Soybean Maturity Group Choices for Early and Late Plantings in the Midsouth

Abstract

Growing conditions in the U.S. 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 (2012) and 10 (2013) locations, four PD, and 16 cultivars (MG 3-6), revealed that the genotype by environment (G×E) interaction accounted for 38 to 22% of the total yield variability. Stability-analysis techniques and probability of low yields were used to investigate this interaction. Planting dates were grouped within early-and late-planting systems. Results showed that MG 4 and 5 cultivars in early-planting systems had the largest average yields, whereas for late-planting systems, late MG 3 to late MG 4 cultivars had the largest yields. Least square means by MG within planting systems at each environment showed that MG 4 cultivars had the greatest yields or were not signi cantly di erent from the MG with the greatest yields in 100% of the environments for 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 only in 20% of the environments with a late planting. e 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. ese results have profound implications for MG recommendations in irrigated soybean in the U.S. Midsouth and indicate the need to reconsider common MG recommendations.

Soybean yield and crop stage response to planting date and cultivar maturity in Iowa, USA

“…In our study we found that the duration of each of these periods was shortened and in turn, led to a decrease in cumulative radiation, precipitation, GDD, and average photoperiod; this is a similar finding to Salmerón et al. (). When precipitation and GDD accumulation decrease during the R3‐R7 period we see a significant decline in relative yield.…”

Delineating Soybean Maturity Groups across the United States

“…In that study, planting occurred earlier in spring and later in the summer by up to 40 d compared to the variety trial data we used. However, our results are within the optimum MG ranges (MGs that exhibited the highest yields) that were identified across Missouri, Arkansas, Tennessee, Mississippi, Louisiana, and Texas (Salmeron et al, 2014). It should be noted that across these states, our data included more than 450 environments (location × year) with multiple MGs, and many varieties tested within each environment.…”

“…In favorable weather conditions and in regions where planting dates can be flexible, such as in the southern states, earlier or later maturing varieties than the optimum can also be successfully grown. This has been observed in a study conducted at several locations in the southern United States where early and late planting dates for the specific locations were tested (Salmeron et al, 2014). In that study, planting occurred earlier in spring and later in the summer by up to 40 d compared to the variety trial data we used.…”

Physiological and management factors contributing to soybean potential yield

“…Finally, early planting (Bastidas et al, 2008;Salmerón et al, 2014;Wilcox and Frankenberger, 1987) and warm early spring temperatures (Cooper, 2003) induce earlier flowering, lengthen the reproductive period, and increase solar radiation interception and BAR during seedfilling. Rowntree et al (2014) compared early (∼May 1) and late (∼June 1) planting dates for 57 MG 3 cultivars released between 1923 and 2008 and found that the rate-of-yield increase was 23% greater (1.74 vs 1.41 kg ha −1 yr −1 ) for the earlyplanted treatment than the late-planted treatment.…”