Through combined high-resolution image-based phenotyping with functional
mapping and
[www.isaaa.org] genome
prediction, a new research conducted at the Australia Plant Phenomics
Facility (APPF) provides insights into the complex genetic architecture and
molecular mechanisms underlying early shoot growth dynamics in
<[www.isaaa.org]
e> rice.

The timing of developmental 'triggers' or switches that initiate tiller
formation and rapid exponential growth in rice are a critical component of
early vigor trait which is important in aerobic rice environments. However,
the search for the switch that initiates this growth has proven challenging
due to the complex genetic basis and large genotype-by-environment effect,
and the difficulty in accurately measuring shoot growth for large
populations.

The APPF team led by PhD student Malachy Campbell phenotyped a panel of ~360
diverse rice accessions throughout the vegetative stage (11-44 day old
plants) at APPF. A mathematical equation was used to describe temporal
growth trajectories of each accession. Regions of the genome that may
regulate early vigor were inferred using genome-wide association (GWA)
mapping. Many loci with small effects on shoot growth trajectories were
identified, indicating that many genes contribute to this trait. GWA,
together with RNA sequencing identified a gibberellic acid (GA) catabolic
gene, OsGA2ox7, which could be influencing GA levels to regulate vigor in
the early tillering stage.

[blog.plantphenomics.org.au]
-the-triggers-behind-early-canopy-closure/