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Morales, M.R. and J.E. Simon. 1996. New basil
selections with compact inflorescences for the ornamental market. p. 543-546.
In: J. Janick (ed.), Progress in new crops. ASHS Press, Arlington, VA.
New Basil Selections with Compact Inflorescences for the Ornamental Market*
Mario R. Morales and James E. Simon
- EVALUATION OF S2 LINES
- FUTURE PROSPECTS
- REFERENCES
- Table 1
- Fig. 1
Basil (Ocimum basilicum L., Lamiaceae) has long been prized as a
culinary herb used in foods and as a source of essential oil for flavors and
fragrances (Simon et al. 1984; 1990). There are many cultivars of basil which
vary in their leaf size and color (green to dark purple), flower color (white,
red, lavender, purple), growth characteristics (shape, height, flowering time),
and aroma, making this plant an increasingly popular culinary and ornamental
herb (Darrah 1984; Morales et al. 1993). Primarily a cross pollinating
species, many cultivars of basil easily intercross (Krishnan 1981; Nation et
al. 1992), and several species of Ocimum can form interspecific hybrids (Sobti
and Pushpangadan 1982). With the increased interest in the use of basil as
ornamental herbs, we initiated a selection and breeding program to identify
promising new ornamental basils.
Our first released cultivar, originally identified in an extensive intermated
germplasm collection of Ocimum spp. in 1989, was developed by selfing and
selection from a tall upright basil with an intense lemon aroma (Morales et al.
1993) and released as 'Sweet Dani' in 1996 (Morales and Simon 1996). In 1993,
three other new and unusual basil phenotypes with intense purple, maroon and
white colored flowers, and very short and compact inflorescences were
identified in our basil nursery and selfed. Selections were grown in central
Indiana in 1994 and selfed to form S2 progenies for further selection. Plants
are compact, early flowering, and have a "flat-top" appearance which is covered
by a mass of flowers at full bloom (Fig. 1). The inflorescences are located
mainly at the top of the plant and each has from 10 to 13 whorls of six flowers
tightly arranged along the rachis. The plants will produce new inflorescences
if the old ones are removed. The growth habits of the purple, maroon and white
flowering basils are very similar. These selections are also highly aromatic,
and may be used for culinary purposes, as well as being suitable as pot or
bedding plants.
A total of 41 S2 basil lines (15 purple, 8 maroon, and 18 white) were sown in
flats in the greenhouse on May 13, 1995, and transplanted into single rows, 5 m
long, with plants spaced 0.5 m apart, at Lafayette, Indiana on June 9, 1995.
Days to flower for each line was determined at the beginning of open bloom.
Plant growth characteristics including plant height, plant width, leaf width
and length, inflorescence length, and overall uniformity and appearance were
assessed at full bloom. At harvest (Aug. 11), five plants from each line were
randomly cut and dried at 37°-39°C in a forced-air dryer for 18-20 days.
Essential oils were extracted via hydrodistillation and oil composition
determined by gas chromatography as reported previously (Charles and Simon
1990).
Each of the lines within each of the three basil phenotypes were significantly
different in most characters measured suggesting that further selection of
targeted traits is possible. Selection at the present time is based on a
subjective evaluation of appearance and esthetic quality, including plant
shape, structure, flower color intensity, and floral quantity (Table 1).
The purple compact flowering phenotypes appeared most uniform and attractive,
had a very compact inflorescence (1.7 to 1.8 cm long), and received positive
response from visitors. Lines 4, 7, 12, and 15 were selected for further
development. The maroon compact flowering phenotypes were not as intense in
flower color as the purple lines. Lines 7 and 14 were selected for further
development. The white phenotypes were planted in a compacted soil area that
led to reduced growth and lower essential oil yields (0.47% to 0.56% of 100 g
of dry material) than the purple and maroon phenotypes. Significant
differences between the 18 white lines allowed us to identify and select lines
2, 3, 13, and 18 as the most attractive and best performers.
All phenotypes were highly aromatic. The essential oils from the purple
compact flowered lines were rich in linalool (48% to 60%) and methyl chavicol
(20% to 24%); while the oils from the maroon compact flowered lines were rich
in linalool (78% and 80%) and low in 1,8-cineole (2.5% to 3.1%). The essential
oils from the white compact flowered lines were lower in linalool (58% to 60%)
and higher in 1,8-cineole (8.4% to 14.7%) than the maroon types.
After two cycles of selfing and selection, we identified several near-uniform
lines of compact-flowering basil with white, maroon, or purple flower. The
basil plants are relatively moderate to short (23-47 cm), with a rounded shape
and flat-top appearance, and exhibit very short and compact inflorescences (2-6
cm long) which cover the otherwise dark green foliage for several weeks. As
days to flowering varied greatly among the lines, it would be possible to
select for early or late maturity types. These basils will reflower if the
original first blooms are removed, a desirable trait for ornamental purposes.
The very short inflorescence length (10 to 13 whorls of six flowers tightly
arranged along its rachis) coupled with an intense flower color appear most
promising for further development.
Herb collections, which are well-known for their diverse genetic
characteristics have principally been screened for materials most suitable for
culinary purposes, for processing and essential oils. This study suggests that
such herb collections, may also offer a unique source of genetic materials for
potential use as ornamentals.
- Charles, D.J. and J.E. Simon. 1990. Comparison of extraction methods for the
rapid determination of essential oil content and composition of basil
(Ocimum spp.). J. Am. Soc. Hort. Sci. 115:458-462.
- Darrah, H.H. 1984. The cultivated basils. Buckeye Printing Company,
Independence, MO.
- Krishnan, R. 1981. Natural outcrossing in sweet basil Ocimum basilicum
L. Indian Perfumer 23(3/4):74-77.
- Morales, M.R. and J.E. Simon. 1996. `Sweet Dani': a new culinary and ornamental
lemon basil. HortScience: (in press).
- Morales, M.R., D.J. Charles, and J.E. Simon. 1993. New aromatic lemon basil
germplasm. p. 632-635. In: J. Janick and J.E. Simon (eds.), New crops. Wiley,
New York.
- Nation, R.G., J. Janick, and J.E. Simon. 1992. Estimation of outcrossing in
basil. HortScience 27:1221-1222.
- Simon, J.E. , A.F. Chadwick, and L.E. Craker. 1984. Herbs: An indexed
bibliography 1971-1980; the scientific literature on selected herbs, and
aromatic and medicinal plants of the temperate zone. Archon Books, Hamden,
CT.
- Simon, J.E., J. Quinn, and R.G. Murray. 1990. Basil: a source of essential
oils. p. 484-489. In: J. Janick and J.E. Simon (eds.), Advances in new crops.
Timber Press, Portland, OR.
- Sobti, S. and P. Pushpangadan. 1982. Studies in the genus Ocimum:
Cytogenetics, breeding and production of new strains of economic importance, p.
457-472. In: C.K. Atal and B.M. Kapur (eds). Cultivation and utilization of
aromatic plants. Jammu-Tawi, India.
*Journal Paper No. 14,985, Purdue University Agricultural Research Program,
West Lafayette, IN 47907-1165.
Table 1. Growth, yield and essential oil characteristics of second generation ornamental basil lines with compact purple, maroon and white inflorescences selected among 41 lines in 1995.
|
| Plant | Leaf | | Main components (% of total essential oil) |
| Flower color | Line | Height (cm) | Width (cm) | Length (cm) | Width (cm) | Inflorescence
length (cm) | Uniformityz (rating) | Appearancey
(rating) | Ess. oil content (%, v/dw) | Days to flower | Linalool | Methyl
chavicol | 1,8-Cineole |
| Purple | 15 | 32 | 42 | 4.8 | 2.4 | 1.7 | 1 | 1 | 1.96 | 79 | 48 | 24 | -- |
| 4 | 32 | 42 | 4.4 | 2.3 | 1.7 | 2 | 1 | 1.32 | 66 | 48 | 22 | -- |
| 7 | 30 | 40 | 4.4 | 2.2 | 1.8 | 4 | 3 | 1.64 | 69 | 50 | 23 | -- |
| 12 | 29 | 40 | 4.8 | 2.5 | 1.7 | 2 | 2 | 2.14 | 76 | 60 | 20 | -- |
| Maroon | 14 | 45 | 60 | 4.9 | 2.9 | 3.9 | 2 | 2 | 2.09 | 72 | 80 | -- | 2.5 |
| 7 | 40 | 50 | 4.7 | 2.7 | 3.5 | 2 | 2 | 2.07 | 76 | 78 | -- | 3.1 |
| White | 13 | 26 | 30 | 4.7 | 2.5 | 3.2 | 1 | 2 | 0.52 | 69 | 58 | -- | 14.7 |
| 18 | 25 | 28 | 4.7 | 2.7 | 2.9 | 2 | 3 | 0.56 | 73 | 60 | -- | 12.1 |
| 3 | 25 | 30 | 4.2 | 2.3 | 3.5 | 3 | 3 | 0.55 | 66 | 60 | -- | 10.6 |
| 2 | 23 | 29 | 4.1 | 2.3 | 3.2 | 3 | 3 | 0.47 | 69 | 59 | -- | 8.4 |
zScale of 1 (uniform) to 5 (nonuniform).
yScale of 1 (attractive) to 5 (unacceptable).
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Fig. 1. Basil with compact inflorescences: (left) purple, (right) white.
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Last update August 24, 1997
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