The genome doubling agent colchicine has been used effectively to obtain tetraploid plants when starting with diploid material. Since the plant meristem consists of many cells, as well as obtaining tetraploids, it is possible to obtain mixoploids (chimeras consisting of diploid and tetraploid tissue) after colchicine treatment. Flow cytometry was used to determine the DNA ploidy level of different tissues of individual hop plants following colchicine treatment of diploid hops. Plants that are shown to be mixoploid after analysis of leaf tissue can display higher levels of tetraploid nuclei in root tissue, such that they could be mistakenly classified as tetraploid. The hop variety Galena-4n, which was previously considered to be a tetraploid, is shown to be a mixoploid based on leaf material. However, Galena-4n consistently produces triploid progeny when crossed with a diploid hop variety, indicating that Galena-4n produces tetraploid reproductive tissues and is effectively a tetraploid from a breeding perspective. The results from this study indicate that care should be taken when determining the DNA ploidy level of an individual plant after exposure to genome-doubling agents based on single tissues and that leaf tissue is a choice material for flow cytometric analysis. © 2005 Elsevier B.V. All rights reserved.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Genetics
Research Field:	Genetics not elsewhere classified
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Environmentally sustainable plant production
Objective Field:	Environmentally sustainable plant production not elsewhere classified
UTAS Author:	Koutoulis, A (Professor Anthony Koutoulis)
UTAS Author:	Roy, AT (Dr Ashish Roy)
UTAS Author:	Price, AJ (Mrs Aina Price)
ID Code:	32847
Year Published:	2005
Web of Science® Times Cited:	24
Deposited By:	Plant Science
Deposited On:	2005-08-01
Last Modified:	2012-12-12
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