Variation in the yield and essential oil of four chamomile varieties grown in Finland in 1985 — 1988

Four chamomile (Matricaria recutita L.) varieties were grown at Puumala, Finland (61°40' N, 28°15' E) in 1985—1989 from spring sowings on stony till soil, pH 5.8. The weather conditions in the experimental years were very different. For instance between 1987 and 1988 there was a difference of 5,3°C in the mean temperature of the growing periods (MaySeptember). The four-year average of the fresh flower yield was 0.4 (0.1 —0.7) kg/m 2 . The yields varied greatly depending on the number of harvests, which depended on the weather conditions. One harvest could be obtained in 1986 and 1987, two in 1985 and three in 1988. In spite of the different weather conditions there were no differences in the content and composition of the essential oil distilled from the dry flowers. Index words: chamomile, varieties, flower yield, essential oil

Index words: chamomile, varieties, flower yield, essential oil Introduction Chamomile {Matricaria recutita L.) is a na- tive plant of the Finnish flora, but it occurs quite rarely due to the widespread use of her- bicides in agriculture and on roadsides.All chamomile used in the pharmaceutical indus- try and sold in health shops a total of 8.7 t to a value of FIM 521.000 was imported in 1982 (Halva 1985).
Field experiments for production of chamo- mile were started in 1984 within the herb cultivation project of the University of Helsinki, Finland, organised by the Department of Hor- ticulture and the Pharmacognosy Division (Galambosi 1989).In addition to the agro- technical experiment, observations on differ- ent cultivars and chemotypes have been start- ed in order to study the effects of the climatic conditions on the herb yield and essential oil.
So far there are no long time observations on chamomile cultivated in the Finnish climate.
The very few experiments with chamomile in Finland are concerned with the accumulation of essential oil and the chamazulene content during ontogenesis (von Schantz and Salo- nen 1966), or with the effects of varions cli- matic factors on chamomile in comparative pot trials in Finland (Helsinki), central Europe (Munich), and Asia Minor (Ismir, Turkey) reported by Franz et al. (1986).The latest observations were carried out in 1984 during a one year experiment in which the morphological characters, yield and essential oil con- tent and composition of seven chamomile species grown in parallel in Hungary and South- Finland were studied (Galambosi et al. 1988).
The purpose of this work was to study the variation of flower yield and essential oil of four chamomile varieties during a longer period under normal field conditions in Finland.

Material and methods
The experiments were carried out at Puu- mala (61°40' N, 28°15' E) in a stony till soil, pH 5.8.The agricultural methods were the same each year and similar to the general Hungarian methods (Svab 1978).The chamo- mile was sown in spring using 5 kg/ha seed (5 g/10 m 2) with diffuse surface sowing.The plot size was 10 m 2 in two replications.The plots were fertilized with 50-80 -85 kg/ha nitrogen, phosphor and potassium at the time of soil preparation.
Harvesting was carried out with a hand- harvester, the flower and herb yields (stems with flowers) being separated by a 18 mm screen.During the four growing seasons one harvest was gathered in 1986 and 1987, two in 1985 and three in 1988.The flower and herb samples were dried at 30°C for 12 h and stored in paper bags at room temperature.The es- sential oil analyses were carried out in the laboratory of the Department of Special Biology, University of Kosice, Czeshoslovakia, in 1986-1988 from the first harvests, in 1988 from the second harvest as well.The essential oil was obtained by 2 h distillation of 2 g dry samples of the ground drug in three replications.The content of essential oil was determined gravimetrically (Holz and Demuth  1975).The main components of the essential oil were determined by means of gas chro- matography (Repcak et al. 1980).
The data on the essential oil content and composition was studied by analyses of vari- ance (Svab 1981).
The meteorological conditions during the experimental periods as measured by the Finnish Meteorological Institute, are presented in Figure 1.The climatic conditions were quite different in each year.In 1986 and 1988, the average temperature of the growing season was higher than 30 year average.In May-June-July the average temperature was 2 to 4°C higher than the long term average.The effec- tive temperature sum (calculated from the sum of the mean daily temperatures above + 5°C between May 15th and August 31th) was 1072°C in 1986 and 1168°C in 1988.In 1987, on the other hand, the growing sea- son was colder and rainier than the 30 year average, the temperature being 2 to 3°C low- er and the precipitation 130 mm higher than the long-term average.The effective temperature sum was only 750°C.The temperature in 1985 did not differ too much from the average, the effective temperature sum being 928°C, but the second half of the growing period was very rainy.Thus the chamomile   ages .
varieties were grown under very different weather conditions.

Results and discussion
Length of the growing periods The average length of the period from sow- ing to the first flower harvest was 71 days, but in 1986 and 1988 it was shorter due to the warm and dry weather (Table 1).In 1987, as a consequence of the cold and rainy summer, the first harvest was collected 84 days after sowing, and a second flowering did not ap- pear.The spring sowings can generally be made in the middle of May after melting of the snow, when the soil surface is rather dry.
The length of the growing periods of chamomile depends on the weather condi- tions: if the spring sowing is successful and there is enough precipitation for second and third flowerings it can be 100-115 days long.

Flower and herb yield
The fresh flower and herb yields are presented in Tables 3-4 and in Figure 2. The quantities were determined by the number of harvests and by the weather conditions.
The four year average yield of fresh flower was 0.4 kg/m 2 .From only one harvest the yields were generally low (0.17 kg/m 2 ), especially in 1986 and 1987.If second and third harvests were available, the yields reached 0.6-0.7 kg/m 2 .The yields from spring sow- ings are at the same low level as reported by Svab (1978) and Zalecki (1978).There was no connection between the flower or herb yield and the temperature sum of the growing season.The highest yields were achieved in 1985 and 1988 with low and high temperature sums (928 and 1168°C, respectively), and the lowest yields were obtained in 1986 and 1987, also with high and low values (1072 and 750°C).The critical factor affecting the yield is the precipitation in early spring.If there is enough precipitation in the period of the vegetative growth of the roots and rosettes, the yield will be good as in 1985.In 1988, the warm summer caused continuous flowering and gave three harvests, but the yield re- mained lower due to lack of moisture in the soil in May.The fresh herb yield obtained after separation of the flowers and which is suitable for distillation or extraction varied from 0.03 to 0.60 kg/m 2 , being on average 0.20 kg/m 2 .The quantitative herb yield of the second harvest was affected by the high precipitation in July, 1985.The response of the different varieties to the varying weather conditions was different.The highest flower and herb yields were produced by the varieties Degumille and Bu- dakalaszi-2.The yield of Bona was lowest due to the low flower mass.The average proportion of flowers in the total phytomass varied from 30 to 38 %, which is a little higher than the results of Gasic et al. (1989).

Content and composition of the oil
The oil contents of Budakalaszi-2 and Degumille were stable 1 %, and no changes were observed from year or between the first and second harvests in 1988 (Table 5).The average essential oil content of Csomdri and Bona was 0.9 °7o.In 1986 and 1987, the oil content of Csomdri was 0.8 %, the oil content of Bona in 1986 and in the second har- vest of 1988 was 0.7 °7o and 0.8 °7o, respectively (p<o.l).
The variation of the main components of the essential oil is shown in Table 5.There were clear differences between the varieties: Degumille, Csomdri and Bona seemed to be a-bisabolol types (35 -60 %), while Budakalaszi-2 is a bisabololoxide type cultivar.There were no big differences in the content of the main components caused by the very different weather conditions during the grow- ing periods.The chamazulene content of the oils varied between 11 and 21 °7o.Some vari- ation can be observed in the content of trans-P-farnesene, the content being highest in the warmest year 1988 and especially in the sec- ond harvest.This observation is in accordance with results of Gasic et al. ( 1989), who ied.Galambosi et al. ( 1988) stated the same reported the highest farnesene content of 16 tendency in a comparative study of 6 chamochamomile varieties in the warmest year stud-mile varieties grown in Hungary and Finland.In Hungary the P-farnesene content was higher when the summer was warm.
The four-year experiment on the cultivation of chamomile in Finland carried out under very different weather conditions confirmed the results reported earlier by Svab et al.  (1967), Honcariv et al. (1979)  and Franz et  al. (1986).The production of phytomass and the flower yield are influenced by climatic factors rather than by the genetically determined chemical characters of the different varieties or chemotypes.
Franz et al. ( 1986) stated that the oil for- mation is related to the flower formation.
Since the summer conditions in Finland are suitable for the flower formation of chamomile, there were no substantial changes in the content and composition of the essential oil during the four years of cultivation.The flow- er yield depends on the field conditions and suitable cultivation techniques.Growers must use the appropriate growing technique for chamomile, especially in the spring period, elaboration of such methods requires more detailed research.

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Fig. I. Mean temperature (A) and precipitation (B) at Puumala during the experimental years and long-term aver-

Table 1 .
Length of the vegetation periods of chamomile during 1985-1988 at Puumala.

Table 2 .
Height and morphological characters of flowers of chamomile varieties.

Table 4 .
Fresh herb yield after separation of the flowers (g/m ! ).Fresh flower yield of the chamomile varieties at Puumala 1985-1988.Roman numerals in the columns indicate first, second and third harvest.

Table 5 .
Content and main compounds of the essential oil of different chamomile varieties1986-1988.