Regional analysis of planting date and cultivar maturity recommendations that improve soybean oil yield and meal protein concentration

Authors: SALMERON, MONTSERRAT - University Of Kentucky; BOURLAND, FRED - University Of Arkansas; BUEHRING, NORMIE - Mississippi State University; EARNEST, LARRY - University Of Arkansas; FRITSCHI, FELIX - University Of Missouri; GBUR, ED - University Of Arkansas; GOLDEN, BOBBY - Mississippi State University; HATHCOAT, DANIEL - Texas A&M University; LOFTON, JOSH - Oklahoma State University; MCCLURE, ANGELA - University Of Tennessee; MILLER, TRAVIS - Texas A&M University; NEELY, CLARK - Texas A&M University; SHANNON, GROVER - University Of Missouri; UDEIGWE, THEOPHILUS - Texas Tech University; VERBREE, DAVID - University Of Tennessee; Vories, Earl; WIEBOLD, WILLIAM - University Of Missouri; PURCELL, LARRY - University Of Arkansas

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2022
Publication Date: 10/17/2022
Citation: Salmeron, M., Bourland, F., Buehring, N., Earnest, L., Fritschi, F., Gbur, E., Golden, B., Hathcoat, D., Lofton, J., McClure, A., Miller, T.D., Neely, C., Shannon, G., Udeigwe, T., Verbree, D., Vories, E.D., Wiebold, W.J., Purcell, L.C. 2022. Regional analysis of planting date and cultivar maturity recommendations that improve soybean oil yield and meal protein concentration. Frontiers in Plant Science. 13. Article 95411. https://doi.org/10.3389/fpls.2022.954111.
DOI: https://doi.org/10.3389/fpls.2022.954111

Interpretive Summary: Planting date and cultivar maturity are major management factors affecting soybean productivity, but their effect on seed protein and oil concentration, and in particular meal protein concentration, is less understood. While U.S. soybean yields increased from 2000 to 2020, seed and meal protein concentrations declined, and a minimum protein concentration is required for proper development of poultry and livestock fed from soybean meal. University and ARS scientists collaborated in a three-year study across nine Midsouth locations to examine the interactive effect of planting date and cultivar maturity on soybean yield, and seed oil and protein concentrations. The results showed that that delayed planting date and later cultivar maturities reduced oil concentration, and this was partially associated with a decrease in temperature during the seed fill phase. Thus, optimum cultivar recommendations to maximize total oil yield for planting in May and June required relatively earlier cultivars than those recommended to maximize seed yield. Meal protein concentration decreased when the start of seed fill occurred after August 15, but short-season cultivars reduced the risk of low meal protein concentration. This study provides cultivar and sowing date strategies for maximizing oil yield, as well as for increasing meal protein concentration without sacrificing seed yield. This research will benefit producers by helping them make the best choices regarding cultivar selection and everyone will benefit from the additional knowledge regarding optimal production of an important food and feed crop.

Technical Abstract: Planting date and cultivar maturity are major management factors affecting soybean [Glycine max (L.) Merr.] productivity, but their effect on seed protein and oil concentration, and in particular meal protein concentration, is less understood. We quantified changes in seed oil and protein concentrations, meal protein concentration, and total oil and protein yield in response to planting date and cultivar maturity group (MG) ranging from 3 to 6 and across locations comprising a 8.3º range in latitude in the U.S. Midsouth. Our results show that delayed planting date and later cultivar maturity reduced oil concentration, and this was partially associated with changes in temperature during the seed fill phase (R2=0.30, p<0.001). Thus, optimum cultivar MG recommendations to maximize total oil yield (in kg ha-1) for planting dates in May and June required relatively earlier cultivar MGs than those recommended to maximize seed yield. For planting dates in April, short-season MG 3 cultivars did not increase oil yield compared to full-season MG 4 or 5 cultivars due to a quadratic yield response to planting date at most locations. Planting date and cultivar maturity effects on seed protein concentration were not always consistent with the effects on meal protein concentration after oil extraction. Meal protein concentration decreased when the start of seed fill occurred after August 15, but short-season cultivar MGs reduced the risk of low meal protein concentration. This study provides cultivar MG and sowing date strategies for maximizing oil yield, as well as for increasing meal protein concentration without sacrificing seed yield.