Wild rice MAGIC

Limited genetic variation in cultivated rice is a major factor responsible for the declining rates of yield improvement since the Green Revolution. Substantial and underexploited genetic variation exists within wild relatives of rice that improve tolerance to stresses. We will initiate the first program to mix alleles from all wild-rices, select those with benefit under stress and introduce them into cultivated rice. To date, alleles from individual non-domesticated rice species have been combined into elite varieties. While useful, this is both limited in scope and ignores much of the uncharacterized allelic variation present in wild-relatives. Furthermore, combining genomes can produce desirable phenotypes in progeny that are absent in parents. This breeding program will be underpinned by analysis of the genomes of the lines that we generate and by phenotyping to assess how each line responds to a wide range of stresses. The germplasm that we generate will be supplied to partners in Africa and India for testing in field sites, and to allow speedy supply of good seed to farmers.

Limited genetic variation in cultivated rice is a major factor responsible for the declining rates of yield improvement since the Green Revolution. Substantial and underexploited genetic variation exists within wild relatives of rice that improve tolerance to stresses. We will initiate the first program to mix alleles from all wild-rices, select those with benefit under stress and introduce them into cultivated rice. This breeding program will be underpinned by deep sequencing and phenotyping to initiate the foundations for a predictive framework whereby beneficial genetic variation from wild species can be transferred efficiently into elite varieties to combat a wide range of stresses. To date, alleles from individual non-domesticated rice species have been combined into elite varieties. While useful, this is both limited in scope and ignores much of the uncharacterized allelic variation present in wild-relatives. Furthermore, combining genomes can lead to transgressive variation, a phenomenon we will investigate to determine the extent to which this produces desirable phenotypes in progeny that are absent in parents. We will use all eight wild rices with double A genomes to initiate a Multi-parent Advanced Generation Inter-Cross (MAGIC) breeding program that will dramatically accelerate the flow of genetic diversity into domesticated accessions of rice. In parallel, we will modify the MAGIC protocol so that representatives of each generation are back-crossed into three locally adapted varieties of O. sativa to accelerate transfer of useful traits into good germplasm as well as to facilitate testing by the National Partners. By generating a highly recombined rice AA genome this process will produce additional genetic variation that can be screened for improved tolerance to biotic and abiotic stress and then introgressed into elite varieties of O. sativa.

Beneficiaries are widespread.
Who will benefit?
In the short term, the research groups of this consortium will benefit from the funding. The international rice research community will then be next in line to benefit from increased knowledge that is generated on genome structure and interactions that are discovered over the course of this project. More information on academic impacts is outlined in the Adademic Beneficiaries section. In the medium to longer term people working on rice breeding, rice farmers and rice consumers will also benefit from this research and the resources that we generate

How will they benefit?
The novel germplasm that we produce will be made available to other researchers so that stresses and phenotypes that we are unable to assess over the course of this project can be assessed.
Lines of rice that we identify that show increased tolerance to stresses will then be likely to impact on millions to billions of people. Average losses in rice production due to drought can be $1.07 billion yr-1 in Asia. In Africa, demand for rice is the growing faster than any other crop. Recurring drought affects nearly 80% of the ~20 million hectares of rain-fed lowland rice growing areas. One or two large effect QTL for drought tolerance in popular varieties can conservatively increase yield by 500 kg ha-1 depending upon severity of stress. Successful improvement of drought tolerance in even 10% of the 23 million ha of drought-prone area could yield an economic return of $345 million (conservative marker price $300 ton-1). If resistance to blast is sustained, average yield gain has been estimated at 0.28 ton ha-1. The economic return in India (43 million ha) would be ~$361 million. No quantitation of RYMV on yield is available, but it is endemic to Africa and so sustained resistance will have large impact. Improved germplasm from the siphoning program to introgress into locally adapted varieties will be possible within 5 years, and will also provide a longer-term legacy. The research and courses will contribute to optimizing gender equality of rice consumers and producers. Women bear most of the burden for rice production in the poorer regions of the world where they assume up to 100% of planting and harvesting responsibilities. Increased yields allow women farmers more time to generate additional income by growing a diversity of cash crops that further alleviate dietary deprivation, and improve family housing and education opportunities. If we are able to generate lines of rice that show increased tolerance to any of these stresses, the work will contribute to global food security and therefore also economic stability and development.