Nutrient solution screening of Fe chlorosis resistance in soybean evaluated by molecular characterization

Nutrient solution systems have been considered an alternative method to fie ld evaluations for studies of iron deficiency chlorosis (IDC) and for breed ing soybeans with improved iron efficiency. To map genes controlling IDC in nutrient solution, 120 F-24 lines in a Pride B216 x A15 population, and 92 F-24 lines in an Anoka x A7 population were grown in nutrient solution in greenhouse plantings and evaluated for IDC by visual scores and determinati ons of chlorophyll concentrations. Eighty-nine restriction fragment length polymorphism (RFLP) and 10 simple sequence repeat (SSR) markers in the Prid e B216 x A15 population, and 82 RFLP, 14 SSR and one morphological (hilum c olor) markers in the Anoka x A7 population were used to construct linkage m aps and to locate quantitative trait loci (QTL) controlling IDC. In the Ano ka x A7 population, one major gene on linkage group N, and modifying QTL on linkage groups Al and I previously mapped during field tests also were ide ntified in the nutrient solution test. Different genetic linkage groups in soybean have been identified by letters, and as such will be used throughou t the paper. One newly identified QTL was mapped on linkage group B2. In th e Pride B216 x A15 population, one QTL previously mapped on linkage group I during field tests was not identified in the nutrient solution test, and t wo newly identified QTL were mapped on linkage groups A2 and B1. QTL on lin kage groups B2, G, H, L, and N were identified in both field and nutrient s olution tests. Due to significant interaction between genotype and environm ent in both field and nutrient solution tests, QTL identifications from mul tiple environments were used to compare the similarity between field and nu trient solution tests. We concluded that similar QTL are identified in nutr ient solution and field tests and therefore, both systems identify similar genetic mechanisms of iron uptake and/or utilization.