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Author

Ping-Fai Lo

Document Type

Dissertation - University Access Only

Award Date

1979

Degree Name

Doctor of Philosophy (PhD)

Department

Plant Science

Abstract

A search was made for a general method of tissue culture primarily for rapid cloning of forage grasses, most of which were cross-pollinated plants.

Eight cool-season grass species were cultured in vitro. An appreciable amount of callus was initiated from segments of young inflorescences of each species cultured in the dark at 25 C on RM or B5 medium supplemented with 5 mg 2, 4-D in combination with O or 0.2 mg kinetin/liter. Transformation of spikelets into vegetative sheets was observed in the primary culture of orchardgrass (Dactylis glomerata L.) while shoot initiation in subcultured calluses occurred in creeping foxtai1 (Aiopecurus arundinacel's Poir.), crested wheatgrass (Agropyron desertorum (Fisch.) Schult. ), green needlegrass (Stipa viridula Trin.), smooth bromegrass (liromus inermis Leyss. ) and western wheatgrass (Agropyron smithii Rydb.). Except intermediate wheatgrass (Agropyron intermedium (Host) Beau.) and reed canarygrass (Phalaris arundinacea L.) cultures in which shoot formation occurred sporadically, all of the callus cultures initiated numerous shoots when transferred en RM basal medium supplemented iith no hormones in the dark at 25° C. The shoots then developed into plantlets on medium with the same formula under 16-h light cycles (cool white fluorescent light at 25 μE/sec m2) at 27° C. An addition of l mg/liter of kinetin to the basal medium enhanced shoot initiation in calluses of western wheatgrass, green needlegrass and creeping foxtail. Albinism was noted in the plantlets developed from the orchardgrass primary culture and the callus subcultures of smooth bromegrass, creeping foxtail, crested wheatgrass and green needlegrass. The relative frequency of albino plantlets emerging from a callus tended to increase as age of the subculture increased. However, albinism incidence was drastically reduced in a differentiating callus grown on RM medium containing 1 mg kinetin/liter, possibly due to a promoting effect of the hormone on plastid formation. All of the calluses were maintained on RM medium supplemented with 5 mg 2, 4-D. An improvement in callus propagation of green needlegrass was obtained with a further supplement of 0.5 mg kinetin/ liter to the RM medium. Although karyological changes and apparent gene mutations occasionally occurred in grass callus cultures as reflected by a small number of variants noted in two established plant populations investigated, these genetic variations seem not to .hinder the feasibility of utilizing the tissue culture techniques for modifying forage grass breeding programs.

Library of Congress Subject Headings

Grasses Forage plants Plant tissue culture

Number of Pages

75

Publisher

South Dakota State University

Rights

Copyright © 1979 David Ping-Fai Lo

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