Water stress conditions have occurred in the past in various places of the world, affecting the yield and production of numerous crops, including wheat. The aim of this research was to estimate standard heterosis under two different water regimes for grain yield and its attributes in 33 crosses, which were obtained by crossing 11 lines and 3 testers in a Line × Tester mating design. The best cross combinations for yield and contributing traits under irrigated condition were C4, C8, C33, C24, and C23, compared to both checks HD2967 and PBW660. Whereas, in rainfed condition, C18, C14, C26, C21, and C20 crosses were superior to the checks. For both irrigated and rainfed conditions, the best cross combinations identified were C29, C15, C32, C2, and C31. As a result, these cross combinations could be used in wheat breeding programmes to improve bread wheat genotypes for increased grain yield, agro-morphological features, and water stress tolerance. The presence of high heterosis for yield-contributing traits not only aids in the development of hybrids by exploiting heterosis but also in the production of transgressive segregants to develop elite lines.

This study examines the extent to which wheat varieties supplied by the formal seed system align with the varieties demanded and used by farmers in Ethiopia. The framework of stated and revealed preferences drawn from the consumer preference theory is used to analyze farmer demand for different wheat varieties. We used official data from the formal seed sector and representative survey data from wheat farm households in Ethiopia. The survey data allow to contrast the farmer reported varietal use with genotyping by sequencing (also known as DNA fingerprinting). Farmers’ reliance on informal seed sources and own saved seed, among others, contributes to the misidentification of the varieties they grow. Consequently, farmers are likely to misinform the formal seed demand assessment leading to either an over- or underestimation of actual seed demand for specific wheat varieties. Genotyping by sequencing, as opposed to farmer reports, established the persistence of old varieties. This also implies vulnerability of wheat production to disease dynamics depending on the longevity of disease resistance by the variety in use. Apart from narrowing the gap between the actual and stated demand and ensuring timely replacement of wheat varieties, genotyping-assisted estimates can save seed carry-over cost. Genotyping by sequencing is increasingly used as the new benchmark and gold standard for identifying and tracking the adoption of crop varieties. The technique has potential to enhance the performance of the seed sector through effective planning that can optimize resource commitments and accelerate the rate of varietal replacement.

Applying the difference-in-difference (DID) estimation procedure, this study quantifies the wheat blast (Magnaporthe oryzae pathotype Triticum) induced losses in wheat yield, quantity of wheat sold, consumed, or stored, as well as wheat grain value in Bangladesh in 2016 following a disease outbreak that affected over 15,000 ha. Estimates show that the blast-induced yield loss was 540 kg ha−1 on average for households in blast-affected districts. Estimated total wheat production loss was approximately 8,205 tons worth USD 2.1 million in during the 2016 outbreak. Based on these insights, we discuss the need for long-term assured investment and concerted research efforts in controlling transboundary diseases such as wheat blast, including the importance of weather forecast driven early warning systems and the dissemination of blast-resistant varieties.

Adoption of cover crops in arid agroecosystems has been slow due to concerns regarding limited water resources and possible soil moisture depletion. In irrigated organic systems, potential ecosystem services from cover crops also must be considered in light of the concerns for water conservation. A constructive balance could be achieved with fall-sown small grain cover crops; however, their impacts on irrigated organic systems are poorly understood. Our first objective was to determine the ability of fall-sown small grains [cereal rye (Secale cereale L), winter wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and oat (Avena sativa L.)] to suppress winter weeds in an irrigated, organic transition field in the southwestern USA. Small grains were planted following the legume sesbania (Sesbania exaltata (Raf.) Rydb. ex A.W. Hill) during Fall 2012 and Fall 2013. In Spring 2013 and 2014, weed densities and biomass were determined within each cover crop treatment and compared against unplanted controls. Results indicated that both barley and oat were effective in suppressing winter weeds. Our second objective was to compare weed suppression and soil moisture levels among seven barley varieties developed in the western United States. Barley varieties (‘Arivat’, ‘Hayes Beardless’, ‘P919’, ‘Robust’, ‘UC603’, ‘UC937’, ‘Washford Beardless’) were fall-sown in replicated strip plots in Fall 2016. Weed densities were measured in Spring 2017 and volumetric soil moisture near the soil surface (5.1 cm depth) was measured at time intervals beginning in December 2016 and ending in March 2017. With the exception of ‘UC937’, barley varieties caused marked reductions in weed density in comparison with the unplanted control. Soil moisture content for the unplanted control was consistently lower than soil moisture contents for barley plots. Barley variety did not influence volumetric soil moisture. During the 2017–2018 growing season, we re-examined three barley varieties considered most amenable to the cropping system requirements (‘Robust’, ‘UC603’, ‘P919’), and these varieties were again found to support few weeds (≤ 5.0 weeds m−2). We conclude that several organically certified barley varieties could fill the need for a ‘non-thirsty’ cover crop that suppresses winter weeds in irrigated organic systems in the southwestern United States.

This study builds upon the existing literature on the Working curve and backwardation to explore the impact of storage regimes on the volatility measures of substitute agricultural commodity markets. We investigate the impact of commodity fundamentals (storage regime and stocks-to-use ratio), commodity-specific financial variables (options hedging pressure-long and -short), world economic activity, market-wide volatility index, seasonality, and time-to-maturity on nearby and deferred implied volatility (IV) series of selected commodity pairs of corn-soybean and winter wheat-spring wheat. Our work confirms that, in some cases, grain and oilseed IV derived from options premia respond to shocks in commodity (and substitute commodity) fundamentals which are in line with the behaviour of volatility in futures markets. Own-storage regime effects on price variability are stronger in the selected markets, while spillover effects from substitute commodity storage regimes show a modest impact on volatilities. We also find some evidence for the stocks-to-use ratio of both corn and soybean to impact both their own and each other’s IV, while options hedging pressure has some impact only on wheat IVs.

High-molecular-weight glutenin subunits (HMW-GS) contribute to dough elasticity and bread baking quality in wheat. In this study, wheat varieties were classified based on their HMW-GS composition into three groups: 1Dx5 (5 + 10, Gaoyou 8901, Xinmai 28, Xinmai 19, Xinmai 26 and Jinbaoyin), 1Dx2 (2 + 12, Zhoumai 24, Xinmai 9 and Yumai) and 1Dx4 (4 + 12, Aikang 58). Sequence analysis showed that 1Dx-GY8901, 1Dx-XM28, 1Dx-XM19 and 1Dx-XM26 were similar to the 1Dx5 gene and clustered on the same branch, while 1Dx-AK58, 1Dx-ZM24, 1Dx-JBY, 1Dx-YM, 1Dx-XM9 and 1Dx-JBY were more similar to the 1Dx2 gene and clustered on the same branch with 1Dx.2.2. There was a mutation of Ser to Cys at position S2, for an extra Cys in the repeat regions of 1Dx-XM19, 1Dx-XM26, 1Dx-XM28 and 1Dx-GY8901. The wheat HMW-GS genes exhibited similar percentages of α-helix, extended strand, β-turn and random coil structure, with ranges of 13.33–13.59, 4.77–5.78, 7.08–9.18 and 72.3–73.94%, respectively. Sequence conservation and the composition of HMW-GS subunits were also analysed for a series of strong gluten wheat varieties, Xinmai 9 (1, 7 + 8, 2 + 12), Xinmai 19 (1, 7 + 9, 5 + 10), Xinmai 26 (1, 7 + 8, 5 + 10) and Xinmai 28 (1, 7 + 9, 5 + 10). The results of this work should facilitate future breeding efforts and provide the theoretical basis for wheat quality improvement.

New production from public and exclusive varieties released by the small grains breeding program at Virginia Tech generated cumulative discounted benefits of $41 million from 2000 to 2018. Fitted yields from field trials were combined with acreage estimates to generate weighted average yields based on adoption of new varieties. Benefits were estimated as the value of additional production from the release and adoption of improved varieties. Public varieties were responsible for most program benefits. The program was found to have a significant impact in Virginia and out-of-state, with much of these benefits due to public-private collaboration.

Limited information exists on the global economic impact of glyphosate-resistant (GR) weeds. The objective of this manuscript was to estimate the potential yield and economic loss from uncontrolled GR weeds in the major field crops grown in Ontario, Canada. The impact of GR weed interference on field crop yield was determined using an extensive database of field trials completed on commercial farms in southwestern Ontario between 2010 and 2021. Crop yield loss was estimated by expert opinion (weed scientists and Ontario government crop specialists) when research data were unavailable. This manuscript assumes that crop producers adjust their weed management programs to control GR weeds, which increases weed management costs but reduces crop yield loss from GR weed interference by 95%. GR volunteer corn, horseweed, waterhemp, giant ragweed, and common ragweed would cause an annual monetary loss of (in millions of Can$) $172, $104, $11, $3, and $0.3, respectively, for a total annual loss of $290 million if Ontario farmers did not adjust their weed management programs to control GR biotypes. The increased herbicide cost to control GR volunteer corn, horseweed, waterhemp, giant ragweed, and common ragweed in the major field crops in Ontario is estimated to be (in millions of Can$) $17, $9, $2, $0.1, and $0.02, respectively, for a total increase in herbicide expenditures of $28 million annually. Reduced GR weed interference with the adjusted weed management programs would reduce farm-gate monetary crop loss by 95% from $290 million to $15 million. This study estimates that GR weeds would reduce the farm-gate value of the major field crops produced in Ontario by Can$290 million annually if Ontario farmers did not adjust their weed management programs, but with increased herbicide costs of Can$28 million and reduced crop yield loss of 95% the actual annual monetary loss in Ontario is estimated to be Can$43 million annually.

Horseweed is a North American indigenous plant species commonly found in Nebraska cropping systems. Horseweed management is challenging because of horseweed’s prolific seed production, long-distance seed dispersal via wind, competitiveness, and rapid evolution of herbicide resistance. Understanding the horseweed emergence pattern across Nebraska can contribute to implementing effective and more sustainable tactics to minimize its impact on cropping systems. Field studies were conducted during fall and spring from 2016 to 2018 in Lincoln (corn and soybean), North Platte (wheat stubble and soybean), and Scottsbluff (corn and fallow) to investigate the emergence pattern of horseweed accessions from Lincoln, North Platte, and Scottsbluff, NE. Results show that most horseweed seedling emergence occurred in fall (99%) and only a few seedlings emerged in spring across locations, except in the wheat stubble experiment at North Platte, where higher spring emergence was detected (3% to 22%). In four out of six experiments, the density of total emerged seedlings of each accession was greatest when established in their site of origin. Our results suggest that late fall and/or early spring is likely the best timing for horseweed management across Nebraska.

Direct belowground nitrogen (N) transfer has often been reported where plants with contrasting nutrients acquisition strategies (N2-fixing and non-fixing) co-occur, and there is still a gap in the knowledge of the extent of this transfer in the top soil under the field conditions. However, assessment under field conditions is challenging. We hypothesized a practical application of the analysis of natural abundance of δ15N supplemented with an isotopic mixing model ‘IsoSource’ to understand the relative direct contribution of N2-fixing Alnus acuminata to wheat intercrop (non-fixing) N isotopic signatures. A field experiment was conducted in an andic soil of high lands in northern Rwanda to quantitatively determine the proportional contribution of nitrogen by Alnus acuminata to wheat vegetative tissue isotope signatures at different distances from the trees (1 m, 3 m, 5 m, and 7 m). The study involved the measurements and analyses of natural abundance of stable isotopes δ15N and isotopic mixing modeling by IsoSource. Leaf samples were collected from twigs of 10 years old Alnus acuminata grown on the terrace-risers, along with soil samples (0–20 cm) and wheat flag leaf samples across terrace at 1 m, 3 m, 5 m, and 7 m from trees for isotopic measurement. The chlorophyll content index of wheat flag leaf at the four points across terrace was estimated by means of SPAD meter 502. The δ15N proportional contribution by Alnus acuminata to wheat was obtained through IsoSource analysis. We noted a significant (p < 0·01) gradient in depletion of wheat δ15N signatures moving further away from the tree line of Alnus acuminata. The wheat at 1 m from the trees exhibited the δ15N values closer to that of the tree, while at 7 m, the crop δ15N signature was significantly different from that of the tree. An isotopic mixing model ‘IsoSource’ indicated that the tree N may have provided 33·6 ± 4·3 % of the wheat intercrop N at 1 m distance from the trees. Therefore, this study shows that the understanding of field-based crop N and nutrient transfer in agroforestry may be enhanced by analysis of the physiological basis of stable isotopes signatures.

Wild radish is the most problematic broadleaf weed in Australian grain production. The propensity of wild radish to evolve resistance to herbicides has led to high frequencies of multiple herbicide–resistant populations present in these grain production regions. The objective of this study was to evaluate the potential of mesotrione to selectively control wild radish in wheat. The initial dose response pot trials determined that at the highest mesotrione rate of 50 g ha−1 applied preemergence (PRE) was 30% more effective than when applied postemergence (POST) on wild radish. This same rate of mesotrione applied POST resulted in a 30% reduction in wheat biomass compared to 0% for the PRE application. Subsequent mesotrione PRE dose response trials identified a wheat selective rate range of >100 and <300 g ai ha−1 that provided greater than 85% wild radish control with less than 15% reduction in wheat growth. Field evaluations confirmed the efficacy of mesotrione at 100 to 150 g ai ha−1 in reducing wild radish populations by greater than 85% following PRE application and incorporation by wheat planting. Additionally, these field trials demonstrated the opportunity for season-long control of wild radish when mesotrione applied PRE was followed by bromoxynil applied POST. The sequential PRE application of mesotrione, a herbicide that inhibits p-hydroxyphenylpyruvate dioxygenase, followed by POST application of bromoxynil, a herbicide that inhibits photosystem II, has the potential to provide 100% wild radish control with no effect on wheat growth.

Aegilops tauschii, the diploid progenitor of the wheat D-genome, is a valuable genetic resource for wheat breeders. In this study, we compared the efficiency of inter-simple sequence repeat (ISSR) (as an arbitrary technique) and start codon targeted (SCoT) (as a gene-targeting technique) markers in determining the genetic diversity and population structure of 90 accessions of Ae. tauschii. SCoT markers indicated the highest values for polymorphism information content, marker index and effective multiplex ratio compared to ISSR markers. The total genetic diversity (Ht) and genetic diversity within populations (Hs) parameters were comparably modest for the two marker systems. The results of the analysis of molecular variance showed that the genetic variation within populations was significantly higher than among them (ISSR: 92 versus 8%; SCoT: 88 versus 12%). Furthermore, SCoT markers discovered a high level of genetic differentiation among populations than ISSRs (0.19 versus 0.05), while the amount of gene flow detected by ISSR was higher than SCoT (2.13 versus 8.62). Cluster analysis and population structure of SCoT and ISSR data divided all investigated accessions into two and four main clusters, respectively. Our results revealed that SCoT and ISSR fingerprinting could be used to further molecular analysis in Ae. tauschii and other wild species. The high-genetic variability found in this study also indicates the valuable genetic potential present in the investigated Ae. tauschii germplasm, which could be utilized for future genetic analysis and linkage mapping in breeding programmes.

Fertilizer nitrogen (N) management in any region following standard general recommendations discount the fact that crop response to N varies between sites and seasons. To devise field-specific N management in wheat at jointing stage (Feekes 6 growth stage) using atLeaf meter and leaf colour chart (LCC), eight field experiments were conducted in three wheat seasons during 2017–2020 in the West Delta of Egypt. In the first two seasons, four experiments consisted of treatments with a range of fertilizer N application levels from 0 to 320 kg N ha−1. Monitoring atLeaf and LCC measurements at Feekes 6 growth stage in plots with different yield potentials allowed formulation of different criteria to apply field-specific and crop need-based fertilizer N doses. In the four experiments conducted in the third season in 2019/20, different field-specific N management strategies formulated in 2017/18 and 2018/19 wheat seasons were evaluated. In the atLeaf-based fertilizer N management experiment, prescriptive application of 40 kg N ha−1 at 10 days after seeding (DAS) and 60 kg N ha−1 at 30 DAS followed by application of an adjustable dose at Feekes 6 stage computed by multiplying the difference of atLeaf measurements of the test plot and the N-sufficient plot with 42.25 (as derived from the functional model developed in this study), resulted in grain yield similar or higher to that obtained by following the standard treatment. The LCC-based strategy to apply field-specific fertilizer N at Feekes 6 stage consisted of applying 150, 100 or 0 kg N ha−1 based on LCC shade equal to or less than 4, between 4 and 5 or equal to or more than 5, respectively. Both atLeaf- and LCC-based fertilizer N management strategies not only recorded the highest grain yield levels but also resulted in higher use efficiency with 57–60 kg N ha−1 in average less fertilizer use than the standard treatment.

Yield losses due to weeds are a major threat to wheat production and economic well-being of farmers in the United States and Canada. The objective of this Weed Science Society of America (WSSA) Weed Loss Committee report is to provide estimates of wheat yield and economic losses due to weeds. Weed scientists provided both weedy (best management practices but no weed control practices) and weed-free (best management practices providing >90% weed control) average yield from replicated research trials in both winter and spring wheat from 2007 to 2017. Winter wheat yield loss estimates ranged from 2.9% to 34.4%, with a weighted average (by production) of 25.6% for the United States, 2.9% for Canada, and 23.4% combined. Based on these yield loss estimates and total production, the potential winter wheat loss due to weeds is 10.5, 0.09, and 10.5 billion kg with a potential loss in value of US$2.19, US$0.19, and US$2.19 billion for the United States, Canada, and combined, respectively. Spring wheat yield loss estimates ranged from 7.9% to 47.0%, with a weighted average (by production) of 33.2% for the United States, 8.0% for Canada, and 19.5% combined. Based on this yield loss estimate and total production, the potential spring wheat loss is 4.8, 1.6, and 6.6 billion kg with a potential loss in value of US$1.14, US$0.37, and US$1.39 billion for the United States, Canada, and combined, respectively. Yield loss in this analysis is greater than some previous estimates, likely indicating an increasing threat from weeds. Climate is affecting yield loss in winter wheat in the Pacific Northwest, with percent yield loss being highest in wheat-fallow systems that receive less than 30 cm of annual precipitation. Continued investment in weed science research for wheat is critical for continued yield protection.

Late-season control of Palmer amaranth in postharvest wheat stubble is important for reducing the seedbank. Our objectives were to evaluate the efficacy of late-season postemergence herbicides for Palmer amaranth control, shoot dry biomass, and seed production in postharvest wheat stubble. Field experiments were conducted at Kansas State University Agricultural Research Center near Hays, KS, during 2019 and 2020 growing seasons. The study site had a natural seedbank of Palmer amaranth. Herbicide treatments were applied 3 wk after wheat harvest when Palmer amaranth plants had reached the inflorescence initiation stage. Palmer amaranth was controlled by 96% to 98% 8 wk after treatment and shoot biomass as well as seed production was prevented when paraquat was applied alone or when mixed with atrazine, metribuzin, flumioxazin, 2,4-D, sulfentrazone, pyroxasulfone + sulfentrazone, or flumioxazin + metribuzin, and with glyphosate + dicamba, glyphosate + 2,4-D, saflufenacil + 2,4-D, glufosinate + dicamba + glyphosate, and glufosinate + 2,4-D + glyphosate. Palmer amaranth was controlled by 89% to 93% with application of glyphosate, glufosinate, dicamba + 2,4-D, saflufenacil + atrazine, and saflufenacil + metribuzin resulting in Palmer amaranth shoot biomass of 15 to 56 g m−2 and production of 1,080 to 7,040 seeds m−2. Palmer amaranth control was less than 86% with application of dicamba, 2,4-D, dicamba + atrazine, and saflufenacil resulting in Palmer amaranth shoot biomass of 38 to 47 g m−2 and production of 3,110 to 6,190 seeds m−2. Palmer amaranth was controlled 63% and 72%, shoot biomass was 178 and 161 g m−2, and seed production was 35,180 and 39,510 seeds m−2, respectively, with application of 2,4-D + bromoxynil + fluroxypyr, and bromoxynil + pyrasulfotole + atrazine. Growers should use these effective postemergence herbicide mixes for Palmer amaranth control to prevent seed prevention postharvest in wheat stubble.

Three herbicide premixes have recently been introduced for weed control in wheat: halauxifen + florasulam, thifensulfuron + fluroxypyr, and bromoxynil + bicyclopyrone. The objective of this study was to evaluate these herbicides along with older products for their control of small-seeded false flax in winter wheat in Oklahoma. Studies took place during the 2017, 2018, and 2020 winter wheat growing seasons. Weed control was visually estimated every 2 wk throughout the growing season, and wheat yield was collected in all 3 yr. Small-seeded false flax diameter was approximately 6 cm at the time of application in all years. Control ranged from 96% to 99% following all treatments with the exception of bicyclopyrone + bromoxynil and dicamba alone, which controlled false flax 90%. All treatments containing an acetolactate synthase (ALS)–inhibiting herbicide achieved adequate control; therefore, resistance is not suspected in this population. Halauxifen + florasulam and thifensulfuron + fluroxypyr effectively controlled small-seeded false flax similarly to other standards recommended for broadleaf weed control in wheat in Oklahoma. Rotational use of these products allows producers flexibility in controlling small-seeded false flax and reduces the potential for development of herbicide resistance in this species.