The aim of every plant production is to reach high and stable yield. But, it is also very important that the products have to be good quality.

A two-year research (in 1998 and 1999) investigated now the yield and quality of sweet basil affected by: row spacing and spacing within a row; seeding and planting (the way of planting establishment) and planting establishment time. Seeding material for the first variant was produced in a glasshouse with two-row spacing: 50x30cm and 70x30cm. In the second variant the seeding was direct with the spacing of 50x0 cm and 70x0 cm. The third variant used seeding material produced in cool seedbeds and transplanted with the spacing of 50x30 cm and 70x30 cm. Phenophases from emerging to flowering, when the harvesting was done, were observed.

The obtained results showed that the highest yield in both years of the research was achieved in the first variant with the spacing of 50x30 cm. The yield of dry aerial part of sweet basil (Ocimum basilicum,) in this variant was 5671 kg/ha in 1998, and 5886 kg/ha in 1999. The lowest yield was recorded in the third variant with the spacing of 70x30 cm. The yield in this variant was 2652 kg/ha in 1998 and 2784 kg/ha in 1999.

The highest percent of essential oil was obtained in the second variant (1.142%) in the first harvest of 1999. with the spacing of 50x0 cm.

Key words: Ocimum basilicum, plant density, yield, quality.

Sweet basil (Ocimum basilicum L.) is an annual herb in Lamiaceae family. It originates from India. It is cultivated in whole Europe, but mostly in Italy and France. In our country it is cultivated as a medical herb, as a spice, and as the herb for obtaining essential oil which is used in the perfumery and as an additive in the manufacture of various drinks. It is sensitive to low temperatures, and because it suffers damage from the early frosts in the fall the second harvest has to be carried out before the first frosts.

Fresh leaves of sweet basil have strong smell and hot savour, which come from the essential oil, which contains methyl-cavicol, linalool, cineol and other aromatic components. These components have bactericide effect. Because of its smell and its healing properties sweet basil is very popular among common people and it has been celebrated in folk verse. It is commonly used in folk medicine as a sedative, as stomachich, also for better digestion and to prevent flatulence. It is related to many folk customs and it is also used in some religion rituals. Sweet basil is often used as spice in culinary. Fresh leaves are used for vegetable soups, omelettes, sausages, mushrooms and especially for sauces and other dishes made of tomato. The leaves are also used to give aroma to wine vinegar which is added to salads (Morales M.R and Simon J.E., 1997).

The aim of this investigation was to point out the most suitable way and time for planting establishment of sweet basil, in order to obtain the highest yield of good quality. The experiment was carried out on the farm of the Institute for Medical Herbs in Pančevo and it was realised in three variants of manner and time of planting establishments, each of which has been done in two-row spacing. The type of soil on which the planting was carried out was swamp blackearth soil. Precipitation in the vegetation period during 1998 amounted to 288 mm of water, and 617 mm in the same period in 1999. Mean temperature per month in the vegetation period was 18.9°C in 1998 and 19.05°C in 1999.

In the first variant, the transplanted seedlings of sweet basil were produced in a glasshouse. The transplanting was carried out in two rows spacing, 50x30 cm and 70x30 cm. The planting was carried out on 4^th May 1998 and on 30^th April 1999. The height of the seedlings was 12-16 cm and the length of root was 6-8 cm in both years of the investigation.

In the second variant the seeding of sweet basil was direct and was carried out with 4 kg/ha seed on a depth of 3 cm. The seeding was carried out in unbroken rows with the spacing of 50 cm and 70 cm. The seeding was done on 20^th May 1998 and on 14^th May 1999. The seed used for the seeding had germination of 94% and 98% purity in 1998, and germination of 94% and 99% purity in 1999. This seed was used for producing the seedlings in a glasshouse for the first variant, as well as for the seedlings in cool seedbeds for the third variant.

In the third variant, the transplanted seedlings of sweet basil were produced in cool seedbeds (Jevđović et al., 2000). Cool seedbeds were planted on April 21, 1998 and on April 16, 1999. Transplanting was carried out on June 14, 1998 and on June 11, 1999. The height of the seedlings was 14-16 cm and the length of root was 7-10 cm in both years of the investigation. All the necessary preventive measures, which included mechanical operations for weed control, were applied.

The first harvest in the first variant was carried out on July 10, 1998 and on July 6, 1999; the second harvest was carried out on August 29, 1998 and on October 15, 1999. The first harvest in the second variant was carried out on August 4, 1998 and on August 2, 1999; the second harvest was carried out on September 25, 1998 and on September 22, 1999. The first harvest in the third variant was carried out on August 6, 1998 and on August 2, 1999, and the second harvest was on September 26, 1999 and on September 22, 1999. The data obtained in the experiment were statistically analysed through the analysis of variance (ANOVA), and the important differences in mean values were established with LSD-test for the risk level of 5% and 1% (Hadživuković, 1991).

Table 1. gives data on total annual yield of sweet basil dry aerial mater and the content of essential oils.

The greatest yield of sweet basil dry aerial matter in both years of the experiment was obtained from the seeding material produced in a glasshouse, with the spacing of 50x30 cm. The yield was 52% higher than in the third variant, where the seeding material was produced in cool seedbeds with the spacing of 50x30 cm, and it was over 110% higher than the yield of the same variant of seeding with spacing within a row of lower density, 70x30 cm. The yield of the first variant of seeding with the spacing of lower density (50x30 cm) also produced greater yield than the second variant of seeding, namely the direct seeding. Row spacing of 50x30 cm in the first variant produced 10-40% higher yield compared to the row spacing of 50x0, and than 50% compared to the row spacing 70x0 cm in the direct seeding.

Among other things, this results from the effect of transplanting time, which is obviously in positive correlation with the obtained level of sweet basil dry aerial matter yield. The earliest transplantation of the transplanting material (late April and early May) was carried out from the glasshouse seedplot, which ensured that three harvests were carried out in time during the year, one thing that the other variants could not offer. With them, only two harvests were carried out.

Direct seeding of seeds in unbroken rows, although carried out only 15 days later than in the first variant of planting, produced considerably worse yield of dry aerial matter, in particular with the spacing within a row of lower density (Graph 1). This variant of seeding has also the longest vegetation period (from the seeding till the first harvest) in both years, a period of 2,5 months.

Transplantation of sweet basil seedlings produced in cool seedbeds was carried out later than in the first and the second variant (mid-June). This variant of transplantation showed that the conditions of producing the transplanting material in cool seedbeds are not suitable for producing the seedlings of sweet basil, especially if the transplantation was carried out with larger row spacing (70x30 cm). Spacing within a row of higher density (50x30 cm) with seedlings produced in cool seedbeds gave approximately the same yield of dry aerial matter as the spacing of lower density (70x0 cm) in the direct seeding.

The second harvest in all three variants of planting in both years of the experiment produced up to 80% higher yield of dry aerial matter, compared to the other harvests in the same variant. There are many reasons for this. First of all, the plants in the second phase have more developed and stronger root system, and because the whole aerial parts more developed the yield is also the highest. The climatic conditions were the most suitable in the vegetation period of growth of the plants for the second harvest (the highest precipitation and the highest temperature). The third variant gave the worst results because the plants could not fully develop, since the harvest had to be carried out before first morning frosts that would have damaged the yield.

In the second year of the experiment (1999) the climatic conditions were more favourable; the quantity of precipitation was two times greater and the temperature was higher than in the previous year, 1998. All that had positive effect on the total yield of sweet basil dry aerial matter in all variants of planting (Graph 1). Total yield in this year was 5-30% higher than in 1998.

It follows that the amount of the produced yield is affected by the time of the planting (seeding) of the transplanting material and by the conditions for producing the seedlings, but it was also affected by the climatic conditions in the vegetation period of production of sweet basil. These results of the experiment are also confirmed by very considerable differences in mean values for both analysed years.

Higher percent of precipitation (617 mm) and higher temperature (19.05°C) in 1999, produced not only higher yield of dry aerial matter but also higher content of essential oil in all variants of seeding and planting. From this it can be concluded that, above all, the yield of sweet basil essential oil depends on the outside weather conditions for production in the vegetation period. Beside that, the first harvest in all variants of planting in both years of the experiment produced higher content of essential oil, which confirms once more that the condition for producing essential oil is favourable weather.

The content of essential oil varied in great extent according to the variants of production of the transplanting material and according of the spacing within a row of planting or seeding (Graph 2). The lowest content of essential oil has been found in the production of sweet basil with the transplanting material produced in a glasshouse. The first variant of seeding produced the greatest yield of sweet basil dry aerial matter but the lowest content of essential oil.

The highest content of essential oil was found in direct seeding of seeds with the row spacing of 50x0 cm (0.811% in 1998 and 1.142% in 1999), and with the transplanting material produced in cool seedbeds, with a lower density spacing of the plants, 70x0 cm (0.815% in 1998 and 1.014% in 1999). Lower density planting of transplanting material (70x30 cm) in the first variant produced 50% higher content of essential oil than higher density spacing in the same variant. Only the higher density seeding of the second variant in both years of the experiment produced higher content of essential oil than the seeding of lower density. It is obvious that the content of essential oil is in positive correlation with lower density of planting of transplanting material and with higher density of direct seeding.

The analysis presented in this paper shows that:

1. Early planting of the seedlings from the glasshouse produces the highest yield of sweet basil dry aerial matter, because it ensures three harvests per year.

2. Row spacing of 50 cm produced higher yield than the spacing of 70 cm in all variants.

3. Greater quantity of precipitation and higher temperature per month in 1999 made it possible that the yields in these variants were higher than in the previous year.

4. The second harvest in all variants in both years gave up to 80% higher yields.

5. Favourable weather conditions in the vegetation period increase the content of essential oil.

6. The earlier the harvest the higher the content of essential oil.

7. The content of essential oil is in positive correlation with lower density spacing within a row and with direct seeding of higher density.

1. Hadživuković, S. (1991): Statistički metodi. Drugo prošireno izdanje. Poljoprivredni fakultet, Novi Sad.

2. Jevđović R., Pavlović R., Radanović D., Jevđović J. (2000): Efekat različitih načina uzgoja semenskog useva na prinos i kvalitet semena bosiljka. Naučno-stručno savetovanje agronoma Republike Srpske sa međurednim učešćem, Teslić, Mart 13-17, 2000, Zbornik izvoda pg. 55.

3. Morales M.R., Simon J.E.: "Sweet Dani" : a new culinary and ornamental lemon basil. Hort Science (1997) 32(1) 148-149 (en. 3 ref) Center for New Crops and Plant Products, 1165 Horticulture Building, Purdue University, West Lafayette, IN 47906-1165, USA.