For hybrid wheat (Triticum aestivum L.) to be successful in the Great Plains, good‐quality hybrid seed production must be reliable, and hybrid yield must exceed best commercial inbred cultivars (commercial heterosis). This research evaluates hybrid wheat cultivars developed from a full diallel of 26 parents that were planted in an augmented design at three locations in Nebraska in each of two years. The effects of using chemical hybridization were evaluated by testing the parents against hybrids that were created as full‐sib crosses and showed no detrimental effects of the chemical hybridization method on the hybrid performance. Maternal effects were tested by comparing the reciprocals for each combination of parents, where it was shown that reciprocal effects were of minor importance. General and specific combining abilities and narrow‐sense heritability were obtained and are being used to select parents for future hybrid combinations.

Hybrid wheat (Triticum aestivum L.) offers potential yield advantages over conventional inbred cultivars. For hybrid wheat to be a commercial success, the cost to produce the hybrid seed needs to be minimized. Although wheat is naturally self‐pollinated, hybrid wheat seed production can be improved by increasing the amount and availability of pollen for cross‐pollination. This research examined 19 pollination traits using the Hard Winter Wheat Association Mapping Panel for 3 years. Anther extrusion, pollen 50 date (date at which a genotype has 50% of spikes pollinating), plant height, and pollination duration (last spike pollen 50 date minus first spike pollen 50 date) were identified as the most important traits for hybrid seed production. Anther extrusion, plant height, and pollen 50 date varied widely among genotypes, while pollination duration had significant genotypic differences in one year of testing. These traits also had significant genotype × year interactions, but better and poorer performers were consistent among years. Anther extrusion was weakly, negatively correlated with plant height, and high anther extrusion semi‐dwarf genotypes were identified. Pollination duration was reduced in a high temperature (>30°C) environment, and genotypic differences in pollination duration were identified only in a milder temperature (24°C) environment. Hierarchical clustering suggested that excellent pollinator genotypes with high anther extrusion and longer pollination duration tended to pollinate early and were of short to moderate stature. Pollination traits were higher when temperatures were mild, which benefited early genotypes because they pollinated before higher temperatures limited their pollination duration.

Hybrid wheat (Triticumspp.) has the potential to boost yields and enhance production under changing climates to feed the growing global population. Production of hybrid wheat seed relies on male sterility, the blocking of pollen production, to prevent self-pollination. One method of preventing self-pollination in the female plants is to apply a chemical hybridizing agent (CHA). However, some combinations of CHA and genotypes have lower levels of sterility, resulting in decreased hybrid purity. Differences in CHA efficacy are a challenge in producing hybrid wheat lines for commercial and experimental use. Our primary research questions were to estimate the levels of sterility for wheat genotypes treated with a CHA and determine the best way to analyze differences. We applied the CHA sintofen (1-(4-chlorphyl)-1,4-dihydro-5-(2-methoxyethoxy)-4-oxocinnoline-3-carboxylic acid; Croisor 100) to 27 genotypes in replicate. After spraying, we counted seed in bagged female heads to evaluate CHA efficacy and CHA-by-genotype interaction. Using logit and probit models with a threshold of 7 seeds, we found differences among genotypes in 2015. Sterility was higher in 2016 and fewer genotypic differences were found. When CHA-induced sterilization is less uniform as in 2015, zero-inflated and hurdle count models were superior to standard mixed models. These models calculate mean seed number and fit data with limit-bounded scales collected by agronomists and plant breeders to compare genotypic differences. These analyses can assist in selecting parents and identifying where additional optimization of CHA application needs to occur. There is little work in the literature examining the relationship between CHAs and genotypes, making this work fundamental to the future of hybrid wheat breeding.

The continual re-evaluation of agronomic practices is necessary to improve crop performance and sustainability of the production of winter wheat (Triticum aestivum L.), particularly as genetics and climate conditions change. Recommendations made about winter wheat planting dates, spacing, variety, and seed rates under normal climatic conditions may not be suitable in current times with more climate variability. Our experiment investigated the effect of planting date (early, historic-optimum, and late), row spacing (19 and 25 cm), variety (Goodstreak, Robidoux, and Wesley), and seed rate (1.8, 2.1, 2.3, 2.4, 2.6, 2.8, 3.1, and 3.4 M seeds ha⁻¹) on winter wheat grain yield and yield components. The seeding rate was nested within row spacing in nested-factorial design. A nested-factorial treatment design was used with testing at several locations in Nebraska across two years. Variety had a substantial effect on winter wheat grain yield (p < 0.05). Variety also had a substantial interaction effect with planting date and row spacing 50% of the time (p ≤ 0.01). At Hemingford, for example, Wesley planted at 19 cm had 5.9% more yield when compared to Robidoux planted at 19 cm (5.5 Mg ha⁻¹). Similarly, biomass was influenced by variety across sites (p < 0.01), but a substantial interaction effect also occurred between planting date and variety at two of the three sites. Narrow row spacing (19 cm) led to significantly more tillers (6.9 M ha⁻¹) when planted with Goodstreak at two of the sites. While planting date by itself did not affect any of the responses evaluated, this research highlights the importance of comprehensive and holistic approaches to wheat production in the High Plains.

Tall wheat (Triticum aestivum L.) stubble can enhance soil water conservation during the fallow-period by trapping snow and decreasing evaporation. However, standing wheat stubble can intercept herbicide spray droplets before they reach their intended targets. This experiment aimed to evaluate the effects of three wheat stubble heights (>70 cm, 35 cm, and no-stubble), four nozzle types (XR, TTJ, AIXR, and TTI), and three application directions (angular (45°), perpendicular (90°), and parallel (0°) to the wheat row) on a spray deposition of glyphosate and a dicamba tank mixture. The ranking of droplet size from smallest to largest based on volume median diameter (VMD) was XR, TTJ, AIXR, and TTI. Wheat stubble greater than 70 cm decreased spray deposition 37%, while 35 cm stubble caused a 23% decrease. Sprayer application directions and nozzle type had significant interaction on spray deposition. Perpendicular application direction decreased spray deposition relative to the angular application direction for TTJ and TTI. Parallel application direction had lower spray deposition than angular application direction for TTJ and XR. Similarly, relatively-high-spray deposition (~75%) was provided by angular application direction regardless of the nozzle type. Applicators should consider traveling in an angular direction to the wheat rows for improved droplet deposition across spray nozzle types.

Winter wheat (Triticum aestivum L.) yield in dryland areas is optimized by the improvement of genetics in combination with ideal production practices. Different combinations of seeding rate and row spacing can influence the development of wheat plants, impacting wheat yield and its components. To determine the influence of these practices, yield components, water use efficiency (WUE), biomass, and subsequent grain yield were evaluated in an experiment conducted at the High Plains Agricultural Laboratory, Sidney, NE, from 2019 until 2022, using a split‐plot randomized complete block design with four replications. Treatments consisted of four different row spacings (19, 25, 31, and 51 cm), three seeding rates (1.05, 2.1, and 3.1 million seeds ha⁻¹), and two high performing winter wheat varieties—‘Ruth’ and ‘Robidoux’. Row spacing showed differences in wheat yield (p < 0.0001) across all years, with a significant effect of seeding rate only in 1 year and an interaction effect of the three factors in 2022 alone. Higher wheat yield was achieved with the two narrower row spacings (19 and 25 cm) compared to the wider row spacings of 38 and 51 cm. The treatment combining the 19 cm row spacing and either 2.1 or 3.1 million seed ha⁻¹ seeding rate had the greatest yields in most years. Narrower row spacings had improved WUE in drier years as compared to wider row spacings.