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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

  4. Table 1
  5. 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.


*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).

Fig. 1. Basil with compact inflorescences: (left) purple, (right) white.

Last update August 24, 1997 aw