DETAILED METHOD TO SCREEN DICOT CULTIVARS FOR RESISTANCE TO FE-CHLOROSIS USING FEDTPA AND BICARBONATE IN NUTRIENT SOLUTIONS

The use of bicarbonate additions to nutrient solutions containing low levels of available Fe have allowed screening for susceptibility to Fe-deficiency chlorosis in many dicots (soybean, bean, chickpea, citrus, etc.). Research has shown that relative susceptibility among cultivars in this nutrient solution has a high correlation with the relative susceptibility observed in wet calcareous soils which induce chlorosis. This paper provided the specific details needed by plant breeders to adapt the research reports to their own laboratory situation. We provide full details on the present recommended method using FeDTPA (ferric diethylenetriaminepentaacetic acid) in place of FeEDDHA (ferric ethylene-di-o-(hydroxyphenylacetic acid) used in earlier screens, including preparation of nutrient solutions, inducing varied severity of Fe-stress or potential chlorosis severity, use of indicator cultivars, and measuring plant response. The method described has been developed in cooperation with industrial and academic plant breeders, and the costs of screening have been substantially reduced by innovative response to time and personnel costs identified by these cooperators. The method is now "robust" enough to be insensitive to minor variation and contamination common to practical screening facilities.