Search

Early detection of herbicide resistance in weeds is crucial for successful implementation of integrated weed management. We conducted a herbicide resistance survey of the winter annual grasses feral rye (Secale cereale), downy brome (Bromus tectorum), and jointed goatgrass (Aegilops cylindrica) from Colorado winter wheat production areas for resistance to imazamox and quizalofop.All samples were susceptible to quizalofop. All downy brome and jointed goatgrass samples were susceptible to imazamox. Out of 314 field collected samples, we identified three feral rye populations (named A, B, and C) that were imazamox resistant. Populations B and C had a target-site mechanism with mutations in the Ser653 residue of the acetolactate synthase (ALS) gene to Asn in B and to Thr in C. Both populations B and C had greatly reduced ALS in vitro enzyme inhibition by imazamox. ALS feral rye protein modeling showed that steric interactions induced by the amino acid substitutions at Ser653 impaired imazamox binding. Individuals from population A had no mutations in the ALS gene. The ALS enzyme from population A was equally sensitive to imazamox as to known susceptible feral rye populations. Imazamox was degraded two times faster in population A compared with a susceptible control. An oxidized imazamox metabolite formed faster in population A and this detoxification reaction was inhibited by malathion.Population A has a nontarget-site mechanism of enhanced imazamox metabolism that may be conferred by cytochrome P450 enzymes. This is the first report of both target-site and metabolism-based imazamox resistance in feral rye. © 2022 The Authors. Pest Management Science published by John WileySons Ltd on behalf of Society of Chemical Industry.

Stripe rust (caused by Puccinia striiformis f. sp. tritici) is one of the most severe diseases for wheat production. An important method to improve the stripe rust resistance of wheat is to introduce resistance genes from related species into the wheat genome. The 1RS.1BL wheat–rye translocation from Petkus rye has contributed substantially to wheat resistance breeding worldwide. However, given the breakdown of the stripe rust resistance gene Yr9 in 1RS, its importance for wheat improvement has decreased. In this study, we developed 166 new primary 1RS.1BL translocation lines by crossing rye varieties Weining, Baili, and Aigan with several wheat cultivars. Cytogenetic and molecular analyses indicated that all of these lines contained a pair of intact 1RS.1BL translocation chromosomes. The stripe rust resistance of these translocation lines and their wheat parents was evaluated in southwestern China during the severe stripe rust epidemics in 2015 and 2021. The results showed diverse effects of the 1RS.1BL translocations from different rye cultivars on resistance to stripe rust. The highest genetic diversity was observed in 1RS.1BL translocations derived from diverse rye varieties but in the same wheat background. The development of diverse 1RS.1BL translocation lines offers ample opportunities to introduce new variations into wheat for improving stripe rust resistance. Finally, 71 new translocation lines, including nine developed from the cross of MY11 × Aigan, four from MY11 × Baili, 40 from MY11 × Weining, 14 from A42912 × Baili, and four from A42912 × Weining. These lines showed consistent resistance to stripe rust in fields under frequent changes of the pathogen races and could be useful genetic stocks for breeding wheat cultivars with resistance to stripe rust.

The grain of rye (Secale cereale L.) used for baking contains a large amount of non-starch polysaccharides, making it an excellent component of functional foods. But rye grain intended for alcohol production and forage use should have a reduced content of these polysaccharides. A comprehensive parameter that can predict the best field of application for winter rye grain is the viscosity of its wholemeal water extract. However, our understanding of the genetic background underlying this key trait and associated features of rye grain is poor. By analyzing six Russian winter rye cultivars, we identified the most contrasting forms and characterized the peculiarities of their water-soluble carbohydrates capable of influencing the viscosity of water extracts. Then, using phylogenetic and transcriptomic analyses, we identified in the rye genome many genes encoding putative glycosyltransferases and glycosylhydrolases responsible for the synthesis and degradation of arabinoxylans, mixed-linkage glucans, cellulose, and some other polysaccharides. We determined the dynamics of mRNA abundance for these genes at three stages of kernel development. Comparisons of gene expression levels in two contrasting cultivars revealed specific members of multigene families that may serve as promising targets for manipulating non-starch polysaccharide content in rye grain. High-viscosity cultivars were characterized by up-regulation of many glycosyltransferases involved in the biosynthesis of arabinoxylans and other cell-wall polysaccharides, whereas low-viscosity cultivars showed up-regulation of several genes encoding polysaccharide-degrading enzymes.

Fusarium head blight (FHB) is one of the most important diseases that occurs in cereal regions worldwide and causes serious economic damage. This disease can be caused by several Fusarium species with Fusarium graminearum sensu stricto being the most common pathogen isolated from several crops. The aim of this study was to report the occurrence of F. graminearum sensu stricto on rye grains collected from field samples in Argentina and to determine the potential ability to produce deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEA). Based on morphological characteristics, the isolate was identified as F. graminearum sensu stricto. To confirm molecularly, portions of the RED and TRI genes were sequenced and showed 99% similarity with the F. graminearum sensu stricto sequences available in the NCBI database. The potential to produce DON, 15-ADON and ZEA was determined. Moreover, Koch´s postulates were carried out. To our knowledge, this is the first report of F. graminearum sensu stricto associated with rye kernels in Argentina. Fil: Martínez, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; Argentina Fil: Dinolfo, María Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; Argentina Fil: Castañares, Eliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; Argentina Fil: Stenglein, Sebastian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; Argentina

The rise in temperature during autumn is one of the most serious negative factors for winter rye (Secale cereale L.), which leads to wilting, plant damage by fungal diseases and yield losses. The a...

To reduce dependency on inorganic phosphorus (P) fertiliser, secondary P fertilisers such as struvite are becoming more important. However, the P uptake of these new fertilisers by plants is often not known and may be enhanced by plant associated microorganisms. We therefore investigated the effect of arbuscular mycorrhizae (AM) on P uptake in rye (Secale cereale L.), grown in the middle compartment of a box with chambers separated by a 30 µm mesh allowing fungal hyphae but not roots to penetrate. Plants with (AM) or without (control) mycorrhizae (Rhizophagus irregularis) were grown in a P limited sand medium for 72 days. After harvest, plants were analysed for mycorrhizal colonization, shoot and root development and nutrient (P, Ca, Mg) uptake. Further, pH was measured in each compartment. Shoot biomass of both treatments was not different, but root biomass was significantly lower in AM plants. Despite plants of the AM treatment being colonised by mycorrhizae, their P uptake was substantially lower compared to the control treatment, but root nutrient concentration was higher. Even though the pH in the mycorrhizal compartment of the AM treatment was significantly lower compared to the control, water- and CAL-extractable P were similar, indicating little P uptake from this compartment. Extractable P was reduced only in the root compartment of the control, which was associated with a lower pH compared to the AM treatment. In conclusion, mycorrhizae did not increase P uptake from struvite in rye plants. Non-mycorrhizal plants which invested more biomass into roots took up more P. Graphical abstract

The effects of cover crops on the biology of the soybean cyst nematode (SCN; Heterodera glycines) are not well established. It is possible that cover crops may reduce SCN population densities by acting as trap crops. Cover crops with potential to serve as trap crops may stimulate hatching and/or attract hatched SCN juveniles and also may be penetrated by large numbers of nematodes that cannot feed. Experiments were conducted to determine whether root exudates (REs) and soil leachates (SLs) from various cover crop plants affected SCN hatching and chemotaxis and if there were significant differences in SCN juvenile root penetration among different cover crop plant types. In 14-day-long hatching experiments, there was greater SCN hatching in crimson clover (Trifolium incarnatum) REs and SLs than in REs and SLs from all other cover crop treatments in the experiments. No other cover crop REs and SLs significantly affected hatching. In chemotaxis experiments, SCN juveniles were attracted to REs and SLs from annual ryegrass (Lolium multiflorum) and cereal rye (Secale cereale) after 24 h. In greenhouse experiments, significantly more SCN juveniles penetrated the roots of single cultivars of crimson clover, mustard (Brassica juncea), and rapeseed (B. napus) than 11 other cover crop species/cultivars evaluated in the experiment over the course of 20 days. Few SCN juveniles penetrated the roots of annual ryegrass and cereal rye. The results suggest that crimson clover, grown as a cover crop, has the most potential to act as a trap crop for SCN. Cover crop plants may affect SCN biology in ways other than the mechanisms investigated in these experiments.

Homoeologous group 5 chromosomes of wheat possess genes that have a significant influence on the time of earing, growth habit (Vrn), frost resistance (Fr) and winter hardiness. The Vrn-A1/Fr-A1, Vrn-B1/Fr-B1 and Vrn-D1/Fr-D1 genes are assigned to the long arm of the 5A, 5B and 5D chromosomes, respectively. In rye (Secale cereale L.), Vrn-R1/Fr-R1 genes, which determine the growth habit and cold/frost resistance, are localized on chromosome 5RL. To investigate the effect of individual chromosomes on winter hardiness, as well as their interactions with the background, wheat-rye 5R(5A)-substituted lines based on winter and spring wheats were used in this study. We created the wheat-rye 5R(5A) substitution lines based on the winter wheats cvs. ‘Filatovka’ and ‘Ulʼynovka’ and based on the spring wheats cvs. ‘Rang’ and ‘Mironovskaya krupnozernaya’ to identify the role of rye chromosome 5R in controlling the growth habit and winter hardiness. Two cultivars of rye—‘Onokhoiskaya’ (spring habit) and ‘Vietnamskaya Mestnaya’—are the source of chromosome 5R. We do not know the growth habit of rye ‘Vietnamskaya Mestnaya’. Field experiments were carried out over three years during the winters of 2015/2016, 2016/2017 and 2017/2018 in the Novosibirsk Region. It was found that 5R(5A) substitution lines for spring cvs. ‘Rang’ and ‘Mironovskaya krupnozernaya’, with the participation of the spring rye ‘Onokhoiskaya’, have a winter habit. The wheat-rye 5R(5A) lines for winter cvs. ‘Ul'yanovka’ and ‘Filatovka’, with the participation of rye ‘Vietnamskaya Mestnaya’, have a facultative habit. These substituted lines can grow in both spring and autumn sowing. The evaluation of winter hardiness conducted was carried out by means of visual scoring on a 1–9 score basis. All wheat-rye-substituted lines survived in the conditions of the Novosibirsk Region. Winter hardiness scores ranged from 5 to 6 after the 2015/2016 and 2016/2017 winters, whereas winter hardiness scores varied from 8 to 9 after the 2017/2018 winter.

A 3-year field study was conducted to assess effects of two winter cover crops, Elbon rye (Secale cereal L.) and Crimson clover (Trifolium incarnatum L.), under till and no till management, on bacterial community composition in soybean (Glycine max L.) field soils using high-throughput sequencing of the 16S rRNA gene. Effects of tillage and cover crop on bacterial composition at the phylum level were minor, with most significant differences between treatments occurring at finer taxonomic levels. Tilled plots displayed higher levels of Xanthomonadaceae, while cover cropped soils had greater Bradyrhizobium abundances. Functional gene prediction indicated that genes associated with decomposition of C and P compounds, as well as biocontrol agents, were elevated in tilled plots, genes associated with root growth promotion were elevated in cover crop treatments, and nitrate reductase and denitrification genes were elevated in both no till and cover crop plots. While valuable functional insights can be gained from sequence analyses, not all differences observed at the sequencing level will translate into functional differences due to variation in gene expression, and further study is needed to validate which functions can be predicted from sequencing data.

Key message Individual stem rust resistance genes could be directly mapped within self-incompatible rye populations. Abstract Genetic resources of rye (Secale cereale L.) are cross-pollinating populations that can be highly diverse and are naturally segregating. In this study, we show that this segregation could be used for mapping stem rust resistance. Populations of pre-selected donors from the Russian Federation, the USA and Austria were tested on a single-plant basis for stem rust resistance by a leaf-segment test with three rust isolates. Seventy-four plants per population were genotyped with a 10 K-SNP chip. Using cumulative logit models, significant associations between the ordinal infection score and the marker alleles could be found. Three different loci (Pgs1, Pgs2, Pgs3) in three populations were highly significant, and resistance-linked markers could be validated with field experiments of an independent seed sample from the original population and were used to fix two populations for resistance. We showed that it is possible to map monogenically inherited seedling resistance genes directly in genetic resources, thus providing a competitive alternative to linkage mapping approaches that require a tedious and time-consuming inbreeding over several generations.

Growing winter cereal rye (Secale cereale) (WCR) has been identified as an effective in-field practice to reduce nitrate-N and phosphorus (P) losses to Upper Mississippi River Basin, USA. In the Midwestern USA, growers are reluctant to plant WCR especially prior to corn (Zea mays L.) due to N immobilization and establishment issues. Precision planting of WCR or ‘skipping the corn row’ (STCR) can minimize some issues associated with WCR ahead of corn while reducing cover crop seed costs. The objective of this study was to compare the effectiveness of ‘STCR’ vs normal planting of WCR at full seeding rate (NP) on WCR biomass, nutrient uptake and composition in three site-yrs (ARC2019, ARC2020, BRC2020). Our results indicated no differences in cover crop dry matter biomass production between the STCR (2.40 Mg ha−1) and NP (2.41 Mg ha−1) supported by similar normalized difference vegetative index and plant height for both treatments. Phosphorus, potassium (K), calcium (Ca) and magnesium (Mg) accumulation in aboveground biomass was only influenced by site-yr and both STCR and NP removed similar amount of P, K, Ca and Mg indicating STCR could be as effective as NP in accumulating nutrients. Aboveground carbon (C) content (1086.26 kg h−1 average over the two treatments) was similar between the two treatments and only influenced by site-yr differences. Lignin, lignin:N and C:N ratios were higher in STCR than NP in one out of three site-yrs (ARC2019) indicating greater chance of N immobilization when WCR was planted later than usual. Implementing STCR saved $8.4 ha−1 for growers and could incentivize growers to adopt this practice. Future research should evaluate corn response to STCR compared with NP and assess if soil quality declines by STCR practice over time.

We isolated the rye serine/threonine protein kinase (S/T PK) gene, which is responsible for intracellular signal transduction mediated by abscisic acid (ABA) synthesized following drought stress, from the huge genome, i.e., 1Cx = 7917 Mb. cDNA was synthesized from poly(A)+ RNA from ABA-treated leaves and then ligated with pUC118 via EcoRI linker to form a cDNA library. RT-PCR amplified DNA fragment of S/T PK gene was used as a probe to screen the cDNA library. One positive cDNA clone was sequenced to determine the overall 1462 bp of the S/T PK gene, which encodes the S/T PK protein consisting of deduced 363 amino acid residues including 12 catalytic subdomains. Total RNA was extracted from both ABA-treated and ABA-untreated rye Petkus leaves and then run on a 1% agarose gel denatured by formaldehyde, and the RNA was transblotted to a nylon membrane. Next, northern hybridization was conducted on the membrane using the 3′ untranslated 244 bp region as probes. The rye S/T PK gene was transcribed in ABA-treated leaves but not in untreated leaves. We have shown that rye S/T PK, localized on the 2R chromosome, is transcribed via ABA mediation, which indicates the relation to intracellular signal transduction.

Background Ergot alkaloids are mycotoxins produced by the fungus Claviceps, which can contaminate grains and pose a health risk to humans and animals. Validation of an ergot alkaloid method in collaborative projects can be challenging due to instability of analytes, a lack of reliable reference materials, and a fully validated reference method. Objective To extensively evaluate performance of a quantitative UHPLC–MS/MS method to detect ten ergot alkaloids at concentrations between 16 and 500 ng/g in grains. Method The method performance was evaluated in the Blinded Method Test (BMT) exercise, which allowed organizers to successfully address the challenges. Forty completely blinded test samples were prepared in an independent laboratory and shipped to a participating laboratory to analyze on two separate days. Results Precision, accuracy, and HorRatr values met or exceeded the U.S. Food and Drug Administration recommendations. The design of the BMT exercise provided a high degree of confidence in data and conclusions drawn. Conclusions The method performed in a manner as expected, and the method can be used by the laboratory for routine testing of wheat and rye grains. Highlights BMT of laboratory methods facilitate validation of tests by evaluating performance in an unbiased manner.

In wheat endosperm, the granule-bound starch synthase or the Waxy protein is the sole enzyme for amylose synthesis and thus determines the amylose content and ratio of amylose/amylopectin. The gene encoding this enzyme has been named as Waxy (Wx) gene. In this study, eight novel Wx alleles from four diploid species belonging to the three Triticeae genera, namely Eremopyrum, Psathyrostachys, and Henrardia have been isolated and characterized. The genetic diversity of these genes was evaluated at the molecular sequence level, and the nucleotides of these Wx genes were also compared with their homologs from wheat and its relatives. The Wx alleles of P. juncea (Fischer) Nevski, E. triticeum (Gaertn.) Nevski, E. bonaepartis (Sprengel) Nevsk, and H. persica (Boiss.) C. E. Hubbard showed obvious differences from the homologous alleles known from wheat and Aegilops as well as Taeniatherum in terms of nucleotide composition, intron length, isoelectric point, and molecular mass. Phylogenetic analysis suggested that the Wx alleles of these four species distantly related to wheat were more closely related to those of Hordeum and Secale than the other species. These Wx alleles are novel candidates with potential application in wheat breeding for modified starch properties.

PmSESY, a new wheat powdery mildew resistance gene was characterized and genetically mapped to the terminal region of chromosome 1RL of wild rye Secale sylvestre. The genus Secale is an important resource for wheat improvement. The Secale species are usually considered as non-adapted hosts of Blumeria graminis f. sp. tritici (Bgt) that causes wheat powdery mildew. However, as a wild species of cultivated rye, S. sylvestre is rarely studied. Here, we reported that 25 S. sylvestre accessions were susceptible to isolate BgtYZ01, whereas the other five confer effective resistance to all the tested isolates of Bgt. A population was then constructed by crossing the resistant accession SESY-01 with the susceptible accession SESY-11. Genetic analysis showed that the resistance in SESY-01 was controlled by a single dominant gene, temporarily designated as PmSESY. Subsequently, combining bulked segregant RNA-Seq (BSR-Seq) analysis with molecular analysis, PmSESY was mapped into a 1.88 cM genetic interval in the terminus of the long arm of 1R, which was closely flanked by markers Xss06 and Xss09 with genetic distances of 0.87 cM and 1.01 cM, respectively. Comparative mapping demonstrated that the corresponding physical region of the PmSESY locus was about 3.81 Mb in rye cv. Lo7 genome, where 30 disease resistance-related genes were annotated, including five NLR-type disease resistance genes, three kinase family protein genes, three leucine-rich repeat receptor-like protein kinase genes and so on. This study gives a new insight into S. sylvestre that shows divergence in response to Bgt and reports a new powdery mildew resistance gene that has potential to be used for resistance improvement in wheat.

Harvest weed seed control (HWSC) may control problematic weeds by decreasing contributions to the weed seedbank. However, HWSC practices will not be effective if plants have shed a great part of their seeds before harvest or if a low proportion of seed production is retained at a height that enables collection during harvest. The seed-shattering pattern of several weed species was evaluated over three growing seasons to determine their potential to be controlled with HWSC in the Pacific Northwest (PNW). The studied weed species were downy brome (Bromus tectorum L.), feral rye (Secale cereale L.), Italian ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot], and rattail fescue [Vulpia myuros (L.) C.C. Gmel.]. Seed retention at harvest, seed production, and plant height differed among species, locations, and years. Environmental conditions influenced seed-shattering patterns, particularly the time plants started to shatter seeds and the rate of the shattering. Agronomic factors such as herbicide use, interrow space, or crop height/vigor also seemed to affect shattering patterns and seed production, but more specific studies must be conducted to determine their individual effects. Bromus tectorum, L. perenne ssp. multiflorum, and V. myuros had an average seed retention at harvest of less than 50%. In addition, the low seed retention height of V. myuros makes this species a poor candidate for HWSC. Secale cereale had average seed retention at harvest greater than 50%, and seed retention height was greater than 30 cm. The variability of seed retention in different species will make the efficacy of HWSC practices species and environment dependent in PNW winter wheat (Triticum aestivum L.) cropping systems. Harvesting the wheat crop as early as possible will be crucial to the success of HWSC.

As herbicide-resistant weeds become more problematic, producers will consider the use of cover crops to suppress weeds. Weed suppression from cover crops may occur especially in the label-mandated buffer areas of dicamba-resistant soybean where dicamba use is not allowed. Three cover crops terminated at three timings with three herbicide strategies were evaluated for their effect on weed suppression in dicamba-resistant soybean. Delaying termination until soybean planting or after and using cereal rye or cereal rye + crimson clover increased cover-crop biomass by at least 40% compared to terminating early or using a crimson clover–only cover crop. Densities of problematic weed species were evaluated in early summer before a blanket POST application. Plots with cereal rye had 75% less horseweed compared to crimson clover at two of four site-years. Cereal rye or the mixed cover crop terminated at or after soybean planting reduced waterhemp densities by 87% compared to early termination timings of crimson clover and the earliest termination timing of the mix at one of two site-years. Cover crops were not as effective in reducing waterhemp densities as they were in reducing horseweed densities. This difference was due to a divergence in emergence patterns; waterhemp emergence generally peaks after termination of the cover crop, whereas horseweed emergence coincides with establishment and rapid vegetative growth of cereal rye. Cover crops alone were generally not as effective as was using a high-biomass cover crop combined with an herbicide strategy that contained dicamba and residual herbicides. However, within label-mandated buffer areas where dicamba cannot be used, a cover crop containing cereal rye with delayed termination until soybean planting combined with residual herbicides could be used to improve suppression of horseweed and waterhemp. Nomenclature: Dicamba; horseweed; Conyza canadensis L. Cronquist; waterhemp; Amaranthus tuberculatus (Moq.) Sauer; cereal rye; Secale cereal L.; crimson clover; Trifolium incarnatum L.; soybean; Glycine max (L.) Merr.

Wheat-rye T1RS·1BL translocations have been widely used worldwide in wheat production for multiple disease resistance and superior yield traits. However, many T1RS·1BL translocations have successively lost their resistance to pathogens due to the coevolution of pathogen virulence with host resistance. Because of the extensive variation in rye (Secale cereale L.) as a naturally cross-pollinating relative of wheat, it still has promise to widen the variation of 1RS and to fully realize its application value in wheat improvement. In the present study, the wheat-rye breeding line R2207 was characterized by comprehensive analyses using genomic in situ hybridization (GISH), multicolor fluorescence in situ hybridization with multiple probes, multicolor GISH, and molecular marker analysis, and then was proven to be a cytogenetically stable wheat-rye T1RS·1BL translocation line. Based on the disease responses to different isolates of powdery mildew and genetic analysis, R2207 appears to possess a novel variation for resistance, which was confirmed to be located on the rye chromosome arm 1RS. Line R2207 also exhibited high levels of resistance to stripe rust at both seedling and adult stages, as well as enhanced agronomic performance, so it has been transferred into a large number of commercial cultivars using an efficient 1RS-specific kompetitive allele specific PCR marker for marker-assisted selection.

Secale cereale is used as a source of genes for disease resistance in wheat cultivation. In this study, a homozygous translocation line (RT14-245) that originated from a cross between a commercial wheat cultivar (Mianyang 11) and a local Chinese variety of rye (Baili) was developed. Multicolor fluorescence in situ hybridization and PCR analysis demonstrated that the translocation chromosome was 7BS.7RL. Resistance analysis showed that RT14-245 was resistant to prevalent pathotypes of stripe rust and powdery mildew. RT14-245 also exhibited high resistance to Fusarium head blight, which was similar to the resistance exhibited by the wheat cultivar Sumai 3. The results indicated that RT14-245 simultaneously exhibited high levels of resistance against stripe rust, powdery mildew, and Fusarium head blight. These results indicate that chromosome arm 7RL in the translocation line RT14-245 is an excellent new resource for wheat breeding programs.

A field experiment was conducted at the research farm of the University of Tehran to evaluate the effect of cover crops and herbicide (nicosulfuron) dosage on corn (Zea mays L.) productivity. Cover crops suppressed weed biomass and density during the fallow period; however, there was no significant effect on weed biomass or weed density in the subsequent corn crop. A mixture of cereal rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth.) was the most weed-suppressive cover in the fallow period. Nicosulfuron applied at different amounts suppressed weed biomass and density in corn when compared with weedy plots. Application of 40 g ai ha−1 of nicosulfuron was as effective on weed control as the recommended application. Cover crops did not affect corn growth; however, corn yield improved with herbicide application.

Integrated strategies for management of glyphosate-resistant (GR) horseweed are needed to reduce reliance on herbicides. Planting a cover crop after corn or soybean harvest in the Upper Midwest may reduce horseweed establishment and growth. Experiments were conducted in Michigan to determine if cereal rye and winter wheat, seeded at 67 or 135 kg ha-1, and terminated with glyphosate at 1.27 kg ae ha-1 1 wk before planting (early termination) or 1 wk after soybean planting (planting green) would suppress establishment and growth of GR horseweed. Cover-crop biomass was 212% to 272% higher when termination was delayed by planting green compared with early termination. At the time of termination, cover crops reduced GR horseweed biomass 41% to 89% compared with no cover. Planting green increased the C:N ratio of cover-crop residue, which improved residue persistence and GR horseweed suppression at the time of POST herbicide application, approximately 5 wk after planting. Planting green reduced GR horseweed biomass 46% to 93% compared with no cover at the time of POST herbicide application; early termination provided less consistent suppression. Cover crops alone did not suppress GR horseweed through soybean harvest. Soybean yield was 30% to 108% greater when planting green compared with early termination at 2 site-years. Cereal rye and winter wheat, seeded at 67 or 135 kg ha-1, provided early-season GR horseweed suppression. Results from this research indicate that the practice of planting green may improve GR horseweed suppression through the time of POST herbicide application.Nomenclature: Glyphosate; horseweed, Conyza canadensis L. Cronq.; winter wheat, Triticum aestivum L.; cereal rye, Secale cereale L.; soybean, Glycine max (L.) Merr

Asparagine synthetase catalyses the transfer of an amino group from glutamine to aspartate to form glutamate and asparagine. The accumulation of free (nonprotein) asparagine in crops has implications for food safety because free asparagine is the precursor for acrylamide, a carcinogenic contaminant that forms during high‐temperature cooking and processing. Here we review publicly available genome data for asparagine synthetase genes from species of the Pooideae subfamily, including bread wheat and related wheat species (Triticum and Aegilops spp.), barley (Hordeum vulgare) and rye (Secale cereale) of the Triticeae tribe. Also from the Pooideae subfamily: brachypodium (Brachypodium dIstachyon) of the Brachypodiae tribe. More diverse species are also included, comprising sorghum (Sorghum bicolor) and maize (Zea mays) of the Panicoideae subfamily and rice (Oryza sativa) of the Ehrhartoideae subfamily. The asparagine synthetase gene families of the Triticeae species each comprise five genes per genome, with the genes assigned to four groups: 1, 2, 3 (subdivided into 3.1 and 3.2) and 4. Each species has a single gene per genome in each group, except that some bread wheat varieties (genomes AABBDD) and emmer wheat (Triticum dicoccoides; genomes AABB) lack a group 2 gene in the B genome. This raises questions about the ancestry of cultivated pasta wheat and the B genome donor of bread wheat, suggesting that the hybridisation event that gave rise to hexaploid bread wheat occurred more than once. In phylogenetic analyses, genes from the other species cluster with the Triticeae genes, but brachypodium, sorghum and maize lack a group 2 gene, while rice has only two genes, one group 3 and one group 4. This means that TaASN2, the most highly expressed asparagine synthetase gene in wheat grain, has no equivalent in maize, rice, sorghum or brachypodium. An evolutionary pathway is proposed in which a series of gene duplications gave rise to the five genes found in modern Triticeae species., This article reviews the asparagine synthetase gene families of several wheat species, rye, barley, brachypodium, sorghum, maize and rice. It shows that TaASN2, the most highly expressed asparagine synthetase gene in wheat grain, has no equivalent in maize, rice, sorghum or brachypodium. It also raises questions about the ancestry of cultivated pasta and bread wheat. The review enabled an evolutionary pathway to be drawn up in which a series of gene duplications gave rise to the five genes found in modern Triticeae species. Asparagine synthetase is important because free asparagine is the precursor for acrylamide, a carcinogenic processing contaminant that forms during frying, baking, roasting and toasting of products made from cereal grains, as well the tubers, beans and storage roots of other crop species.

Key message Hyperspectral and genomic data are effective predictors of biomass yield in winter rye. Variable selection procedures can improve the informativeness of reflectance data. Abstract Integrating cutting-edge technologies is imperative to sustainably breed crops for a growing global population. To predict dry matter yield (DMY) in winter rye (Secale cereale L.), we tested single-kernel models based on genomic (GBLUP) and hyperspectral reflectance-derived (HBLUP) relationship matrices, a multi-kernel model combining both matrices and a bivariate model fitted with plant height as a secondary trait. In total, 274 elite rye lines were genotyped using a 10 k-SNP array and phenotyped as testcrosses for DMY and plant height at four locations in Germany in two years (eight environments). Spectral data consisted of 400 discrete narrow bands ranging between 410 and 993 nm collected by an unmanned aerial vehicle (UAV) on two dates on each environment. To reduce data dimensionality, variable selection of bands was performed, resulting in the least absolute shrinkage and selection operator (Lasso) as the best method in terms of predictive abilities. The mean heritability of reflectance data was moderate ($$h^{2}$$ h 2 = 0.72) and highly variable across the spectrum. Correlations between DMY and single bands were generally significant (p

Current recommendations for the control of glyphosate-resistant horseweed [Conyza canadensis (L.) Cronquist var. canadensis] in soybeans [Glycine max (L.) Merr.] consist of comprehensive herbicide programs, which often include herbicide applications outside the soybean growing season. Integration of cover crops with herbicides could potentially improve C. canadensis control and allow for a reduction in herbicide inputs. Two separate field studies were conducted from 2016 through 2018 with the objectives of: (1) determining the effect of planting date and seeding rate of a cereal rye (Secale cereale L.) cover crop on C. canadensis population density and control in the subsequent soybean crop; and (2) determining whether the cover crop could replace a fall herbicide treatment or allow for a reduction in the use of spring-applied residual herbicides. There was no effect of rye planting date, late September versus late October, on C. canadensis density in either study. In 2016 to 2017, C. canadensis density was greater in the absence of a rye cover crop in both studies, but otherwise not affected by seeding rates of 50 versus 100 kg ha−1. In the 2017 to 2018 season, the presence of rye resulted in an increased C. canadensis density in the spring residual herbicide study (Study I), and had no effect in the fall herbicide study (Study II). Conyza canadensis densities were lowest in the treatments where a comprehensive spring residual or fall herbicide treatment had been applied, averaged over rye planting date and seeding rate. Earlier-planted rye at a higher seeding rate produced the most biomass but did not result in lower C. canadensis densities. These results suggest that cereal rye planted at a density of 50 kg ha−1 as a cover crop before no-till soybeans may be sufficient to reduce glyphosate-resistant C. canadensis plant density, but cannot be relied upon to reduce the need for fall herbicide treatments and spring residual programs.

A field experiment with separately tile‐drained plots was used to study the ability of oilseed radish (Rhaphanus sativus L.), as a cover crop sown after harvest of a main crop of cereals or peas, to reduce nitrogen (N) and phosphorus (P) leaching losses from a clay loam in southern Sweden over 6 years. In addition to oilseed radish in pure stand, two cover crop mixtures (hairy vetch (Vicia villosa) and rye (Secale cereale) for 3 years and oilseed radish in mixture with buckwheat (Fagopyrum esculentum) for 2 years) were tested. The cover crop plots (three replicates per treatment) were compared with unplanted plots as a control. Plots cropped with oilseed radish during autumn (August–November) had significantly smaller yearly mean N concentration in drainage water over 5 of 6 years compared with unplanted controls. Mineral N content in the soil profile in autumn was significantly less in oilseed radish plots than for control plots in all years. The cover crop mixtures of hairy vetch and rye or buckwheat and oilseed radish also showed the potential to reduce soil mineral N in autumn and N concentration in drainage water, compared with unplanted controls. The cover crops had no impact on P leaching. In conclusion, oilseed radish has the ability to reduce leaching losses of N, without increasing the risk of P leaching.

Rye (Secale cereale L.) has been widely used to improve wheat (Triticum aestivum L.) cultivars. Oligo probes combined with non-denaturing fluorescence in situ hybridization (ND-FISH) technology provide a convenient and efficient way to identify individual rye chromosomes. However, suitable ND-FISH-positive oligo probes for recognizing specific segments of rye chromosomes are lacking. Five new ND-FISH-positive oligo probes: Oligo-5BL.46, Oligo-5A8080, Oligo-5A8080.1, Oligo-1AL.73, and Oligo-0R3, combined with two previously reported oligo probes, Oligo-44 and Oligo-45, were used in this study. Probes Oligo-5BL.46, Oligo-5A8080 and Oligo-44 produced signals only in intercalary regions of arms 1RS, 5RS, and 5RL, respectively. Probe Oligo-5A8080.1 combined with probe Oligo-45 distinguished the intercalary regions of arms 1RS, 5RS, and 6RS simultaneously. Oligo-5A8080 and Oligo-5A8080.1 revealed variation in the distribution of 5S rDNA sequences and polymorphism among 5R chromosomes. Probe Oligo-1AL.73 produced signals only on chromosomes 4R and 7R and contributed to the construction of an improved FISH map of chromosome 4RKu and to the confirmation of 4RLKu breakpoints in wheat-rye 4RLKu translocation chromosomes. Oligo-0R3 produced signals in the telomeric and subtelomeric regions of 14 rye chromosomes. These oligo probes also revealed five new tandem repeats in rye. Using the oligo probes reported in this study, the short arms of 1R, 5R, and 6R and the long arms of 4R and 7R can be easily discriminated when these chromosomes are broken. Keywords: Wheat, Rye, ND-FISH, Oligo probe, Tandem repeats

Legume cover crops can play a valuable role in maintaining and increasing soil quality and nitrogen availability, but are infrequently grown in the Upper Midwest due to short growing seasons with minimal management windows; cold, wet springs; and harsh winters. This study was performed to assess the viability of winter annual legume species in northern climates as a potential source of nitrogen (N) fertility to a 75-day sweet corn (Zea maysconvar. saccharatavar.rugosa) cash crop in Lamberton and Grand Rapids, MN in 2016 and 2017. Treatments included medium red clover (Trifolium pratense), two cold-hardy ecotypes of hairy vetch (Vicia villosaRoth), a cereal rye-hairy vetch biculture (Secale cerealeL.,Vicia villosaRoth), cereal rye as a non-legume control, and a fallow weed-free control. Legumes were split into rhizobia inoculated and non-inoculated treatments. Inoculation had no effect on nodulation, biomass production, or N fixation likely due to competition with endogenous rhizobia strains. The rye monoculture and biculture produced the most biomass at all site-years averaging 7.7 and 7.0 Mg ha−1respectively while the two vetch ecotypes averaged 4.5 and 3.9 Mg ha−1. Both vetch ecotypes contributed among the most nitrogen in all site-years, contributing up to 211 kg N ha−1from aboveground biomass. Data from natural abundance isotopic approaches indicate that 75% of vetch tissue N in Grand Rapids and 59% of vetch tissue N in Lamberton was derived from atmospheric N fixation, with equal or higher percent fixation of vetch in biculture at all site-years. More studies should be performed to better understand controls on N fixation of legume cover crops in cold climates.

Organic grain producers are interested in interseeding cover crops into corn (Zea mays L.) in regions that have a narrow growing season window for post-harvest establishment of cover crops. A field experiment was replicated across 2 years on three commercial organic farms in Pennsylvania to compare the effects of drill- and broadcast-interseeding to standard grower practices, which included post-harvest seeding cereal rye (Secale cereale L.) at the more southern location and winter fallow at the more northern locations. Drill- and broadcast-interseeding treatments occurred just after last cultivation and used a cover crop mixture of annual ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot] + orchardgrass (Dactylis glomerata L.) + forage radish (Raphanus sativus L. ssp. longipinnatus). Higher mean fall cover crop biomass and forage radish abundance (% of total) was observed in drill-interseeding treatments compared with broadcast-interseeding. However, corn grain yield and weed suppression and N retention in late-fall and spring were similar among interseeding treatments, which suggests that broadcast-interseeding at last cultivation has the potential to produce similar production and conservation benefits at lower labor and equipment costs in organic systems. Post-harvest seeding cereal rye resulted in greater spring biomass production and N retention compared with interseeded cover crops at the southern location, whereas variable interseeding establishment success and dominance of winter-killed forage radish produced conditions that increased the likelihood of N loss at more northern locations. Additional research is needed to contrast conservation benefits and management tradeoffs between interseeding and post-harvest establishment methods.

Cover crops can provide many benefits to peanut and cotton crops planted in rotation including suppressing weeds, conserving soil moisture after termination, increasing soil organic matter, and reducing soil erosion. However, herbicide carryover can affect cover crop establishment. The objective of this study was to investigate the responses of 6 cover crops (daikon radish, cereal rye, oat, crimson clover, winter wheat, and common vetch) to 12 soil residual herbicides. A multiyear (2016–2018), multilocation study was conducted in Macon and Henry counties, Alabama. Herbicide treatments included S-metolachlor, acetochlor, pyroxasulfone, diclosulam, imazapic, chlorimuron-ethyl, bentazon plus acifluorfen, pyrithiobac-sodium, trifloxysulfuron-sodium, diuron, prometryn, and flumioxazin, each applied at 10% of the full-labeled rate. At 42 to 52 and 145 to 149 d after planting (DAP), cover crop plant heights and stand counts were evaluated, as was biomass at 145 to 149 DAP. Treatments varied from year to year but not locations. In 2016, significant stand reductions (P ≤ 0.10) of 36% to 43% in rye and 44% to 75% in wheat were observed at 48 to 52 DAP for S-metolachlor, acetochlor, pyroxasulfone, imazapic, and bentazon plus acifluorfen compared with nontreated plants. Vetch had stand reductions ranging from 14% to 80% for all treatments 50 DAP except for plants treated with prometryn. S-metolachlor, pyroxasulfone, and acetochlor reduced stands of rye, wheat, and vetch more than any other herbicides. In 2017, at 147 to 149 DAP, clover stands were reduced by 29% with diclosulam and by 38% with trifloxysulfuron-sodium. Similarly, radish stands were reduced by 64% with diclosulam treatment. No significant biomass reductions were observed for any cover crop species either year. Oat showed the most tolerance with no treatments reducing any growth parameters either year. Although initial injury and stunting may occur, biomass at termination of cover crops were not affected by herbicide residues evaluated in this study.Nomenclature: Acetochlor; acifluorfen; bentazon; chlorimuron-ethyl; diclosulam; diuron; flumioxazin; imazapic; prometryn; pyroxasulfone; pyrithiobac-sodium; S-metolachlor; trifloxysulfuron-sodium; cereal rye; Secale cereal L.; common vetch; Vicia villosa L.; cotton, Gossypium hirsutum L.; crimson clover, Trifolium incarnatum L.; daikon radish, Raphanus sativis L.; oat, Avena sativa L.; peanut, Arachis hypogaea L.; winter wheat, Triticum aestivum L.

Cover cropping is an effective management practice for reducing nitrogen (N) losses to the environment from agriculture fields in the Upper Mississippi River Basin (UMRB). Cereal rye (CR; Secale cereale L.) and hairy vetch (HV; Vicia villosa Roth) are two of the most common cover crop species grown in the UMRB. Few studies have examined the effect of corn (Zea mays L.) or soybean (Glycine max L.) management on the rate and timing of N and carbon (C) release from CR and HV residue. The objective of this study was to measure the effect of cash crop rotation (continuous corn, corn–soybean, and soybean–corn), cover crop selection (CR, HV, and a CR/HV mixture), and tillage (spring disk or transitional no-till) on the rate and timing of N and C loss from litterbags as an estimate of N and C release from cover crop residue. Our results demonstrated that rotation did not impact cover crop N and C release. However, HV released both N and C at rates 2.1 and 1.6 times faster, respectively, than treatments that included CR. Furthermore, where residue was incorporated, rates of N and C release were 2.7 and 3.0 times faster, respectively, than where residue was not incorporated. When averaged across cover crop species and tillage, 17% to 56% of nutrient release occurred, after planting, during vegetative cash crop growth stages. Results from this study advanced the understanding of how cropping systems management can influence release of N and C from cover crop residue.

Increased emphasis on implementation of conservation practices (terraces, conservation tillage including no-till or reduced tillage, and cover crops [CC]) have led to the integration of best management practices. However, research on integration of best management practices is limited. Therefore, a field trial was established at the University of Missouri Grace Greenley Research Center near Leonard, Missouri, to evaluate the effects of terraces with landscape positions and CCs on soil health parameters, CC biomass accrual, and no-till corn (Zea mays L.)–soybean (Glycine max [L.] Merr.) yields. Additionally, total suspended solids (TSS), nitrate-nitrogen (NO3-N), and total phosphorus (TP) export and discharge were evaluated from terraces with or without CCs. Six parallel terraces were installed at 36.5 m spacing with each consisting of an individual underground tile outlet. Soybean was planted in 2016 and 2018, and a CC blend was overseeded at R6. Corn was planted in 2017 and cereal rye (Secale cereal L.) CC was drill-seeded after corn harvest. Soil health parameters had significant (p

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is a devastating disease of wheat that seriously affects yield and quality worldwide. Because of the extensive growth of wheat cultivars with homogeneous genetic background, exploring novel resistant resources from wheat relatives has become important for increasing the genetic diversity of wheat. Rye (Secale cereale) is a wheat relative possessing abundant resistance genes because of its high variation. Wheat line AL69, resistant to powdery mildew, was developed by crossing, backcrossing, and self-pollination for multiple generations between hexaploid triticale Zhongsi 237 and common wheat cultivar Zimai 17. Through genomic in situ hybridization (GISH) and multicolor fluorescence in situ hybridization (FISH), nondenaturing FISH, multicolor GISH, and selection with specific molecular markers, AL69 was determined to be a wheat-rye 2R (2D) disomic substitution line. Testing with different B. graminis f. sp. tritici isolates and genetic analysis showed that the all-stage resistance (also called seedling resistance) of AL69 was conferred by the cataloged powdery mildew resistance gene Pm4b derived from Zimai 17, and its adult-plant resistance was derived from the alien chromosome 2R of Zhongsi 237, which was found to be different from the previously reported rye-derived Pm genes, including Pm7 on 2RL. In addition, AL69 showed improved spike number per plant, spike length, fertile spikelet number per spike, kernel number per spike, and grain yield per plant compared with its wheat parent Zimai 17. An elite line S251 combining powdery mildew resistance with excellent agronomic performance was selected from the progenies of AL69 and wheat cultivar Jimai 22. Therefore, AL69 has two types of resistance genes to powdery mildew and improved agronomic traits through pyramiding and thus can be used as a promising genetic stock for wheat breeding.

Organic soil amendments such as modified lignite and biostimulants like arbuscular mycorrhizal fungi (AMF) may have the potential to improve soil biological conditions of agricultural soils. The aim of the study was to test if nitrogen-modified lignite granules (NH) are beneficial for mycorrhization, root and shoot development compared to common mineral nitrogen (Nmin) in a nitrogen and phosphorus limited soil. A greenhouse experiment with Secale cereale L. was carried out using non-sterilized and sterilized sand substrate treated with NH, AMF or Nmin and AMF+NH and AMF+Nmin and was compared to an untreated substrate (control). 7.5 t ha−1 NH and 120 kg Nmin ha−1 led to a similar increase of AMF colonization compared to the control; however, Nmin had a more positive influence on biomass development. Significantly highest mycorrhizal colonization intensity was found for AMF+NH. The co-application of AMF+NH revealed that shoot and root development and shoot nutrient concentrations were significantly higher or were among the significantly highest values, when compared to the other treatments. AMF+NH may be a suitable soil amendment for nutrient-limited soils and may be more sustainable than Nmin due to a combined increase of nitrogen, AMF and carbon/humic acids in the soil that comes with the NH.

International audience; In the recent years, the agricultural world has been progressing towards integrated crop protection, in the context of sustainable and reasoned agriculture to improve food security and quality, and to preserve the environment through reduced uses of water, pesticides, fungicides or fertilizers. For this purpose, one possible issue is to cross elite varieties widely used in fields for crop productions with exotic or wild genetic resources in order to introduce new diversity for genes or alleles of agronomical interest to accelerate the development of new improved-cultivars. However, crossing ability (or crossability) often depends on genetic background of the recipient varieties or of the donor, which hampers a larger use of wild resources in breeding programmes of many crops. In this review we tried to provide a comprehensive summary of genetic factors controlling crossing ability between Triticeae species with a special focus on the crossability between wheat (Triticum aestivum L.) and rye (Secale cereale), which lead to the creation of Triticale (xTriticosecale Wittm.). We also discussed potential applications of newly identified genes or markers associated with crossability for accelerating wheat and Triticale improvement by application of modern genomics technologies in breeding programmes.

Rye (Secale cereale ssp. cereale L.) is a secondary domesticate, considered to have originated as a weed in wheat fields and to have developed traits of domestication by evolving similar physiological and morphological characteristics to those of wheat. Although it migrated into Europe as a weed possessing domestication traits, it became one of the most significant crops grown in large parts of Europe from the medieval period onward. Within the modern borders of Germany, rye was grown using at least two divergent cultivation practices: eternal rye monoculture and three-field rotation. The straw of rye was used to produce Wellerhölzer, which are construction components in traditional half-timbered houses that have enabled a desiccated preservation of the plant remains. In order to assess the impact of cultivation practices, local environmental conditions and genetic variation on the genetic diversification of rye, we seek to integrate well-established archaeobotanical methods with aDNA sequencing of desiccated plant remains obtained from Wellerhölzer from Germany. In the current contribution, we present a proof of concept, based on the analysis of plant remains from a Wellerholz from the Old Town Hall of Göttingen. We use arable weed ecology to reconstruct cultivation practices and local environmental conditions and present a phylogenetic analysis based on targeted loci of the chloroplast and nuclear genome. Our results emphasise that the study of desiccated remains of plants from Wellerhölzer offer a unique opportunity for an integration of archaeobotanical reconstructions of cultivation practices and local environment and the sequencing of aDNA.

Cover crops are essential tools in agro-ecosystems for reducing the reliance on synthetic inputs and associated environmental risks. Alongside their benefits to soil fertility, cover crops can control weeds by their competitive and allelopathic attributes. Laboratory and field experiments were conducted to assess the allelopathic potential of two cover crop species, rye (Secale cereale L.) and squarrose clover (Trifolium squarrosum L.), alone or in a mixture, on seed germination and growth of arable weeds. Aqueous extracts of the two cover crops and their mixture were tested in a bioassay on Conyza canadensis (L). Cronq., Amaranthus retroflexus L. and Digitaria sanguinalis (L.) Scop. In vitro effects of aqueous extracts varied in a dose-dependent manner, with cover crops and weed species. All three extracts were able to reduce the germination of A. retroflexus (–87%) considerably. Inhibitory effects by rye and mixture extracts on radicle growth of all weed species ranged between 51 and 82%. Rye extract was the best at reducing shoot length of C. canadensis and D. sanguinalis (–39 to 44%), while squarrose clover was more effective on A. retroflexus (–79%). Plant extracts also delayed the germination time of weed species with a substantial effect of the mixture on C. canadensis seeds. In the field experiment, no significant weed suppression was provided by cover crop residues incorporated as green manure compared to control plots, despite tillage being more effective in reducing weed density than no-till. Still, the mulch of the mixture controlled weed emergence significantly better than single cover crop mulches. The chemical characterization of cover crop residues, both shoots and roots, revealed a notable richness of allelopathic phenolic acids and flavonoids, which may constitute potential natural herbicides through slow decomposition. From the analysis of the aqueous extracts, other non-analysed and/or unidentified water-soluble allelopathic compounds should underlie the phytotoxicity observed in vitro, at least for rye. For cover crop mixture, positive interactions among plant materials leading to a better release of allelochemicals and weeding effectiveness are discussed according to chemical profiles and field data. Our study demonstrated the allelopathic activity of the cover crops and their potential to be included in weed management strategies according to cropping system needs. Additional trials are needed to confirm the performance of cover crop residues under field conditions. Highlights - Rye and squarrose clover are cover crops with potential allelopathic effects. - Aqueous extracts of residues of rye, squarrose clover, and their mixture reduced and/or slowed weed germination of A. retroflexus and C. canadensis in the in vitro bioassays. - Depending on the concentration of residues, the aqueous extracts had inhibitory effects on radicle and shoot growth of A. retroflexus, C. canadensis, and D. sanguinalis. - The mulch of a mix of rye and squarrose clover under field conditions suppressed weeds better than the single species.

Terminating winter cereal rye (Secale cereale L.) cover crops (CCs) 10 or more days before planting corn is recommended to minimize seedling disease and potential yield loss. In Iowa, cold temperatures and frequent precipitation can prevent farmers from following that recommendation and sometimes forcing them to plant corn while the rye plants are still green, referred to as planting green (PG). A field trial was established to evaluate the effect of rye termination shortly before or after corn planting on growth, seedling root disease, and yield of corn. A rye CC was terminated 17 and 3 days before planting (DBP), and 6 and 12 days after planting (DAP) corn; corn planted following no rye was included as a control. Rye biomass, C:N ratio, and N accumulation increased when terminated 6 or 12 DAP corn compared with rye terminated 17 or 3 DBP corn. Corn seedlings were taller from the PG treatments. More radicle root rot was observed when rye was terminated 3 DBP, 6 DAP, and 12 DAP corn than for the 17 DBP treatment and the no-rye control. Generally, greater Pythium Clade B populations were detected on radicles and seminal roots of corn from the PG treatments. Corn populations, ears, or barren plants were not affected by the treatments. In both years, the no-rye control had the greatest corn yield and the 12 DAP treatment had the lowest yield. Our results suggest that PG increased corn seedling root disease and contributed to reduced corn yield.

Despite numerous environmental benefits associated with cover crop (CC) use, some farmers are reluctant to include CCs in their production systems because of reported yield declines in corn. There are numerous potential reasons for this yield decline, including seedling disease. A winter rye CC can serve as a “green bridge” for corn seedling pathogens. We hypothesized that proximity of corn seedling roots to decaying rye CC roots contributes to corn seeding disease. An experimental field plot and an on-farm study were conducted over 2 years to evaluate growth, development, and disease severity of corn seedlings planted at various distances from decaying winter rye CC plants. The experimental field plot study was conducted in a no-till corn–soybean rotation with five replications of a winter rye CC treatment seeded as (i) no-CC control, (ii) broadcast, (iii) 19-cm drilled rows, and (iv) 76-cm drilled rows. The on-farm study was no-till corn–soybean rotation with four replications of a winter rye CC seeded as 38-cm drilled rows, 76-cm drilled rows, and no-CC control. The corn was planted on 76-cm rows shortly after rye was terminated. With multiple seeding arrangements of winter rye, corn was planted at different distances from winter rye. Corn radicle root rot severity and incidence, shoot height, shoot dry weight, corn height and chlorophyll at VT (tasseling), ear parameters, and yield were collected. Soil samples were taken in the corn row and the interrow at winter rye termination, corn planting, and corn growth stage V3 (three leaves with fully developed collars) to estimate the abundance of Pythium clade B members present in soil samples. Our results showed that increased distance between winter rye residue and corn reduced seedling disease and Pythium clade B populations in the radicles and soil and increased shoot dry weight, leaf chlorophyll, plant height, and yield. This suggests that physically distancing the corn crop from the winter rye CC is one way to reduce the negative effects of a winter rye CC on corn.

Winter rye (Secale cereale L.), a potential alternative biogas substrate, is traditionally bred for grain yield. Thus, our objective was to evaluate the possibility to predict dry matter yield combining vegetation indices derived from visible to NIR spectral data as a proxy for agronomic traits. A total of 404 elite rye hybrids were tested for grain yield, and a subset of this comprising 274 hybrids were also tested for dry matter yield over 2 years and at 4 locations in Germany bringing the total number of environments to 8. Spectral data were collected around solar noontime on mostly clear sky by an unmanned aerial vehicle (UAV) on two dates and measured in the wavelength range between 410 and 993 nm. Observed variation among tested hybrids ranged between 3.64–10.53 Mg ha–1 for grain yield and 8.44–14.66 Mg ha–1 for dry matter yield across different sites. The 23 vegetation indices and the agronomic traits, such as plant height, grain yield, and dry matter yield, showed mostly moderate to high heritability estimates (h2 > 0.50), and their genetic variances were significantly (P < 0.001) different from zero. Plant height was more informative than grain yield for indirect selection of high dry matter yield. An index combining hyperspectral and agronomic data developed by a multiple regression procedure showed a cross-validated prediction ability of 0.75, representing an improvement of about 6% to a model incorporating only agronomic traits. During earlier selection stages, the developed index could be a suitable tool for the cost-effective selection of superior candidates for biomass trials based on grain yield trials.

Water availability is one of the major physiological factors influencing plant growth and development. An assessment study has been done at the Szent István University, Gödöllő to evaluate and identify the water footprint of protein yield of field crop species. Twelve field crop species (Sugar beet Beta vulgaris, spring and winter barley Hordeum vulgare, winter wheat Triticum aestivum, maize Zea mays, sunflower Helianthus annuus, peas Pisum sativum, potato Solanum tuberosum, alfalfa Medicago sativa, oilseed rape Brassica napus, rye Secale cereale and oats Avena sativa) were involved in the study. Evapotranspiration patterns of the crops studied have been identified by the regular agroclimatology methodology and physiologically reliable protein ranges within crop yields were evaluated. The results obtained suggest, that water footprint of cereals proved to be the lowest, however maize values were highly affected by the high variability of protein yield. Oilseed crops had considerably high protein yield with medium water efficiency. Alfalfa, potato and sugar beet water footprints were in accordance with their evapotranspiration patterns. Protein based water footprint assessment seems to be more applicable in crop species evaluations than that of yield based methodologies.

Horseweed is one of Kentucky's most common and problematic weeds in no-till soybean production systems. Emergence in the fall and spring necessitates control at these times because horseweed is best managed when small. Control is typically achieved through herbicides or cover crops (CCs); integrating these practices can lead to more sustainable weed management. Two years of field experiments were conducted over 2016 to 2017 and 2017 to 2018 in Versailles, KY, to examine the use of fall herbicide (FH; namely, saflufenacil or none), spring herbicide (SH; namely, 2,4-D; dicamba; or none), and CC (namely, cereal rye or none) for horseweed management prior to soybean. Treatments were examined with a fully factorial design to assess potential interactions. The CC biomass in 2016 to 2017 was higher relative to 2017 to 2018 and both herbicide programs reduced winter weed biomass in that year. The CC reduced horseweed density while growing and after termination in 1 yr. The FH reduced horseweed density through mid-spring. The FH also killed winter weeds that may have suppressed horseweed emergence; higher horseweed density resulted by soybean planting unless the CC was present to suppress the additional spring emergence. If either FH or CC was used, SH typically did not result in additional horseweed control. The SH killed emerged plants but did not provide residual control of a late horseweed flush in 2017 to 2018. These results suggest CCs can help manage spring flushes of horseweed emergence when nonresidual herbicide products are used, though this effect was short-lived when less CC biomass was present. Nomenclature: 2,4-D; dicamba; saflufenacil; horseweed, Conyza canadensis (L.) Cronq.; cereal rye, Secale cereale L.; soybean, Glycine max (L.) Merr.

Background: Among the regulated mycotoxins that contaminate global food supplies, ochratoxin A is particularly harmful as a nephrotoxin and suspected carcinogen. Objective: To support global measurement comparability, certified calibration solutions for ochratoxin A and [13C6]-ochratoxin A (OTAN-1 and OTAL-1, respectively) as well as a mycotoxin-contaminated rye flour certified reference material (CRM) known as MYCO-1 were developed. Methods: Quantitative proton NMR was used along with maleic acid as an external standard traceable to the Système international (SI) to measure the concentration of ochratoxin A and [13C6]-ochratoxin A for the calibration solutions. OTAN-1 and OTAL-1 were then used as a pair in double isotope dilution MS to certify the mass fraction of ochratoxin A in MYCO-1. The natural ochratoxin A CRM served as the primary standard for traceable quantitation, while the synthetic [13C6]-ochratoxin A CRM served as the internal standard. Results: The certified mass fraction of ochratoxin A or [13C6]-ochratoxin A in the two mycotoxin calibration solution standards was established to be 11.03 ± 0.32 µg/g (k = 2) for OTAN-1 and 4.89 ± 0.18 µg/g (k = 2) for OTAL-1. The mass fraction of ochratoxin A in the rye flour standard MYCO-1 was certified at 4.05 ± 0.88 µg/kg (k = 2). Conclusions: These CRMs will support regulatory testing as they can be used in the method development, validation, calibration, and QC analysis of ochratoxin A. Highlights: This report highlights the methods used to certify OTAN-1, OTAL-1, and MYCO-1 as well as the challenges associated with producing such materials, which can be applied to a wide variety of other CRMs.

Downy brome, feral rye, and jointed goatgrass are problematic winter annual grasses in central Great Plains winter wheat production. Integrated control strategies are needed to manage winter annual grasses and reduce selection pressure exerted on these weed populations by the limited herbicide options currently available. Harvest weed-seed control (HWSC) methods aim to remove or destroy weed seeds, thereby reducing seed-bank enrichment at crop harvest. An added advantage is the potential to reduce herbicide-resistant weed seeds that are more likely to be present at harvest, thereby providing a nonchemical resistance-management strategy. Our objective was to assess the potential for HWSC of winter annual grass weeds in winter wheat by measuring seed retention at harvest and destruction percentage in an impact mill. During 2015 and 2016, 40 wheat fields in eastern Colorado were sampled. Seed retention was quantified and compared per weed species by counting seed retained above the harvested fraction of the wheat upper canopy (15 cm and above), seed retained below 15 cm, and shattered seed on the soil surface at wheat harvest. A stand-mounted impact mill device was used to determine the percent seed destruction of grass weed species in processed wheat chaff. Averaged across both years, seed retention (±SE) was 75% ± 2.9%, 90% ± 1.7%, and 76% ± 4.3% for downy brome, feral rye, and jointed goatgrass, respectively. Seed retention was most variable for downy brome, because 59% of the samples had at least 75% seed retention, whereas the proportions for feral rye and jointed goatgrass samples with at least 75% seed retention were 93% and 70%, respectively. Weed seed destruction percentages were at least 98% for all three species. These results suggest HWSC could be implemented as an integrated strategy for winter annual grass management in central Great Plains winter wheat cropping systems. Nomenclature: Downy brome, Bromus tectorum L. BROTE; feral rye, Secale cereale L. SECCE; jointed goatgrass, Aegilops cylindrica Host, AEGCY; wheat, Triticum aestivum L. TRZAX

Hexaploid triticale (×Triticosecale, AABBRR) is an important forage crop and a promising energy plant. Transferring D-genome chromosomes or segments from common wheat (Triticum aestivum) into hexaploid triticale is attractive in improving its economically important traits. Here, a hexaploid triticale 6D(6A) substitution line Lin 456 derived from the cross between the octoploid triticale line H400 and the hexaploid wheat Lin 56 was identified and analyzed by genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH), and molecular markers. The GISH analysis showed that Lin 456 is a hexaploid triticale with 14 rye (Secale cereale) chromosomes and 28 wheat chromosomes, whereas non-denaturing fluorescence in situ hybridization (ND-FISH) and molecular marker analysis revealed that it is a 6D(6A) substitution line. In contrast to previous studies, the signal of Oligo-pSc119.2 was observed at the distal end of 6DL in Lin 456. The wheat chromosome 6D was associated with increased grain weight and decreased spikelet number using the genotypic data combined with the phenotypes of the F2 population in the three environments. The thousand-grain weight and grain width in the substitution individuals were significantly higher than those in the non-substitution individuals in the F2 population across the three environments. We propose that the hexaploid triticale 6D(6A) substitution line Lin 456 can be a valuable and promising donor stock for genetic improvement during triticale breeding. Keywords: In situ hybridization, Spikelet number, Substitution line, Thousand-grain weight, Triticale

Weeds can cause significant yield loss in watermelon production systems. Commercially acceptable weed control is difficult to achieve, even with heavy reliance on herbicides. A study was conducted to evaluate a spring-seeded cereal rye cover crop with different herbicide application timings for weed management between row middles in watermelon production systems. Common lambsquarters and pigweed species (namely, Palmer amaranth and smooth pigweed) densities and biomasses were often lower with cereal rye compared with no cereal rye, regardless of herbicide treatment. The presence of cereal rye did not negatively influence the number of marketable watermelon fruit, but average marketable fruit weight in cereal rye versus no cereal rye treatments varied by location. These results demonstrate that a spring-seeded cereal rye cover crop can help reduce weed density and weed biomass, and potentially enhance overall weed control. Cereal rye alone did not provide full-season weed control, so additional research is needed to determine the best methods to integrate spring cover cropping with other weed management tactics in watermelon for effective, full-season control.Nomenclature: Common lambsquarters, Chenopodium album L.; Palmer amaranth, Amaranthus palmeri S. Watson; smooth pigweed, Amaranthus hybridus L.; cereal rye, Secale cereale L.; watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai