Phytophthora sojae has re-emerged as a serious soybean pathogen in the past decade. This may be due in part to changes in resistance levels in current cultivars, adoption of P. sojae populations to deployed Rps genes, and highly favorable environments in the past decade. This multilocation study evaluated the effect of seed treatments on the incidence and severity of Phytophthora root and stem rot on soybeans with different combinations of Rps genes and levels of partial resistance. The efficacy of the seed treatments was highly variable across locations. Seed treatments (metalaxyl and mefenoxam) provided protection and increased yields across cultivars in locations where rain or irrigation occurred shortly after planting (Ohio, South Dakota, and Ontario). However, there were no significant differences in stand or yield consistently across cultivars in Iowa, Nebraska, Wisconsin, or Ohio, where heavy precipitation did not occur until later growth stages. The environment, levels of inoculum, and pathogen complex may have played a role in the different responses to the seed treatments and to the different combinations of Rps genes and levels of partial resistance to P. sojae in the cultivars. Fields that are poorly drained and have P. sojae populations with complex pathotypes may benefit the most from seed treatments. Individual fields where producers may see the greatest benefit to utilizing these integrated management strategies will need to be identified.

Linolenic acid is the unstable component of soybean [Glycine max (L.) Merr.] oil responsible for undesirable odors and flavors commonly associated with poor oil quality. The objective of this study was to determine the inheritance of fatty acid composition in A5, a soybean mutant with the lowest linolenic acid percentage of any genotype that has been evaluated for the character. Reciprocal crosses were made between A5 and two soybean cultivars, Weber and Pella. The parents were significantly different for all fatty acids, except palmitic acid in A5 and Pella. The F1 seeds, F2 seeds from F1 plants, and seeds from replicated tests of F2‐derived lines were evaluated for the percentage of palmitic, stearic, oleic, iinoleic, and linolenic acids. The F1 seeds from reciprocal crosses differed significantly for oleic, linoleic, and linolenic acids in both crosses, and for palmitic acid in the Weber cross, which indicated a maternal effect on composition for these fatty acids. Cytoplasmic inheritance of fatty acid composition was not observed, based on the lack of reciprocal cross differences for fatty acid composition in the analysis of F2 seeds from F1 plants. The composition of the F2‐derived lines exhibited a continuous distribution typical of a quantitative character for each of the fatty acids in both crosses. There were 14% of the F2‐derived lines in the Pella cross and 10% in the Weber cross that had a linolenic acid percentage as low as A5. Heritability estimates on a plot basis averaged across crosses from the analysis of F2‐derived lines were 33% for palmitic, 5% for stearic, 54% for oleic, 59% for linoleic, and 58% for linolenic acid. The results indicated that fatty acid composition should be considered a quantitative character in crosses that involve A5 as a parent.