10:55 〜 11:10
[O44-05] Physiological Traits and Genomic Regions Associated with Rice (Oryza sativa L.) Root Cone Angle Grown in an Aerobic Production System
*Nominated for Presentation Awards
Aerobic rice production system (AP) uses less water than traditional flooded culture, and could be a solution to the imminent water availability crisis brought about by changing climate. Genotypes with narrow root cone angle (RCA) could produce deep root system, and are considered to be adapted to AP. This study aims to physiologically characterise recombinant inbred lines derived from IRAT109 for RCA and related traits and to determine genomic loci associated with these traits through genome wide association (GWA) mapping. The second season field trial which evaluated 18 selected top and tail lines identified in a glasshouse experiment, revealed significant genotypic variation in RCA, early vigour (EV), light interception, canopy temperature depression, leaf death, pulling score (PS), days-to-heading (DTH), biomass, plant height, panicle weight (PW), harvest index, and grain yield. Genotypes with narrower RCA achieved higher EV and PS, indicating their advantage in early growth and root system development. GWA identified a consistent genomic region associated with RCA located in chromosome 4. Genotypes with the target allele had narrower RCA, higher EV, PS, DTH and PW compared with genotypes with non-target allele. Post QTL analysis and allele mining identified a NAC TF candidate gene. Evaluation of narrow RCA in intermittent water stress conditions and development of molecular markers are underway. This study provides physiological and genomic understanding of RCA and with genomics-based breeding, will hasten the development of AP-adapted, sustainably produced rice.