Effects of Plant Density on Root Yield and Leaf Area in Chicory (Cichorium intybus L.) J. Panahandeha, S. Abdollahi, H.D. Kazemnia and N. Mahna Department of Horticultural Sciences Faculty of Agriculture University of Tabriz 5166616471 Tabriz Iran Keywords: chicory, plant density, root yield, leaf area, cultivar Abstract Chicory (Cichorium intybus L.) belonging to the Asteraceae family has prominent medicinal properties and its root has been reported to be the most abundant source of inulin which has valuable applications in pharmaceutical and food industries. It also contains important compounds such as bitter sesquiterpene lactones, cumarins, flavonoids and vitamins. Due to its various uses as a vegetable and a medicinal plant and considering that it is not yet cultivated in Iran, we endeavored to investigate the effects of plant density on the root yield and characteristics as well as leaf area in two cultivars of chicory. The experiment was conducted in Khalat-Pushan Agricultural Research Station (KARS), University of Tabriz, Tabriz, Iran. Four intrarow spacing (5, 10, 15, and 20 cm) and two cultivars (‘Pagana’ and ‘Yellow Star’) were compared in a randomized complete block design with three replications. The results showed significant differences in leaf area per plant between cultivars and plant densities. The intra-row distance of 20 cm and ‘Pagana’ had the highest leaf area per plant. There were significant differences in root length and diameter with plant density but not between cultivars. Moreover, differences in root fresh weight per plant either between cultivars or plant density appeared to be significant. In conclusion, the cultivar ‘Pagana’ was identified as the highest in root fresh weight per plant and when cultivated at 15 and 20 cm spacings. INTRODUCTION Chicory (Cichorium intybus L.) is a plant species belonging to the Asteraceae family and not currently cultivated in Iran. This plant is an important medicinal plant and contains important compounds such as inulin, bitter sesquiterpene lactones, cumarins, flavonoids and vitamins. Chicory has anti-hepatotoxic, appetizer, high immune function, tonic and anti-inflammatory effects and is used for treating health problems like AIDS, cancer, diabetics, migraines and arthritis (Velayutham et al., 2006). The roots can also be forced in the dark and produce chicon that is a new vegetable crop. The production efficiency of a plant is determined by the genotype and the environment it is being grown. Among the environmental factors, planting density, which affects growth rate, efficiency of solar energy utilization and conversion, seems to determine the total biomass accumulation (Suleiman and Sasaki, 2001). The plant density of red chicory (Cichorium intybus L. var. foliosum Hegi) was studied at a field in Linares, south central Chile. Four and five plants/m2 were established, using a single or a double planting line/row. The distance between rows was 0.60 m. The treatments were 60,000, 80,000, 130,000 and 170,000 plants/ha. The average total fresh weight/plant, the marketable fresh weight/plant and head size were higher at the lower plant density. The total yield was higher at the 4 plants/m2 treatment and a double planting line/row and the lowest marketable yield was observed in the highest plant density treatment. The critical plant density was 0.2 m with a single row (Carrasco et al., 1998). a panahandeh@tabrizu.ac.ir Proc. XXVIIIth IHC – Plant Physiol. from Cell to Fruit Prod. Sys. Eds.: J.W. Palmer et al. Acta Hort. 932, ISHS 2012 427 Baert and Van Bockstaele (1993) reported that optimum chicory root yields were achieved in Belgium when seed was sown in April, at a depth of 0.5 to 1.0 cm and at a spacing of 9 cm within the row, to achieve a plant density of 150,000 plants ha-1. In this study we aimed to find the effect of plant density and cultivar on parameters like leaf area, leaf area index and root characters in two cultivars of witloof chicory, ‘Pagana’ and ‘Yellow Star’, in a field experiment. MATERIALS AND METHODS The experiment was conducted in Khalat-Pushan Agricultural Research Station (KARS), University of Tabriz, Tabriz, Iran. Four intra-row spacings (5, 10, 15, and 20 cm) (providing plant densities of 500,000, 250,000, 166,700, and 125,000 plants/ha, respectively) as well as two cultivars (‘Yellow Star’ and ‘Pagana’) were studied in a randomized complete block design with three replications following the steps below: a) Preparing 24 plots (2.5×3 m) and then sowing of seeds with inter-row spacing of 40 cm. b) Flow irrigating and hand weeding during plant growth. c) Thinning out and arrangement of intra-row spaces. d) Fertilization (100 kg/ha triple phosphate, 100 kg/ha K2SO4, 100 kg/ha urea). e) Harvesting. After harvesting the aerial parts (rosette leaves) of plants, the leaf area was measured using a leaf area meter (Model Li1300, LiCor, USA). The roots were weighed and root shoulder diameter as well as root length was measured. For the estimation of root yield, sampling was done from 1.5 m of row in each plot and then the roots were cleaned and weighed. Analysis of available data was done using SPSS software. RESULTS AND DISCUSSION The results obtained in this study indicated that plant density and cultivar both significantly affected leaf area per plant in witloof chicory. Maximum leaf area per plant (6206 cm2) was achieved at the lowest plant density (125,000 plants/ha) with the cultivar ‘Pagana’. Increasing plant density led to a decrease in leaf area per plant (Table 1). The plant densities did not significantly affect leaf area index (LAI). However, this parameter increased with increase of plant density, so that the density of 500,000 plants/ha showed the highest LAI. LAI obtained from two different cultivars were statistically different and the cultivar ‘Pagana’ had maximum LAI (Table 1). Plant density and cultivar significantly affected root fresh weight per plant (RFW/P) which increased with decrease of plant density. Maximum RFW/P was obtained with ‘Pagana’ (Table 2). Significant difference in root length (RL) and diameter (RD) were observed in different plant densities but not between the two cultivars. Maximum RL and RD was obtained at the two lower plant densities (166,700 and 125,000 plants/ha) with 26.5, 27.0 cm for RL and 37.1, 50.0 mm for RD, respectively (Table 2). There were no significant differences in RFW/P, RL and RD between these two plant densities. Wilson et al. (2004) reported that chicory cultivar influenced plant stand, leaf area development, bolting, root yield, total sugar content, and the distribution of carbohydrates in roots. Root yields were greater for ‘Cassel’ and ‘Rubis’ compared with ‘Bergues’ and ‘Orchies’. ‘Orchies’ had the greatest total sugar content (189 mg g-1 fresh weight) and a greater percentage of fructans in the DP (degree of polymerization) 11 to 20 and DP > 20 categories than the other cultivars. Results from this experiment indicated that chicory cultivar influenced root yield, total sugar, and carbohydrate distribution. The chicory cultivars, ‘Cassel’, ‘Madona’ (Chicoline, Warcoing, Belgium) and ‘Orchies’ produced a greater root yield than ‘Rubis’ or ‘Katrien’ (Chicoline) when averaged across harvest dates. In a study on valerian, plant density significantly increased the grain yield, essential oil yield, essential oil percentage, root yield, flowering stem number, root diameter and root length (Morteza et al., 2009). However, the longest root length was recorded at 12 plants/m2 (4, 8, 12 plants/m2 studied in a field experiment) while other 428 plant features were reduced at 12 plants/m2. The highest grain yield, essential oil yield and root yield were achieved at 8 plants/m2 and the highest essential oil percentage, flowering stem number and root diameter were achieved at 4 plants/m2. Also the highest root yield was achieved by an optimal plant density of 8 plants/m2. Leilah et al. (2005) studied the effect of plant populations (57,120, 71,400, 114,240, and 142,800 plants ha-1) on sugar beet productivity in Egypt. A plant population of 57,120 plants ha-1 produced the highest root diameter, root fresh weight, foliage fresh weight, root/top ratio, total soluble solids percent and sucrose percent. The highest root and sugar yields ha-1 were obtained with sowing sugar beet on both sides of ridges, 70 cm width and 25 cm between plants (114,240 plants ha-1), while planting 142,800 plants ha-1, i.e. sowing sugar beet on both sides of ridges, 70 cm width and 20 cm between plants recorded the maximum root length and top yield. The increase in root yield with sowing sugar beet on both sides of ridges, 25 cm apart (114,240 plants ha-1) might be due to the high leaf light interception, which contributes positively to higher photosynthesis with the relative increase in number of roots ha-1. In this current study, there were no significant differences between the four plant densities in terms of total root yield, and the lowest plant density showed the lowest root yield. Figueria and Magalhaes (1999) reported that 0.5×0.25 m spacing in chicory had double the root crop production as compared with the 0.5×0.5 m spacing. Of the two cultivars, the cultivar ‘Pagana’ showed the higher root yield (Table 2). Root size in 20 cm intra-row distance was too large to be used for forcing, because large roots produce multiple heads per root which are unmarketable. Also 10 cm distance could be adopted for chicon production (because produce higher yield of marketable chicons). Although ‘Pagana’ is higher yielding than ‘Yellow Star’, (in root and also in chicon production), chicons from ‘Yellow Star’ were more marketable than the other cultivar because this cultivar produced compact and tight heads (data not presented). CONCLUSIONS In conclusion, the cultivar ‘Pagana’ was better in terms of root fresh weight per plant and was highest when cultivated in 15 and 20 cm intra row distances. An increase of plant density led to a decrease of leaf area per plant, root fresh weight per plant, root length and root diameter. LAI obtained from two different cultivars were statistically different and cultivar ‘Pagana’ had maximum LAI. Also 10 cm distance should be adopted for chicon production, because this produced the highest yield of marketable chicons. Roots from ‘Yellow Star’ produced tight and marketable chicons compared with ‘Pagana’. Literature Cited Bais, H.P. and Ravishankar, G.A. 2001. Cichorium intybus cultivation, processing, utility, value addition and biotechnology, with an emphasis on current status and future prospects. J. Sci. Food Agric. 81:467-484. Carrasco, G., Carmona, C., Sandoval, C. and Urrestarazu, M. 1998. Plant density on yield of red chicory heads – Radicchio Rosso – (Cichorium intybus L. var. foliosum Hegi) grown in south-central Chile. Acta Hort. 467:269-275. Figueria, G.M. and Magalhaes, P.M. 1999. The effect of plant density and fertilization on the production of Cichorium intybus L. roots and inulin content. Acta Hort. 502:129131. Leilah, A.A., Badawi, M.A., Said, E.M., Ghonema, M.H. and Abdou, M.A.E. 2005. Effects of planting dates, plant population and nitrogen fertilization on sugar beet productivity under the newly reclaimed sandy soils in Egypt. Sci. J. King Faisal Univ. 6(1):95-110. Monti, A., Amaducci, M.T., Pritoni, G. and Venture, G. 2005. Growth, fructan yield, and quality of chicory (Cichorium intybus L) as related to photosynthetic capacity, harvest time, and water regime. J. Exp. Bot. 56(415):1389-1395. Morteza, E., Akbari, G.A., ModaresSanavi, S.A.M. and AliabadiFarahani, H. 2009. 429 Effects of sowing date and planting density on quantity and quality features in valerian (Valeriana officinalis L.). J. Ecol. Natl. Environ. 1(9):201-205. Suleiman, H. and Sasaki, O. 2001.Studies on effect of planting density on the growth and yield of sweet potato (Ipomoea batatas Lam.). Mem. Fac. Agr. Kagoshima Univ. 37: 1-10. Velayutham, P., Ranjithakumari, B.D. and Baskaran, P. 2006. An efficient in vitro plant regeneration system for Cichorium intybus L. an important medicinal plant. J. Agric. Technol. 2(2):287-298. Wilson, R.G., Smith, J.A. and Yonts, C.D. 2004 Chicory root yield and carbohydrate composition is influenced by cultivar selection, planting, and harvest date. Crop Sci. 44:748-752. Tables Table 1. Effect of plant density and cultivar on leaf area per plant (LA/P) and leaf area index (LAI) of chicory grown in Tabriz, Iran. Plant density (plants/ha) Cultivar Treatments 500,000 250,000 166,700 125,000 LA/P (cm2) 1853c* 3428b 4221b 6206a LAI 9.26a 8.57a 7.03a 7.75a Yellow Star Pagana 3513b 4539a 6.62b 8.90a *Different letters show significant difference at 5% level. Table 2. Effect of plant density and cultivar on root fresh weight per plant (RFW/P), root length (RL), root diameter (RD) and root yield (RY) of chicory grown in Tabriz, Iran. Plant density (plants/ha) Cultivar Treatments 500,000 250,000 166,700 125,000 RFW/P (g) 86c* 161b 283a 305a RL (cm) 21.5b 22.7b 26.5a 27.0a RD (mm) 28.6c 39.3b 37.1a 50.0a RY (kg/m2) 4.32a 4.02a 4.70a 3.81a Yellow Star Pagana 192b 225a 25.1a 23.8a 41.0a 41.6a 3.80b 4.62a *Different letters show significant difference at 5% level. 430