Paul K.I.,CSIRO |
Roxburgh S.H.,CSIRO |
England J.R.,CSIRO |
Ritson P.,DAFWA |
And 14 more authors.
Forest Ecology and Management | Year: 2013
To quantify the impact that planting indigenous trees and shrubs in mixed communities (environmental plantings) have on net sequestration of carbon and other environmental or commercial benefits, precise and non-biased estimates of biomass are required. Because these plantings consist of several species, estimation of their biomass through allometric relationships is a challenging task. We explored methods to accurately estimate biomass through harvesting 3139 trees and shrubs from 22 plantings, and collating similar datasets from earlier studies, in non-arid (>300mm rainfallyear-1) regions of southern and eastern Australia. Site-and-species specific allometric equations were developed, as were three types of generalised, multi-site, allometric equations based on categories of species and growth-habits: (i) species-specific, (ii) genus and growth-habit, and (iii) universal growth-habit irrespective of genus. Biomass was measured at plot level at eight contrasting sites to test the accuracy of prediction of tonnes dry matter of above-ground biomass per hectare using different classes of allometric equations. A finer-scale analysis tested performance of these at an individual-tree level across a wider range of sites. Although the percentage error in prediction could be high at a given site (up to 45%), it was relatively low (<11%) when generalised allometry-predictions of biomass was used to make regional- or estate-level estimates across a range of sites. Precision, and thus accuracy, increased slightly with the level of specificity of allometry. Inclusion of site-specific factors in generic equations increased efficiency of prediction of above-ground biomass by as much as 8%. Site-and-species-specific equations are the most accurate for site-based predictions. Generic allometric equations developed here, particularly the generic species-specific equations, can be confidently applied to provide regional- or estate-level estimates of above-ground biomass and carbon. © 2013 Elsevier B.V.
News Article | November 26, 2015
Researchers from West Australia are relying on genetically modified fruit flies to solve pest problems in the region. Mediterranean fruit flies (Ceratitis capitata) is causing significant dilemma among households and orchards in West Australia. Also known as Medfly, these pests feed on more than 250 kinds of fruits such as apricots, peaches, citrus, apples, nectarines, pears and mangoes. The damage occurs in fruits when the female fly "sting" on it during the process of egg-laying. The fruits then become susceptible to decomposition and subsequent infection. As per estimates, the damage in West Australian crops every year due to fruit flies is about $200 million. The Department of Agriculture and Food Western Australia (DAFWA) has been searching for a strong solution to address the problem. The agency has banned the use of an insecticide called fenthion but its quest for alternative methods has not ceased. Now, DAFWA has partnered with Oxitec, a technology firm based in the UK, to see the effectiveness of an innovative strategy that involves the use of genetically modified organisms (GMO). Neil Morrison, leader of the Oxitec group explained that a so-called "self-limiting gene" is injected into male fruit flies. Such action will halt female fruit fly offsprings from surviving through the adult life stages. When the engineered organisms are released to the natural environment, it will mate with the same species and pass the gene to its offspring, which will succumb to death prior to having the ability to damage crops. "If you reduce the number of females, that knocks down the pest population in the next generation," said Morrison. The said technique was used by his company to decrease the number of dengue-carrying Aedes aegypti in various countries such as Panama, Brazil and the Caribbean. For the Australia-UK collaboration, eggs were obtained in the UK and raised at the DAFWA, which already confirmed that it will perform an indoor evaluation of the GMOs. Dr. Nikolai Windbichler, a researcher from Imperial College concurred that multiple tests should be conducted first before arriving at a final conclusion of whether or not Medfly damage can finally be eradicated through genetic modification. In the U.S., a similar intervention was recently performed at the University of California. In the experiments, researchers reared a genetically-engineered mosquito that cannot, in any way, be infected by malaria. They specifically rearranged the DNA of a mosquito infected with malaria to fight off the parasite. After testings, the DNA was inherited by close to 100 percent of the offsprings, up until the third generation.
Snowball R.,DAFWA |
Snowball R.,University of Western Australia |
Mahdere A.,National Agricultural Research Institute |
Tesfay E.,National Agricultural Research Institute |
And 3 more authors.
Plant Genetic Resources: Characterisation and Utilisation | Year: 2013
This is the first report of a pasture plant collecting mission to the highlands of Eritrea and a preliminary examination of the potential of species for both Eritrea and southern Australia. In 2004, seeds from 53 legume species were collected from 58 locations in the southern highlands between Keren, Adi Quala and Senafe. Strains of Rhizobium from 18 species were also collected. Seed collections of 11 species with Rhizobium were established in germplasm nurseries at the Medina Research Station, Western Australia between 2005 and 2010. Observations on their growth, flowering and seed production were recorded. Based on a climate match analysis and observations from germplasm nurseries, it was suggested that species with most promise for parts of southern Australia include the annual legume Biserrula pelecinus ssp. leiocarpa and the perennial shrub Colutea abyssinica. The greatest potential, however, is reserved for the highlands of Eritrea where germplasm is well adapted. Species found low in the landscape including from the genera Lotus, Trifolium and Medicago appeared well utilized. Different species found higher in the landscape including from the genera Indigofera, Tephrosia, Crotalaria, Trifolium schimperi, B. pelecinus ssp. leiocarpa and C. abyssinica were much less common, appeared under-utilized and may be under threat from genetic erosion. Animal production on the non-arable dry hillsides of the highlands would benefit from better utilization of these species through replanting some areas, careful grazing management and demonstration of the benefits of increasing the native legume component of these wild pastures. Copyright © 2013 NIAB.
News Article | November 25, 2015
The WA Department of Agriculture and Food (DAFWA) and Oxford University spin-out company Oxitec are set to trial the effectiveness of a genetically modified medfly. They hope this new breed can help growers combat a pest which costs between $10-14 million annually to control and spoils up to 15 per cent of fruit crops. The technique involves researchers inserting two genes into the medfly, a self-limiting gene which prevents female offspring from surviving to reproductive age and a fluorescent track-and-trace marker (DsRed2). "This is a new approach to the Sterile Insect Technique in which radiation sterilisation of flies is replaced with a genetic method," DAFWA's David Windsor says. "It's a glimpse into the future of 21st century pest control." The Sterile Insect Technique (SIT) has been used globally since the 1950s and is considered the most environmentally-friendly form of eradication. It involves scientists sterilising male medflies through radiation and releasing them in large numbers to compete for mating opportunities. As females who couple with sterile males have no viable offspring, insect populations decrease. The new genetic approach works in a similar way but will require fewer insects, making it more cost-effective yet equally environmentally benign. "Our method only affects the target species, and because it is self-limiting, the genes and insects disappear from the environment once we stop releasing," Oxitec's Dr Neil Morrison says. "The medflies are non-toxic, non-allergenic and insecticide-free, and our studies have demonstrated that if a predator were to feed on our insects, it's just the same as eating other insects—there are no adverse effects." The project is one of a number Oxitec has under way, including breeding the mosquito Aedes aegypti, the main vector for dengue fever. Field trials of A. aegypti saw a reduction in insect populations of 93 per cent in Panama and 96 per cent in the Cayman Islands. This rate of success is good news for WA growers, who since October can no longer access broad-spectrum organophosphate insecticides such as Fenthion and Dimethoate. However, a number of challenges need to be met. "First, we need to work out whether female WA medflies want to mate with Oxitec males," Mr Windsor says. "The populations have been isolated from one another for a long time and may be slightly genetically different."
News Article | December 12, 2016
Oxitec announced today that after a series of successful contained environment studies across multiple countries with its self-limiting Mediterranean fruit fly (Medfly), the Company is ready to move forward towards open field trials. The studies demonstrated the self-limiting Medfly's ability to successfully mate with wild Medfly and subsequently suppress the pest population. The efficacy of the Oxitec Medfly and existing control methods were also examined. Oxitec's Chief Scientific Officer, Simon Warner, Ph.D., said, "Over the past few years, the performance of our Medfly solution in testing across different countries has confirmed our belief that this product may deliver superior efficacy and an improved environmental profile as compared to many products on the market today. We are now planning to advance our environmentally-friendly Medfly product into field trials in different countries to demonstrate its potential in open environments." The Medfly (Ceratitis capitata) is considered one of the world's most destructive agricultural pests capable of causing billions of dollars in damage by attacking more than 250 types of fruits, nuts and vegetables. Females lay their eggs inside fruit making them vulnerable to infection and rot, and larvae feed on the fruit reducing crop yields and quality. It is found throughout the Mediterranean and Africa, and is an invasive pest in Australia and the Americas. Medfly is difficult to manage by conventional methods because of its ability to infest many types of crops year-round, and growers need alternative technologies for control. Oxitec's approach uses genetically engineered self-limiting Medfly males that are released to mate with wild females. Their female offspring do not survive to adulthood and repeated releases result in a reduction of the pest population. In the latest study, the Western Australia Department of Agriculture and Food (DAFWA) compared the mating performance of Oxitec's Medfly with that of sterile insects treated with radiation, another technique used to control the pest population, to examine whether Oxitec's solution offered an improved option for industry to control Medfly. As reported by DAFWA the mating performance of Oxitec's Medfly "was comparable with that of sterile males irradiated at low levels, and exceeded that of sterile males treated with a higher dose of radiation which is used to provide a better guarantee of sterility." In 2010, Oxitec conducted the first study to demonstrate the efficacy of the self-limiting Medfly in collaboration with the University of Crete, Greece. In the trial, the Medfly pest population was eliminated in glasshouses in 12 weeks. These results were then confirmed in netted trials in Morocco in collaboration with the leading agricultural group in the country, SAOAS. Oxitec's Medfly showed equivalent mating performance with the wild Moroccan Medfly and again successfully suppressed the wild population. Furthermore, excellent control was also shown when the self-limiting Medfly insects were released at different life stages, which would provide growers with a more flexible application regimen than only releasing adult male flies. Trials in Morocco also compared the protection of fruit crops provided by Oxitec's Medfly with that of a leading insecticide used to combat Medfly globally. Sustained releases of Oxitec males resulted in a superior marketable yield of fruit compared to treatment with the leading insecticide. The data showed that Oxitec's solution has the potential to be more cost-effective for the same level of control provided by insecticides and mass trapping. The trial results also demonstrated the potential for combining control practices in an integrated pest management programme in order to provide flexibility to growers. "Advancing to open field trials is an important milestone for our pipeline of self-limiting insect products addressing pest damage to high value fruit and vegetable crops. Studies indicate that annual losses of crops due to these pests, including Mediterranean fruit fly, can reach billions of dollars. Additionally, these difficult to control insects can cause devastating impacts to agricultural economies dependent on high-value produce export," noted Sekhar Boddupalli, Ph.D., President of Intrexon Crop Protection and Head of Intrexon's AgBio Division. Oxitec is a pioneer in using genetic engineering to control insect pests that spread disease and damage crops, and was founded in 2002 as a spinout from Oxford University (UK). Oxitec is a subsidiary of Intrexon Corporation (NYSE: XON), which engineers biology to help solve some of the world's biggest problems. Follow us on Twitter at @Oxitec.