Fig. 1. Mean iron deficiency chlorosis (IDC) scores over time for five western Minnesota environments studied in 2002. Values represent visual chlorosis scores (Cianzio et al., 1979) where 1 = green and 5 = severe chlorosis with some necrosis for each environment, and are means of 10 genotypes and four replications ± SE (n = 40). Scores were recorded on 21 June, 3 July, 12 July, 24 July, and 3 August.