Source: Business Mirror

19/07/2017 – The Philippine Rice Research Institute (PhilRice) is currently developing the country’s first series of heat-tolerant rice varieties as an answer to the ill effects of climate change.

 

In a study, titled “Quantitative Trait Loci [QTL] for high-temperature tolerance in rice [Oryza sativa L.]”, PhilRice researchers Norvie L. Manigbas, Jupier L. Gorospe and Evaristo A. Abella of the Central Luzon State University has found a way to produce the first heat-tolerant rice variety in the Philippines.

 

“As of now, we do not have any heat-tolerant rice varieties released in the country. Through this study, we’ve learned that the heat-tolerant trait is associated to the plants’ heading days, time of flowering, fertility and dehiscent temperature—most of which are found in the nine QTLs,” Manigbas added in a news statement on July 18.

 

Manigbas added they found out nine QTLs containing the genes that can counter the ill effects of high temperature. QTLs are sections of DNA containing the genes that control the trait.

“These QTLs were found through the backcrossing of Dular and NSIC Rc150 [Tubigan 9]. Dular is an Indian heat-tolerant rice variety that has low yield potential,” Manigbas said.

 

“Tubigan 9, on the other hand, is a Philippine rice variety with an average yield of 8.5 tons per hectare but not resistant to high temperature,” Manigbas added.

 

Backcrossing is an effective method to transfer one or a few genes controlling a specific trait from one line into a second—usually elite—breeding line.

 

The researchers identified six major QTLs—qHTfert1, qHTfert3  qHTfert4, qHTtof10, qHTdht3, and qHThd3—and three minor QTLs, namely, qHTdht4, qHTdht10 and qHTdht5.

 

Manigbas said these QTLs will be used in mapping genes using molecular markers and incorporating the genes into high-yielding cultivars through marker-assisted breeding. “Through this process, breeding new cultivars becomes faster,” Manigbas said.

 

The attached agency of the Department of Agriculture said earlier studies have confirmed that high temperature affects all growth stages of rice.

 

“However, it is from the booting to flowering stage that rice is most sensitive to high temperature,” PhilRice said. “Moreover, temperature exceeding 35 degrees at flowering stage can cause high pollen and grain sterility in rice. This leads to serious yield loss, low grain quality  and low harvest index,” it added.

 

At present, six advanced promising lines are currently being tested for multilocation trials in the National Cooperative Test under high temperature environments, according to PhilRice.

 

Manigbas and company’s study won the Outstanding Scientific Paper Award during the 39th National Academy of Science and Technology Annual Scientific Meeting recently held at the Manila.