Nuclear Magnetic Resonance Analysis for Oil in Soybeans, Glycine max ( L.) Merrill, with Implications in Selection.1

Nuclear magnetic resonance spectrometry was used to characterize intragenotypic between‐ and within‐plant variability for percent oil in soybeans. Differences among pods and among plants were the largest source of withinline variability in field and greenhouse tests, respectively. Oil content was found to be inconsistent for different positions on the plant. For the environmental conditions of this study, the error variance of a line mean was minimized by sampling at the intermediate flowering node in the field and either the intermediate or basal node in the greenhouse. Two pods (two seeds/pod) these positions were sufficient to classify high and low oil plants with 94 and 86% accuracy in the field and greenhouse, respectively. Sampling additional plants or pods per plant should increase the accuracy of classification for selection purposes.