01140671%2E2000%2E9514120

8/2/2019 01140671%2E2000%2E9514120

http://slidepdf.com/reader/full/011406712e20002e9514120 1/9

This article was downloaded by: [82.137.8.39]On: 10 January 2012, At: 07:56Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registeredoffice: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

New Zealand Journal of Crop andHort icultural SciencePublication details, including instructions for authors andsubscript ion informat ion:

http:/ / www.t andfonline.com/ loi/ tnzc20

Effect of plant populat ion on calendula(Calendula off icinal is L.) flowerproductionR. J. Martin a & B. Deo b

aNew Zealand Institute for Crop & Food Research Limited, Private

Bag 4704, Christchurch, New Zealand E-mail: mart [email protected] .nzb

New Zealand Institute for Crop & Food Research Limited, PrivateBag 4704, Christchurch, New Zealand

Available online: 22 Mar 2010

To cite this article: R. J. Martin & B. Deo (2000): Effect of plant population on calendula (Calendula

officinalis L.) f lower product ion, New Zealand Journal of Crop and Hort icultural Science, 28:1, 37-44

To link t o this art icle: http:/ / dx.doi.org/ 10.1080/ 01140671.2000.9514120

PLEASE SCROLL DOWN FOR ARTICLE

Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions

This article may be used for research, teaching, and private study purposes. Anysubstantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,systematic supply, or distribution in any form to anyone is expressly forbidden.

The publisher does not give any warranty express or implied or make any representationthat the contents will be complete or accurate or up to date. The accuracy of anyinstructions, formulae, and drug doses should be independently verified with primarysources. The publisher shall not be liable for any loss, actions, claims, proceedings,demand, or costs or damages whatsoever or howsoever caused arising directly orindirectly in connection with or arising out of the use of this material.

http://www.tandfonline.com/loi/tnzc20

http://www.tandfonline.com/page/terms-and-conditions

http://dx.doi.org/10.1080/01140671.2000.9514120

http://www.tandfonline.com/loi/tnzc20

8/2/2019 01140671%2E2000%2E9514120


New Zealand Journal of Crop and Horticultural Science, 2000, Vol. 28: 37-44001 4-067 1/00/2 801 -0037 $7.00 © The Royal Society of New Zealand 2000

37

Effect of plant population on ca lendula (Calendula officinalis L.)flower production

R. J. MARTIN

B . D E O

New Zealand Institute for Crop & FoodResearch Limited

Private Bag 4704Christchurch, New Zealandemail: m [email protected]

Abstract Calendula (Calendula officinalis L.) wasdrilled at 3, 6, 12, 24, 48 , and 96 kg seed/ha in a trialat Lincoln, New Zea land, in Novem ber 1997. Plotswere divided into five equally sized sections. Fullyopen flowers were harvested from Sections 2 and 4of all plots twice or three times weekly from earlyFebruary to mid M arch 1998, after w hich plant popu-lation and crop biomass were determined from thesame sections and seed yield/flower determined fromSections 1, 3, and 5. Plant counts increased from 9

plants/m2 at the 3 kg seed/ha rate, to 26 at 6, 46 at12, 101 at 24, 179 at 48, and 332 plant/m 2 at 96 kgseed/ha. Total flower yield was not significantlydifferent at populations over 46 plants/m 2, but de-clined with lower plant populations. The total freshweight (and number) of fully opened flower headscollected off each plot increased from 0.5 (164) to1.4 kg/m 2 (650/m 2) with increasing plant pop ulation,but did not differ at the four highest populations.Dried petals made up between 7 and 9% of flowerfresh weight. Yields of dry petals/m 2 were 36 g at 9

plants/m2 compared to an average of 89 g over thefour highest plant po pulations. Seed weight/head was0.78 g at 9 plants/m 2 compared to c. 0.5 g for theother plant populations. Seed yield increased withincrea sing p lant popu lation from 128 g/m2 at

H99025Received 12 July 1999; accepted 3 Decem ber 199 9

9 plants/m 2 to 300 g/m2 at the three highestpopulations.

Keywords Calendula officinalis L.; calendula;marigold; seed yield; flower yield

INTRODUCTION

Calendula (Calendula officinalis L.), also known aspot marigold, is an annual or short-lived perennialherb native to southern Europe that produces oran geto yellow flowers. It is commonly grown as an or-namental throughout the world and is cultivated insouthern and eastern Europe. It is grown for a drug,calendulae flos, obtained from the flowers, particu-larly the petals (Bissett 1994). Calendulae flos is acomplex m ixture including essential oils, glycosides,saponins, triols, and xanthophylls, with the

triterpenoids being the most important anti-inflam-matory principles (Delia Loggia et al. 1994).Calendulae flos has been used historically as a tra-ditional medicine and food dye (Khodzhaeva &Turakhozhaev 1993), but is currently being increas-ingly used as an external anti-inflammatory andwound healer (Bissett 1994; Akihisa et al. 1996;Patrick et al. 1996). This has prompted investigationof the potential for calendula flower production andprocessing in New Zealand.

There is also interest in growing calendula seed

in New Zealand. Seed has an oil content of 5-20%(Meier zu Beerentrup & Robbelen 1987; Angeliniet al. 1997; Cromack & Smith 1998), of which upto 60% is calendic acid (Angelini et al. 1997;Cromack & Smith 1998). This seed oil has similarproperties to rung oil and, therefore, could be usedas a binder in paints, coatings, and cosmetics (Muuseetal. 1992).

Calendula seed is very expensive (c. NZ $700/kg).Therefore, as a first stage to evaluating calendula asa field crop in New Zealand, a trial was carried out

to determine whether seeding rate affected theproduction and/or size of calendula flowers, andhence seed yield.

8/2/2019 01140671%2E2000%2E9514120


38 New Zealand Journal of Crop and Horticultural Science, 2000, Vol. 28

MATERIALS AND METHODS

A field experiment was conducted in the 1997-98season on a Templeton silt loam overlying sand(New Zealand Soil Bureau 1968) at Lincoln, NewZealand. The experiment followed a crop of oca(Oxalis tuber-osa) or a 1-year fallow, both of whichfollowed Echinacea purpurea and Valerianaofficinalis trials. The soil fertility status of the top300 m m of the whole area, taken just before sowing,was pH 5.9, Ca 10 mg /g, K 14 mg /g, P 22 mg/g, S6 mg/g, NO 3-N 5 mg/g, and total N 0.21%. S.oil

physical characteristics on an adjacent area havebeen given by Martin et al. (1992).

The crop was sown on 27 November 1997 with a9-row Oyjord Drill at six seeding rates: 3,6 , 12,2 4,48, and 96 kg/ha. A randomised block design was

used w ith four replicates, three on the area followingoca, and one on the area following fallow. Plots were10 m long by 1.35 m w ide. Seeding depth was 1-2 cm , and the crop was covered using light harrowsattached to the drill.

The crop was sprinkler irrigated at 2-4-weekintervals from mid Decem ber to the end of February,with c. 25 mm applied at each irrigation. On 29January 100 kg/ha N w as applied as urea (46% N),jus t at the start of flowering. It was irrigated in with25 mm water on the next day. The crop was hand

weed ed tw ice, at 1 and 3 months after drilling. Thecrop was sprayed with carbendazim (0.5 kg a.i./ha)and benzimidazole (0.25 kg a.i./ha) on 20 M arch tocontrol an unidentified white fungal growth on theleaves.

Each plot was divided into five 2 m lengths. Thesecond and fourth lengths were sampled 2 -3 times/week from 2 February until 19 March 1998. On eachoccasion all fully opened flowers in the samplinglength were plucked by hand, w eighed and counted,then dried at 30°C and reweighed. On 5 March

height to the tallest flower was measured at fourplaces in each plot. On 19 March each plot wasvisually assessed for lodging using a score of 1 forno lodging to 5 for completely lodged. On 2 and 3April all plant material in the second and fourthsampling lengths was cut at ground level. The cutplants were weighed and a 1.2 to 2.2 kg subsamplewas d ried at 80°C in a forced-draft oven. On 16 Aprilc. 50 dry flowers heads were taken from the first,third, and fifth lengths of the plots, dried at 35°C,and the seed rem oved and w eighed. Thousand seed

weights were determined on triplicate samples froma seed counter.

oe

II

on

5-

la

o f

stp .

pa

dy

p .

,—s

Si00

r we

CT3a .O

Cc a

8"SC

ubo

lo

iM

g.e

Eish

3aCO

to

3 .op

cca

"p .

is)

a

c

I"3rac

p h

o

o

l«

3

^B

0 0

'5

la

Cu

" ^

me

15

sa

Oc

Pa

ca

=5M

te

bO

H •»

dy

w

oV

•a -2

boO

8/2/2019 01140671%2E2000%2E9514120


Martin & Deo—Effect of plant population on calendula flower production 39

Fig 1 Calendula (Calendulaoffwinalis) cumulative f lowernumber/m 2 at six plant densitiesfrom early February to mid March1998. • = 9 plants/m 2, O = 26plants/m 2, T = 46 plants/m 2, V =101 plants/m 2, • = 179 plants/m 2,and • = 332 plants/m2. Verticalbars represent LSDs between treat-ment means (P < 0.05) at each har-vest.

800

Data were analysed with analysis of varianceusing the Genstat statistical package (Genstat 5Com mittee 1993). The lodging scores were analysedafter a (log 10)+1 transformation.

R E S U L T S

The season was one of the warmest and driest onrecord at Lincoln with mean temperatures of 15.2,17.9, 19.6, and 16.8°C for December 1997 andJanuary, February, and March 1998 respectively.These tem peratures w ere, on average, 1.3°C higherthan the long-term mean. Rainfalls for these monthswere 42.5, 17.2, 13.6, and 31.4 mm respectively,comp ared to the long-term mean of 55.5 mm/m onthover this period. App roxim ately 100 mm of irri-gation water was applied during the growth of thecrop, but, because of the high temperatures and lowhumidities during application, this may have beenless effective than an equivalent amount of rainfall.

Plant numb er, height, lodging, and biomass

Plant counts increased from 9 plants/m2 at 3 kg seed/ha to 332 plant/m 2 at the 96 kg seed/ha rate (Table 1).Establishment based on a seed weight of 8mg w as notsignificantly different among all sowing rates; it aver-aged 30 %. Plant height at 544 mm for 9 plants/m2 wassignificantly shorter than the 697 mm for all other plantpopulations. We also observed that as plant densityincreased the height of the flowers in the canopy be-

came m ore even. The log-transformed lodging scoredata showed increased lodging at the two highest plant

populations (Table 1). Plant height and lodging dif-fered considerably between replicates. Taller plantsand more severe lodging occurred at higher plantpopulations in the replicates following the oca crop.Little lodging occurred in the replicate in areas of lowresidual fertility, which followed fallow. The lodgingreduced flower production and increased rotting ofplants. Lodging started in some plots after high w indsin late February. Crop biomass doubled over the rangeof plant populations established, but biomass/plantdecreased 15-fold from 45 g for the m ulti-branchedbushy plants at 9 plants/m 2 to 3 g for the single-stemmed, spindly plants at 332 plants/m 2.

Flower number

Cumulative flower numbers were not significantlydifferent for plant populations over 46/ha up to theend of February, or over 101/ha during March, bu twere significantly lower at lower plant po pulations(Fig. 1). For the three highest plant populationsc. 600 flowers/m 2 were collected over the 45 daysof flower sampling (Table 2), and flower prod uctionrates averaged c. 15 flowers/m 2 per day from midFebruary (Fig. 1). How ever, only 2-6 flowers w ereproduced by each plant at these high plantpopulations, compared to over 18 at 9 plants/m 2

(Table 2). There was no consistent replicate effecton flower number.

Flower yield

The total weight of fresh flower heads collected off

each plot increased nearly 3-fold from 488 g/m 2 at9 plants/m 2 to a mean of 1330 g/m 2 at the four

8/2/2019 01140671%2E2000%2E9514120


Table 2 Total number of calendula (Calendula officinalis) flowers harvested per m 2 and per plant, flower fresh weight (fwt) and dry weight (dwt) per m 2, flowerfresh weight per plant, fresh weight per flower, and flower dry matter (DM)%. (NS = not significant.)

Plant no./m 2 Flowers/m2

9 164

26 334

46 451

101 576

179 583

332 650LSD (5%) 111.4

(d.f. 15) ^

F-test probability O.0 01 <0.01 O.0 01 <0.001 <0.001 <0.001 NS g

o-

oc

o

OTable 3 Ratio of calendula (Calendula officinalis) petal dry weight (dwt) to flower fresh weight (fwt) and to flower dry weight (dwt), petal dry matter (DM) %, ^

calculated petal dwt/m2, and petal harvest index (HI). (NS = not significant.)

Flowers/plant

18.6

13.3

10.3

6.13.4

2.13.01

Flower fwt (g/tir)

48 8

927

1197

1411

1349

1361241.2

Flower dwt (g/n r)

61

110

144

171

159

16326.8

Flower fwt /plant (g)

55.0

37.1

27.3

15.17.9

4.38.19

Fwt/flower (g)

2.97

2.78

2.66

2.46

2.31

2.100.165

Flower DM (%)

12.6

11.9

12.1

12.1

11.9

12.00.67

CL

Plant no./m 2 Petal dw t: flower fwt Petal dw t: flower dwt Petal DM (%) Petal dwt/m 2 (g) Petal HI X

0.588 14.2 36.0 0.091 §•0.611 12.7 6 7.2 0.113 B.0.599 13.6 86.3 0.138 g0.550 13.4 93.9 0.135 £-0.533 12.4 85.4 0 .122 %0.533 13.5 89.8 0.109 §'0.0406 1.29 13.81 0.0293 §

<0.01 NS <0.001 <0.05 gp<;

o_

oo

92646

101179332LSD (5%)

(d.f. 15)F-test probability

0.08600.08120.08500.07820.07250.07650.00871

<0.05

8/2/2019 01140671%2E2000%2E9514120



Fig 2 Calendula (Calendulaofficinalis) cumulative flower freshweight/m2 at six plant densitiesfrom early February to mid March1998. • = 9 plants/m2, O = 26plants/m2, T = 46 plants/m2, V =

101 plants/m

2

, • = 179 plants/m

2

,and • = 332 plants/m2. Verticalbars represent LSDs between treat-ment means (P < 0.05) at each har-vest.

highest plant populations, which did not have sig-nificantly different flower weights (Table 2). Simi-larly, the mean dry weight of flowers increased to159 g/m 2 for the four highest plant populations.Flower fresh weight per plant decreased 13-foldfrom 55 g/plant at 9 plants/m 2 to 4 g/plant at 332plants/m 2 (Table 2), and the w eight per flower alsodecreased by 30% from 3 g to just over 2 g. As aresult, there was a considerable range in flower

num ber and flower yield accumulation among plantpopulations (Fig. 1 and 2). Flower dry matter per-centage varied from 11.6 to 14.1 % over the seasonwith no con sistent trend (data not presented); at finalharvest there was no significant difference betweenplant populations (Table 2). There was no consist-ent replicate effect on flower yield, indicating thatany potential increased flower production associatedwith increased fertility was offset by the increasedlodging.

Petal yieldThe d ried orange petals made up between 7 and 9%of the fresh weight and 53 and 61% of the dry weightof the flowers; the higher proportion w as at the fourlower plant populations (Table 3). There was noeffect of plant population on petal dry matter per-centage. Yields of dry petals/m 2 were significantlylower for 9 plant/m 2 (36 g) compared to the fourhighest plant populations (89 g on average). Petalharvest index (dry weight of petals/biomass dryweight) ranged from 9 to 14%, but, apart from the 9

plants/m 2 density, did not differ with increasing plantpopulation (Table 3).

Seed yield

Seed yield, calculated from flow er numbers and seedyield per head, increased with increasing plantpopulation from 128 g/m 2 at 9 plants/m 2 to 335 g/m 2 at 332 plants/m 2, but did not differ significantlyat the three highest plant populations (Table 4). Seedweight/head w as significantly higher at 9 plants/m 2

(0.78 g) than the other plant populations, whichaveraged 0.51 g. The dry weights of heads excludingseeds followed a similar pattern. Seed made up 8 5 -90% of the head dry weight. There was no significanteffect of plant popu lation on individual seed weight.The estimated harvest index for seed was c. 29%,with no significant differences among treatments(Table 4).

DISCUSSION

Seed yields increased at a decreasing rate with in-creasing plant density up to 332 plants/m 2, with 85 %of maximu m seed yield produced at 101 plants/m 2.This latter density is somewhat higher than the 40-60 plants/m 2 suggested as optimum by Van Dijk &Borm (1992) and Cromack & Sm ith (1998). Flowernumbers and weights show ed a similar response, butwith maxima at 101 plants/m 2, indicating that theoptimum plant density for flower production is simi-lar to that for seed production.

Our establishment rate was about half that ofCromack & Smith (199 8), but probably reflects the

difficult conditions under which this crop estab-lished. Crusting soils and hot drying winds made

8/2/2019 01140671%2E2000%2E9514120



C/3

Z

T 3

'5

1

1

I1

d §S

•<» 'S3'5

oooooooZ

N O

OOOOOOOV

m ft.av rN rr 4s

• o r- rn c« y— — r<i -J t ,

emergence through a capped soil difficult. Our es-tablishment rate was also affected by weed compe-tition. Although there are no herbicide labelrecommendations for calendula in New Zealand,herbicides have been successfully used overseas tocontrol weeds in this crop (Lamont & O'Connell

1986; Pank & Ennet 1988). Therefore, the o ptimumseeding rate of 24 kg/ha (10 1 plants/m 2) in this trialmay be reduced under more favourable establish-ment conditions tow ards the 10 kg/ha optimumfound by Van Dijk & Borm (1992).

Zhukova et al. (1996) found that densepopulations delayed development of plants and di-minished their size. In our trial any initial delay inflower production at higher plant populations wouldsoon have been compensated for by the increasednumbers of flowers produced at the higher seeding

rates. Plant size decreased with increasing plantpopulation, but the flowers appeared to be at a moreeven height near the top of the canopy, which m adehand harvesting easier and may make mechanicalharvesting easier because less vegetative bulk willhave to be handled. Ano ther approach m ay be to usegrowth regulators to comp ensate for delayed devel-opment in dense populations. Growth regulatorshave been shown to increase flowers per plant (Palet al. 1986) and the volume of some of the ch emicalconstituents of calendulae flos (Abdalla et al. 1986).

Growth regulators may also reduce lodging, espe-cially under higher fertility situations, as we ob-served that the higher density plants in the replicatesin the area which had oca as the previous crop grewtaller and lodged more than those in the replicate inthe area which had be en left fallow the previous year.

Our seed was a mixture producing singles, semidoubles and doubles, mainly with orange petals butsome lemon. Seed catalogues show a range of cal-endula flower types in terms of size, appearance,colour, and time to flowering. Whether the differ-ent flower types or colours have any effect on chem i-cal composition and yield of calendulae flos isunknown, although Angelini et al. (1997) found awide range in seed oil and calendulic acid contentsbetween calendula types. In Italy, time from plant-ing to flowering ranged from 17 to 59 days, depend-ing on cultivar and season (Angelini et al. 1997).There may therefore be considerable scope to in-crease yields by selecting the best type suited toCanterbury co nditions. Consistency of quality needsto be examined as Piccaglia et al. (1997) found thatpigment levels in calendula flower heads variedconsiderably between years.

8/2/2019 01140671%2E2000%2E9514120



The seed yields obtained here were similar tothose of Cromack & Smith (1998) who harvestedyields of 2-2 .5 1 seed/ha with an oil yield up to 19%.Oil content was n ot measured in this trial. Angeliniet al. (1997) stated that, for calendula to be economic,cultivars with high seed oil content and a reduced

tendency to shed seed should be selected. In com-mon with overseas studies (Meier zu Beerentrup &Robbelen 1987; Baraynk et al. 1995) we found shed-ding of seed a problem when sampling our crop.The re is scope to select for improved fruit shape andseed retention (Theobald & Robbelen 1989).

Our harvested seed weights were at the low endof the range ob tained by A ngelini et al. (1997), andwere lighter than the seed sown for this trial. Thereasons for this are not known but may be becauseof the shorter time to maturity under the high

temperatures experienced by our crop in the warm1997-98 season. Seed yields have been increasedwith nitrogen fertiliser applications (Nordestgaard1988; Barman & Pal 1994), although in this triallodging was worse in those parts of the trial wheremore fertiliser had been applied to previous crops.

The m ajor problem w ith the commercialisation ofcalendula will be the harvesting of the flowers andthe seed (Barayn k et al. 1995). The calendula plantis indeterminate, and unharvested plants in our trialcontinued to flower throughout the winter. An esti-

mate will have to be made about the best time toharvest flowers or seed. For seed production in theNetherlands, Breemhaar & Bouman (1995) sug-gested that the optional harvest time was when 50-70% of the seeds were mature. Semi-mechanicalmetho ds for harvesting flowers are being developedbut still result in considerable yield losses (van derM heen 1993). For seed production, the crop has tobe swathed or desiccated (Nordestgaard 1988;Breem haar & Bou man 1995). The seed is curly andneeds multistage cleaning (Breemhaar & Bouman1995), although an experimental dresser has beendeveloped to remove appendages from seed(Bilsland & Berlage 1986).

This preliminary study has shown that calendulacan be easily grown in New Zealand for flower orseed production. Small areas are already grown tosupply hand-picked flowers to the local pharmaceu-tical industry. W hether the crop will be grown on alarger scale will depend on ma rkets, profitability, andthe development of suitable harvesting technology.Furthe r agronomic research is needed to ensure thatvalidated crop managem ent guidelines are availableto growers if and when large-scale calendula produc-tion occurs.

ACKNOWLEDGMENTS

We thank Natures Kiss (New Zealand) Ltd for supply-ing the seed and Julian Hodgkinson for assistance withmaintaining and samp ling the crop. The trial was fundedthrough the Public Good Science Fund administered bythe New Zealand Foundation for Research, Science and

Technology.

REFERENCES

Abd alla, N. M.; El-Gengaihi, S.; Sadrak, I. 1986: A studyon the influence of Cycocel and A lar 85 on growth,flowering and active ingredients of Calendulaofficinalis L. Acta Agronomica Hungarica 35:41-45 .

Akihisa, T.; Yasukawa, K.; Oinuma, H.; Kasahara, Y.;Yamanouchi , S. ; Takido, M.; Kumaki, K.;

Tamura, T. 1996: Triterpene alcohols from theflowers of Compositae and their anti-inflamma-tory effects. Phytochemistry 43: 1255-1260.

Angelini, L. G.; Moscheni, E.; Colonna, G.; Belloni, P.;Bonari, E. 1997: Variation in agronomic charac-teristics and seed oil composition of new oilseedcrops in central Italy. Industrial Crops and Prod-ucts 6: 313-323.

Baranyk, P.; Zeleny, V.; Zukalova, H.; Horejs, P. 1995:Oil content of some species of alternative oilplants. Rostlinna Vyroba 41: 433-438.

Barman, D.; Pal, P. 1994: Effect of nitrogen and phos-phorus on seed yield in calendula {Calendulaofficinalis L.). Orissa Journal of Agricultural Re-search 7: 17-21.

Bilsland, D. M.; Berlage, A. G. 1986: A filament thresherfor seed. American Society of Agricultural E ngi-neers Paper 86-3061. 9 p.

Bisset, N. J. 1994: Herbal drugs and phytoph armac euticals.Medpharm, Stuttgart and CRC, Bota Raton, AnnArbor, London and To kyo. 566 p.

Breemhaar, H. G.; Bouman, A. 1995: Harvesting andcleaning Calendula officinalis, a new arable

oilseed crop for industrial application. IndustrialCrops and Products 4: 255-260.

Cromack, H. T. H.; Smith, J. M. 1998: Calendulaofficinalis—production po ten tial and cropagronomy in southern England. Industrial Cropsand Products 7: 223-229.

Delia Loggia, R.; Tubaro, A.; Sosa, S.; Becker, H.; Saar,St.; Isaac, O. 1994: The role of triterpenoids inthe topical anti-inflammatory activity of Calen-dula officinalis flowers. Planta Medica 60: 516-520.

Genstat 5 Committee 1993: Genstat 5 Release 3 Refer-ence Manual. Oxford University Press, Oxford.796 p.

8/2/2019 01140671%2E2000%2E9514120



Khodzhaeva, M. A.; Turakhozhaev, M. T. 1993: Carbo-hydrates of Calendula officinalis. Chemistry ofNatural Compounds 29: 533-534.

Lamont, G.; O'Connell, M. A. 1986: An evaluation ofpre-emergent herbicides in field grown cut flow-ers. Plant Protection Quarterly 1: 95-100.

Martin, R. J.; Jamieson , P. D.; Wilson, D. R.; Francis, G.S. 1992: Effects of soil moisture deficits on theyield and quality of 'Russet Burbank' potatoes.New Zealand Journal of Crop and HorticulturalScience 20: 1-9.

Meier zu Beerentrup, H.; Robbelen, G. 1987: Calendulaand coriandrum—new potential oilcrops for in-dustrial uses. Zeitschrift für Fett Wissenschaftund Technologie der Fette, Öle und Wachse 89:227-230.

Muuse, B. G.; Cuperus, F. P.; Derksen, J. T. P. 1992:Com position and physical prop erties of oils fromnew oilseed crops. Industrial Crops and Products1: 57-65.

New Zealand Soil Bureau 1968: General survey of thesoils of the South Island. New Zealand Soil Bu-reau Bulletin N o. 27. 404 p.

Nordestgaard, A. 1988: Trials with calendulas for seedproduction. Tidsskriftfor Planteavl 92: 213-215.

Pal, P.; Hore, J.; Poi, A. K. 1986: Effect of growth

regulating chemicals on growth and yield of flow-ers of Calendula officinalis. Environment andEcology 4: 541-543.

Pank, F.; Ennet, D. 1988: Chemical weed control inmedicinal plant crops. Part 10: marigold (Calen-dula officinalis L.). Pharmazie 43: 503-506.

Patrick, K. F. M.; Kumar, S.; Edwardson, P. A. D.;Hutchinson, J. J. 1996: Induction of vasculariza-tion by an aqueous extract of the flowers of Cal-endula officinalis L., the European marigold.Phytomedicine 3: 11-18.

Piccaglia, R.; M arotti, M.; Chiavari G.; Gandini, N. 1997:Effects of harvesting date and climate on theflavonoid and carotenoid contents of marigold(Calendula officinalis L.). Flavour and FragranceJournal 12: 85-90.

Theobald, D .; Röbbelen, G. 1989: Flowering biology andfruit formation of Calendula officinalis as a basisfor continued breeding success. AngewandteBotanik 63: 313-322.

Van der Mheen, H. J. 1993: Research on herb cultivation

for flower production. Publikatie Proefstationvoor de Akkerbouw en de Groenteteelt in deVollegrond, Lelystad No. 70A: 154-156.

Van Dijk, N.; Borm, G. E. L. 1992: Crop managementresearch on Calendula officinalis (marigold) in1992. Publikatie Proefstation vo or de Akkerbouwen de G roenteteelt in de Vollegrond, Lelystad No.73A: 108-109.

Zhukova, L. A.; Voskresneskaya, O. L.; Grosheva, N. P.1996: Morphological and physiological charac-teristics of ontogenesis in pot marigold (Calen-

dula officinalis L.) plants grown at differentdensities. Russian Journal of Ecology 27: 100—106.

Documents

01140671%2E2000%2E9514120