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ARTICHOKE OR GLOBE ARTICHOKE AND CARDOON
Cynara scolymus L.,¹³ family Compositae

The artichoke is grown almost entirely in California where there were about 11,000 acres in 1969 with a farm value of about $7 million.
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¹³ Cardoon (Cynara cardunculus L.) is similar to artichoke except that it is spiny and more robust. It is cultivated, on a much smaller scale than artichoke, for its edible root and thickened leafstalk. The inflorescence and pollination relationships are similar to artichoke (Bailey 1949*).

Plant:

The artichoke is a herbaceous perennial, the plant being renewed from year to year by lateral offshoots that arise just below the surface of the ground. Each offshoot forms a rosette of leaves, in the center of which the flower stalk later appears. The plant will grow indefinitely, but is usually replaced every 4 to 7 years. It grows to a height of 3 or 4 feet but as much as 6 feet across.

The marketable portion is the 1- to 4-inch immature flower head (fig. 43), including the tender bases and inner portion of the numerous fleshy bracts, the enclosed immature staminal column, and the receptacle or base.

If seed heads are allowed to mature, the flower stalk withers. Propagation is usually vegetative by use of the lateral offshoots or "suckers" (Wellington 1917, Tavernetti 194 7). Propagation by planting seed has been considered impractical (Wellington 1917) because of the variation in the offspring. With improved breeding techniques and development of pure lines, however, the use of planting seed is more practical.

Inflorescence:

The unremoved buds develop centripetally into purple-centered globular flower heads 6 to 8 inches in diameter, resembling those of a gigantic thistle (fig. 44). The numerous 1- to 2-inch long florets, with their slender corolla tubes, are set closely together on the receptacle. The pistil is elongated and conspicuous and appears to be receptive throughout its upper portion (Jones and Rosa 1928*). The anthers discharge their pollen near the stigmatic area of the style, and, according to Foury (1967), the elongating style and stigma take with them a considerable quantity of pollen ready to germinate, but the stigma is not receptive until 5 to 7 days later. By then, the pollen is no longer viable.

[gfx] FIGURE 43. - Artichoke at the proper bud-harvesting stage.
FIGURE 44. - Longitudinal section of artichoke flower, x 1/3, and floret, x 2.

Pollination Requirements:

The pollen must be transferred from anthers of one floret to the stigma of another. According to Harwood and Markarian (1968), pollination is brought about by insects or mechanical agitation of each flower. This indicates that the flower is incapable of self-fertilization, although it is self-compatible. Harwood and Markarian (1968) stated that seed production problems in Russia were reported by Panov (1949).

Pollinators:

Foury (1967) stated that insects are the exclusive pollinators of artichoke. The flowers are freely visited by honey bees and other pollinating insects. Harwood and Markarian (1968) stated that seed yields are uncertain, which they associate with vernalization and weak floral development. The relation of increased pollinating insect population to seed production is not mentioned. The fragmentary information indicates that where maximum seed production is desired, the use of an adequate concentration of pollinating insects would be necessary.

Pollination Recommendations and Practices:

There have been no recommendations for the use of pollinating insects on artichoke, and there is no indication that growers take steps to use such insects.

LITERATURE CITED:

FOURY, C.
1967. [STUDY OF THE FLORAL BIOLOGY OF THE ARTICHOKE (CYNARA SCOLYMUS L.); APPLICATION TO SELECTION. PART 1: DATA ON FLORAL BIOLOGY.] Ann. de l'Amelior. des Plantes 17(4): 357-373. [In French, English summary.]

HARWOOD, R. R., and MARKARIAN, D. HARWOOD, R. R., AND MARKARIAN, D.
1968. ANNUAL CULTURE OF GLOBE ARTICHOKE CYNARA SCOLYMUS L. 1. PRELIMINARY REPORT. Amer. Soc. Hort. Sci. Proc. 92: 400-409.

PANOV, M. A.
1949. [PRODUCING ARTICHOKE SEED.] Sad i Ogorod 12: 55-57. [In Russian.] Cited by Harwood and Markarian (1968)

TAVERNETTI, A. A.
1947. PRODUCTION OF THE GLOBE ARTICHOKE IN CALIFORNIA. Calif. Agr. Ext. Serv. Cir. 76, rev., 19 pp.

WELLINGTON, J. W.
1917. CULTURE OF THE GLOBE ARTICHOKE. N.Y. (Geneva) Agr. Expt. Sta. Bul. 435: 311-319.

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