64. The receiving environment forms part of the context in which the risks associated with dealings involving the GMOs are assessed. This includes the geographic region where the release would occur and any relevant biotic/abiotic properties of this location; the intended agronomic practices, including those that may be altered in relation to normal practices; other relevant GMOs already released; and any particularly vulnerable or susceptible entities that may be specifically affected by the proposed release (OGTR 2007).
65. The size, location and duration of the proposed release are outlined in Chapter 1, Section 3.2. The proposed dealings involve planting at one site at a CSIRO research station in the ACT (population approximately 340,300Australian Bureau of Statistics 2008), approximately 0.5 km from the Canberra suburb of Spence. The location can be accessed via a private road.
66. The proposed site is located in the suburb of Ginninderra and surrounded by CSIRO land. CSIRO proposes to use the site for other trials with GM wheat and GM barley.
6.1 Relevant abiotic factors
67. Wheat is grown in a wide range of environments around the world. Ideal growth conditions are temperatures around 25oC and annual rainfall of 375 to 875 mm. The abiotic factors relevant to the growth and distribution of commercial wheat can be found in The Biology of Triticum aestivum L. em Thell. (Bread Wheat) (OGTR 2008), available from the OGTR or from the website at Documents relating to the Risk Assessment process.68. The release is proposed to take place in the ACT, which has a typical temperate climate (as defined by the Koeppen classification system used by the Australian Bureau of Meteorology. The rainfall and temperature statistics for the nearest weather station are given in Table 3. The proposed site is on land that is not subject to flooding and is 1000 m away from the nearest waterway.
Table 3. Climatic data for Canberra (Airport), ACT
| Canberra (Airport) | |
|---|---|
| Average daily max/min temperature (winter) | 12.2 ºC /0.6 ºC | Average daily max/min temperature (spring) | 19.4 ºC /6.0 ºC |
| Average monthly rainfall (winter) | 42.8 mm |
| Average monthly rainfall (spring) | 59.7 mm |
Source: Australian Bureau of Meteorology. Monthly mean temperatures and rainfall were collected over 70 years and were averaged for all months of a season to obtain the reported data (winter: June – August; spring: September – November).
6.2 Relevant biotic factors
69. CSIRO uses Ginninderra Experimental Station as a field research and breeding site for a number of plant species, including wheat. With the exception of other material grown at Ginninderra Experimental Station, the nearest cultivation of wheat to the site is approximately 11 km away in the direction of Yass.70. The biotic factors relating to the growth and distribution of commercial wheat in Australia are discussed in the reference document, The Biology of Triticum aestivum L. em Thell. (Bread Wheat) (OGTR 2008).
71. Of relevance to this proposed release are the following points:
- CSIRO proposes to use the site simultaneously for this and other intentional releases of GM wheat and barley subject to approval by the Regulator. Applications for two other limited and controlled releases have been received by the OGTR: DIR 093, Limited and controlled release of wheat and barley genetically modified for altered grain starch composition; and DIR 094, Limited and controlled release of wheat and barley genetically modified for enhanced nutrient utilisation efficiency1.
- Invertebrates, vertebrates and microorganisms could be exposed to the introduced RNAi constructs and their associated effects. In particular, rodents and native birds may visit the proposed release site.
6.3 Relevant agricultural practices
72. It is anticipated that the agronomic practices for the cultivation of the GM wheat by the applicant will not differ significantly from conventional practices, with the exception that the applicant proposes to harvest by a small mechanical single row harvester. Conventional cultivation practices for wheat are discussed in more detail in The Biology of Triticum aestivum L. em Thell. (Bread Wheat) (OGTR 2008).73. In Australia, spring wheat varieties are commonly grown as a winter crop and are usually planted in May and June. Harvest of the mature wheat generally occurs from mid-November to late December. If the proposed release is approved the applicant anticipates planting the trial in July 2009.
74. There are a number of pests and diseases of wheat (for further details see OGTR 2008), which may require management (eg application of pesticides such as herbicides or insecticides) during the growing season. Weed control using specific classes of herbicides may involve a pre- or post-emergence application.
75. The trial is proposed to take place over three growing seasons. The applicant states that specific planting arrangements of this and other trials at the site over the three seasons will be determined by yields from each season. For each planting, the applicant aims to avoid re-use of plots within the site for the purpose of managing fungal soil diseases. However, the applicant proposes that if replanting is necessary in the third season, first season areas will be planted with the same GMOs as previously planted, except for where season one plots have been free of volunteers for the 6 months prior to season three planting (in which case different GMOs would be planted from DIR 092). The applicant does not intend to plant GMOs from other DIRs running concurrently at the same site, subject to their approval, over areas planted previously to DIR 092.
76. Non-propagative plant material remaining at the field location after harvest (for example, residual stem stubble) would be ploughed into the ground after the trial. The harvested areas would then be watered to encourage germination of any fallen seed, then treated with herbicide to destroy volunteers, and this process repeated twice more. The areas would then be sown with a break crop such as lucerne or forage brassica which will be monitored for volunteers. Excess seed not required for experimental analysis, or future trials would be removed from the site and destroyed.
6.4 Presence of related plants in the receiving environment
77. The applicant proposes to maintain a 500 m zone in which there is no cultivation of wheat breeding lines around the site of the trial for the full duration of the trial. A 200 m isolation zone for all other wheat cultivation will also be maintained.78. At the request of the applicant, Dr Brendan Lepschi from the Centre for Plant Biodiversity Research, Australian National Herbarium, carried out a survey of Ginninderra Experimental Station in August 2008 to identify occurrence of species related to wheat. Of those members of the Triticeae known to occur in Australia, Elymus scaber, Hordeum leporinum and Hordeum marinum were identified on the site (information supplied by the applicant). Dr Lepschi reported that other species of Elytrigia, Secale and Triticum could possibly be accidentally introduced to the Ginninderra site from elsewhere, however the likelihood of this happening was reported as low. Additionally, Dr Lepschi reported that other weedy taxa of Hordeum could be expected to occur at the site.
79. Wheat is sexually compatible with many species within the genus Triticum, and in closely related genera such as Aegilops and Elytrigia. Wheat can hybridise with Hordeum marinum only with substantial human intervention (Pershina et al. 1998; Islam & Colmer 2008). The resultant hybrids are usually infertile and have been studied following chromosome doubling, although fertility in the resultant plants is still reduced (Islam et al. 2007). Inconclusive genetic evidence suggesting one instance of natural hybridisation occurring in previous generations has also been detected in northern Europe (Guadagnuolo et al. 2001). The interspecific crossing potential of wheat is discussed in more detail in The Biology of Triticum aestivum L. em Thell. (Bread Wheat) (OGTR 2008).
6.5 Presence of the introduced sequences or similar genes and encoded proteins in the environment
80. All of the introduced sequences were isolated from naturally occurring organisms that are already widespread and prevalent in the environment.81. Each RNAi construct consists of a high molecular weight glutenin subunit promoter (from the Dx5 or Bx17 genes) isolated from wheat, controlling expression of an inverted repeat of wheat sequences targeted for silencing (see Table 2). The inverted repeats are separated by intron sequences isolated from the rice SBEI gene (either intron 9 or introns 4 and 9). Wheat and rice are widespread and prevalent in the environment and have been safely consumed by humans and animals for centuries.
82. All of the GM wheat lines contain the nptII plant selectable marker gene. The nptII gene is derived from the common gut bacteria E. coli which is widespread in human and animal digestive systems as well as in the environment (Blattner et al. 1997). As such, it is expected humans routinely encounter the encoded protein through contact with plants and food.
83. The biolistic transformation plant selectable marker construct contains promoter and terminator sequences from CaMV, and an intron sequence from the potato STLS2 gene. The plant selectable marker used for Agrobacterium-mediated transformation contains the actin promoter isolated from rice, an intron from the same gene, and the terminator sequence from the A. tumefaciens nos gene. Rice and potato are widespread and prevalent in the environment and have been safely consumed by humans for centuries. Although CaMV and A. tumefaciens are plant pathogens, the regulatory sequences comprise only a small part of their total genomes and are not capable of causing disease.
1Licence applications DIR 093 and DIR 094 are currently under assessment by staff at the OGTR. A summary for each of the applications can be found at the OGTR website (DIR 093 and DIR 094) or by contacting the OGTR (Free call 1800 181 030).