The Biology of Brassica Napus L. (Canola)
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The Biology of Brassica napus L. (canola) Version 2.1: August 2011 This document provides an overview of baseline biological information relevant to risk assessment of genetically modified forms of the species that may be released into the Australian environment. Cover photo courtesy of Brian Weir. Version 2 (February 2008) has been updated to include an appendix containing a weed risk assessment of canola and the sexually compatible species Indian mustard based on the National Post-Border Weed Risk Management Protocol. References to the new appendix have been added in the text. For information on the Australian Government Office of the Gene Technology Regulator visit <http://www.ogtr.gov.au> ii BIOLOGY OF BRASSICA NAPUS L. (CANOLA) Office of the Gene Technology Regulator TABLE OF CONTENTS Preamble ..........................................................................................................................................1 Section 1 Taxonomy........................................................................................................................1 Section 2 Origin and cultivation ....................................................................................................2 2.1 Centre of diversity and domestication.............................................................................2 2.2 Commercial uses .............................................................................................................3 2.3 Cultivation in Australia...................................................................................................3 2.3.1 Commercial propagation.............................................................................3 2.3.2 Scale of cultivation ......................................................................................4 2.3.3 Potential for expansion of the Canola growing region ...............................5 2.3.4 Cultivation practices ...................................................................................7 2.4 Crop Improvement ..........................................................................................................8 2.4.1 Breeding ......................................................................................................9 2.4.2 Genetic modification .................................................................................11 Section 3 Morphology...................................................................................................................13 3.1 Plant morphology..........................................................................................................13 3.2 Reproductive morphology.............................................................................................13 SECTION 4 DEVELOPMENT...............................................................................................................13 4.1 Reproduction.................................................................................................................13 4.2 Pollination and pollen dispersal ....................................................................................13 4.2.1 Pollen characteristics................................................................................13 4.2.2 Pollen movement .......................................................................................14 4.2.3 Pollen viability ..........................................................................................15 4.3 Fruit/seed development and seed dispersal ...................................................................16 4.3.1 Fruit and seed development.......................................................................16 4.3.2 Seed dispersal............................................................................................16 4.4 Seed dormancy and germination...................................................................................18 4.4.1 Viability/germination.................................................................................18 4.4.2 Dormancy..................................................................................................18 4.4.3 Seed banks/persistence ..............................................................................19 4.5 Vegetative growth .........................................................................................................21 Section 5 Biochemistry.................................................................................................................21 5.1 Toxins ..........................................................................................................................21 5.2 Allergens .......................................................................................................................22 5.3 Other undesirable effects of phytochemicals ................................................................23 5.4 Beneficial phytochemicals ............................................................................................23 Section 6 Abiotic Interactions ......................................................................................................25 6.1 Abiotic stresses .............................................................................................................25 6.1.1 Nutrient stress............................................................................................25 6.1.2 Temperature stress ....................................................................................25 6.1.3 Water stress ...............................................................................................26 Section 7 Biotic Interactions.........................................................................................................26 7.1 Weeds............................................................................................................................26 7.2 Pests and pathogens.......................................................................................................26 7.2.1 Pests ..........................................................................................................26 7.2.2 Diseases.....................................................................................................26 Section 8 Weediness ......................................................................................................................27 8.1 Weediness status on a global scale................................................................................27 8.2 Weediness status in Australia........................................................................................28 8.2.1 Cultivated areas ........................................................................................28 8.2.2 Non-cropped disturbed habitats ................................................................28 8.2.3 Undisturbed natural habitats.....................................................................29 8.3 Control measures...........................................................................................................29 8.4 Weed risk assessment of canola....................................................................................30 Section 9 Potential for Vertical Gene Transfer ..........................................................................30 9.1 Intraspecific crossing ....................................................................................................30 9.2 Interspecific crossing ....................................................................................................32 9.2.1 Brassica rapa ............................................................................................35 9.2.2 Brassica juncea .........................................................................................37 iii BIOLOGY OF BRASSICA NAPUS L. (CANOLA) Office of the Gene Technology Regulator 9.2.3 Brassica oleracea ......................................................................................38 9.3 Intergeneric crossing .....................................................................................................38 9.3.1 Tribe Brassiceae species ...........................................................................38 9.3.2 Other plant species....................................................................................43 References ........................................................................................................................................45 Appendix 1 Weed Risk Assessment....................................................................................................62 iv BIOLOGY OF BRASSICA NAPUS L. (CANOLA) Office of the Gene Technology Regulator PREAMBLE This document describes the biology of canola (Brassica napus L.) with particular reference to the Australian environment, cultivation and use. Information included relates to the taxonomy and origins of cultivated B. napus, general descriptions of its morphology, reproductive biology, biochemistry, and biotic and abiotic interactions. This document also addresses the potential for gene transfer to occur to closely related species. The purpose of this document is to provide baseline information about the parent organism for use in risk assessments of genetically modified canola that may be released into the Australian environment. The term ‘canola’ refers to those varieties1 that meet specific standards on the level of erucic acid and glucosinolates. The word