John C. Volin

Document Type

Thesis - Open Access

Award Date

1988

Degree Name

Master of Science (MS)

Department / School

Agronomy

First Advisor

C. Dean Dybing

Abstract

Interspecific hybridization between the cultivated sunflower, Helianthus annuus L., and other Helianthus species is an important aspect of sunflower improvement, because it extends the array of genes available for use in breeding programs. Sunflower species have demonstrated resistance to many pests that affect the cultivated sunflower. Oil content and quality may also be improved through interspecific hybridization, as Helianthus species are sources of genetic variation for these traits. Attempts to cross H. annuus with sixteen other Helianthus species were only 40 % successful. It is generally assumed that failure of interspecific hybridization in sunflowers is due to abortion of the hybrid embryos during early developmental stages. In other genera such as Gossypium and Hordeum, the solution to this problem has been to rescue these embryos prior to abortion by growing them on an artificial media. Embryo rescue in sunflower, however, has only been successful at the torpedo stage or later. The torpedo stage normally occurs four to seven days after fertilization. The purpose of this investigation can be summarized in two objectives. The first was to improve current in vitro techniques in sunflower by providing for the rescue of younger embryos, for example, the globular to heart stages which normally occur one to four days after pollination. The second objective was to investigate how the embryo develops in vitro during the first eleven days after pollination, compared to its normal development in vivo.

Library of Congress Subject Headings

Sunflowers -- Breeding

Helianthus -- Breeding

Sunflowers -- Embryology

Format

application/pdf

Number of Pages

79

Publisher

South Dakota State University

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