Product Line 2.5. Hybrid rice for the public and private sector
Hybrid rice generally outyields inbred rice varieties by 10–20% and has been used in commercial rice production since 1976. Currently, about 20 million hectares are grown to hybrid rice, with China having the largest share of 17 million ha. Outside China, the major hybrid rice-growing countries are India, Bangladesh, Indonesia, the Philippines, and Vietnam in Asia, and the U.S. and Brazil in the Americas. In Africa, no hybrids are in large-scale commercial rice production yet. IRRI, collaborating with public and private partners, has been playing a crucial role in hybrid rice research and development internationally for the last 30 years, with a large number of hybrid rice varieties and parental lines shared with partners and numerous varieties released for commercial production. Hybrid rice R&D has been one of the main investments at IRRI for increasing yield potential and promoting rice production. In 2008, IRRI established the Hybrid Rice Development Consortium (HRDC), a public-private partnership with the objectives of renewing and strengthening collaboration between the private and public sector, and enhancing the dissemination of hybrid rice technology. Hybrid rice R&D programs at IRRI and in other public institutes are currently shifting to a product-oriented approach, focusing more on product development with key private-sector partners, but also with NARES programs and selected NGOs.
2.5.1. Rice hybrids for Asia
Developing hybrids derived from male-sterile systems is currently the best and most stable approach for using heterosis in rice. Among the factors affecting hybrid rice dissemination, yield in hybrid seed production is the most critical component. The aim is to produce hybrid seeds with reduced cost and have acceptable seed prices for farmers. Recent research at IRRI and in other commercial programs showed that seed yield could be increased to 3–4 t/ha from the current 1–2 t/ha through breeding. Germplasm with high outcrossing traits will be identified from diverse sources collected or developed at IRRI, and used in developing new female parents. Higher heterosis, which is required to achieve the advantage of hybrid rice over inbred varieties, is closely related to germplasm diversity. Germplasm will be exploited and heterotic patterns will be studied for developing hybrids with higher heterosis. Good grain quality is one of the factors influencing acceptance by consumers, and the high broken rice and chalkiness that can occur with hybrids need to be overcome. Hybrid rice grain quality should be studied, and the genetic and environmental components controlling grain quality will be identified for use in improving quality. As hybrid rice is grown widely, traditional biotic stresses (diseases and insects) may change with new rice cultural practices and management. Resistance or tolerance should be introduced into hybrid rice parents for developing improved rice hybrids. Traditional breeding methods combined with new molecular technologies will be employed in hybrid rice breeding to speed up product development.
2.5.2. Rice hybrids for Africa
F1 hybrids from Egypt, IRRI, China, and other Asian sources will be tested with parental lines in multilocation trials for evaluating their yield and resistance to abiotic and biotic stresses of Africa. Maintainer lines for developing locally adapted CMS lines will be identified.
2.5.3. Rice hybrids for Latin America
Parents of Asian and other hybrids will form the basis for identifying the best hybrids for Latin American conditions. Cirad activities include the integration of molecular markers into the reciprocal recurrent selection scheme through QTL mapping for combining ability, within the B and R breeding populations, for combining ability and pyramiding of QTLs of interest.
The next users are rice breeders working in GRiSP, private enterprises, and NARES. Intermediate users are seed producers and distributors in the public and private sector, and final users are farmers. Hybrid products developed in GRiSP will be transferred to small and large private companies through appropriate licensing mechanisms that ensure wide availability, also for the public sector. Private seed companies will produce hybrid rice seeds and deliver them to farmers. Government policies should facilitate the release of commercial hybrid cultivars. For the countries in Asia, the HRDC will play a key role to link improved hybrids with appropriate product delivery systems. For Africa, hybrid rice cultivation is still only in the testing phase (varietal performance and socioeconomic feasibility studies). IRRI will provide support to AfricaRice and CIAT/FLAR for establishing hybrid rice breeding and research programs.
The hybrid rice research at IRRI is currently funded by the HRDC, partially by other projects (ACIAR-Chalk, BMGF-STRASA, Pioneer-SKEP), and IRRI unrestricted funding. Income from HRDC membership fees, germplasm development fees, and hybrid licensing is expected to grow steadily so that other funding could be reduced or eliminated over time. All HRDC income will go back to supporting hybrid rice research (HRDC has established a mechanism for this). New funding will be required for work on more breeding efforts and product evaluation in multilocation environments. National partners are contributing through in-kind support and funding for product testing in local environments. The BMGF-GSR project supports work on hybrid evaluation in Asia and Africa.