Field and Nutrient Solution Tests Measure Similar Mechanisms Controlling Iron Deficiency Chlorosis in Soybean

Abstract

Nutrient solution systems have been considered an alternative method to field evaluations for studies of iron deficiency chlorosis (IDC) and for breeding soybeans [Glycine max (L.) Merr.] with improved iron efficiency. Although rates of gain are similar for both methods, it has not been previously demonstrated that field tests and nutrient solution tests for IDC measure similar genetic mechanisms. To test this, quantitative trait loci (QTL) identified in nutrient solutions were compared with those previously identified in field studies. F2:4 lines from two populations, Pride B216 × A15 and Anoka × A7, were grown in nutrient solution and evaluated for IDC by visual scores and determinations of chlorophyll concentrations. In the Anoka × A7 population, one major gene on linkage group N, and modifying QTL on linkage groups A1 and I, that were previously mapped during field tests, also were identified in the nutrient solution test. In the Pride B216 × A15 population, one QTL previously mapped on Linkage Group I during field tests was not identified in the nutrient solution test, and a newly identified QTL was mapped on Linkage Group BI. QTL on Linkage Groups B2, G, and N were identified in both field and nutrient solution tests. We concluded that similar QTL are identified in nutrient solution and field tests and, therefore, both systems identify similar genetic mechanisms of iron uptake and/or utilization.