During the 1990's, genetic modification of plants became a reality.
World-wide in excess of 44 million hectares of genetically modified plants were grown in 2000 and this is expected to increase to 50 million hectares in 2001
While vegetables represent, only a small portion of these figures, potato cultivars with resistance to Colorado beetle and Potato Leaf Roll Virus (PLRV), tomatoes with delayed ripening and squash with virus resistance have been commercialised in the USA.
The vegetable industry in partnership with the Institute for Horticultural Development - Knoxfield and Horticulture Australia Ltd are developing integrated crop management (ICM) programmes for diamondback moth and clubroot.
For the past three years, researchers at IHD - Knoxfield have been developing ways to genetically modify vegetable brassicas with genes that may be useful to control insects and diseases to complement these ICM programmes.
This report summarises research to develop and use genetic modification to transfer agronomically useful genes to vegetable brassicas and describes four aspects of our research :
- Develop tissue culture regeneration systems
- Develop appropriate gene transfer systems
- Prepare gene constructs
- Preliminary assessment of genetically modified plants for their response to clubroot and diamondback moth
James F. Hutchinson
- The insect pest diamondback moth and fungal disease clubroot are major problems world-wide with vegetable brassicas, resulting in reduced yield and produce quality.
- Integrated crop management systems for both organisms are being developed to reduce reliance on chemical control.
- For crops such as broccoli, improved shelf life is also a desirable attribute. Breeding for resistance to diamondback moth and clubroot and improved shelf life are difficult, as known sources of resistance are either not available or difficult to incorporate into cultivated lines using sexual hybridisation.
- Gene technology is able to overcome these barriers and provides a new, novel and powerful tool to study these problems.
- Tissue culture methods have been developed to reliably and reproducibly regenerate adventitious shoots from :
- broccoli (8 cultivars)
- brussels sprout (3 cultivars)
- cabbage (2 cultivars)
- cauliflower (15 cultivars)
- There is considerable variation in the way inpidual cultivars regenerate with an order of magnitude difference between the worst and best cultivars.
- Gene transfer systems have been developed for a number of cultivars.
- Research using a construct with the gusA gene has not been particularly useful to develop a transformation system.
- A population of genetically modified vegetable brassicas has been produced with potentially useful genes.
- In excess of 21,000 explants were processed resulting in 105 transgenic lines.
This transformation frequency is very low and requires improvement.
- A number of gene constructs have been produced, with different anti-microbial genes, a proteinase inhibitor gene and a gene associated with cytokinin biosynthesis.
- These have been transferred to a number of cultivars, including Marathon (broccoli), Atlantis and Plana (cauliflower) and Pak Choi (Chinese cabbage).
- These transgenic lines are in various stages of assessment in glasshouse trials.
- Transgenic material has been screened in the glasshouse for their response to clubroot and diamondback moth and a number of lines with promise identified.
- Future work will characterise these further and screen the remaining transgenic lines.
We would like to thank our collaborators at IHD - Knoxfield, in particular Josie Lawrence, Caroline Donald and Ian Porter for assistance with the clubroot studies
We acknowledgealso thank, Nancy Endersby and Peter Ridland at IHD - Knoxfield, for assistance with the diamondback moth feeding experiments.
We also thank Kiang Lee (Henderson Seeds) for providing some of the germplasm used in these experiments.
This project was funded by the Agriculture Victoria and Horticulture Australia Ltd through the National Vegetable R&D Levy .
The Australian Government provides matched funding for all HAL’s R&D activities.