Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/14/2004
Publication Date: 7/1/2005
Citation: Charlson, D.V., Bailey, T.B., Cianzio, S.R., Shoemaker, R.C. 2005. Molecular marker satt481 is associated with iron deficiency chlorosis resistance in a soybean breeding population. Crop Science. 45:2394-2399. Interpretive Summary: Soybean cyst nematode and iron deficiency chlorosis can be devastating diseases of soybean, each costing many millions of dollars in lost production. Because conditions for both diseases are often present in the same field and affected plants produce similar symptoms, it is difficult to determine which disease is causing the damage. In this study, the authors measured chlorosis of soybean plants relative to presence or absence of nematode resistance genes. They also measured the number of nematode eggs in the soil. They found that nematode resistant plants also seemed to be somewhat resistant to iron deficiency chlorosis as well. However, true to the nature of both diseases, the environment had a strong affect on disease expression. This study is the first step in analyzing the complex interactions of biotic and non-biotic diseases and will be useful to students and breeders in designing future experiments.
Technical Abstract: Iron-deficiency chlorosis (IDC) and soybean cyst nematode (SCN) result in yield and income losses for soybean growers in the U.S. Breeding programs are identifying soybean genotypes with resistance to IDC using calcareous soils infested with SCN, where SCN might interfere with evaluation. Two breeding populations, their parents, and five SCN-susceptible, IDC-control genotypes (IDC controls) were evaluated for IDC symptoms on SCN-infested calcareous soils in 2000 and 2001. In general, no significant correlations were detected between chlorosis expression and SCN infestation in either year, although a negative correlation (r = -0.93, P ' 0.05) was observed for the IDC controls in 2001. Although IDC controls were all equally susceptible to SCN and chlorosis, SCN-resistant genotypes expressed resistance to IDC in the field, but severe susceptibility to IDC in nutrient solution. For one breeding population in 2001, positive correlations (P ' 0.05) were detected for chlorosis with calcium carbonate (r = 0.62) and electrical conductivity (r = 0.59), and a negative correlation (r = -0.41) with soil Fe-DTPA-TEA. No significant correlations were observed for the remaining genotypes. Our study indicated that associations between IDC, SCN, and calcareous soil properties are dependent on genotype and environment. In addition, our study demonstrated a potential association between plant health and SCN reproduction in SCN-susceptible genotypes, the possibility that SCN-resistant genotypes may be sensitive to iron availability, and the importance of genotype on the detection of associations between IDC expression and SCN infestation.