The Science Behind Rice Hybrids
A History of Collaboration Breeds Modern Solutions
Vietnam is the second largest rice exporter in the world, and the Mekong Delta lies at the heart of the country’s rice-producing region. But the Delta is not static. In an effort to feed themselves year-round and maximize opportunities produced by the river’s ebb and flow, farmers in the Mekong Delta flood rice fields with saline water in the dry season to raise shrimp. In the wet season, they use rain and fresh river water to flush the salt out of the soil to prepare for rice planting. This practice poses severe challenges: namely, rice crops do not adapt well to the high salinity caused by the shrimp farming, and crop failures are a frustrating legacy for a people steeped in the agrarian traditions of generations.
One such farming couple, the Thucs, who were featured in the mini-documentary “Salt of the Earth,” can now dream of sending their children to university after planting Pioneer® brand rice hybrid PHB71, a seed that prospers in salty soils and low water levels, producing predictably higher yields in the short four- to five-month planting season that choreographs the rhythm of the Thucs’ lives.
Addressing world hunger requires a global effort to hone in on local solutions. Over a period of several years, DuPont Pioneer worked with research institutes and local partners throughout Asia testing PHB71 to address the very challenges that have kept generations famers like the Thucs in poverty.
PHB71 is the commercial hybrid developed from crossing a female parent line developed in the Philippines by the International Rice Research Institute (IRRI) with a male parent line developed by Pioneer. Bringing together positive attributes from both parent plants resulted in a hybrid with improved roots, vigorous growth and increased yield over local varieties. Very adaptable to different environments, PHB71 has proven to be a top-performing hybrid across the board, standing up in rigorous tests in Vietnam, India, the Philippines, Indonesia and Cambodia. For the Thucs and their neighboring farmers, PHB71 demonstrated strong tolerance for the high salinity of the Mekong Delta soil, producing a 30-40% higher yield. It has also proven to be more resistant to Bacterial Leaf Blight and Leaf Blast than local seed varieties. With its extensive root system and enhanced vegetative vigor, the hybrid is also more drought tolerant than the open pollinated varietals (OPVs).
Although the hybrid has been used in Vietnam since 2008, the science behind developing hybrid rice and commercializing it for use by farmers in the region has a much longer history. Governments, multinational research organizations and private companies have contributed key links in the chain. The first generation of hybrid rice technology was developed in China some 40 years ago.
Up until the last 40 years, rice was strictly a varietal crop. A breakthrough came in the 1970s when Chinese scientists created the cytoplasmic genetic male-sterile (CMS) line *(see box), which allowed the establishment of the female lines necessary for hybrid production. India has also played a leading role, dating back to the launch of its government’s hybrid rice program in the early 1990s. Pioneer started its hybrid rice program in 1988.
Hybrid testing for response to regional environmental and climactic challenges is rigorous, collaborative and wide-reaching. Before being used by farmer Thuc for “rice after shrimp farming” in the Mekong Delta, numerous organizations put PHB71 through its paces, including the Food Crop Research Institute and the South Center for Plant and Fertilizer Testing (SCPFT) of the Ministry of Agriculture and Rural Development (MARD) in Vietnam, the All India Co-ordinate Rice Improvement Project (AICRIP) of the India Council of Agricultural Research (ICAR), India’s Directorate of Rice Research (DRR), the Indonesia Center for Rice Research (ICRR), IRRI and the National Seed Industry Council in the Philippines, and the Cambodian Agricultural Research and Development Institute (CARDI).
The Pioneer testing team also used large areas for demonstrations under certain soil conditions. This process can take 2-3 years, and agronomists work closely with local farmers to ascertain the costs and benefits of introducing new seeds. Pioneer also sampled PHB71 with growers to allow them to grow the hybrid side by side with their local varieties under their own management practices. In most cases growers realized a significant yield advantage with PHB71.