PhilRice develops heat-tolerant rice varieties

NUEVA ECIJA, Philippines – The Philippine Rice Research Institute (PhilRice) is developing rice varieties that can withstand intense heat brought by climate change.

According to Norvie Manigbas, lead researcher at PhilRice, the institute has identified 25 new advanced breeding lines after rigorous selection for high temperature tolerance using conventional method and marker-assisted selection.

Manigbas noted that the development of heat-tolerant rice varieties is important in addressing the adverse effects of climate change in rice growing areas on which 90 to 95 percent of the population depends.

Rice grows optimally between 20°C-35°C but becomes sensitive to increasing temperatures especially during flowering, which eventually reduce yields.

In 2010, Manigbas and his team started to develop new rice genotypes that can tolerate and adapt to high temperatures at 37°C-39°C under irrigated lowland conditions.

They identified N22 (Nagina 22 from India), Dular (India), and Nipponbare (Japan) as donor parents and used conventional breeding and molecular marker-assisted selection to generate new high temperature tolerant breeding populations.

“We established breeding nurseries in high temperature prone areas in Cagayan and Nueva Ecija to screen and select breeding materials under field conditions. Planting was done on staggered basis so that flowering, or reproductive stage, of all test entries would coincide with the highest temperature during the growing season. Thus, selection pressure for high temperature is enhanced,” Manigbas explained.

“After that, we identified twenty-five new breeding lines tolerant and 16 of those had lower percent sterility compared with the tolerant checks and donor parent N22,” he added.

The new lines will be evaluated further for other traits and if they passed, they can be nominated to the National Cooperative Test for Multi-Environment Testing.