[MUSIC] Hello, my name is Wallace Cowling and I'm the professor in plant breeding at the University of Western Australia. This part of the course on the future of farming in 2050 looks at a new, green revolution in plant breeding that could change the future of agriculture and food production. We rely on our crops to convert the sun's energy into food, plants can be bred to do this more efficiently. Today, we will discuss a new approach to plant breeding which will speed up the process and allow genetic improvements to continue long into the future. The goal is to breed crops that yield more grain, suffer less disease, and tolerate stresses better than current crop varieties. The Food and Agriculture Organization of the United Nations has stated that we must increase agricultural production by 70% by 2050 with sustainable use of genetic resources for food and agriculture. Plant breeding underpins future improvements in crop production. Today's talk is built on three ideas. First, traditional plant breeding methods are slow and they suffer from low genetic diversity which will prevent us from reaching FAO food production goals by 2050. Second, a new green revolution is occurring in plant breeding by stone methods derive from animal breeding. And third, the new plant breeding methods will help us to improve sustainability of agriculture while coping with climate change Plants are incredibly important as the primary food source for humans. More than 85% of the world's human food calories come from plants. Threats to crop food production are a threat to the future of humanity. Future agriculture will depend on crops that can be grown safely and sustainably without irreversible damage to the environment, but the environment is changing. Global temperatures are expected to increase by at least two degrees Celsius in this century. The area of land is decreasing. Now, crops must survive increasing heat stress and they must yield more grain per hectare to meet increasing demand for food. This is the challenge to genetically improve our crops, so they yield more grain per hectare, tolerate heat and other stresses, resist disease, and supply food for a hungry world safely and sustainably and with less input of fertilizer and chemicals. This may sound like a big ask, how can we be sure that the new green revolution in plant breeding will help us reach these targets? Currently, genetic improvement of crops is occurring at less than 1% per year. In fact, yield improvement has stalled in wheat in southern Australia since 1990, due to the impact of climate change. Evidence suggests we are approaching a yield plateau with traditional plant breeding methods, as a result of climate change. How do we breed grain crops? Here you can see a picture of a small grain harvester in a wheat breeding experiment. Stripping the grain from the plants in a small plot. The grain from each plot is weighed and hundreds of these plots make up a weed breeding experiment. Only the highest yielding varieties process then tested and they have to have the best grain quality. Seed of those best varieties is increased and eventually, the best new varieties are released to farmers. Breeders use these varieties in crossing to start the next generation of breeding. And this process may take ten to 12 years from crossing to commercial release of new varieties. But plant breeding field trials are an essential component of crop genetic improvement. They allow us to measure grain yield in the same environment as farmers where they grow their crops. These results help us to breed better varieties for local condition. The main question today is how can we make plant breeding more efficient and faster, our peers in animal breeding are racing ahead in genetic terms. Egg production, milk production, meat production per animal has doubled over the past 40 to 50 years, and efficiency of feed conversion has improved. Crop breeders have not kept pace with animal breeders in terms of rate of genetic improvement. In traditional grain crop breeding, cycles of selection are relatively slow. In quantitative genetics terms, this is called generation interval. The time it takes from crossing of parents in the current cycle to selection of superior progeny, and crossing them as new parents to begin the next cycle of selection. This can take up to eight or ten years in traditional plant breeding. One process that takes time is self pollination and no crops die and set self seed every year. After several years of selfing, progeny become more and more homozygous, and eventually, become uniform pure lines. Most plant breeders wait until they have pure lines before they test them for economic traits such as grain yield. It is possible to speed this up, for example, by undertaking several selfing generations very quickly in the laboratory. All by using a tissue culture procedure called double haploiding. Even then, the generation interval can take five years by the time good parents are identified in field experiments and used in crossing. There is another problem with this traditional approach to grain crop breeding. A lot of genetic diversity is lost during the process of selfing to produce purer lines. The genetic diversity in a breeding program is estimated by effective population size. In most crop breeding programs, the effective population size is low. We estimate that most crop breeding programs have less than ten percent of the effective population size found in animal breeding programs. Low effective population size results in low genetic diversity, and eventually, we will reach a a yield plateau due to insufficient genetic diversity. Today, we will talk about a new plant breeding method that increases effective population size and genetic diversity in crop breeding programs, and reduces generation interval. But first, let us turn our attention to selection, choosing progeny to become parents in the next cycle. In animal breeding, a new selection procedure called Optimal Contribution Selection or OCS has improved a long term genetic gain. Our group was the first to try this in plant breeding with exciting results. With OCS, we showed a potential increase in the rate of genetic progress for grain yield and disease resistance that could help us reach the FAO's goal for 70% increase in food production by 2050. To make things more complicated, increasing global temperatures will cause predictable drop in crop yields, unless we find a process that allows us to breed for stress tolerance and grain yield simultaneously. Our group at the University of Western Australia, with help from colleagues at the University of New England in New South Wales, are researching ways to improve methods of plant breeding. Our approach is to breed plants like animals. We have started using BLUP breeding in plants. This approach was introduced into animal breeding over forty years ago. In BLUP breeding animals proven to be better than their ancestors or peers are used in mating as soon as they are identified. Data from all relatives and ancestors are used in the analysis to predict breeding values. BLUP breeding with information from relatives is known as the animal model in quantitative genetics and now, we are applying it to self pollinating plant. So why was this method not applied to crop breeding years ago? Possibly because pure line testing provides accurate estimates of genetic value. But making pure lines takes time, several years, in fact, and this slows down genetic progress. It also tends to reduce genetic diversity in crop breeding programs. BLUP breeding in contrast is designed for heterozygous animals which cannot be selft. So we asked the question, can we make faster genetic progress by estimating BLUP breeding values on heterozygous cross progeny in plants? We show that BLUP breeding values for grain yield and disease resistance were very accurate on heterozygous progeny, and these progeny when tested in field trials with data from relatives, all of the ancestors and peers were included in the BLUP analysis just as in animal breeding. With this approach, we reduce the generation interval down to one or two years and accelerated response to selection. Our results show that it is no longer necessary to wait for pure lines before evaluating genetic merit in cross progeny. In addition, we have increased genetic diversity in the breeding program due to higher effective population size through the use of optimal contribution selection. We show that these advances would occur long into the future at double the right of existing methods. And in our models, the new methods achieved the FAO goal of 70% improvement in crop production by 2050. Whereas, traditional breeding methods did not. With the new animal model method in plants, it is possible to make parallel improvements in disease resistance, stress tolerance, and grain yield, and quality. BLUP bleeding methods are based on a selection index, which combines all these traits into one economic value, such as dollar value per hectare, which is then used for selection of progeny for crossing. On top of these new BLUP methods for breeding plants, we will overlay new genomic selection technologies, and these will help to speed up the process. Genomic selection has reduced generation interval and improved efficiency of animal breeding. New technologies will work more effectively in the new BLUP breeding methods compared with traditional methods of plant breeding. Plant breeding is an important part of the solution for future farming in 2050. To be a successful plant breeder in the 21st Century, you will need skills ranging from molecular genetics through to quantitative genetics, field trial experimentation, and data analysis. But it's fun to see the results of your research on farms and to get feedback from farmers who grow your crop varieties. You can help make farming more sustainable into the future through improved crop varieties. In this talk, I have described a new plant breeding method which is looking very promising in the field. This is an exciting time to join plant breeding and improve the future of farming in the 21st century. [MUSIC]
