SRC Using Radiation to Create Disease Resistant Crops

The Scientific Research Council (SRC) is currently undertaking a $10.3 million Plant Breeding and Diagnostics Technologies project, to improve the yields, and disease resistance of certain crops.
The procedure involves the use of radiation to induce mutation, to develop plants with desirable characteristics.
The project, which began in February of last year, is expected to end in December 2010 and is being funded jointly by the Government and the International Atomic Energy Agency (IAEA), which provides grant assistance and undertakes technical co-operation projects in countries that are able to undertake certain research whereby nuclear technology (radiation) is utilized in some beneficial way.
Process Development Officer in the Tissue Culture Department at the SRC, Jodie Spence, in an interview with JIS News, says the project is focusing on two crops – ginger and sweet yam, which she says were chosen following consultations with the Bodles Agricultural Research Station, the research arm of the Ministry of Agriculture.
“When the project came out, because SRC is really involved in agro-processing, and supporting the agricultural industry, we were trying to think of crops that would really benefit from the programme and we also consulted with the Ministry of Agriculture’s crop research section out at Bodles and they had already a list of about six or so crops that they wanted to target, so based on discussion with them and other stakeholders, those two crops were chosen,” Miss Spence explains.
She notes that these tubers “have the potential to earn a lot of foreign exchange for the country, but at the current time are not in a position to do that because they are being hampered by disease. So the yield is not what we would like it to be. With ginger, that disease is the Ginger Rhizome Rot, and with sweet yam, it’s Anthracnose.”
Miss Spence points out that one of the ways in which nuclear technology can assist with improving the yield of these plants, is to generate new varieties of the plant that will show tolerance or resistance to diseases. “So what we are hoping to do is to take these plants and expose them to radiation and in that way cause changes in the plants that cause the plants to develop qualities that they didn’t previously have, and one of the qualities we are hoping to get is increased disease resistance. So that’s the main aim of the project – produce varieties of ginger and sweet yam that are able to resist diseases that currently affect them,” Miss Spence explains.
She notes that even though radiation can be very damaging, there are different types of radiation and different levels of damage and that the effects of some levels of radiation can be good. “The negative effects of radiation are when the exposure is too intense or too long and so you get changes that are bad that cause disease and deterioration and so on. However, changes can be good, in that they cause qualities to develop that were not present before,” she points out.
“So what we are hoping is that is by exposing these plants to a very low level of radiation, we can cause a minimal amount of changes, one or two changes here and there in the genetic material that will turn out to be beneficial,” she asserts.
However, she notes, “because (with) this process, you cannot tell before hand what exactly will be changed, or how the change will occur, we will have to expose quite a bit of material to the radiation and then afterwards screen it, test it and allow the plants to develop, watch them under various conditions to see whether any of the plants that we have exposed have these changes that will be beneficial to us,” the Process Development Officer explains further. She points out however, that this low dose of radiation will not be harmful to humans who consume these foods.
Miss Spence notes that part of the objectives of the project is to produce advanced mutants, in that plants would be exposed to radiation and “hopefully get some beneficial changes being induced in the plants. So if you have a plant that has been changed it is going to be termed a mutant because it’s different from the original.”
“So that’s what we are trying to generate, advanced mutants that will show more of the changes. Because mutation is a change, sometimes you get two changes, a good one and a bad one, so for example you have exposed the plants to mutation and you have developed a mutant that has disease resistant qualities, but you may have found that in addition to this disease resistance, you may also have lost a beneficial quality that the plant originally had and in order to get it back, you will have to now cross-breed the original plant with the mutated plant to try and get the mix of the qualities until you can get a plant that has everything you want – both the increased disease resistance, as well as the original qualities that the farmers wanted in the first place,” she expounds.
Miss Spence further explains what is involved in the radiation process. “What occurs with this low dosage of radiation that the plants are exposed to, normally only a few cells of the plant will be changed and we have to then keep growing the plants and cutting away the unchanged cells and allowing the changed ones to grow a bit more until you reach a stage where the majority of the plants will consist of those cells that have undergone a change, (the advanced mutants). So the first time that you apply the radiation, that would be the first level or the zero generation, then with each successive generation, where you remove more and more of the unchanged portion, you are going to go further and further down the line to get a purer mutant plant,” she outlines.
The creation of the advanced mutants is just the first step in the project. The next step is the screening to select the mutants that will be beneficial, after which, they will have to be subjected to field trials under normal conditions to determine how well they fare.
“Usually when you do a small scale or lab-based screening, you try to induce the conditions where the disease will develop so you can test the plant to see if they will withstand it. But always, your aim is not to be comfortable with lab results. For the final test or the final proof, you must do trials where the plants will be grown out in the fields and in the hands of farmers,” Miss Spence informs.
Therefore, the laboratory-based trials will be done at the SRC. Funds have been approved to construct a greenhouse to perform the screens and prepare the plants, while the Ministry of Agriculture, through the Bodles Agricultural Research Station, will be responsible for conducting the field trials.
“The idea is that when we have gotten these different varieties or these different mutant lines, we are going to have to test them to see which one stands up best to the diseases or have other qualities (that may occur). If possible, we might have lines that show improved resistance but they may have other qualities that are not so desirable. So then there is the possibility that we’d have to do some breeding with other lines that have the good qualities in terms of whether it’s flavour or size or some other thing that we would want to incorporate to see resistance qualities in. So you would have to do regular crossing and breeding in order to get the best of both worlds,” Miss Spence explains.
Miss Spence notes that the project is still at a very early stage, and that it was only last month, that the person who will be conducting the radiation on the plants went to Vienna to the IAEA headquarters to start that work. She also informs that most of the material/equipment that had been applied for under the project have already arrived. “Because as a part of the project, we are going to be strengthening our capacity for disease diagnostics and be building a molecular biology laboratory,” she says.
It is also expected that for this project, local officers will be trained in mutation assisted breeding overseas and a national training course on mutation assisted breeding will also be undertaken. In addition, plant diagnostics and plant breeding facilities are to be established.
Miss Spence hopes that with this project, farmers will be assisted by “giving them new varieties (of crops) that are better able to withstand diseases, because it is said that especially with the ginger, Rhizome Rot is one of the main factors that has contributed to the decline of the ginger industry.”
“At a point in time,” she continues, Jamaican Ginger was the industry standard but production fell significantly in great part due to the effect of this disease, and while it can be managed to a certain extent with chemicals, fungicides and so forth, many of the farmers who are involved in producing ginger currently, are small holder farmers who cannot afford those expensive inputs.”
“So we are hoping now if you can give them something that is naturally resistant, they would be able to make better life for themselves, produce more and benefit the country and we will be able to regain our footing as a world exporter of ginger (as well as sweet yam),” she adds.