A study recently identified 25 new advanced breeding lines after rigorous selection for high temperature tolerance using conventional method and marker-assisted selection.
Titled Development of new rice varieties for high temperature tolerance in the Philippines, the research was the bronze winner of the Gold AFMA Best R&D Paper Award.
Dr. Norvie Manigbas, lead researcher, said that the development of rice varieties for high temperature tolerance is important in addressing climate change in rice growing areas where 90-95% of the population depends on rice.
Manigbas said that rice grows optimally between 20-35°C and becomes increasingly 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 37-39°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 at reproductive stage of all test entries will concide with the highest temperature during the growing season. Thus, selection pressure for high temperature is enhanced. 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,” Manigbas explained.
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.
With his co-researchers, Luvina Madrid, Corazon Cardenas, Evelyn Ladia, and Ferdinand Enriquez, Manigbas targets the promising line to be released as a new heat-tolerant rice variety in 2016-2017.