ARS | Publication request: Characterizing the Environment Response of a Gibberellic Acid Deficient Rice for Use As a Model Crop

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 22, 2004
Publication Date: July 21, 2004
Publisher's URL: http://agron.scijournals.org/cgi/reprint/96/4/1172.pdf
Citation: Frantz, J., Pinnock, D., Klassen, S., Bugbee, B. 2004. Characterizing the environment response of a gibberellic acid deficient rice for use as a model crop. Agronomy Journal. 96:1172-1181.

Interpretive Summary: The main higher plant use in research is Arabidopsis thaliana. While an excellent species for many genomic studies, it is a poor species to use in studies investigating factors associated with yield. This paper summarizes the evaluation of 'Super Dwarf' rice (Oryza sativa), an extremely short rice cultivar, in different day lengths, temperatures, and light. This provides guidelines for its use as a research plant for studies investigating the genetic factors associated with yield, and issues that are unique to grasses such as their unique plant nutrient requirements. Because topics associated with yield are important for this plant, many additional studies were performed to investigate the factors that control flowering. Specifically, supplying the plant hormone gibberelllic acid, applying nitrogen stress, and changing the day length were used to stimulate flowering. The environmental responses and basic growth requirements of this rice cultivar is now well characterized which provides other researchers base-line conditions for which this model plant can be used in other studies.

Technical Abstract: Most published genomes are of small organisms that have characteristics that lend themselves to study in space limitations of a laboratory. Rice has a relatively small genome and was the first crop plant to have its complete genome sequenced, but can be inconvenient to study because conventional rice cultivars are too tall to grow multiple plants in small laboratory growth chambers. We recently identified an extremely short rice variety (20-cm tall), which we called 'Super Dwarf' rice, that would be ideal to use as a model rice cultivar for laboratory studies. We have characterized the response of 'Super Dwarf' to temperature, photoperiod, photosynthetic photon flux (PPF), and factors controlling heading. Vegetative biomass increased 6% per degree Celsius with increasing temperature from 27 degrees Celsius to 31 degrees Celsius. Seed yield did not increase significantly at warmer temperatures, and as a result, harvest index decreased from 60% to 50%. The time to heading was increased by two days for every hour above a 12-h photoperiod. Yield and yield efficiency (grams per mol photons) increased with increasing PPF. Heading was delayed by addition of GA-3 to rootzones, but was hastened under nitrogen stress. Overall, short height, high yield, and high harvest index make 'Super Dwarf' rice an excellent model plant for yield studies in small laboratory conditions.