Abstract

In order to evaluate the different irrigation and nitrogen levels on yield, morphological traits and water usage efficiency of Cichorium intybus L., an experiment was conducted in the Agricultural Research Station of Islamic Azad University, Birjand Branch, in 2009. The experimental design was split plots based on randomized complete block design in three replications. The main plots were three irrigation levels (irrigation after 60, 120 and 180 mm evaporation from pan class A), and the sub-plots were four nitrogen rates (0, 60, 120, and 180 kg N/ha). The results showed that irrigation after 180 mm evaporation from pan treatment in comparison with irrigation after 60 mm evaporation from pan treatment decreased number of leaves per plant, root diameter, the number of root branches, leaf, root, and biological dry yields by 51.1, 28.2, 46.3, 58.5, 57, and 58.3%, respectively, while root: leaf dry weight ratio and water use efficiency (WUE) for root production were 8.6 and 30.4% higher under severe water deficit stress than under moderate stress and no-stress treatments, respectively. Also, as nitrogen (N) rate was increased from 0 to 180 kg.ha^-1, the number of leaves per plant, root diameter and the number of root branches, leaf, root and total dry yields were increased by 77.1, 25, 50, 125.8, 69.1, and 118.9%, respectively, while root: leaf dry weight ratio was decreased by 25.7%. Also, increasing the applied nitrogen rate caused an improvement in leaf, root, and total dry matter WUE. Overall, the results showed that irrigation after 60 mm accumulative evaporation from evaporation pan and the application of 180 kg N.ha^-1 can be recommended for the cultivation of chicory in Birjand, Iran, because of its higher economical yield in spite of the resulting partial loss of WUE.

Key words: Cichorium intybus, water stress, nitrogen, yield, water use efficiency (WUE), morphology.