Genome-wide mapping, allelic fingerprinting, and haplotypes validation
provide insights into the genetic control of carbon dioxide
responsiveness in rice
Abstract
Plant density significantly impacts photosynthesis, canopy structure,
crop growth, and yield, thereby shaping the [CO 2]
fertilization effect and intricate physiological interactions in rice.
An association panel of 171 rice genotypes was evaluated for
physiological and yield-related traits, including the cumulative
response index, under both normal planting density (NPD) and low
planting density (LPD) conditions. LPD, serving as a proxy for elevated
atmospheric [CO 2], significantly increased all
trait values, except for harvest index, compared to NPD. For the
genome-wide association study, 386,817 high-quality SNPs were
considered, employing both single-locus and multi-locus models, which
collectively identified 172 QTNs, including 12 QTNs associated with at
least two different traits under NPD or LPD conditions. A significant
rÂelationship between the percentage of favorable alleles in the
genotypes and their performance under NPD and LPD conditions was
observed. Potential haplotypes were validated using genotypes with
contrasting [CO 2] responses, grown under LPD and
Free-Air CO 2 Enrichment facility. These findings can
enable efforts to selectively breed genotypes with favorable alleles
and/or superior haplotypes for enhancing [CO 2]
responsiveness in rice. Climate smart rice varieties, with increased
[CO 2] responsiveness, have the potential to
simultaneously enhance grain yield and quality while mitigating losses
induced by high night temperatures.