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Theme 1: Harnessing Genetic Diversity to Chart New Productivity, Quality, 
and Health horizons

Overview

 Rationale and objective 

    Genetic diversity is the foundation of the genetic improvement of crops. Knowledge of multiple facets of rice genetic diversity from the molecular to the phenotypic is essential for effective conservation and use to meet both current and future needs. Although the genetic makeup of rice, a vast catalogue of genes, has been revealed as a result of recent advances in biotechnology, most of their functions remain largely unknown. Thousands of undiscovered genes can potentially benefit rice productivity and quality and the processes to decipher their functions are complex—requiring cutting-edge biotechnology, phenotyping methods, and bioinformatics. An individual institution can cope with only a few at a time. If we are to exploit the rice genome adequately in a timely manner to help increase the world’s rice harvests, a global research effort is needed, integrating the strengths of public and private organizations and facilities from high-tech laboratories to farmers’ fields. The CGIAR, through existing centers and new research networks as a basis for wider partnerships, is ideally placed to lead this effort. 
Theme 1 draws together germplasm conservation, diversity analysis, gene discovery, and dissemination of advanced genetic/breeding resources, presenting a unique opportunity to maximize the use of conserved and customized germplasm. Because water is fundamental to rice productivity, traits dealing with stress related to water—too little or too much—are the core concern of this global effort to reduce risks to farmers and to mitigate the effects of a changing climate. Research will also include a wide spectrum of genes for other traits that have high impact in the various rice production environments.  

 Research approach

    The basic approach is to improve the conservation, characterization, and use of the world’s rice gene pool for varietal development by joining the resources of organizations across the globe. This will mean joint management of the world’s rice genetic resources both in genebanks and in research, development, and extension institutions. The theme will capitalize on the rapid advances in DNA sequencing technologies to reveal rice diversity in a comprehensive manner. We will also learn from plant species with better photosynthetic efficiency (Box 8) to redesign the rice plant for greater productivity for the future. Theme 1 will also provide capacity development for many NARS collaborators in new molecular biology approaches. 

Box 8. C4 rice—re-engineering photosynthesis

Construction of C4 rice, in which the 3-carbon metabolic pathway of photosynthesis in present rice plants is converted into a 4-carbon one, is a revolutionary, elegant concept and a grand challenge to be addressed in GRiSP. C4 rice would increase rice yields dramatically, by up to 50%, independently of the rice-growing environment (unlike all other interventions), while using water and fertilizer up to 30% more efficiently. The metabolic components already exist in C3 rice plants. However, the anatomical and biochemical features of C4 plants must be understood and transferred to rice plants. A technological innovation of this magnitude requires the skills and technologies of a global alliance of multidisciplinary partners. In GRiSP theme 1, this is being pursued by a group of scientists and their resources from advanced institutions around the world in the international C4 Rice Consortium. The aim is to construct a functioning C4 rice plant within the next 20 years. Success would mean a quantum leap in securing the world’s future rice supply.

 R&D product lines and outputs

1.1. Ex situ conservation and dissemination of rice germplasm 

1.2. Characterizing genetic diversity and creating novel gene pools 

1.3. Genes and allelic diversity conferring stress tolerance and enhanced nutrition 

1.4. C4 rice

        These product lines will provide the foundation for new international rice breeding programs, leading to new and improved rice varieties (addressed in theme 1) and cropping systems (theme 3). They will also improve both in situ and ex situ conservation of the world’s rice genetic resources. Broadened access to genetic resources and tools by breeders, researchers, and plant biologists is expected to improve the efficiency of rice breeding and gene discovery activities among partners, enable precision breeding, and accelerate the achievement of breeding targets in theme 2. The research products will all be international public goods to be used by the global rice research and breeding communities. This outcome requires an open environment for germplasm exchange and sharing. 

 Innovative contributions

    The collective research capacity under theme 1 provides opportunities for innovation not possible in individual institutions. Key innovations of significant scale and scope include 

  • integrating management of the world’s largest collection of rice genetic resources;
  • a new, global public genetic diversity research and gene discovery platform;
  • modernizing trait evaluation using high-throughput precise phenotyping;
  • designing a plant ideotype for climate-change scenarios; and
  • producing a more efficient rice plant (C4) for the future.

 Partnerships

        Leading rice genetic resources centers and research groups worldwide will become fully aligned under this theme, in which IRRI, AfricaRice, and CIAT will join forces with Cirad, IRD, JIRCAS, leading research institutions and universities from many countries, NARES, and private companies. Strong NARES systems such as those in China, India, and Brazil are expected to also make significant contributions to theme 1. The partners in theme 1 will share collections of genetic stocks and databases, take part in a global genotyping and phenotyping network, and exchange staff. Importantly, there will be close liaison between research under this theme and similar programs in the CGIAR on other crops, as is currently the case with the Generation Challenge Program (GCP). Partnership with the GCP is particularly important to theme 1 given the shared objective of building an efficient gene discovery platform. Solid links with theme 2 efforts will ensure that outputs are picked up in the rice breeding process and feedback is obtained from farmers and other rice development stakeholders. 

 Impact pathways

     To date, only a small fraction of the rice genetic resources has been used in breeding.  Sustained access to, exchange of, and use of these materials are essential because demand for them to solve production and environmental problems will increase in the future. This means greater demand for the genetic knowledge and tools needed to identify and use them. 

        The product lines of theme 1 are closely aligned with theme 2 by providing a comprehensive, well-documented germplasm and breeding resource base and a genetic diversity platform to enable the identification of gene combinations important for varietal development. The expected immediate users are scientists involved in genetic improvement efforts within and beyond the GRiSP in NARES, advanced research institutes, and the private sector. In relation to other Mega-Programs, rice as a genetic model has much to offer to other crop species. Gene discovery in rice will directly benefit genetic research on other commodities in TA 3 (Thematic Area 3 of the CGIAR Strategy and Results Framework). Comparative biology using plant systems other than rice will enable re-designing of the rice plant with a huge potential impact on production. At the level of discovery science, theme 1 can play an important role in leveraging the plant science community to apply genetic knowledge to reach new frontiers, as illustrated by the C4 project, which will engage a broad community of researchers around the world.