Innovative Green Super Rice (GSR) molecular breeding strategy: achievements and advances

Exploitation of genetic response to higher inputs is currently being practiced in most rice varietal breeding programs ever since the green revolution of the mid sixties. In the process, fertilizer and pesticide consumption patterns are showing increasing trends leading to frequent pest outbreaks. A new breeding strategy was initiated to promote resilience into our rice varieties right at the beginning of the breeding cycle. The resilient rice varieties are known as Green Super Rice (GSR) and are more efficient at using nutrients and water and can withstand various abiotic and biotic stresses for any given ecosystem, and retain high yields and grain quality. Currently, a total of 500 donors are being used for introgressing them into the elite adaptable varietal recipients in China involving a huge research manpower in the process of development of GSR lines. However, in this paper, the success of drought pyramiding lines using designed QTL pyramiding (DQP) in IR64 recipient background will be highlighted and a unique GSR breeding strategy developed at IRRI using Huang-Hua-Zhan (HHZ) (recipient parent) and 16 donors will be discussed. Combination of massive introgression breeding to unravel hidden and known tolerance QTLs/genes along with DQP approach for pooling the favorable target trait QTLs across donors has made this breeding strategy quite robust and efficient. Forty high yielding stable introgression lines (ILS) with multiple abiotic and biotic stresses tolerance developed within a short span of five years using GSR breeding approach were nominated to the national cooperative testing (NCT) of the Philippines and Multi-Environment Testing (MET) of IRRI. Ten high yielding GSR lines were advanced to MET2 under GRiSP and 26 promising GSR cultivars that were nominated earlier to NCT Philippines and other NARES partners across Asia will be soon released within 1-2 years from now.