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Morales, M.R., D.J. Charles, and J.E. Simon. 1993. Fennel: A new specialty vegetable for the fresh market. p. 576-579. In: J. Janick and J.E. Simon (eds.), New crops. Wiley, New York.

Fennel: A New Specialty Vegetable for the Fresh Market*

Mario R. Morales, Denys J. Charles, and James E. Simon

  1. METHODOLOGY
  2. RESULTS AND CONCLUSION
  3. REFERENCES
  4. Table 1
  5. Table 2
  6. Table 3
  7. Fig. 1
  8. Fig. 2
Finocchio or Florence fennel (Foeniculum vulgare Mill. ssp. vulgare var. azoricum Mill. Thell, Apiaceae), is being marketed as "anise" in supermarkets throughout the United States. While many cultivars of fennel are grown for the aromatic seed and foliage, finocchio fennel is produced for the enlarged bulb (thickened leaf bases) (Simon et al. 1984). The bulbs are becoming increasingly popular as an specialty vegetable where the bulbs are either consumed raw or prepared by baking, blanching, or boiling. The bulbs are sold as "anise" because of the strong "licorice" or "anise" aroma. Increased consumption and demand for the fresh product offers expanded opportunities for American growers yet very little information is available for potential producers on production or varietal selection (Morales et al. 1991). Fennel, a perennial herb grown as an annual, has a tendency to bolt, a periodic problem with the splitting of the bulb and formation of excessive side shoots within the bulb. Yet, high quality bulbs should be firm, white, sweet, and whole with a minimum diameter of not less than 5 cm (Seelig 1974). The objective of this project was to evaluate fennel cultivars for yield and quality.

METHODOLOGY

Commercial seed of ten fennel cultivars was sown on Apr. 4 of 1990 and 1991. Seedlings were grown in a greenhouse for 38 days and then transplanted to the field onto raised beds on May 11 in 1990 and May 14 in 1991. The experiment was planted in a completely randomized block design with three replications consisting of single row plots. Rows were 1 m apart, 15 cm between plants and 27 plants/plot in 1990 and, 10 cm between plants and 15 plants/plot in 1991. Plants (Fig. 1) were harvested on July 17 in 1990 and Aug. 2 in 1991. In late May and June of 1991, black swallowtail caterpillars (Pappio sp.) were observed feeding on the leaves of the young transplants and manually removed from the plants. The middle 13 plants from each plot were harvested and the roots from each plant discarded. Five representative bulbs per plot were selected for qualitative evaluation of quality and visual appearance (Fig. 2).

RESULTS AND CONCLUSION

Significant variation among cultivars in bulb yield, bulb dimensions, days to 50% bolting, plant height, and number of side shoots was observed (Table 1, 2). The cultivar 'Zefa fino', from Royal Sluis and Johnny's Seed Company, was the highest in bulb weight, the lowest in foliage yield, and the second lowest in plant height, indicating an increased allocation of carbohydrates into the bulbs rather than to the foliage. 'Zefa fino' had significantly greater bulb circumference than the other cultivars (Table 1). Disease and insect damage to the bulbs was minimal and not different among cultivars (Table 2). Bulb width and circumference were correlated with bulb weight (Table 3).

'Zefa fino' also showed significant differences from the other cultivars in days to 50% bolting. The later maturity of this cultivar is highly desirable because a longer vegetative period permits the plant to produce larger and heavier bulbs. 'Zefa fino' had the lowest number of side shoots on the bulbs, an undesirable genetic trait among some cultivars.

The time from sowing in the greenhouse to harvest was 104 days in 1990 and 120 days in 1991; time from field transplanting to harvest was 67 days in 1990 and 80 days in 1991. Average growing season of direct seeded fennel in California ranges from 110 to 125 days (Seelig 1974). 'Zefa fino' had the greatest bulb weight and circumference. Because the width and thickness of finocchio fennel bulbs continues to increase over time (Suhonen and Kokkonen 1990), the determination of the optimum harvest period is difficult. While bulbs from all cultivars met the minimum requirement for bulb size (Seelig 1974), significant differences in visual appearance and shape suggests that genotype is very important in bulb quality. The most attractive appearance among the cultivars evaluated was 'Zefa fino', whose bulbs were white, firm, highly aromatic with no visual discolorations.

REFERENCES

*Journal Paper No. 13,211, Purdue Univ. Agr. Expt. Sta., West Lafayette, IN 47907-1165. This research was supported in part by grants from the Indiana Business Modernization and Technology Corporation, Indianapolis, and the Purdue University Agricultural Experiment Station (Specialty Crops Grant No. 014-1165-0000-65178). We thank Tom DeBaggio and Jules Janick for providing us with some of the Italian germplasm.
Table 1. Foliage and bulb means per plant of ten finocchio fennel cultivars grown in central Indiana for two growing seasons, 1990-1991.

Bulb characteristics
Cultivar Seed source Foliage weight (g/plant) Weight (g) Length (cm) Width (cm) Circumference (cm)
Zefa fino RSz 111 75ay 14.1a 9.8a 10.8a
Zefa fino JS 106 74a 13.8a 10.0a 21.5a
Wandenromen RS 144 58b 14.8a 8.9ab 18.9b
Romano precoce FM&C 130 58b 14.4a 8.9ab 18.6b
Romanesco, Urbe SAIS 132 57b 15.1a 8.9ab 18.9b
Grossissimo mammuth FM&C 135 54bc 14.7a 8.8ab 18.5bc
Romagna SAIS 134 48bc 14.2a 8.3bc 17.5bcd
Parma, Fucino SAIS 113 45bc 14.3a 7.6c 16.7cd
Florence CP 132 42c 13.8a 7.9bc 16.6d
Mantovano SAIS 116 41c 12.2b 8.1bc 17.6bcd
Grand mean 125 55 14.1 8.7 18.5
CV 22 20 8.5 10.5 7.7
zSeed sources were RS = Royal Sluis, Holland; JS = Johnny's Selected Seeds, Albion, Maine; SAIS = Societa Agricola Italiana Sementi, Cesena (FO), Italy; FM&C = Faraone Mennella & Co., Pagani (SA), Italy; C = Companion Plants, Athens, Ohio.
yValues followed by same letter are not significantly different at P = 0.05.

Table 2. Characteristics of ten finocchio fennel cultivars grown in central Indiana, 1991.

Cultivar Seed source Days to 50% bolting Plant height (cm) Disease damagex Insect damagex No. side shoots
Zefa fino RSy 114az 41cd 1.3ab 0.0 5.1b
Zefa fino JS 116a 42cd 1.1ab 0.3 5.1b
Wandenromen RS 103bcd 52a 1.1ab 0.0 7.2a
Romano precoce FM&C 107b 48ab 0.8ab 0.0 5.5ab
Romanesco, Urbe SAIS 106bc 49a 1.1ab 0.2 6.0ab
Grossissimo mammuth FM&C 106bc 50a 0.7b 0.0 5.6ab
Romagna SAIS 102bcd 49a 1.1ab 0.2 6.7ab
Parma, Fucino SAIS 101cd 45bc 1.2ab 0.2 5.1b
Florence CP 100d 53a 0.8ab 0.2 6.3ab
Mantovano SAIS 100d 40d 1.7a 0.0 5.6ab
Grand mean 105.5 47 1.1 0.1 5.8
CV 2.7 4 17.3
xBased on visual estimation of damage rating scale from 0 (no damage) to 5 (severe damage).
ySeed sources were RS = Royal Sluis, Holland; JS = Johnny's Selected Seeds, Albion, Maine; SAIS = Societa Agricola Italiana Sementi, Cesena (FO), Italy; FM&C = Faraone Mennella & Co., Pagani (SA), Italy; CP = Companion Plants, Athens, Ohio.
zValues followed by same letter are not significantly different at P = 0.05.

Table 3. Correlations of plant characteristics from ten finocchio fennel cultivars grown in 1990 and 1991.

Traits Bulb wt. Bulb length Bulb width Bulb circumference Days to 50% boltingz Plant heightz
Foliage weight 0.48** 0.18 0.58** 0.60** -0.29 0.36
Bulb weight 0.24 0.70** 0.84** 0.46** 0.04
Bulb length 0.23 0.22 -0.01 0.22
Bulb width 0.92** 0.47** 0.02
Bulb circumference 0.54** -0.16
Days to 50% bolting -0.36
*, ** Significance different from zero at P = 0.05 and 0.01, respectively.

zData from only 1991.

Fig. 1. Finocchio fennel plants growing in central Indiana.

Fig. 2. Close-up of finocchio fennel 'bulb' cv. Zefa fino, comprised of thickened leaf bases formed at the base of the plant.

Last update September 17, 1997 aw