|De Cianzio, Silvia|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/1997
Publication Date: N/A
Citation: N/A Interpretive Summary: Some soybeans are unable to efficiently take up iron from soil with high pH. When this occurs, the leaves become yellow and productivity declines. Millions of dollars a year are lost by growers due to this deficiency. Breeders have selected for genetically better soybeans in fields with high pH soil and in nutrient solutions where iron is limited. The question has always arisen as to whether both field and nutrient solution studies allowed breeders to select for the same genes. In this study the authors identified the chromosomal location of genes controlling iron efficiency in soybeans in nutrient solution. They demonstrated that the locations were the same as for those genes controlling the trait under field conditions. This information will allow breeders to use hydroponics to breed for iron efficient beans, thus allowing selection to take place year around. This should speed-up the development of new efficient cultivars.
Technical Abstract: Nutrient solution systems have been considered an alternative method to field evaluations for studies of iron deficiency chlorosis (IDC) and for breeding soybeans with improved iron efficiency. To determine the efficiency of nutrient solution evaluation for soybean IDC, 120 F2:4 lines in a Pride B216 x A15 population, and 92 F2:4 lines in an Anoka x A7 population were grown in nutrient solution in greenhouse plantings and evaluated for IDC by visual scores and determinations of chlorophyll concentrations. Eighty-nine RFLP and ten SSR markers in the Pride B216 x A15 populations, and 82 RFLP, 14 SSR and I (hilum color) markers in the Anoka x A7 population were used to construct linkage maps and to locate quantitative trait loci (QTL) controlling IDC. In the Anoka x A7 population, one major gene on linkage group N, and modifying QTL on linkage group A1 and I previously mapping during field tests also were identified in the nutrient soil test. One newly identified QTL was mapped on linkage group B2. In the 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 tow newly identified QTL were mapped on linkage groups A2 and B1. QTL on linkage groups B2, G, H, L and N were identified in both field and nutrient solution tests. Due to significant interaction between genotype and environment (G x E) in both field and nutrient solution tests, QTL identifications from multiple environments were used to compare the similarity between field and nutrient solution tests. We concluded that similar QTL are identified in nutrient solution and field tests and that nutrient solution tests demonstrated high effectiveness in evaluating IDC of soybean.