Green Super Rice (GSR) Breeding Technology

Green Super Rice (GSR) resilience breeding involves introgression breeding and designed QTL pyramiding (DQP) efforts for developing varieties with multiple abiotic and biotic stress tolerance without compromising on grain yield and quality. BC₁F₂ populations derived from HHZ and WTR1 (recipient parents) and 16 donors at IRRI were screened simultaneously for three rounds for different abiotic (Drought, salinity, submergence and low fertilizer input conditions) and biotic stresses (blast, BLB, tungro) and normal irrigated condition that resulted in identification of 1333 (HHZ-ILs) + 2232 (WTR 1-ILs) trait specific introgression lines (ILs) superior over tolerant checks. 497 HHZ ILs from 8 donor parents were sequenced and phenotyped under different 11 conditions (6 high yielding irrigated sites, 3 cold, 1 nitrogen stressed, 1 drought) resulting in detection large number of QTLs for high yield (66 QTLs), cold (36QTLs), drought (16 QTLs) and nitrogen stressed (29 QTLs). 130 promising GSR materials were nominated to national and multi-environment testing (MET) trials in Asia and Africa. Utilizing elite HHZ ILs, 191 pyramiding crosses were made and 76 (two batches 36 + 40) showed promising results upon their screening under drought, salinity, submergence and low input conditions. Further, selected 2212 pyramiding lines (PLs) over two rounds of selection under three conditions and the second round comprised of selections under irrigated (632), Low input (977), Drought (603). A subset of these will be used for genotyping with 50K SNP chip. Out of these only two sets of 125 PLs each is being advanced to Preliminary Yield Trial (PYT) stage during 2015DS. Simultaneously, 33 elite PLs were submitted to AYT stage of the Multi-Environment Trials (MET).  Successful genomics-assisted breeding approach requires innovative cross-tolerance screening and skillful selection techniques.  We developed and released five multiple biotic stress tolerant varieties with high yield potential and many in pipeline in Asia & Africa.