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  • Author or Editor: J. A. Principe x
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Abstract

Breeding of artichoke (Cynara scolymus L.), a cross-pollinated species, has been hindered by the lack of any recognized system of self-incompatibility or male-sterility (1). While making controlled pollinations with bagged flower heads during the spring of 1981, 3 male-sterile (MS) plants in the same half-sib family were found. The female parent of these plants, which had been selected from a segregating population derived from seed of unknown origin, produced abundant pollen.

Open Access

The artichoke, Cynara scolymus, is normally propagated by cuttings from mother plants; however, it is possible to produce some types of artichokes from seed. Methods used for producing open-pollinated seed of onion and carrots may be suitable for producing artichoke seed. Outcrossing in artichokes occurs because of differences in maturity of the staminate and pistillate phases within flowers. Producing artichoke seed by simple inbreeding techniques is usually not successful because of vigor loss and low pollen production, low seed production, and late maturity of progeny. Outcrossing is the preferred method of creating a new variety. The cultivar `Imperial Star' was developed by crossing a thornless French line with an Italian line that had sharp woody spines, and a uniform, olive-green color. The French line was a bright green with some light purple at the base of the bracks. The F1 generation from this cross had good hybrid vigor, and produced abundant seed and pollen. The F2 generation segregated widely with many recombinant types that neither parent showed (e.g., extreme thorniness of leaves and petioles). Two plants were selected for sibling pollination. Subsequent generations of siblings within this type produced higher percentages of the desired type—glossiness, earliness, and high seed yield. Subsequent sibling crossing led to the selection of `Imperial Star', PVP. 9000179.

Free access

Abstract

Resistance to the western biotypes of Aphis gossypii Glover in Cucumis melo L. breeding line LJ 90234 (inbred of P.I. 371395 from India) included tolerance expressed as freedom from curling of leaves following aphid infestation. The flat and curled phenotypes in progenies from a cross of this line with cv. PMR 45 were differentiated by a single gene, melon aphid tolerance (Ag, Aphis gossypii tolerance) with flat leaves dominant. Tolerance expressed as nearly normal ht of F1 and some F2 plants following mass infestation appeared to be less simply inherited. Its measurement was masked by inherent variation in growth rate and environmental factors including variation in insect attack.

LJ 90230, selected from P.I. 161375 from Korea, was stunted by the aphid but its leaves remained free from curl. F2 hybrids from the cross 90234 × 90230 were free from curl but they varied in stunting after aphid attack. Single-peaked distribution curves for ht suggested complex inheritance of tolerance. LJ 90254, selected from P.I. 255478 from Korea, possessed tolerance to aphids expressed as freedom from stunting and curling. F2 plants from the cross 90234 × 90254 were free from curl but varied in ht after aphid attack. The single-peaked distribution curves suggested complex inheritance of tolerance.

Open Access