Published in Crop Sci. 43:2118-2124 (2003).
© 2003 Crop Science Society of America
677 S. Segoe Rd., Madison, WI 53711 USA
CROP ECOLOGY, MANAGEMENT & QUALITY
Optimizing Marigold (Tagetes erecta L.) Petal and Pigment Yield
Theresa L. Bosmaa,
John M. Dole*,b and
Niels O. Manessa
a Dep. of Horticulture and Landscape Architecture, Oklahoma State University, Stillwater, OK 74078-6027
b Dep. of Horticultural Science, North Carolina State University, Box 7609, Raleigh, NC 27695-7609
* Corresponding author (john_dole{at}ncsu.edu).
 |
ABSTRACT
|
|---|
African marigold (Tagetes erecta L.) flower pigments can be extracted and used as a natural food additive to color egg yolks orange and poultry skin yellow. Five cultivars were examined for their ability to be grown commercially and mechanically harvested. ‘E-1236’ was consistently a top producer for three seasons in terms of flower number, flower diameter, plant and flower canopy height, plant stand, and fresh flower, dried flower, and dried petal yield. E-1236 produced the greatest quantity of lutein, a carotenoid pigment, in 1998 (22.0 kg ha-1), and E-1236 and ‘Orange Lady’ both produced the greatest quantities in 1999 (20.7 and 21.3 kg ha-1, respectively). Transplanted rather than direct-seeded plants produced two more harvests in a single season resulting in greater amounts of lutein production by transplants. In 1998, one mid-season ammonium nitrate application (28 kg ha-1) resulted in larger flower diameters with direct-seeded plants but did not affect dried petal yield. Plants were hedge trimmed in 1999 to mimic mechanical harvesting; this resulted in a 45 to 55% reduction in flower harvest data compared with hand-harvested flowers. Of the cultivars tested, Orange Lady produced the greatest quantity of lutein (10.6 kg ha-1) when hedge trimmed.
|
INTRODUCTION
|
|---|
AFRICAN MARIGOLD PETALS are commercially valuable as a natural source of lutein pigments (yellow–orange pigments). The poultry industry uses them primarily as feed additives to color egg yolks orange and poultry skin yellow. Over the years, consumers have equated orange egg yolks with healthiness; colorless bland products are undesirable (Williams, 1992). These pigments must be included as a feed additive if the final product is to attain the desired color since birds lack the ability to synthesize them (Marusich and Bauernfeind, 1981). Lutein and zeaxanthin are the main xanthophyll pigments present in egg yolks because of their highly absorptive nature with fatty tissue (Karunajeeva et al., 1984). Yellow corn (Zea mays L.), alfalfa (Medicago sativa L.), and marigold can serve as natural sources of xanthophylls. Lutein (C40H56O2) is the primary xanthophyll pigment that produces the orange color in marigold flowers, composing roughly 90% of the petals' identified pigments (Quackenbush and Miller, 1972). Marigold has been most commonly used by the poultry industry to augment the xanthophyll present in corn and alfalfa feed to standardize the feed's xanthophyll content (Delgado-Vargas et al., 1998).
Xanthophylls are one of two classes of carotenoid pigments which are also beneficial as a natural pigment source and have many commercial applications. Carotenoid pigments have shown positive benefits in slowing the growth of induced skin tumors, treating dermatological diseases, and lowering the overall risk of cancer in human beings (Mathews-Roth, 1982). Lutein has special pharmacological use as an ophthalmologic ointment with the trade name Adaptionol (Gau et al., 1983). Thus, the potential for broad commercial use of carotenoids should generate further interest in marigold as an alternative crop.
Baldwin et al. (1993) conducted an 8-yr study in which five marigold cultivars were grown in Virginia and Mexico for pigment extraction and lesion-nematode reduction. All plants were direct seeded, and flowers were hand harvested. Highest xanthophyll yields were achieved by ‘Toreador’ (31.20 kg ha-1). Baldwin et al. (1993) noted that plant "vigor" decreased as the season progressed, which was attributed to nitrogen deficiency. In the following season, the addition of ammonium nitrate (28 kg ha-1) after the first two harvests improved subsequent harvests. Pigment yield increased most after three nitrogen applications in a single season. The authors also concluded that the two greatest problems for marigold production were plant stand establishment and weed control.
Plant stand establishment is always an important consideration in commercial field production (Bennett et al., 1992). Direct seeding often results in uneven germination, slow emergence, and poor stand establishment but is less expensive initially and widely used in field operations (Wurr and Fellows, 1983). However, unless a precision seeder is used to plant the seed, additional labor is required to thin seedlings to the desired spacing. While transplants are initially more expensive to grow and set in the field, they can be planted at the exact space desired for the crop and have the benefit of quickly producing a uniform stand allowing earlier harvests. Transplanted plants often produce their first harvestable crop of flowers before direct-seeded plants begin to flower.
Currently, marigold plants are grown for pigment production in Mexico, Peru, and India. The flowers are hand picked, stored, dried, and processed into a pelletized form for pigment extraction. After harvest, flowers may be stored outside unprotected for days or weeks before drying, exposing the pigment to damaging heat, light, and mold growth. High air temperatures during the drying process also reduce pigment quality. During pelletization, seeds and other green material may be included which lowers the product's purity (Buser et al., 1999). Hence, a more efficient program must be developed for harvesting and processing lutein.
One key to successful commercial marigold production will be to select a cultivar that can withstand typical environmental conditions including wind, drought, and heat stress. The cultivar should consistently produce a large number of orange flowers that do not vary in the degree of orange color and be relatively unaffected by pests and diseases. Also, the plant must withstand the destruction a mechanical harvester can inflict on plants after multiple harvests. Although Baldwin et al. (1993) investigated commercial African marigold production, they did not examine cultivar suitability for mechanical harvest. The objectives of this project are to determine which cultivar and production methods would be most suitable for commercial marigold lutein pigment production using mechanical harvest.
|
MATERIALS AND METHODS
|
|---|
Four marigold cultivars, A-975, E-1236, I-822, and X-986, developed by Goldsmith Seeds, Inc. (Gilroy, CA) and one commercial cultivar, Orange Lady were evaluated over a 4-yr period. In 1996, plants were grown in raised beds in Stillwater, OK, (USDA climatic zone 6b–7a) with a Norge Loam (fine-silty, mixed, thermic Udic Paleustoll) soil, pH near 6.5. Plots were watered as required to maintain field capacity using drip irrigation. In 1997, 1998, and 1999, plants were grown in Hinton, OK, (USDA climatic zone 7a) at S. S. Farms. Soil type was Pond Creek loam (deep, fine sandy loam) with soil pH near 6.5. Plots were watered with sprinkler irrigation as required to maintain field capacity. Transplants were produced by directly sowing seed into 66- by 34-cm plug flats with 200 cells per flat and filled with a commercial peat-based growing substrate. Transplants were irrigated during weekdays with 200 mg L-1 N from a commercial premixed 20-4.4-16.6 fertilizer and on weekends with unamended water. Plants were transplanted when the root balls had enough roots to remain intact at the time of planting but before excessive shoot and root growth that would have induced rapid wilting in the field and prevented plant establishment.
1996 Season
Orange Lady was evaluated both as direct-seeded plants and transplants in 3.7 m long and 1.2 m wide plots. Transplant flats were started on 27 March, and seedlings were field planted on 1 May along with direct-seeded plants (3 seeds per hole). Rows were spaced 31 cm apart with three different spacings, 10 cm, 23 cm, and 36 cm used within the rows. Six harvests were made over the entire season. Mature flowers with outer petals reflexed were hand picked approximately every 2 wk. Data collected included the number of flowers and yield of fresh flowers, dried flowers, dried petals, and dried receptacles produced per repetition. Fresh flowers were dried for 24 h at 49 to 52°C to obtain dry weights. Soil was analyzed and amended as needed for nutrient content (Baldwin et al., 1993). Experimental design was a completely randomized design with four repetitions.
1997 Season
A-975, E-1236, I-822, Orange Lady, and X-986 were evaluated as transplants only at the 23-cm within-row spacing in rows spaced 31 cm apart. Transplant flats were started on 27 March and field-planted on 8 May. Plots were 1.2 m wide and 1.5 m long allowing 0.6 m between plots. Nine harvests were made over the season. Flowers were dried with air heated to 66°C and then blown through the flowers suspended on a wire mesh for 3 to 4 h. Flowers were considered dry when the petals were brittle, but receptacles remained flexible. Petal moisture content was determined by the Association of Official Analytical Chemists (AOAC) method (1984). All other procedures were the same as in 1996.
1998 Season
A-975, E-1236, I-822, and Orange Lady were evaluated both as direct-seeded plants and transplants. Transplant flats were started on 10 April, and seedlings were field planted on 11 May along with direct-seeded plants (3 seeds per hole). Plots were 1.2 m wide and 1.5 m long. Rows were spaced 23 cm apart, and plants were spaced 23 cm within each row. A preplant soil analysis was made, and soil was amended with ammonium nitrate (56 kg ha-1) before planting. An additional ammonium nitrate application (28 kg ha-1) was made midseason (20 August) to one half of the plots. Eleven harvests were made throughout the season. The same data were collected as in 1996 with the addition of lutein pigment analysis, flower diameter, plant and flower height, and plant stand. Plant and flower canopy heights were measured as the distance from the ground to the uppermost leaves and the base of the flower receptacles, respectively. The AOAC Method 43.018 (1984), which requires a spectrophotometer (Shimadzu UV 160U, UV-visible recording, Shimadzu Corp., Kyoto, Japan), was used to estimate lutein quantity in the petal material. The experimental design was a randomized complete block with four repetitions. Plots were blocked according to nitrogen application. Correlation analysis was used to evaluate the relationship between pigment concentration and dried petal moisture content and average daily air temperature. Daily air temperatures were averaged for the 2-wk time period preceding the harvest which generated the pigment concentration.
1999 Season
The same cultivars, establishment methods, plot size, spacing, and data were used as in the 1998 season. Transplant flats were started on 16 April, and seedlings were field planted on 13 May along with direct-seeded plants (3 seeds per hole). Plots received either no added nitrogen or ammonium nitrate (28 kg ha-1) was applied monthly on 23 June, 26 July, 26 August, and 22 September. Plots were either hand-harvested or cut at the flower canopy height specific for each repetition using a hedge-trimmer, intended to mimic the action of a mechanical harvester. Eight harvests were made on hand-harvested plants, and hedge-trimmed plants were harvested five times. Three weeks between harvests were necessary to produce mature flowers with hedge trimming while only 2 wk were required for hand harvesting. Experimental design was a split-split plot with four repetitions. Nitrogen application was the main plot with harvest method as the sub-plot. Cultivar and establishment methods were equally randomized as the sub-subplots.
Statistics
Within each repetition, data were collected only from interior plants. Flowers from border plants were harvested but not collected to eliminate edge effect. Data were subjected to a general linear model procedure, trend analysis, Duncan's multiple range test, and an interaction least squares difference where applicable (SAS Institute, Inc., Cary, NC). Percent data were transformed by the arcsin procedure before statistical analysis.
Insects
Spider mites (Tetranychus urticae Koch.) were a problem in 1998 and 1999 but not in 1996 or 1997. The 1998 and 1999 growing seasons were hotter and drier than in previous years, and these conditions usually correspond with spider mite infestation. Dry and hot environmental conditions limit effectiveness of a predatory mite (Amblyseius fallacis Garman) that parasitizes spider mites and keeps populations in check (Berberet, personal communication). Chemical control of spider mites was achieved by spraying O,O-dimethyl-S-1,2-di(carboethoxy) ethyl phosphorodithioate (Malathion, Miller Chemical and Fertilizer Corp., Hanover, PA) and 1,1-bis-(chlorophenyl)-2,2,2-trichloroethanol (Kelthane, Rohm and Haas Co., Philadelphia, PA) at recommended label rates. Corn earworms (Helicoverpa zea Boddie) were found to be feeding from within the flower receptacle in 1998 and 1999. Plants were sprayed with O,O-diethylO-(2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate (Diazanon, Prentiss Drug and Chemical Co., Inc., Newark, NJ) and (s)-cyano (3-phenoxyphenyl) methyl (s)-4-chloro-
-(1-methyl ethyl) benzeneacetate (Asanâ, duPont Corp., Wilmington, DE) in 1998 for control. Interestingly, in 1999, blister beetles (family Meloidae) voraciously fed on the majority of the A-975 plants but did not feed on plants from other cultivars. Undoubtedly, beetle damage contributed to the increased percentage of dead plants for that cultivar. Baldwin et al. (1993) stated that mites and thrips were a problem only in the early season, and corn earworms were buried within the blooms from mid to late season. Routine insecticide applications were used to control the pests (chemicals not specified). Baldwin et al. (1993) also had problems with Alternaria leaf spot (cause by Alternaria Nees spp.).
|
RESULTS AND DISCUSSION
|
|---|
Establishment Method
In all years, transplants produced 33 to 223% greater amounts of all measured yield parameters than direct-seeded plants (Tables 1, 2, 3, and 4). While transplants had more harvests early in the season than direct-seeded plants (data not presented), direct-seeded plants did not compensate with larger harvests than transplants at the end of the season as might be expected. Transplants often produce higher yields within a season than direct-seeded plants. Leskovar and Cantliffe (1993) found that within a single season transplants yielded 78% more in the first planting and 43% more in the second planting of bell pepper (Capsicum annuum L.) fruit compared with direct-seeded plants. However, Cooksey et al. (1994) found that transplanted paprika pepper (C. annuum) plants had higher fruit yields compared with direct-seeded plants in only 1 out of 3 yr.
View this table:
[in this window]
[in a new window]
|
Table 1. Effect of establishment method and spacing on African marigold Orange Lady yield. Only main effects are shown as no interactions occurred. Values shown are means of eight to 12 repetitions over six harvests (1996).
|
|
View this table:
[in this window]
[in a new window]
|
Table 2. Effect of four African marigold cultivars and establishment method on yield. Soil was amended with ammonium nitrate (56 kg ha-1) before planting and an additional ammonium nitrate application (28 kg ha-1) was made midseason (20 August) to one half of the plots. Nitrogen application did not affect any of the following yield parameters and was not included. Only main effects are shown as no interactions occurred. Values shown are means of 16 to 32 repetitions over eleven harvests (1998).
|
|
View this table:
[in this window]
[in a new window]
|
Table 3. Effect of four African marigold cultivars, direct-seeded (DS) or transplanted (TR) establishment, and hand harvesting (HH) or hedge trimming (HT) on yield. Values shown are means of eight repetitions (1999).
|
|
View this table:
[in this window]
[in a new window]
|
Table 4. Effect of African marigold cultivar, establishment method, nitrogen application, and harvest method on yield and plant mortality. Only main effects are shown as no interactions occurred. Values shown are means of 32 to 64 repetitions (1999).
|
|
Spacing
Increasing plant spacing decreased flower production because plots with tighter spacing contained more plants than those with wider spacing (Table 1). While increased spacing increased flower number per plant from 29 for 10-cm spacing to 49 and 66 for 23- and 36-cm spacings, respectively (data not presented), the increase per plant was not enough to offset the decline in plant number per acre. However, even though the 10-cm spacing had the highest yields, plants were short lived and prone to insect damage and disease pressure (data not presented). Thus, the 23-cm within row spacing was used for all subsequent experiments. Certainly, producers should experiment with various plant spacings to determine the optimum spacing for their operations.
Cultivar
In all years, E-1236 had flower numbers and fresh flowers, dried flowers, and dried petal yields higher than or equal to the other cultivars, making it a possible candidate for commercial production (Tables 2, 3, 4, and 5). In the first year, X-986 had yields well below those for all other cultivars and was dropped from further testing (Table 5). Lutein pigment yield was probably the most important data parameter since it determined the feasibility of commercial production and mechanical harvesting. Thus, treatments that generated the greatest pigment yield outweighed positive aspects of other treatments, such as larger flower number. E-1236 pigment yield (22.0 kg ha-1) was 31% greater than the next highest cultivar, I-822 (15.2 kg ha-1), in 1998 (Table 2). In 1999, establishment method interacted with cultivar such that among direct-seeded treatments E-1236 yielded the most pigment, but Orange Lady yielded the most pigment among transplanted treatments (Table 3). In both years, the amount of pigment produced was less than the top producing marigold, ‘Toreador’ (31.2 kg ha-1), as reported by Baldwin et al. (1993) but comparable to 20.3 kg ha-1 produced by ‘Xanthophyll’ (methodology not specified).
View this table:
[in this window]
[in a new window]
|
Table 5. Effect of five African marigold cultivars on yield. Transplants were used for field establishment. Values shown are means of four repetitions over nine harvests (1997).
|
|
Interestingly, while Orange Lady produced the highest dried receptacle yield in all years, dried petal yield was 30 to 50% below that of E-1236 (Tables 2, 3, and 5). In 1999, dried Orange Lady receptacles composed 75% of the dried flower yield and dried petals only 25% (Table 4). Percent composition of the other cultivars' dried flower yield by dried receptacle weight ranged from 64 to 67%. Orange Lady had a higher percentage of dried receptacles than the other cultivars in 1997 and 1998 also indicating that this is a consistent characteristic of the Orange Lady cultivar (Tables 2 and 5).
Transplanting enhanced height of naturally tall cultivars as compared with direct seeding (Table 6). Plant and flower canopy height is an important consideration for mechanical harvesting as tall cultivars with a uniform flower canopy are more likely to produce easily harvestable crops. In 1998, I-822 was the tallest cultivar and A-975 the shortest (Table 6). In 1999, I-822 plants also had the tallest flower and plant canopies, 55.9 and 44.5 cm, respectively, and A-975 had the shortest canopies, 32.9 and 28.0 cm, respectively (data not presented). E-1236 flower and plant canopies heights were 48.1 and 40.3, and Orange Lady heights were 47.9 and 40.7 cm, respectively. The greater the disparity between flower and plant canopies, the more likely that a mechanical harvester could collect the flowers without severely damaging the plant's foliage and flower buds allowing the potential for more harvests in a single season. In 1998, flower canopies of E-1236, I-822, and Orange Lady, were 7.6, 7.7, and 6.3 cm, respectively, above the plant canopy. Plant and flower canopy heights for A-975 (27.9 and 34.2 cm, respectively) were too low for mechanical harvesting. Plant height of cultivars used in Baldwin et al. (1993) ranged from 35.0 to 96.9 cm.
View this table:
[in this window]
[in a new window]
|
Table 6. Effect of four African marigold cultivars and direct-seeded (DS) or transplanted (TR) establishment on plant and flower canopy heights and plant mortality. Soil was amended with ammonium nitrate (56 kg ha-1) before planting and an additional ammonium nitrate application (28 kg ha-1) was made mid-season (20 August) to one half of the plots. Nitrogen application did not effect any of the following yield parameters and was not included. Values shown are means of eight repetitions over eleven harvests (1998).
|
|
The percentage of dead plants at midseason was affected by cultivar and establishment method in 1998 (Table 6). Interestingly, E-1236 had both the highest percentage of dead plants (39%) as transplants and the lowest percentage (3%) as direct-seeded plants. This pattern was not evident among the other cultivars. The percentage of dead plants at midseason was similar between direct-seeded (37%) and transplanted (29%) A-975 plants and E-1236 transplants. At the end of the season, cultivar was the only variable affecting the percentage of dead plants with A-975 having the highest percentage (55%) (data not presented). Orange Lady had the lowest percentage of dead plants (23%) and E-1236 and I-822 produced intermediate percentages of dead plants, 43 and 33%, respectively. A-975 would not perform well in commercial production due to the small plant stature and excessive plant loss by the end of the season. In 1999 cultivar did not influence plant stand (data not presented) and no significant interactions occurred.
Nitrogen Application
Flower diameter was the only data parameter affected by nitrogen application in 1998; the flower diameter of direct-seeded plants receiving nitrogen were larger (5.7 cm) than direct-seeded plants that did not receive nitrogen (5.1 cm). In 1999, establishment method and nitrogen addition significantly affected diameter within a cultivar, but no single treatment caused flowers of one cultivar to be larger than the other (data not presented). In 1998, a preplant soil test revealed 6.7 kg ha-1 of nitrate existed in the soil. After subsequent nitrate application, soil tests showed there was 21 kg ha-1 of nitrate in the soil. Preplant testing in 1999 showed 22 kg ha-1 of nitrate existed. Thus, equal quantities of soil nitrate were available to the plants during each growing season. Decline of flower diameter of the biennial Hydrophyllum appendiculatum Michx. was due to ontogenic changes within the plant and not due to decreasing resource status of the plant within a single growing season (Wolfe, 1992). However, decline of inflorescence size and seed weight were found to correlate with limited resource availability. In the present study, nitrogen application over both years did not increase pigment yield (data not presented) and consequently, would be of little commercial use. In contrast, Baldwin et al. (1993) found that pigment yield increased most after three nitrogen applications (ammonium nitrate at 28 kg ha-1 each time) within a single season.
Plants that received nitrogen also had higher percentages of dead plants in 1999 than those that did not receive nitrogen (Table 4). Excessive nitrogen fertilization may result in lush growth, and subsequently increased insect damage and disease problems often follow (Agrios, 1997).
Harvest Method
Hand harvesting produced the largest flower number and fresh flower weight compared with hedge-trimming plants, but cultivar selection and establishment method were also critical factors (Table 3). Hand harvesting recovered greater flower numbers because hedge trimming missed flowers not in the main flower canopy plane, and because hand harvesting allowed more frequent harvests than hedge trimming. In addition, hedge trimming undoubtedly damaged the top part of the plant canopy, which may have directed photosynthates from reproductive structures to foliage. For instance, transplanted E-1236 plants produced 43% more fresh flower yield with hand harvesting than hedge trimming. Direct-seeded E-1236 plants that were hand harvested produced as well as transplants from A-975, E-1236, and Orange Lady that were harvested under both harvest methods. Regardless of which establishment or harvest method is used, I-822 would not be a good choice when maximum flower number is desired because of low yield.
Hand harvesting yielded more dried petals and pigment than hedge trimming (Table 3). With hedge trimming, transplants produced a larger yield of dried petals suggesting that transplants would be feasible with mechanical harvesting. Highest pigment yields resulted from hand harvesting transplanted Orange Lady and direct-seeded E-1236 plants (Table 3). All hedge-trimmed plants produced the lowest amounts except for transplanted Orange Lady (10.6 kg ha-1) plants that were statistically similar to hand-harvested A-975 direct-seeded plants (9.5 kg ha-1). Hedge-trimmed direct-seeded plants' pigment production was less than half of that reported by Baldwin et al. (1993) for hand-harvested direct-seeded plants.
Interestingly, the treatments that produced more flowers and dried flower yield, hand harvesting and transplants, had higher percentages of dead plants at midseason and end of the season compared with hedge-trimmed and direct-seeded plants, respectively (Table 4). One would assume that hedge trimming would cause more plant damage, leading to higher percentages of dead plants than hand harvesting, but this did not occur. More hand-harvested plants died than hedge-trimmed plants.
Environmental Conditions
A positive correlation between pigment concentration and dried petal moisture content showed that drying of petal material resulted in pigment loss in both years tested (R2 = 0.20 for 1998 and R2 = 0.21 for 1999). As the petal material dried and the percentage of moisture contained within the petals decreased, the pigment concentration recovered also decreased. However, consistent R2 values of approximately 0.20 for both years indicates that the effect of drying on pigment concentration was relatively limited. Similarly, the production of paprika pepper from C. annuum ‘Bola’ with rapid, high temperature oven drying accounted for approximately 25% loss in carotenoid pigment content (Minguez-Mosquera et al., 1994). The exact temperatures and process of oven drying was not stated.
A negative correlation (R2 = -0.26 for 1998 and 1999) existed between pigment concentration and the average daily air temperature at the growing location for both years examined. As air temperatures increased, pigment concentration within the petals decreased. As air temperatures increase, plant respiration would increase leaving limited photosynthates available for pigment synthesis. It is understood that high temperatures degrade pigment content after pigments are extracted (Minguez-Mosquera et al., 1994; Cai et al., 1998; Delgado-Vargas et al., 1998), but this research links high air temperatures before harvest with lower pigment content after extraction. High temperatures during plant production have been shown to decrease flower color in Anigozanthus Labill. (Ben-Tal and King, 1997) and bract anthocyanin content in Euphorbia pulcherrima Willd. ex. Klotsch (Marousky, 1968).
|
CONCLUSIONS
|
|---|
E-1236 produced the greatest quantity of lutein, a carotenoid pigment, in 1998 (22.0 kg ha-1), and E-1236 and Orange Lady both produced the greatest quantities in 1999 (21.3 kg ha-1). E-1236 was also a top producer for flower number and fresh flower, dried flower, and dried petal yield for 3 yr. Transplanted plants produced higher amounts for all yield parameters as compared with direct-seeded plants for 3 yr. Surprisingly, nitrogen application created mixed results by increasing flower diameter, increasing the percentage of dead plants, and reducing dried receptacle yield. However, nitrogen application did not increase pigment yield in our work and consequently would not be recommended. In any case, annual preplant soil fertility analysis should be conducted to ensure proper nutrient availability (minimum of 21 kg ha-1 nitrate). Dried flower and pigment yields were greatly increased by hand harvesting compared with hedge trimming.
On the basis of yield per hectare alone, we recommend hand picking E-1236 transplanted plants for commercial production of marigold. E-1236 was also the top producer with hand harvesting, producing high pigment yields (20.7–22.0 kg ha-1) over both years tested. For simulated mechanical harvesting, transplanted Orange Lady plants performed best, producing the highest pigment yield (10.6 kg ha-1) for that treatment.
Even though the highest yield was obtained from hand-harvesting transplants, such practices would be labor intensive and cost prohibitive. Future research should examine practices that would make mechanical marigold harvesting more profitable if marigolds are to be considered as an alternative crop.
|
ACKNOWLEDGMENTS
|
|---|
This research was supported in part by the Oklahoma Center for the Advancement of Science and Technology and OAES under project H-2119. Appreciation is expressed to Leah Aufill and Donna Chrz for technical support, Goldsmith Seed for seed, and Oklahoma Mesonet Project, a cooperative venture between Oklahoma State University (Stillwater, OK) and the University of Oklahoma (Norman, OK), for air temperature data. Special appreciation is given to Dean Smith of S.S. Farms who provided land and ensured plants were watered as needed.
Received for publication March 7, 2002.
|
REFERENCES
|
|---|
- Agrios, G.N. 1997. Plant pathology. 4th ed. Academic Press, London.
- Association of Official Analytical Chemists (AOAC). 1984. Official methods of analysis of the AOAC. 14th ed. AOAC, Washington, DC.
- Baldwin, R.E., C.M. Waldenmaier, and R.C. Lambe. 1993. Marigold research report 1986–1993. Va. Polytechnic Inst. and State Univ., Painter, VA.
- Ben-Tal, Y., and R.W. King. 1997. Environmental factors involved in colouration of flowers of kangaroo paw. Sci. Hortic. (Amsterdam) 72:35–48.
- Bennett, M.A., V.A. Fritz, and N.W. Callan. 1992. Impacts of seed treatments on crop stand establishment. HortTechnology 2:345–349.[Free Full Text]
- Buser, M.D., M.L. Stone, G.H. Brusewitz, N.O. Maness, and D.P. Whitelock. 1999. Thin-layer drying of marigold flowers and flower components for petal removal. Trans. ASAE 42:1367–1373.
- Cai, Y., M. Sun, and H. Corke. 1998. Colorant properties and stability of Amaranthus betacyanin pigments. J. Agric. Food Chem. 46:4491–4495.
- Cooksey, J.R., B.A. Kahn, and J.E. Motes. 1994. Plant morphology and yield of paprika pepper in response to method of stand establishment. HortScience 29:1282–1284.[Abstract/Free Full Text]
- Delgado-Vargas, F., O. Paredes-Lopez, and E. Avila-Gonzalez. 1998. Effects of sunlight illumination of marigold flower meals on egg yolk pigmentation. J. Agric. Food Chem. 46:698–706.[Medline]
- Gau, W., H.J. Ploschke, and C. Wunsche. 1983. Mass spectrometric identification of xanthophyll fatty acid esters from marigold flowers (Tagetes erecta) obtained by high-performance liquid chromatography and Craig counter-current distribution. J. Chromatogr. 262:277–284.
- Karunajeeva, H., R.S. Hughes, M.W. McDonald, and F.S. Shenstone. 1984. A review of factors influencing pigmentation of egg yolks. Worlds Poult. Sci. J. 40:52–65.[ISI]
- Leskovar, D.I., and D.J. Cantliffe. 1993. Comparison of plant establishment method, transplant or direct seeding, on growth and yield of bell pepper. J. Am. Soc. Hortic. Sci. 118:17–22.[Abstract/Free Full Text]
- Marousky, F.J. 1968. Effects of temperature on anthocyanin content and color of poinsettia bracts. J. Am. Soc. Hortic. Sci. 92:678–684.
- Marusich, W.L., and J.C. Bauernfeind. 1981. Oxycarotenoids in poultry feeds. p. 319–462. In J.C. Bauernfeind (ed.) Carotenoids as colorants and vitamin A precursors. Academic Press, New York.
- Mathews-Roth, M.M. 1982. Medical applications and uses of carotenoids. p. 297–307. In G. Britton and T.W. Goodwin (ed.) Carotenoid chemistry and biochemistry. Pergamon Press, London.
- Minguez-Mosquera, M.I., M. Jaren-Galan, and J. Garrido-Fernandez. 1994. Influence of the industrial drying processes of pepper fruits (Capsicum annuum cv. Bola) for paprika on the carotenoid content. J. Agric. Food Chem. 42:1190–1193.
- Quackenbush, F.W., and S.L. Miller. 1972. Composition and analysis of the carotenoids in marigold petals. J. Assoc. Off. Anal. Chem. 55:617–621.[Medline]
- Williams, W.D. 1992. Origin and impact of color on consumer preference for food. Poult. Sci. 71:744–746.[Medline]
- Wolfe, L.M. 1992. Why does the size of reproductive structures decline through time in Hycrophyllum appendiculatum (Hydrophyllaceae)?: Developmental constraints vs. resource limitation. Am. J. Bot. 79:1286–1290.
- Wurr, D., and J. Fellows. 1983. The effect of the time of seedling emergence of crisp lettuce on the time of maturity and head weight at maturity. J. Hortic. Sci. 58:561–566.
Related articles in Crop Science:
- THIS ISSUE IN CROP SCIENCE
Crop Science 2003 43: 1897-1898.
[Full Text]
TOP
ABSTRACT
INTRODUCTION
