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Planting date and cultivar maturity group (MG) are major management factors affecting soybean [ Glycine max (L.) Merr.] yield, but their effect on seed oil and protein concentration, and in particular meal protein concentration, is less understood. We quantified changes in seed oil and protein, and estimated meal protein concentration, and total oil and protein yield in response to planting date and cultivar MG ranging from 3 to 6 and across locations comprising a 8.3° 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 a decrease in temperature during the seed fill phase. 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 estimated meal protein concentration after oil extraction. Meal protein concentration decreased with lower temperatures during seed fill, and when the start of seed fill occurred after August 15, but relatively short-season cultivar MGs reduced the risk of low meal protein concentration. Meal protein concentration is a trait of interest for the feed industry that would be beneficial to report in future studies evaluating genetic, management, and environmental effects on seed protein concentration.

Annual bluegrass is one of the most problematic weeds in the turfgrass industry, exhibiting both cross-resistance and multiple-herbicide resistance. Prodiamine, pronamide, and indaziflam are commonly used preemergence herbicides for the control of this species on golf courses in the southern United States. There have been increasing anecdotal reports of annual bluegrass populations escaping control with these herbicides, but resistance has yet to be confirmed. To evaluate the response of annual bluegrass to three herbicides, populations were collected from golf courses, athletic fields, and landscape areas in Texas and Florida, and a dose-response assay was conducted on populations that were suspected to be resistant to and known to be susceptible to prodiamine, pronamide, and indaziflam. The suspected-resistant populations showed survival to prodiamine at 32 times the recommended field rate (both populations from Florida and Texas) of 736 g ai ha–1, and to pronamide at 32 times (the Florida populations) or 16 times (the Texas populations) the recommended field rate of 1,156 g ha–1. In contrast, the known susceptible populations attained 100% mortality at rates as low as 46 and 578 g ha–1, respectively, from applications of prodiamine and pronamide. For indaziflam, the suspected-resistant populations showed reduced sensitivity up to the recommended field rate of 55 g ha–1, but they were controlled when treated with a rate twice that of the field rate. Overall, annual bluegrass populations with resistance to prodiamine and pronamide, and reduced sensitivity to indaziflam (at the recommended field rate) were confirmed from golf courses in Florida and Texas. In the presence of herbicide-resistant annual bluegrass populations, especially to commonly used herbicides such as prodiamine and pronamide, turfgrass managers should adopt integrated management strategies and frequently rotate herbicide sites of action, rather than relying solely on microtubule-assembly inhibitors or cellulose biosynthesis inhibitors, to control this species. Nomenclature: Indaziflam; prodiamine; pronamide; annual bluegrass, Poa annua L.

Cultivar selection, planting rate, and row spacing are key considerations when planting canola (Brassica napus L.) and vary by region. Canola offers a possible solution for producers in Texas and the broader southern region looking for a winter rotational crop, but the lack of data on region‐specific agronomic practices is a roadblock to adoption. Our objective was to identify the optimum row spacing and planting rate to achieve maximum seed and oil yield in fall‐planted spring canola in the southern United States. Replicated studies were conducted at College Station and Perry, TX during the 2017–2018 winter growing season. Treatments included three row spacings (19, 38, and 76 cm), three planting rates (1.7, 3.4, and 5.1 kg ha−1), and two cultivars (HyCLASS 930 and HyCLASS 970). HyCLASS 970 outperformed HyCLASS 930 in all yield and seed parameters except seeds pod−1 and oil content at both locations. While row spacing had no effect on yield at College Station, a 15% reduction in seed and oil yield was observed at the widest row spacing at Perry. A cultivar × planting rate interaction at Perry showed yield declining for HyCLASS 930 as planting rate increased, while HyCLASS 970 showed no response. This suggests rates as low as 1.7 kg ha−1, which is substantially lower than the rate commonly recommended (5.6 kg ha−1), can be used for fall‐planted spring canola. High yield at Perry and lack of freeze damage suggest spring canola may be a good winter rotational crop for the southern United States.

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 significantly different 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. The 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 U.S. Midsouth and indicate the need to reconsider common MG recommendations.

While soybean [Glycine max (L.) Merr.] production risk is typically managed by planting a range of maturity groups (MGs) across a few different planting dates (PDs), there have been no reports that have quantified changes in risk and profitability using this diversification strategy. Three years of field‐trial data from eight locations in six states were analyzed to determine risk–return tradeoffs across MG and PD. Producer revenue expectations were adjusted by soybean harvest date, assessing oil and meal premiums or discounts, and differential irrigation requirements by MG and PD, whereas costs for seed, fuel, fertilizer, equipment, and chemicals were held constant. Using portfolio theory, an efficient frontier—maximizing net returns for a given level of risk or minimizing risk for a given level of net return—was estimated by location. Cultivars from MG III and MG IV had higher expected net returns than MG V and VI at all locations. Early‐season planting combinations were found to be riskier than the three successive planting dates but led to oil, protein, and seasonal sale price premiums. Across different environments, selecting two to six MG×PD combinations was sufficient to lower risk by 29 to 40% when compared to the single, profit‐maximizing MG×PD choice. Depending on location, this risk reduction decreased net returns between 2 and 22% when compared to the profit‐maximizing MG×PD choice. Core Ideas Producers often like to diversify by planting across a range of dates and maturity groups. Diversification is common but risk–return tradeoffs have not been meaningfully quantified. Early‐season planting combinations were riskier but led to sale price premiums. Using two to six combinations lowered risk by 29–40% but decreased returns by 2–22%.