Hybrid rice for Latin America

23 April, 2013 by (comments)

Published in the CIAT Annual report 2012-2013, out now.

A new public-private partnership across Latin America promises to boost rice productivity and could help bolster the region as an emerging food basket for the world.

Launched in 2012, the Hybrid Rice Consortium for Latin America (HIAAL, by its Spanish acronym) brings CIAT researchers together with other rice scientists, traders, millers, and farmer organizations in 13 countries to develop high-yielding rice hybrids specifically adapted to the region. The move reflects the high importance given to hybrid rice by the CGIAR Research Program on Rice, also known as the Global Rice Science Partnership (GRiSP), whose research aims to help meet the ever-growing world demand for rice.

Biofortified Rice 7_lo

Hybrid rice involves crossing two distinct inbred rice lines to obtain genetically superior offspring that are up to 20% more productive. While well-established in Asia – over half of China’s rice comes from hybrids – and to a lesser extent in Africa, hybrid rice accounts for less than 2% of Latin America’s rice area.

More vigorous rice

Rice is self-pollinating, containing both male and female parts that produce offspring genetically identical to the parent plant. While this ensures the passage of particular characteristics from one generation to the next, it limits the options for crop improvement. To produce superior, hybrid rice that combines the beneficial traits of distinct rice varieties and takes advantage of “heterosis” – the tendency of crossbred varieties to outperform the parent plants – scientists first have to develop rice varieties with male sterility so that cross-pollination can occur.

As well as higher yields, the hybrid rice varieties developed by the Consortium will combine multiple additional traits that target some of the most critical constraints in the region. These include resistance to diseases, such as rice blast and rice
hoja blanca virus, and the need for high grain quality – essential for rice traders and processors. The varieties will also be developed to be better suited to the practice of direct seeding – the machine planting of rice seed straight into the ground, rather than the manual transplanting of seedlings common in Asia and Africa. Direct-seeded rice needs to have deep roots to avoid lodging – the windblown toppling of plants – and strong stems to bear the weight of heavy panicles.

HIAAL’s hybrid rice research could combine all of these traits into single “super varieties.”

Building on the best

In the newly established Consortium, CIAT will make the initial test crosses based on rice varieties in its own collection, those of the International Rice Research Institute (IRRI) in the Philippines, and the top-performing commercial rice varieties and experimental “elite lines” developed by participating institutions in Latin America. After initial testing, CIAT will distribute the hybrids to Consortium partners for subsequent testing and further improvement.

A system of royalties has been established to reward participating institutions when their rice varieties are used as parents of the new hybrid plants. The payments help ensure that participating institutions provide the breeding program with their best varieties and partners receive a steady stream of funds for continued investment in the initiative. “It’s high-risk, expensive research, but the benefits are potentially huge,” said Edgar Torres, leader of CIAT’s Rice Program. “But by forming a public-private partnership of this kind, we have two main advantages: access to the best germplasm – a lot of which is well adapted to the region – plus a strong, extensive testing network to test the varieties in different regions and environmental conditions. This is extremely expensive for private companies to do.”

One potential issue is that the benefits of the hybrid varieties only last one generation, before yields begin to drop and variability in the traits begins to creep in. For this reason, farmers will need to buy hybrid seed each year, instead of keeping a portion of their harvested seed for planting. For Torres, this is actually one of the advantages of hybrid rice in the region:

“It means that farmers will have high-quality, certified seed each season, which will help to ensure consistently high yields and limit the spread of diseases and problems such as red rice. It also means that a seed market can be established, enabling us to reach many more farmers.

“With the deeper roots associated with lodging tolerance, we expect the hybrids to be able to access nutrients deeper in the soil, so the cost of buying the seeds will be partially offset by reduced expenditure on fertilizer.”

The first varieties to result from the partnership are expected to be formally released in 2016, with the establishment of a robust seed system to supply farmers with seed on a large scale, in around 5 years.

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