Rice Genotype Survey-90



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Project Leader and Principal UC Investigators

R.W. Breidenbach, Agronomist and Lecturer, UC Davis

R.S. Criddle, Professor of Biochemistry, UC Davis

J.E. Hill, Extension Agronomist and Associate in the Experiment Station, UC Davis


This is a new project that seeks to quantify the factors that determine the rate of growth for different rice cultivars. Its three primary objectives are to:

  • Correlate heat rate from various rice tissues with growth rates and yields.
  • Evaluate how different parts of the rice plant respond to different temperatures.
  • Examine the interaction between temperature and chemical stresses to different rice tissues.

The major accomplishment of this project was the development of a mathematical model that can predict growth rates of different cultivars. This equation gives researchers a new analytical tool to evaluate existing cultivars, as well as new cultivars in genetic screening studies.

One significant point about this mathematical expression is that all of the quantities needed for it are measurable by existing research methods. To collect their data, the researchers took measurements from seedlings monitored by a modified calorimeter.

"Equation developed for predicting growth rates of different cultivars"

In addition to predicting relative plant growth rates, the equation also determines carbon use efficiency, energy efficiency, redox state of substrate, respiratory quotient and metabolic pathways dominant in energy production-all values of central importance in improving crop productivity.

The researchers demonstrated readily measurable differences in cold tolerant and more sensitive cultivars that may be used in screening for cold tolerance. The measurements do not yet provide simple, quantitative procedures for large-scale screening, but offer promise that these may be developed.



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