Iron accumulation in seed of common bean

Abstract

The effect of soil and genotype on iron concentration [Fe] in common bean (Phaseolus vulgaris L.) seed was studied in the greenhouse. Liming an acid soil increased soil pH from 6.0 to 7.3 but had no effect on seed [Fe] of three bean genotypes (Voyager, T39, UI911) from the Middle American gene pool in North Dakota. However, liming decreased seed-manganese concentration [Mn]. The influence of FeEDDHA on Fe accumulation in seed of the three bean genotypes, grown on acid (pH=6.0) and naturally calcareous (pH=8.2) soils, was also studied in North Dakota. Seed from the acid soil contained 25% higher [Fe] than seed from the calcareous soil. FeEDDHA increased seed [Fe] only on the calcareous soil, but reduced seed [Mn] on both soils. Voyager seed, characterized by a relatively low [Fe] in the seed coat, had a higher seed [Fe] than the other two genotypes. The hypothesis that high seed [Fe] is characterized by a low seed-coat [Fe] was next investigated. Voyager, T39 and 10 diverse Latin American genotypes from the Middle American gene pool were grown on a soil (pH=7.0) with Andic properties in Mexico in the presence and absence of FeEDTA. FeEDTA increased seed [Fe]. Seed of Voyager and a Mexican genotype (Bayo 400) had the highest seed [Fe]. However, Bayo 400, unlike Voyager, contained a high percentage of its seed Fe in the seed coat. Consequently, a high seed [Fe] genotype does not necessarily have a low seed-coat [Fe]. Both soil and genotype affect Fe accumulation in bean seed.