Root iron‐reduction capacity for genotypic evaluation of iron efficiency in soybean

Abstract

Genetic resistance to Fe‐deficiency chlorosis is the most viable and economical means to overcome this problem in soybean [Glycine max (L.) Merr.], but current field evaluation is slowed and constrained by soil heterogeneity and environmental fluctuation. Highly resistant (Fe‐efficient) cultivars have been shown to reduce Fe³⁺ to Fe²⁺ more actively by the roots under Fe‐deficiency stress than highly susceptible genotypes. The objective of this study was to determine if Fe³⁺ reduction could be used to predict the degree of resistance or susceptibility to Fe‐deficiency chlorosis. Thirteen genotypes (both commercial and experimental) with known field susceptibility ratings were grown in a growth chamber in modified Hoagland solution. The more Fe‐efficient genotypes reduced Fe³⁺ earlier and to a greater extent than the less Fe‐efficient types. The sum of the seven daily Fe³⁺ reduction measurements was negatively correlated with field chlorosis ratings, as high as ‐0.864 (p > 0.01), and was a good predictor of the Fe‐efficiency of the genotypes.

Notes

Dept. of Botany and Range Science, BYU, Provo, UT 84602 and Dept. of Agronomy and Plant Genetics, Univ. of Minnesota, St. Paul, MN 55108, respectively.