ROOT SIZE AND DISTRIBUTION OF FIELD-GROWN WHEAT GENOTYPES

Extraction of held grown wheat (Triticum aestivum L.) roots is cumbersome, tedious, and labor intensive, whereas the roots of wheat plants grown in hydroponics are clean and easy to extract. To determine if wheat root growth in hydroponics is related to held root growth and grain yield under varying soil conditions, we grew six winter wheat genotypes in three field environments. Genotypes were selected based on the size of their root systems when grown hydroponically: three had large root systems and three had small root systems. Subsurface root length density (SRLD) was measured from soil cores in incremental depths between 13 and 120 cm. Averaged across environments, the root fresh weight in hydroponic culture was correlated with SRLD (r = 0.93**). As a group, genotypes with larger root systems in hydroponic culture produced larger SRLD values and higher grain yields than did those with smaller root systems, but for individual genotypes, the correlation between SRLD and grain yield was not significant. Results from this limited number of genotypes indicate that selection for seedlings with large root systems in hydroponic culture may select genotypes capable of producing more roots in the field.