Abstract

A mapping population of IR24 (indica) chromosome segment substitution lines (CSSLs) in Asominori (japonica) background was used to detect quantitative trait loci (QTLs) for response to elevated CO₂ in yield and its components of rice in free air CO₂ enrichment (FACE, atmospheric CO₂ plus 200 µmol CO₂• mol^-1) and natural atmospheric CO₂ (Ambient) conditions. Transgressive segregation and continuous distribution in the CSSLs were observed for elevated CO2 response values (the value in FACE minus that in Ambient), in panicle number per plant (PN), grain number per panicle (GN), 1000 grain weight (GW) and yield per plant (YD), suggesting that all the tested traits responding to elevated CO₂were quantitatively inherited. Three (qYD-1, qYD-10, qYD-12), two (qPN-5, qPN-10) and one (qGN-1) QTLs were detected for CO₂ response to YD, PN and GN, respectively, but non-QTL for GW. Interestingly, both qYD-1 and qGN-1 were located at the same marker interval of C112-C2340, on chromosome 1, and had all positive response values from IR24. The results might be useful for understanding the genetic basis for responding to elevated CO₂ and breeding new rice varieties adapted to the higher atmospheric CO₂ environment in the future.

Key words: Free air CO₂ enrichment (FACE), quantitative trait loci (QTLs), rice (Oryza Sativa L.), yield and its component.