Exploitation of interspecific biodiversity for wheat improvement

The world's population is set to increase from 6-9 billion by 2050 and thus food production needs to increase by 70% over its present levels. In addition, climate change and the need to develop lower-input farming practises will significantly reduce the production of crops such as wheat. Unfortunately, due to modern breeding practises relatively little genetic variation is available in modern wheat varieties for breeders to develop superior adapted genotypes.

The wild relatives (alien species) of wheat provide a vast and largely untapped reservoir of genetic variation (for traits such as tolerance to abiotic and biotic stress, biomass, yield and photosynthetic potential). This variation can be exploited for the development of new high yielding varieties adapted to climate change and environmentally friendly agricultural practises. Examples of previously successful introgressions from alien species into wheat include leaf rust resistance from Aegilops umbellulata (which saved US wheat production from catastrophic failure in 1960); resistance to a range of diseases, tolerance to acid soils and increased yield advantage from rye (in the late 1990s a 1B/1R translocation was present in the majority of the world's wheat varieties and is still present in leading varieties such as "Rialto"); a gene from Ae. ventricosa conferring resistance to eyespot is present in many wheat varieties; many of the top wheat varieties in Europe, e.g. "Robigus", carry genes derived from introgressions from Triticum dicoccoides.

The BBSRC have recently funded a research programme aimed at transferring genetic variation to wheat from its wild relatives. These lines will ultimately be exploited to develop new superior high yielding wheat varieties which are adapted to climate change and environmentally friendly farming practises. This funded research programme is in the process of developing 1) large numbers of wheat/alien hybrids, produced by crossing wheat with its distant relatives, and 2) a series of lines of wheat carrying single chromosome segments derived from a range of alien species. For the full potential of this programme to be realised it is essential that the wheat/alien germplasm being generated is screened for a diverse range of traits in multiple environments. In order to do this the present application will assemble an international crop physiology cluster involving groups in the UK, Australia and India. While the research will have global application the emphasis of this programme will focus on developing superior Indian wheat varieties. Over recent years wheat production has stagnated in India with new varieties failing to provide significant improvements in yield potential primarily because of the adverse affects of biotic and abiotic stresses. The introduction of alien germplasm which combats these stresses is thus of critical importance for future wheat production in India.

This group will undertake research and screen the wheat/alien germplasm being developed for a range of traits including tolerance to heat, drought (including water use efficiency), acid and alkaline soils and salt; resistance to disease; increased photosynthetic capacity/biomass production and nitrogen use efficiency.

As a result of this research the crop physiology cluster will enable the identification of specific alien chromosome segments that carry genes that e.g. confer resistance/tolerance to biotic/abiotic stresses, etc. These alien chromosome segments will be directly incorporated into wheat breeding programmes in India at DWR and at the ARI. Furthermore, the data obtained from this programme will be channelled back into the BBSRC funded germplasm programme and in particular to the breeders associated with it in the UK for commercial exploitation. The material will also be exploited by Australian breeders thus providing a further link between the BBSRC and the Grain Research and Development Corporation (GRDC).

In this programme we propose to undertake research that will exploit wheat/alien hybrids and introgression lines (that are being developed in BBSRC research programme BB/100260X/1) that will lead to the development of superior high yielding Indian wheat varieties that are adapted to climate change and environmentally friendly farming practises. An international crop physiology cluster, i.e. groups based in the UK, Australia and India, will screen four introgression series (the four introgression series will be derived from Aegilops urartu, Ae. speltoides, rye and Thinopyrum bessarabicum, with each introgression series being composed of circa 140 different introgression lines, i.e. 540 plants in total) and 250 new amphidiploids, for genetic variation from introgressed genes for the following traits: tolerance to heat, drought (including water use efficiency), acid and alkaline soils and salt; resistance to disease; increased photosynthetic capacity/biomass production and nitrogen use efficiency.
These alien chromosome segments will be directly incorporated into wheat breeding programmes in India at DWR and at the ARI providing they lack deleterious genes which reduce yield potential. If the alien chromosome segments are found to carry deleterious genes then the introgressed segments will be reduced further to remove them. This will be achieved by intercrossing introgression lines which carry overlapping alien chromosome segments where the target alien gene lies within the overlap. The resulting F1 hybrid will be backcrossed to normal wheat and lines with a reduced alien chromosome segment will be identified via SNP analysis.

Beneficiaries

The world's population is set to increase from 6-9 billion by 2050 and thus food production needs to increase by 70% over its present levels. In addition, climate change and the need to develop lower-input farming practises will significantly reduce the production of crops such as wheat. Wheat is a key crop globally with 680 million tons produced in 2009. It is the leading source of vegetable protein in human food, having a higher protein content than either maize (corn) or rice and, in terms of total production tonnages used for food, it is currently second to rice as the main human food crop. However, over recent years wheat production has stagnated in countries such as India with new varieties failing to provide significant improvements in yield potential primarily because of the adverse affects of biotic and abiotic stresses. The programme described will exploit genetic variation in wild and cultivated related species to develop high yielding wheat varieties that are adapted to the changing climate and environmentally friendly breeding practises. The programme will thus have a major impact in addressing elements of the global challenge of food security. The immediate beneficiaries of this work will be the Indian, UK, and Australian breeding communities, the international academic wheat community, international breeding centres and the developing world.

How will the beneficiaries benefit from the research

The programme will result in the identification of alien chromosome segments, and subsequently alien genes, that confer resistance/tolerance to biotic and abiotic stresses, deliver increases in grain yield and use resources such as fertiliser and water more efficiently. The germplasm carrying the alien chromosome segments will initially be incorporated into breeding programmes at ARI and DWR in India and will then be made available for exploitation, free of IP, globally. As a result this work will contribute to the development of superior high yielding wheat varieties that are required to meet the needs of the global food security crisis. While the time frame for the impact of this work is initially aimed at 5 to 10 years it is our intent to develop a much longer term research and breeding platform.

Economic impact

There are clear examples of the exploitation of wild relatives and exotic germplasm to introduce novel resistance, yield or drought characteristics into wheat which have resulted in economic impacts globally of hundreds of millions and in some cases billions of pounds/dollars e.g. leaf rust resistance from Ae. umbellulata and the 1B/1R translocation. More recently 30% of wheat now produced for developing countries from CIMMYT's wheat programme is derived from wheat synthetics. If a novel source of drought/salt/heat tolerance or resistance to disease, in wild species is transferred to wheat, this would have substantial economic and quality of life benefits.

Social and training impact.

This programme will bring together a skill base, providing a framework within which young Indian researchers and students can be trained in a wide range of skills involved in plant population development, genotyping and phenotyping. These key skills will be required to underpin future Indian wheat programmes.