With the changing climate and environment, rice researchers have explored a more efficient method called precision breeding to improve the traits of existing rice varieties.
In a recent seminar conducted at the Philippine Rice Research Institute (PhilRice), Dr. Rosalyn B. Angeles-Shim, assistant professor from Nagoya University in Japan, said that scientists practice precision breeding through marker-assisted selection to increase yield of rice and enhance its tolerance to biotic and abiotic stress.
Precision breeding transfers specific desired traits, such as those that can tolerate drought conditions or resist certain disease, into existing outstanding cultivars. It improves speed and precision as desirable traits within the entire map of genetic material of related plants are identified and targeted.
On the other hand, conventional breeding takes more time as it entails backcrossing of generations, then selecting and field testing them to get the desired result or cultivar.
Angeles-Shim said that the use of the technology had resulted in the identification of Gn1a and the Wealthy Farmer’s Panicle (WFP) as two potential genes that can increase rice production in Africa. Transferring Gn1a to existing rice cultivars increases grain number in rice while WFP promotes primary branching.
Through the breeding program, Wonder rice initiative for food security and health (WISH) of the International Rice Research Institute and the Japan International Cooperation Agency, the existing rice cultivars in which these genes were transferred are now being tested.
“The WISH project aims to increase rice production in Africa. Instead of introducing new varieties to farmers, we focused on improving the ones that are known and widely used and adopted in the area by breeding them with the identified genes. This promotes faster acceptance by the rice farmers in the area,” Angeles-Shim explained.
PhilRice scientist Roel Suralta said that precision breeding enables plant breeders to target traits that can be quantitatively associated with specific genes, which enhance plant performance.
These genes can be “tagged” using genetic markers uniquely associated with the desired traits. Rather than crossing the parents’ genes and growing the offspring to maturity to check if the trait is present, breeders can search for these discrete markers or “tags” at the early seedling stage, significantly shortening the breeding program.
“Precision breeding has been practiced in the Philippines for years. A classic example of PhilRice-released variety that is also a product of precision breeding include the NSIC Rc194 or Submarino 1 which has a submergence-tolerant trait. Other PhilRice varieties with improved disease-resistance are also a product of precision breeding,” Suralta said.
On-going studies using precision breeding are also up in PhilRice to map and identify genes that promote root plasticity, tolerant to anaerobic conditions, resistant to pests and diseases, and quantitative trait loci/ genes that help increase rice yield under drought condition.