FACTORS AFFECTING THE MEASUREMENT OF ELECTRICAL IMPEDANCE OF ALFALFA TISSUE

The electrical impedance of alfalfa tissue was measured at a range of root depths and stem heights. The results showed that only for unhardened roots was position of the measuring device important. Partial correlation coefficients for the relation of both stem and root diameter with impedance were significant for cold-conditioned and untreated material. Stems had higher impedance values than roots. Higher impedances were also associated with lower relative water contents. Differences in impedance readings for individual cultivars were large below 60% relative water content. In their present form, none of the methods used would be of value in identifying fine differences in the segregating populations used in plant-breeding programs.