events occurring in the chicory plants during the second phase of the growing season were monitored. A new concept of potential gradients in the root tissue, expressed in terms of root water, solute and pressure potentials was derived to determine the most optimal field harvest date of chicory. The influence of physiological maturity on the forcing results was investigated for the early hybrid Mont Blanc. The focus was explicitly on the characterization of chicon quality since the financial benefit for endive growers mainly depends on the quality as defined by the Belgian auction guidelines. Based on the produced chicory heads meeting the internal and external quality characteristics and preserved from red discoloration, a particular harvest range was defined, matching the right physiological state of the roots. In this period the dry weight of the leaves decreased, LAI was minimal and an adequate fructan reserve had built up, together with a sufficient but restricted amount of sucrose. In addition, the declining amplitude of the diel variation in soil matric potential at 60 cm was found a non-destructive method for prediction of the maturity stage. During postharvest storage and commercialization of chicory heads, several physiological disorders might develop. One kind of physiological defects occurring both at harvest and during storage is red discoloration in the chicory heads (reddening). The origin of this disorder is complex with different possible triggers throughout the whole production chain. Morpho-anatomical analyses revealed that red discoloration mainly manifests as scattered red spots, parallel stripes or a red film in the basal part of the outer leaves of the chicory head and different types of tissue (e.g. sub-epidermal and vascular tissue) in the etiolated leaf. In addition to the identification of the most optimal harvest moment, storage time of the roots and temperatures during forcing have all been examined with respect to the occurrence of red discoloration. Moreover, chemical analyses showed that the amount of amino acids that were remobilized from the roots during the forcing process and the abundance of free amino acids in the chicory heads correspond well with the appearance of red discoloration during post harvest storage of the chicory heads. Immediate cooling of the chicory heads at harvest and a solid cold chain are essentially to reduce the hazard of reddening.