Submitted to: International Symposium on Rice Germplasm Evaluation and Enhancement
Publication Type: Proceedings
Publication Acceptance Date: 9/1/1998
Publication Date: N/A
Technical Abstract: Recent research has shown promise in using wild species to improve cultivated crops for yield and quality traits (Tanksley, et al., 1996 and Xiao, et al., 1996). This study was initiated to evaluate the potential of using the wild species Oryza rufipogon to improve a southern US long grain rice cultivar (Oryza sativa), Jefferson. The O. rufipogon donor parent (IRGC 105491) is characterized as being tall, pubescent, awned, high tillering, late maturing, dormant, susceptible to shattering and having a black hull, medium grain shape, and an apparent amylose content of 22-24 percent. In contrast, Jefferson, is a semidwarf cultivar that is glaborous, awnless, low tillering, early maturing, not dormant, resistant to shattering, and has a straw colored hull, long grain shape, and an apparent amylose content of 20-22 percent. Both Jefferson and O. rufipogon were observed to be resistant to races IC-17 and IE-1k of the blast fungus, Pyricularia grisea. Divergent reactions were observed between the two parents for reaction to race IB-49 (Jefferson is susceptible) and race IG-1 (O. rufipogon is susceptible) of blast. Three hundred fifty-three backcross progeny (BC2F1) were produced at CIAT with the next generation produced in quarantine and were used to cull out families carrying noxious weed traits (e.g. dormancy and high shattering). A total of 258 BC2F2 progeny were used for QTL analysis and were planted in a replicated field trial in 1998. A summary of the QTL analysis will be presented using data collected under greenhouse conditions. These data will be compared with field data that are being collected in the 1998 field trial.