HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Wilson, R. G. Articles by Yonts, C. D. Search for Related Content PubMed Articles by Wilson, R. G. Articles by Yonts, C. D. Agricola Articles by Wilson, R. G. Articles by Yonts, C. D. Related Collections Crop Growth and Development

CROP BREEDING, GENETICS & CYTOLOGY

Chicory Root Yield and Carbohydrate Composition is Influenced by Cultivar Selection, Planting, and Harvest Date

^a Dep. of Agronomy, Univ. of Nebraska, Panhandle Research and Extension Center, Scottsbluff, NE 69361
^b Dep. of Biological Systems Engineering, Univ. of Nebraska, Panhandle Research and Extension Center, Scottsbluff, NE 69361

^* Corresponding author (rwilson1{at}unl.edu).

	ABSTRACT

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
Chicory (Cichorium intybus L.) is not extensively grown in the USA for fructan production, and there is limited information available on the effect of cultural practices on root yield. Three field experiments were conducted from 1995 through 2002 to determine the influence of planting and harvest date and cultivar on yield and carbohydrate composition of chicory roots. Different chicory cultivars were planted from the first of April through mid-May and were monitored for plant stand, leaf area, and bolting during the growing season and for root yield in late summer, fall, and the following spring. Roots were characterized for carbohydrate composition with high performance anion exchange chromatography. Plant stands and root yields were similar when chicory was planted in early and mid-April, but root yields declined 35% when planting date was delayed until mid-May. Harvest date was closely associated with root yield and total sugar content. Root yields increased 84% from 1 September to 15 November. Total sugar content was 197 mg g^–1 fresh weight when roots were harvested in early November. The degree of fructan polymerization (DP) was also influenced by harvest date. The percentage of longer chain-length fructans increased until the first fall frost (–3°C). Forty-five days following the first frost, the percentage of longer chain-length fructans in the DP > 20 category declined from 23 to 13% of the total carbohydrate, and the percentage of shorter chain-length fructans in the DP 3 to 10 category increased from 36 to 45% of the total carbohydrate. Chicory stand, leaf area, bolting percentage, root yield, total sugar content, and degree of fructan polymerization were influenced by cultivar selection. Results from 7 yr of research indicated that chicory could be successfully grown in western Nebraska.

Abbreviations: DP, degree of polymerization

	INTRODUCTION

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
TYPES OF CHICORY have been selected for a number of specialty purposes. Chicory leaves have been used for human consumption in salads and for cattle feeding as forage. Some types of chicory have been developed for their root. Witloof chicory, which is also called Belgium endive, is a market class of chicory that is harvested in the fall, stored at freezing temperatures, and grown in the dark to produce chicons, and used in salads (Corey and Whitney, 1987). Chicory roots can also be harvested in the fall, dried, roasted, and used for drink flavoring or roots can be processed for saccharide production (Van den Ende et al., 2002). The chicory root contains up to 20% storage carbohydrates as fructans, which can be used as a functional food ingredient (Baert and Van Bockstaele, 1993). Fructans are polymers of fructose with a terminal glucose molecule (Van den Ende et al., 2002). The fructose moieties are bonded together by ß (2 1) linkages and are synthesized from sucrose. Additional fructose moieties can be added during the growing season to increase fructan chain length. The degree of polymerization (DP) refers to the number of fructose moieties in the fructan chain. Recently, several companies in the USA have become interested in purchasing a domestic source of fructans (inulin) for use in both human and pet foods.

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 150000 plants ha^–1 (Baert and Van Bockstaele, 1993). If the crop was sown in March, certain cultivars of chicory bolted and diverted carbohydrates away from root development. In Belgium, root yields were 30% greater when chicory was sown 14 April compared with sowing dates in early to mid-May (Baert, 1997).

Chicory roots were harvested in Belgium in the fall with optimum harvest date defined as the moment the maximum yield of extractable fructan per hectare was met (Baert and Van Bockstaele, 1993). From mid-September to mid-October, chicory root yield increased from 60 to 70 Mg ha^–1; from mid-October to mid-November, root yield increased an additional 3 Mg ha^–1 (Baert, 1997). As the harvest season progressed and soil temperatures declined, the carbohydrate content of chicory roots changed (Baert, 1997). The content of free fructose and sucrose increased and the content of free glucose and fructans decreased with harvest date. The occurrence of the first frost (0°C) in fall, and not daylength, was the critical factor in initiation of long chain-length fructan breakdown to short chain-length fructan in chicory roots (Van den Ende et al., 1996). A high root yield, high fructan content, high percentage of long-chain fructans, and low free-sugar content are preferred by the European chicory industry (Baert, 1997).

Because chicory has not been extensively grown in the USA for root production, there is limited information available on crop production. To better understand the influence of planting and harvesting date and cultivar on chicory production, we conducted the following field experiments to assess (i) the influence of planting and harvesting date, and cultivar on root yield, and (ii) the effect of these cultural practices on the levels of free sugars and fructans in chicory roots at various harvest dates in the fall.

	MATERIALS AND METHODS

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
A series of three field experiments were conducted near Scottsbluff, NE: the first in 1995 and 1996, the second in 1997 and 1998, and the third from 1999 through 2002. Experiment 1 was designed to determine optimum planting and harvesting dates and potential chicory cultivars adapted to Nebraska. The experimental design was a split-split plot. The main plots consisted of four planting dates, the subplot of four chicory cultivars, and the sub-subplot of three harvest dates (Table 1). Each treatment in the experiment was replicated six times, sub-subplots were two rows spaced 56 cm apart by 15.2 m long, and the study was conducted in 1995 and again in 1996. Experiment 2 examined additional chicory cultivars harvested during a longer time period. The experimental design was a split plot with the main plots consisting of five chicory cultivars and subplots of six harvest dates with treatments replicated six times (Table 2). Subplots were three rows spaced 56 cm apart by 15.2 m long, and the study was conducted in 1997 and again in 1998. Experiment 3 continued the study of chicory root development from the first of September through mid-November. The experimental design was a randomized complete block. Treatments were six harvest dates, replicated four times, and the experiment was repeated each year from 1999 through 2002. Individual plots were two rows spaced 56 cm apart by 15.2 m long. The experiments were located in different fields each year on a Glenberg silt loam (coarse-loamy, mixed, superactive, calcareous, mesic Ustic Torrifluvents), pH 7.8 to 8.0, and 0.8 to 1% organic matter. The crop the previous year was corn (Zea mays L.).

Chicory density in two rows of each plot for a distance of 15 m was recorded in early June. Leaf area index was estimated with a plant canopy analyzer (LI-COR, Inc., Lincoln, NE) in mid-July and early August (Wilson, 1999). Bolted chicory plants were recorded in each plot in late August. The number of plants bolted was divided by the number of plants in each plot to determine the percentage of bolted plants. Chicory leaves were removed with a mechanical topper and roots were harvested with a mechanical two-row harvester. A random subsample of 10 roots per plot was washed, weighed after drying at room temperature, and sectioned longitudinally into quarters with a knife. Each quarter from each of the roots was combined and run through a juicer (Omega Products, Inc., Harrisburg, PA). A portion of the juice was analyzed for soluble dry matter with a refractometer (Atago, Tokyo, Japan). The total sugar content of the sample was estimated from the refractometer reading by the procedure developed by Van Waes et al. (1998). A 0.3-g sample of juice was diluted with high performance liquid chromatography-grade water to a final volume of 100 mL. A 10-mL aliquot of the diluted sample was filtered with a 0.45-µM filter (Advantec MFS, Inc., Pleasanton, CA) and analyzed by high performance anion exchange chromatography-pulsed amperometric detector with a Dionex 500 system (Dionex Corp., Sunnyvale, CA) with the procedure described by Wilson et al. (2001). Glucose, fructose, sucrose, and fructans were reported as a percentage of total sugar content. Fructans were further grouped into three categories: DP 3 to 10 fructans (short chain-length fructans), DP 11 to 20 fructans (medium chain-length fructans), and DP > 20 fructans (long chain-length fructans).

Results were analyzed by ANOVA, followed by comparison of means by a Fisher's protected LSD at the 0.05 level of significance. In Exp. 1 and 2, there was a harvest date x year interaction for the variables root yield and total sugars, but the size of the interactions relative to the average treatment effects was small and the ranking of the treatments across years was similar. Therefore, the ranking of treatments across years was expected to be stable, and data were combined across years (Gomez and Gomez, 1984). Means from data collected in Exp. 1, 2, and 3 were combined and analyzed with a nonlinear correlation analysis to measure the degree of nonlinear association between chicory root yield and harvest date with the SAS procedure NLIN (SAS Institute, 1990).

	RESULTS AND DISCUSSION

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
The results from Exp. 1 showed that planting date influenced plant stand, leaf area, bolting, and root yield (Table 1). Plant stands declined as planting dates changed from mid-April to the first of May, to mid-May. Air temperatures in May were 5.5°C warmer than in April and even though rainfall was greater in May and fields were irrigated it was difficult to keep the soil moist at the 1-cm depth and chicory seedlings died. The reduction in plant stand and the shorter growing period that accompanied the later plantings was reflected in leaf area measurements taken in mid-July. Chicory planted in mid-April had a leaf area that was 133% greater than chicory planted the first of May. This trend was still evident the first of August when leaf area was recorded.

Chicory is considered a biannual and plants must be subjected to a cold period before flowering will occur (Baert, 1997). Where chicory is grown as a root crop, it is not desirable to have the plant bolt and divert energy into flowering. Planting date did have an influence on bolting, with the percentage of plants bolting greatest with the first of April planting and decreasing as planting was delayed to mid-April (Table 1). Although bolting did occur, the percentage of plants bolting was 1% or less.

Root yields were similar when the crop was planted on 1 or 15 April, but declined 35% when the crop was seeded in mid-May (Table 1). The reduction in root yield was influenced by the shorter growing season and by the decrease in plant stand. Planting date did not influence the total sugar content of roots. The fructose content of roots decreased from the 1 April planting compared with the 15 May planting.

Chicory cultivar influenced plant stand, leaf area development, bolting, root yield, total sugar content, and the distribution of carbohydrate in roots (Table 1). Crop stand in mid-June was greater in areas seeded with ‘Cassel’ (Florimond Desprez) and ‘Rubis’ compared with ‘Bergues’ and Orchies. The leaf area in mid-July and early August was greater for Rubis compared with the other cultivars. In early August, Orchies had the smallest leaf area. The incidence of bolting was greatest with Cassel. 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 11 to 20 and DP > 20 categories than the other cultivars.

Harvest date influenced root yield, total sugar content, and the distribution of carbohydrate in roots (Table 1). Root yields and total sugar content increased as harvest date was delayed. From mid-September to late October, root yield increased 25% and total sugar content increased 8%. Harvest date also influenced fructan distribution. In mid-September, the percentage of fructans present as DP 3 to 10 was lowest and the percentage present as DP > 20 was highest compared with the 1 and 21 October harvest dates. As the harvest season progressed into late October, the percentage of fructans present as DP 3 to 10 increased and the percentage present as DP > 20 decreased. At the same time, fructan polymerization changed the percentage of carbohydrate present as sucrose increased from 2.6% in mid-September to 6.6% in late October. The changes in fructans observed in this study are similar to those reported by Baert (1997) that occurred in Belgium during fall harvest.

Fructose polymers are synthesized from sucrose by the combined activity of sucrose: sucrose 1-fructosyl transferase (1-SST, EC 2.4.1.99) and fructan: fructan 1-fructosyl transferase (1-FFT, EC 2.4.1.100) (Van den Ende and Van Laere, 1996). The 1-SST enzyme catalyzes the production of a trisaccharide from sucrose, and 1-FFT performs chain elongation (Edelman and Jefford, 1968). Depolymerization in fructans are triggered by the occurrence of the first frost in the fall (Van den Ende et al., 1996). After the first frost, the activity of fructan 1-exolydrolase (1-FEH, EC 3.2.1.80) increases and leads to the breakdown of fructans in chicory roots.

The first frost (–3°C) in 1995 occurred on 21 September and in 1996 on 29 September. After the occurrence of the first frost we would anticipate depolymerization of fructans. Observations made on 1 and 21 October indicated that breakdown of mid- (DP 11 to 20) to high-DP (DP > 20) fructans had begun.

Results from Exp. 2 indicated that chicory cultivar influenced root yield, total sugar, and carbohydrate distribution (Table 2). The chicory varieties, Cassel, ‘Madona’ (Chicoline, Warcoing, Belgium), and Orchies produced a greater root yield than Rubis or ‘Katrien’ (Chicoline) when averaged across harvest dates. Total sugars were greatest for Katrien followed by Orchies. Katrien and Cassel had a greater percentage of fructans in the DP 11 to 20 category than Rubis or Orchies. Cassel also had more fructans in the DP > 20 category than Rubis or Orchies.

Harvest date influenced root yield, total sugar content, and distribution of carbohydrates in roots (Table 2). The greatest root yield was achieved from the 1 November harvest date. From 1 September to 1 November, root yield increased 29.8 Mg ha^–1. During this same time period, concentration of total sugars present in roots increased from 172 mg g^–1 fresh weight on 1 September to 197 mg h^–1 fresh weight on 1 November. Allowing chicory roots to overwinter in the field led to a 33% reduction in root weight and a 22% reduction in total sugar content. Most of the loss both years could be attributed to root deterioration caused by the fungus Sclerotina sclerotiorum (Lib.) de Bary (Baert and Van Bockstaele, 1993). The first frosts occurred on 9 October in 1997 and 17 October in 1998. Fructan measurements taken on 1 November reflect the effects of the October frost with decreased concentrations of fructans in the DP 11 to 20 and DP > 20 categories and the increase in DP 3 to 10 fructans and sucrose. The maximum amount of fructans in the DP > 20 category were achieved with a 1 October harvest (Table 2). The maximum amount of fructans in the DP 11 to 20 category were achieved with a 15 September harvest date, while the maximum amount of fructans in the DP 3 to 10 category was achieved by allowing roots to overwinter and harvest in mid-March. Overwintering of roots caused a dramatic decrease in fructans in the DP > 20 and DP 11 to 20 categories and an increase in fructans in the DP 3 to 10 category, and an increase in free sugars glucose, fructose, and sucrose. Harvest date played an important role in determining the DP of fructans in chicory roots and root yield.

Experiment 3 showed trends similar to those observed in the previous experiments, that harvest date was a key factor in determining root yield, total sugar content, and carbohydrate distribution (Table 3). During the 4-yr period from 1999 to 2002, the mid-November harvest date produced the greatest root yield with an increase in root yield of 26.7 Mg ha^–1 from early September to mid-November. The total sugar content was greatest on 1 November and began to decline if harvest was delayed until mid-November. The first frost (–3°C) in 1999 through 2002 occurred on 28 September, 25 September, 5 October, and 22 September, respectively. There was a trend for the greatest concentration of fructans in the categories DP 11 to 20 and DP > 20 to occur on 20 September. Following the first frosts, the concentration of fructans in the categories DP 11 to 20 and DP > 20 declined and fructans in the category DP 3 to 10 increased.

View larger version (24K): [in this window] [in a new window]   Fig. 1. Quadratic response of chicory root yields to different harvest dates from 1 September to 15 November, means from data collected in Exp. 1, 2, and 3.

	NOTES

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
A contribution of the Univ. of Nebraska Agricultural Research Division, Lincoln, NE. Journal Series No. 14067. This research was supported in part by funds provided through the Hatch Act.

Received for publication April 22, 2003.

	REFERENCES

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 

• Baert, J.R. 1997. The effect of sowing and harvest date and cultivar on inulin yield and composition of chicory (Cichorium intybus L.) roots. Ind. Crops Prod. 6:195–199.
• Baert, J.R., and E.J. Van Bockstaele. 1993. Cultivation and breeding of root chicory for inulin production. Ind. Crops Prod. 1:229–234.
• Corey, K.A., and L.F. Whitney. 1987. Production of Belgian endive: Description and prospects for the United States. HortScience 22:1044.
• Edelman, J., and T.G. Jefford. 1968. The mechanism of fructan metabolism in higher plants as exemplified in Helianthus tuberosus. New Phytol. 67:517–531.
• Gomez, K.A., and A.A. Gomez. 1984. Statistical procedures for agriculture research. John Wiley and Sons, New York.
• SAS Institute. 1990. SAS/STAT user's guide. Release 6.12. SAS Inst., Cary, NC.
• Van den Ende, W., A. Michiels, J. DeRoover, and A. Van Laere. 2002. Fructan biosynthetic and breakdown enzymes in dicots evolved from different invertases. Expression of functional genes throughout chicory development. Sci. World J. 2:1273–1287.
• Van den Ende, W., A. Mintiens, H. Speleers, A. Onuoha, and A. Van Laere. 1996. The metabolism of fructans in roots of Cichorium intybus during growth, storage and forcing. New Phytol. 132:555–563.
• Van den Ende, W., and A. Van Laere. 1996. Variation in the in vitro generated fructan pattern from sucrose as a function of the purified chicory root 1-SST and 1-FFT concentrations. J. Exp. Bot. 47:1797–1803.
• Van Waes, C., J.B. Baert, L. Carlier, and E. Van Bockstaele. 1998. A rapid determination of the total sugar content and the average inulin chain length in roots of chicory (Cichorium intybus L.). J. Sci. Food Agric. 76:107–110.
• Wilson, R.G. 1999. Response of nine sugarbeet (Beta vulgaris) cultivars to postemergence herbicide applications. Weed Technol. 13:25–29.
• Wilson, R.G., S.D. Kachman, and A.R. Martin. 2001. Seasonal changes in glucose, fructose, sucrose, and fructans in the roots of dandelion. Weed Sci. 49:150–155.

This article has been cited by other articles:

				A. Monti, M. T. Amaducci, G. Pritoni, and G. Venturi Growth, fructan yield, and quality of chicory (Cichorium intybus L.) as related to photosynthetic capacity, harvest time, and water regime J. Exp. Bot., May 1, 2005; 56(415): 1389 - 1395. [Abstract] [Full Text] [PDF]

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Wilson, R. G. Articles by Yonts, C. D. Search for Related Content PubMed Articles by Wilson, R. G. Articles by Yonts, C. D. Agricola Articles by Wilson, R. G. Articles by Yonts, C. D. Related Collections Crop Growth and Development