Development of sorghum root system phenotyping and screening methods for phosphorus efficiency
Viktor Tishchenko (Univestity of Georgia), Ming Li Wang (USDA – PGRCU), Daniel Sabo (Georgia Institute of Technology)
Phenotype screening and selection for tolerance to low-phosphorus stress conditions was developed at the Georgia Envirotron. Methodology that uses P-loaded alumina as a phosphorus buffer in the quarts sand culture was used to perform efficient, economical, high throughput sorghum screening for P-efficiency under controlled nutrition conditions. Solid-phase sand-alumina culture system provided stable, diffusion-limited, slow-release conditions with varying P availability to plants. This technique provided better media conditions control and reproducibility compared to complex soil systems and, at the same time, better mimicked natural conditions compared to hydroponic cultures. Sorghum was selected due to its wide range adaptability to abiotic stress (such as drought and barren soil). Significant genetic variation in tolerance to abiotic stress exists in sorghum germplasm and cultivars. In situ electrical capacitance tomography (ETC) method was used for monitoring root development with greater accuracy due to media and plants consistency. The identified materials may be used in plant breeding programs for development of cultivars with high phosphorus use efficiency.