Soybean maturity group choices for early - and late - plantings in the US Midsouth

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

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2014
Publication Date: 8/19/2014
Citation: Salmeron, M., Gbur, E.E., Bourland, F.M., Buehring, N.W., Earnest, L., Fritschi, F.B., Golden, B., Hathcoat, D., Lofton, J., Miller, T.D., Nelly, C., Shannon, G., Udeigwe, T., Verbree, D.A., Vories, E.D., Wiebold, W.J., Purcell, L.C. 2014. Soybean maturity group choices for early - and late - plantings in the US Midsouth. Agronomy Journal. 106(5):1893-1901.

Interpretive Summary: Soybean is a major crop throughout the US, and while growing conditions in the midsouthern US allow for high yields under irrigation, there is limited information on planting date and maturity group studies that can aid in cultivar selection. University and ARS scientists collaborated in a study across eight locations in 2012 and 10 locations in 2013 with four planting dates and 16 soybean cultivars. Results showed that maturity group 4 cultivars were at the top of the yield ranking in all environments studied in both early- and late-planting systems. Yields of maturity group 5 cultivars were similar with an early planting but often lower with late planting. These results have profound implications for maturity group recommendations for irrigated soybean in the Midsouth and indicate the need to reconsider common maturity group recommendations. This research will benefit producers by helping them make the best choices regarding cultivar selection; furthermore, everyone will benefit from more effective use of water for irrigation.

Technical Abstract: Growing conditions in the US Midsouth allow for large soybean (Glycine max L. (Merr.)) yields under irrigation, but there is limited information on planting dates (PD) and maturity group (MG) choices to aid in cultivar selection. Analysis of variance across eight locations in 2012 and 10 locations in 2013, four PD, and 16 soybean cultivars (MG 3 to 6), revealed that the genotype by environment interaction accounted for 38 to 22% of the total yield variability. Stability-analysis techniques and probability of low yields were used to further investigate this interaction. Planting dates were grouped within early- and late-planting systems. Results showed that in early-planting systems, MG 4 and 5 cultivars had the largest average yields, whereas for late-planting systems, late MG 3 to late MG 4 cultivars had the largest average yields. Least square means by MG within planting system at each environment showed that MG 4 cultivars were at the top of the yield ranking in 100% of the environments studied in both early- and late-planting systems. Yields of MG 5 cultivars were similar to those of MG 4 in 100% of the environments with an early planting but were lower in 80% of the environments with a late planting. MG 3 cultivars were the best second choice for late plantings, with similar yields to MG 4 cultivars in 55 to 75% of the environments. These results have profound implications for MG recommendations in irrigated soybean in the US Midsouth and indicate the need to reconsider common MG recommendations.