The Breeding Biology of Waxflowers A report for the Rural Industries Research and Development Corporation by Guijun Yan July 2001 RIRDC Publication No 01/… RIRDC Project No UWA 35A © 2001 Rural Industries Research and Development Corporation. All rights reserved. ISBN 0 642 (…RIRDC to assign) ISSN 1440-6845 Title of your publication Publication No. 01/ Project No. UWA-35A The views expressed and the conclusions reached in this publication are those of the author and not necessarily those of persons consulted. RIRDC shall not be responsible in any way whatsoever to any person who relies in whole or in part on the contents of this report. This publication is copyright. However, RIRDC encourages wide dissemination of its research, providing the Corporation is clearly acknowledged. For any other enquiries concerning reproduction, contact the Publications Manager on phone 02 6272 3186. Researcher Contact Details (Name) Dr Guijun Yan (Address) Plant Sciences Faculty of Agriculture The University of Western Australia Nedlands, WA 6009 Phone: (08) 9380 1240 Fax: (08) 9380 1108 Email: [email protected] RIRDC Contact Details Rural Industries Research and Development Corporation Level 1, AMA House 42 Macquarie Street BARTON ACT 2600 PO Box 4776 KINGSTON ACT 2604 Phone: 02 6272 4539 Fax: 02 6272 5877 Email: [email protected]. Website: http://www.rirdc.gov.au Published in June 2001 Printed on environmentally friendly paper by Canprint ii Foreword The continued growth of Australian native plants as cutflowers depends largely on the breeding of new cultivars which are attractive, vigorous and productive, durable in transit and storage, resilient to pests and diseases, and with a greater seasonal spread of production. The understanding of the breeding biology is the key to success in these matters and can increase the breeding efficiency considerably. With the support of RIRDC, a waxflower breeding program was initiated in Western Australia in 1995. This program aims at making wide hybridisations (interspecific and intergeneric) to produce new or novel cutflower cultivars for the Australia industry. The study of the breeding biology in Waxflowers is an integral part of that program. This publication considers the breeding biology of waxflowers (Chamelaucium) with special emphases on chromosome numbers, ploidy levels, ploidy manipulation, chloroplast DNA inheritance, identification of natural and artificial hybrids, hybridisation barriers, embryology and early embryo rescue. It discusses how this information and methodologies can be used in waxflower breeding programs to increase the breeding efficiency. This project was funded from RIRDC Core Funds, which are provided by the Federal Government. This report, a new addition to RIRDC’s diverse range of over 700 research publications, forms part of our Wildflowers and Native Plants R&D program, which aims to identify and develop new fresh products. Most of our publications are available for viewing, downloading or purchasing online through our website: • downloads at www.rirdc.gov.au/reports/Index.htm • purchases at www.rirdc.gov.au/eshop Peter Core Managing Director Rural Industries Research and Development Corporation iii Acknowledgements I wish to thank the following organisations and people for their contributions to this project and the final report (Alphabetical order): Agriculture Western Australia King Park and Botanic Gardens Sunglow Flowers John Considine Anousk Cousin a Ben Croxford Simone Cunneen Lindsay Forrester Nina Foulkes-Taylor Nic George Digby Growns Lorreine Lawson Xuanli Ma Chris Newell Fucheng Shan Philip Watkins Mark Webb Shubiao Wu iv Abbreviations BAP 6-benzylaminopurine c-mitosis colchicine-mitosis °C degrees Celsius DNA deoxyribose nucleic acid F1 first generation hybrid F2 second generation hybrid FLP orcein formic lacto-propionic orcein g/L grams per litre IBA indole-3-butyric acid L-I layer first germlayer (outermost) L-II layer second germlayer L-III layer third germlayer (innermost) Mmolar mL millilitre mm millimetre mM millimolar µM micromolar MS mixture of salts of Murashige and Skoog (1962) n.a. not applicable NAA naphthalene acetic acid NaOH sodium hydroxide p p-value PCB para-dichlorobenzene pers. comm. personal communication std dev. standard deviation w/v weight by volume x basic ploidy number 2n somatic ploidy number 2x diploid 4x tetraploid v Table of contents Foreword..................................................................................................................................................................... iii Acknowledgements .................................................................................................................................................... iv Abbreviations .............................................................................................................................................................. v Executive Summary................................................................................................................................................. viii 1. Cytogenetic studies in Chamelaucium................................................................................................................... 1 1.1 Introduction .............................................................................................................................................. 1 1.2 Materials and methods.............................................................................................................................. 2 Chromosome examination................................................................................................................ 2 The flower size and leaf length ........................................................................................................ 2 The morphology and viability of pollens .........................................................................................3 1.3 Results ...................................................................................................................................................... 4 Chromosome number and ploidy level............................................................................................. 4 The flower size and leaf length ........................................................................................................ 4 The morphology and viability of pollens .........................................................................................4 1.4 Discussion................................................................................................................................................. 8 Chromosome number and intraspecific ploidy variation of Chamelaucium .................................... 8 The origin of polyploids in Chamelaucium uncinatum .................................................................... 8 Pollen morphology and viability of C. uncinatum ........................................................................... 8 Ploidy diversity and implication for breeding of C. uncinatum ....................................................... 9 1.5 References ................................................................................................................................................ 9 2. Chromosome doubling of waxflower plantlets regenerated in vitro ............................................................ 11 2.1 Introduction ............................................................................................................................................ 11 2.2 Materials and Methods ........................................................................................................................... 11 Plant material.................................................................................................................................. 11 Regeneration procedures ................................................................................................................ 11 Immersion procedures .................................................................................................................... 12 Assessment of the plant material.................................................................................................... 12 Assessment of mitotic chromosomes in root tips ........................................................................... 12 Statistical analysis .......................................................................................................................... 13 2.3 Results .................................................................................................................................................... 13 Survival rate after colchicine treatment.......................................................................................... 13 Shoot proliferation.......................................................................................................................... 14 Morphological assessment of plant material .................................................................................. 14 Chromosome assessment................................................................................................................ 15 Anatomical assessment of tetraploid plant material ....................................................................... 15 2.4 Discussion..............................................................................................................................................