Protein and Oil Discount/Premium Price Structure and Soybean Cultivar Selection Criteria

Proposed changes in the pricing structure of soybean [Glycine max (L.) Merr.] based on their constituent value of protein and oil may complicate cultivar selection. We evaluated profitability of different soybean cultivars under the assumption that farmers were paid a premium/discount based on the protein and oil content of the grain. Trade-offs between yield per acre and price per bushel may exist if a sufficiently large difference in price per bushel is paid because of genetic differences in protein and oil content among cultivars. Soy oil and meal prices vary over time and the unknown future price of each of these commodities might require soybean breeders and farmers to speculate on the ratio of soyoil to meal when selecting cultivars. Our objective was to compare several soybean cultivars based on yield, protein content, and oil content at a range of market prices for each of these variables to aid farmers and plant breeders in cultivar selection. The commercial cultivars most commonly grown in North Dakota and some experimental lines were evaluated for grain yield, protein, and oil content and gross value per acre was calculated using three sets of oil and protein prices. Twelve genotypes from maturity group 0 (MG0) and 15 genotypes from maturity group 00 (MG00) were evaluated in separate experiments consisting of six environments each. The expected soybean meal and oil prices of the 1989 marketing year, a high soybean meal and low oil price, and low soybean meal and high oil price were each used to calculate gross value per acre (GVA) for the three price situations. The constituent yield index (CONY), percent protein plus percent oil multiplied by grain yield, was used as an additional selection criteria. The cultivars ranked highest for GVA were ranked similarly using CONY among MG0 and MG00 genotypes. The CONY index, which was a better predictor of GVA than yield in ranking cultivars, may be useful in cultivar performance bulletins for ranking cultivars as economic worth changes from year to year.