Emerging new races of wheat stem rust(Puccinia graminis f.sp.tritici)are threatening global wheat(Triticum aestivum L.)production.Host resistance is the most effective and environmentally friendly method of controllin...Emerging new races of wheat stem rust(Puccinia graminis f.sp.tritici)are threatening global wheat(Triticum aestivum L.)production.Host resistance is the most effective and environmentally friendly method of controlling stem rust.The stem rust resistance gene Sr59 was previously identified within a T2DS 2RL wheat-rye whole arm translocation,providing broad-spectrum resistance to various stem rust races.Seedling evaluation,molecular marker analysis,and cytogenetic studies identified wheat-rye introgression line#284 containing a new translocation chromosome T2BL 2BS-2RL.This line has demonstrated broad-spectrum resistance to stem rust at the seedling stage.Seedling evaluation and cytogenetic analysis of three backcross populations between the line#284 and the adapted cultivars SLU-Elite,Navruz,and Linkert confirmed that Sr59 is located within the short distal 2RL translocation.This study aimed physical mapping of Sr59 in the 2RL introgression segment and develop a robust molecular marker for marker-assisted selection.Using genotyping-by-sequencing(GBS),GBS-derived SNPs were aligned with full-length annotated rye nucleotide-binding leucine-rich repeat(NLR)genes in the parental lines CS ph1b,SLU238,SLU-Elite,Navruz,and Linkert,as well as in 33 BC4F5progeny.Four NLR genes were identified on the 2R chromosome,with Chr2R_NLR_60 being tightly linked to the Sr59resistance gene.In-silico functional enrichment analysis of the translocated 2RL region(25,681,915 bp)identified 223 genes,with seven candidate genes associated with plant disease resistance and three linked to agronomic performance,contributing to oxidative stress response,protein kinase activity,and cellular homeostasis.These findings facilitate a better understanding of the genetic basis of stem rust resistance provided by Sr59.展开更多
Interactions of the stripe rust pathogen （Puccinia striiformis f. sp responses. Among various genes involved in the plant-pathogen related （PR） protein genes determine different defense responses tritici） with wh...Interactions of the stripe rust pathogen （Puccinia striiformis f. sp responses. Among various genes involved in the plant-pathogen related （PR） protein genes determine different defense responses tritici） with wheat plants activate a w^ae range OT nost nteractions, the expressions of particular pathogenesis-Different types of resistance have been recognized and utilized for developing wheat cultivars for resistance to stripe rust. All-stage resistance can be detected in seedling stage and remains at high levels throughout the plant growth stages. This type of resistance is race-specific and not durable. In contrast, plants with only high-temperature adult-plant （HTAP） resistance are susceptible in seedling stage, but become resistant when plants grow older and the weather becomes warmer. HTAP resistance controlled by a single gene is partial, but usually non-race specific and durable. The objective of this study was to analyze the expression of PR protein genes involved in different types of wheat resistance to stripe rust. The expression levels of 8 PR protein genes （PR1, PRI.2, PR2, PR3, PR4, PR5, PR9 and PRIO） were quantitatively evaluated at 0, 1, 2, 7 and 14 days after inoculation in single resistance gene lines of wheat with all-stage resistance genes YrTrl, Yr76, YrSP and YrExp2 and lines carrying HTAP resistance genes Yr52, Yr59, Yr62 and Yr7B. Races PSTv-4 and PSTv-37 for compatible and incompatible interactions were used in evaluation of PR protein gene expression in wheat lines carrying all-stage resistance genes in the seedling- stage experiment while PSTv-37 was used in the HTAP experiment. Analysis of quantitative real-time polymerase chain reaction （qRT-PCR） revealed that all of the PR protein genes were involved in the different types of resistance controlled by different Yr genes. However, these genes were upregulated at different time points and at different levels during the infection process among the wheat lines with different Yr genes for either all-stage resistance or HTAP resistance. Some of the genes were also induced in compatible interactions, but the levels were almost always higher in the incompatible interaction than in the compatible interaction at the same time point for each Yr gene. These results indicate that both salicylic acid and jasmonate signaling pathways are involved in both race-specific all-stage resistance and non-race specific HTAP resistance. Although expressing at different stages of infection and at different levels, these PR protein genes work in concert for contribution to different types of resistance controlled by different Yr genes.展开更多
Greenbug(Schizaphis graminum, Rondani) is a serious insect pest in many wheat growing regions and has been infesting cereal crops in the USA for over a century. Continuous occurrence of new greenbug biotypes makes it ...Greenbug(Schizaphis graminum, Rondani) is a serious insect pest in many wheat growing regions and has been infesting cereal crops in the USA for over a century. Continuous occurrence of new greenbug biotypes makes it essential to explore all greenbug resistant sources available to manage this pest. Gb1, a recessive greenbug resistance gene in DS28A, confers resistance to several economically important greenbug biotypes and is the only gene found to be resistant to greenbug biotype F. A set of 174 F_(2:3)lines from the cross DS28A × Custer was evaluated for resistance to greenbug biotype F in 2020 and 2022. Selective genotyping of the corresponding F_(2) population using single nucleotide polymorphism(SNP) markers generated by genotyping-by-sequencing(GBS) led to the identification of a candidate genomic region for Gb1. Thus, SSR markers previously mapped in this region were used to genotype the entire F2population,and kompetitive allele specific PCR(KASP) markers were also developed from SNPs in the target region.Gb1 was placed in the terminal region of the short arm of chromosome 1A, and its location was confirmed in a second population derived from the cross DS28A × PI 697274. The combined data analysis from the two mapping populations delimited Gb1 to a < 1 Mb interval between 13,328,200 and 14,241,426 bp on1AS.展开更多
Wheat leaf rust is a prevalent foliar disease in wheat worldwide. Growing resistant cultivars is an effective strategy to minimize the impact of leaf rust on yield and grain quality. Lr42 is a leaf rust resistance gen...Wheat leaf rust is a prevalent foliar disease in wheat worldwide. Growing resistant cultivars is an effective strategy to minimize the impact of leaf rust on yield and grain quality. Lr42 is a leaf rust resistance gene identified from Aegilops tauschii and is still effective against current predominant leaf rust races in the United States and many other countries. In this study, we developed diagnostic DNA markers for Lr42 using the sequence polymorphisms of a differentially expressed gene(TaRPM1) encoding a putative NBARC protein in the Lr42 candidate region identified by RNA-sequencing of two near-isogenic lines contrasting in Lr42 alleles. Markers were designed based on a deletion mutation and a single nucleotide polymorphism(SNP) in the gene. Haplotype analyses of the newly developed markers in the three diversity panels demonstrated that they are diagnostic for Lr42, and superior to previously used markers in selection accuracy. These markers have the advantages of low cost and easy assay, and they are suitable for marker-assisted selection in breeding programs with either high-or low-throughput marker screening facilities.展开更多
Greenbug(Schizaphis graminum Rondani)is a destructive insect pest that not only damages plants,but also serves as a vector for many viruses.Host plant resistance is the preferred strategy for managing greenbug.Two gre...Greenbug(Schizaphis graminum Rondani)is a destructive insect pest that not only damages plants,but also serves as a vector for many viruses.Host plant resistance is the preferred strategy for managing greenbug.Two greenbug resistance genes,Rsg1 and Rsg2,have been reported in barley.To breed cultivars with effective resistance against various greenbug biotypes,additional resistance genes are urgently needed to sustain barley production.Wild barley accession WBDC053(PI 681777)was previously found to be resistant to several greenbug biotypes.In this study,a recombinant inbred line(RIL)population derived from Weskan×WBDC053 was evaluated for response to two greenbug biotypes(E and TX1)and genotyped using genotyping by sequencing(GBS).A set of 3347 high quality GBS-derived single nucleotide polymorphisms(SNPs)were then used to map the greenbug resistance gene in this wild barley accession.Linkage analysis placed the greenbug resistance gene in a 2.35 Mb interval(0-2,354,645 bp)in the terminal region of the short arm of chromosome 2H.This interval harbors 15 genes with leucine-rich-repeat(LRR)protein domains.An allelism test indicated that the greenbug resistance gene in WBDC053,designated Rsg2.a3,is likely allelic or closely linked to Rsg2.GBS-SNPs 2H_1318811and 2H_1839499 co-segregating with Rsg2.a3 in the RIL population were converted to Kompetitive allele specific PCR(KASP)markers KASP-Rsg2.a3-1 and KASP-Rsg2.a3-2,respectively.The two KASP markers can be used to select Rsg2.a3 and have the potential to tag Rsg2 in barley improvement programs.展开更多
The bluestem gall midge (Stenodiplosis wattsii Gagné) is native to the grasslands of North America. It feeds on the developing seeds of warm-season grasses during a portion of its lifecycle, but little is known o...The bluestem gall midge (Stenodiplosis wattsii Gagné) is native to the grasslands of North America. It feeds on the developing seeds of warm-season grasses during a portion of its lifecycle, but little is known of the biology and extent of gall midge infestations in native warm-season grasses in the USA. We investigated the infestations of the bluestem gall midge in big bluestem (Andropogon gerardii Vitman), sand bluestem (Andropogon gerardii var paucipilus), little bluestem [Schizachyrium scoparium (Michx.) Nash], and indiangrass [Sorghastrum nutans (L.) Nash] commercial seed production fields during 2001 through 2004. Our objectives were to determine the annual production cycle of the bluestem gall midge, the range of the infestation in Nebraska, and estimate its impact on seed production. In eastern Nebraska, the midge goes through four generations with the fourth entering a larval diapause, overwintering in seeds and emerging in mid-June of the following year. The bluestem gall midge damaged from 31% of the little bluestem seed to 67% of the big bluestem seed, and, on average, reduced the production of viable seed by 54% across the four grass species in eastern Nebraska. Additionally, the warm-season prairie grasses were surveyed in nine other counties in Nebraska and the bluestem gall midge was found in each species surveyed from all nine counties. This study is the first to document the negative effects of the bluestem gall midge on the production of viable seed in sand bluestem and indiangrass.展开更多
In addition to their value as cereal grains, wheat (Triticum aestivum L.) and triticale (× Triticosecale Wittmack) are important cool-season annual forages and cover crops. Yearling steer (Bos taurus) performance...In addition to their value as cereal grains, wheat (Triticum aestivum L.) and triticale (× Triticosecale Wittmack) are important cool-season annual forages and cover crops. Yearling steer (Bos taurus) performance was compared in the spring following autumn establishment as for age cover crops after soybean [Glycine max (L.) Merr.] grain harvest. Replicated pastures (0.4 ha) were no-till seeded in three consecutive years into soybean stubble in autumn, fertilized, and grazed the following spring near Ithaca, NE, USA. Each pasture (n = 3) was continuously stocked in spring with four yearling steers (380 ± 38 kg) for 17, 32, and 28 d in 2005, 2006, and 2007, respectively. In 2005, average daily gain (ADG) for steers grazing triticale exceeded the ADG for wheat by 0.31 kghd<sup>-1</sup>d<sup>-1</sup>. In 2006, wheat ADG exceeded that for triticale by 0.12 kghd<sup>-1</sup>d<sup>-1</sup>. In 2007, steers grazing wheat lost weight, while steers grazing triticale gained 0.20 kghd<sup>-1</sup>d<sup>-1</sup>. Based on the 3-year average animal gains valued at $1.32 kg<sup>-1</sup>, mean net return ($ ha<sup>-1</sup> yr<sup>-1</sup>) was $62.15 for triticale and $22.55 for wheat. Since these grazed cover crops provide ecosystem services in addition to forage, grazing could be viewed as a mechanism for recovering costs and adds additional value to the system. Based on this 3-year grazing trial, triticale was superior to wheat and likely will provide the most stable beef yearling performance across years with variable weather for the western Cornbelt USA.展开更多
Kernel texture(grain hardness) is a fundamental and determining factor related to wheat(Triticum spp.) milling, baking and flour utilization.There are three kernel texture classes in wheat: soft and hard hexaploid(T.a...Kernel texture(grain hardness) is a fundamental and determining factor related to wheat(Triticum spp.) milling, baking and flour utilization.There are three kernel texture classes in wheat: soft and hard hexaploid(T.aestivum), and very hard durum(T.turgidum subsp.durum).The genetic basis for these three classes lies with the Puroindoline genes.Phenotypically, the easiest means of quantifying kernel texture is with the Single Kernel Characterization System(SKCS), although other means are valid and can provide fundamental material properties.Typical SKCS values for soft wheat would be around 25 and for durum wheat≥80.Soft kernel durum wheat was created via homeologous recombination using the ph1b mutation, which facilitated the transfer of ca.28 Mbp of5 DS that replaced ca.21 Mbp of 5 BS.The 5 DS translocation contained a complete and intact Hardness locus and both Puroindoline genes.Expression of the Puroindoline genes in durum grain resulted in kernel texture and flour milling characteristics nearly identical to that of soft wheat, with high yields of break and straightgrade flours, which had small particle size and low starch damage.Dough water absorption was markedly reduced compared to durum flour and semolina.Dough strength was essentially unchanged and reflected the inherent gluten properties of the durum background.Pasta quality was essentially equal-to-or-better than pasta made from semolina.Agronomically, soft durum germplasm showed good potential with moderate grain yield and resistance to a number of fungal pathogens and insects.Future breeding efforts will no doubt further improve the quality and competitiveness of soft durum cultivars.展开更多
Dear Editor,Genome editing has been widely applied in nuclei but not so in organelles such as the mitochondria and chloroplasts.The challenge for organelle genome editing is the limited accessibility of editing reagen...Dear Editor,Genome editing has been widely applied in nuclei but not so in organelles such as the mitochondria and chloroplasts.The challenge for organelle genome editing is the limited accessibility of editing reagents to the compartments of organelles(Zhu et al.,2020).Recently,fusion proteins of cytidine deaminase domain(DddAtox)and transcription activator-like effectors(TALEs)have been developed for DNA base editing in mitochondria of human cells and mice(Mok et al.,2020;Lee et al.,2021).展开更多
Dear Editor,Pan-genomes with high quality de novo assemblies are shifting the paradigm of biology research in genome evolution,speciation,and function annotation(Shi et al.,2023).An all-vs.-all comparison across assem...Dear Editor,Pan-genomes with high quality de novo assemblies are shifting the paradigm of biology research in genome evolution,speciation,and function annotation(Shi et al.,2023).An all-vs.-all comparison across assemblies potentially overcomes the limitation of mapping short reads to a single assembly in cataloging polymorphisms,especially large insertions and deletions(indels)contributing to phenotypic variations through altering gene structure or expression(Chen et al.,2021).展开更多
基金the financial support from FORMAS(2018-01029)the Swedish Institute(01132-2022)for supporting Ivan Motsnyi’s visit and research at Swedish University of Agricultural Sciences。
文摘Emerging new races of wheat stem rust(Puccinia graminis f.sp.tritici)are threatening global wheat(Triticum aestivum L.)production.Host resistance is the most effective and environmentally friendly method of controlling stem rust.The stem rust resistance gene Sr59 was previously identified within a T2DS 2RL wheat-rye whole arm translocation,providing broad-spectrum resistance to various stem rust races.Seedling evaluation,molecular marker analysis,and cytogenetic studies identified wheat-rye introgression line#284 containing a new translocation chromosome T2BL 2BS-2RL.This line has demonstrated broad-spectrum resistance to stem rust at the seedling stage.Seedling evaluation and cytogenetic analysis of three backcross populations between the line#284 and the adapted cultivars SLU-Elite,Navruz,and Linkert confirmed that Sr59 is located within the short distal 2RL translocation.This study aimed physical mapping of Sr59 in the 2RL introgression segment and develop a robust molecular marker for marker-assisted selection.Using genotyping-by-sequencing(GBS),GBS-derived SNPs were aligned with full-length annotated rye nucleotide-binding leucine-rich repeat(NLR)genes in the parental lines CS ph1b,SLU238,SLU-Elite,Navruz,and Linkert,as well as in 33 BC4F5progeny.Four NLR genes were identified on the 2R chromosome,with Chr2R_NLR_60 being tightly linked to the Sr59resistance gene.In-silico functional enrichment analysis of the translocated 2RL region(25,681,915 bp)identified 223 genes,with seven candidate genes associated with plant disease resistance and three linked to agronomic performance,contributing to oxidative stress response,protein kinase activity,and cellular homeostasis.These findings facilitate a better understanding of the genetic basis of stem rust resistance provided by Sr59.
基金supported by the U.S. Department of Agriculture, Agricultural Research Service (2090-22000018-00D)the Washington Grain Commission, USA (13C3061-5665)+2 种基金the Idaho Wheat Commission, USA (13C3061-5665 13C-3061-4232)The Fulbright fellowship
文摘Interactions of the stripe rust pathogen （Puccinia striiformis f. sp responses. Among various genes involved in the plant-pathogen related （PR） protein genes determine different defense responses tritici） with wheat plants activate a w^ae range OT nost nteractions, the expressions of particular pathogenesis-Different types of resistance have been recognized and utilized for developing wheat cultivars for resistance to stripe rust. All-stage resistance can be detected in seedling stage and remains at high levels throughout the plant growth stages. This type of resistance is race-specific and not durable. In contrast, plants with only high-temperature adult-plant （HTAP） resistance are susceptible in seedling stage, but become resistant when plants grow older and the weather becomes warmer. HTAP resistance controlled by a single gene is partial, but usually non-race specific and durable. The objective of this study was to analyze the expression of PR protein genes involved in different types of wheat resistance to stripe rust. The expression levels of 8 PR protein genes （PR1, PRI.2, PR2, PR3, PR4, PR5, PR9 and PRIO） were quantitatively evaluated at 0, 1, 2, 7 and 14 days after inoculation in single resistance gene lines of wheat with all-stage resistance genes YrTrl, Yr76, YrSP and YrExp2 and lines carrying HTAP resistance genes Yr52, Yr59, Yr62 and Yr7B. Races PSTv-4 and PSTv-37 for compatible and incompatible interactions were used in evaluation of PR protein gene expression in wheat lines carrying all-stage resistance genes in the seedling- stage experiment while PSTv-37 was used in the HTAP experiment. Analysis of quantitative real-time polymerase chain reaction （qRT-PCR） revealed that all of the PR protein genes were involved in the different types of resistance controlled by different Yr genes. However, these genes were upregulated at different time points and at different levels during the infection process among the wheat lines with different Yr genes for either all-stage resistance or HTAP resistance. Some of the genes were also induced in compatible interactions, but the levels were almost always higher in the incompatible interaction than in the compatible interaction at the same time point for each Yr gene. These results indicate that both salicylic acid and jasmonate signaling pathways are involved in both race-specific all-stage resistance and non-race specific HTAP resistance. Although expressing at different stages of infection and at different levels, these PR protein genes work in concert for contribution to different types of resistance controlled by different Yr genes.
基金supported by the USDA ARS CRIS Project (3072– 21000–009–00D)。
文摘Greenbug(Schizaphis graminum, Rondani) is a serious insect pest in many wheat growing regions and has been infesting cereal crops in the USA for over a century. Continuous occurrence of new greenbug biotypes makes it essential to explore all greenbug resistant sources available to manage this pest. Gb1, a recessive greenbug resistance gene in DS28A, confers resistance to several economically important greenbug biotypes and is the only gene found to be resistant to greenbug biotype F. A set of 174 F_(2:3)lines from the cross DS28A × Custer was evaluated for resistance to greenbug biotype F in 2020 and 2022. Selective genotyping of the corresponding F_(2) population using single nucleotide polymorphism(SNP) markers generated by genotyping-by-sequencing(GBS) led to the identification of a candidate genomic region for Gb1. Thus, SSR markers previously mapped in this region were used to genotype the entire F2population,and kompetitive allele specific PCR(KASP) markers were also developed from SNPs in the target region.Gb1 was placed in the terminal region of the short arm of chromosome 1A, and its location was confirmed in a second population derived from the cross DS28A × PI 697274. The combined data analysis from the two mapping populations delimited Gb1 to a < 1 Mb interval between 13,328,200 and 14,241,426 bp on1AS.
基金funded by the National Research Initiative Competitive Grants (2017-67007-25939) from US Department of Agriculture, the National Institute of Food and Agriculture。
文摘Wheat leaf rust is a prevalent foliar disease in wheat worldwide. Growing resistant cultivars is an effective strategy to minimize the impact of leaf rust on yield and grain quality. Lr42 is a leaf rust resistance gene identified from Aegilops tauschii and is still effective against current predominant leaf rust races in the United States and many other countries. In this study, we developed diagnostic DNA markers for Lr42 using the sequence polymorphisms of a differentially expressed gene(TaRPM1) encoding a putative NBARC protein in the Lr42 candidate region identified by RNA-sequencing of two near-isogenic lines contrasting in Lr42 alleles. Markers were designed based on a deletion mutation and a single nucleotide polymorphism(SNP) in the gene. Haplotype analyses of the newly developed markers in the three diversity panels demonstrated that they are diagnostic for Lr42, and superior to previously used markers in selection accuracy. These markers have the advantages of low cost and easy assay, and they are suitable for marker-assisted selection in breeding programs with either high-or low-throughput marker screening facilities.
基金supported by USDA-ARS CRIS project 3072-21000-009-00D。
文摘Greenbug(Schizaphis graminum Rondani)is a destructive insect pest that not only damages plants,but also serves as a vector for many viruses.Host plant resistance is the preferred strategy for managing greenbug.Two greenbug resistance genes,Rsg1 and Rsg2,have been reported in barley.To breed cultivars with effective resistance against various greenbug biotypes,additional resistance genes are urgently needed to sustain barley production.Wild barley accession WBDC053(PI 681777)was previously found to be resistant to several greenbug biotypes.In this study,a recombinant inbred line(RIL)population derived from Weskan×WBDC053 was evaluated for response to two greenbug biotypes(E and TX1)and genotyped using genotyping by sequencing(GBS).A set of 3347 high quality GBS-derived single nucleotide polymorphisms(SNPs)were then used to map the greenbug resistance gene in this wild barley accession.Linkage analysis placed the greenbug resistance gene in a 2.35 Mb interval(0-2,354,645 bp)in the terminal region of the short arm of chromosome 2H.This interval harbors 15 genes with leucine-rich-repeat(LRR)protein domains.An allelism test indicated that the greenbug resistance gene in WBDC053,designated Rsg2.a3,is likely allelic or closely linked to Rsg2.GBS-SNPs 2H_1318811and 2H_1839499 co-segregating with Rsg2.a3 in the RIL population were converted to Kompetitive allele specific PCR(KASP)markers KASP-Rsg2.a3-1 and KASP-Rsg2.a3-2,respectively.The two KASP markers can be used to select Rsg2.a3 and have the potential to tag Rsg2 in barley improvement programs.
文摘The bluestem gall midge (Stenodiplosis wattsii Gagné) is native to the grasslands of North America. It feeds on the developing seeds of warm-season grasses during a portion of its lifecycle, but little is known of the biology and extent of gall midge infestations in native warm-season grasses in the USA. We investigated the infestations of the bluestem gall midge in big bluestem (Andropogon gerardii Vitman), sand bluestem (Andropogon gerardii var paucipilus), little bluestem [Schizachyrium scoparium (Michx.) Nash], and indiangrass [Sorghastrum nutans (L.) Nash] commercial seed production fields during 2001 through 2004. Our objectives were to determine the annual production cycle of the bluestem gall midge, the range of the infestation in Nebraska, and estimate its impact on seed production. In eastern Nebraska, the midge goes through four generations with the fourth entering a larval diapause, overwintering in seeds and emerging in mid-June of the following year. The bluestem gall midge damaged from 31% of the little bluestem seed to 67% of the big bluestem seed, and, on average, reduced the production of viable seed by 54% across the four grass species in eastern Nebraska. Additionally, the warm-season prairie grasses were surveyed in nine other counties in Nebraska and the bluestem gall midge was found in each species surveyed from all nine counties. This study is the first to document the negative effects of the bluestem gall midge on the production of viable seed in sand bluestem and indiangrass.
文摘In addition to their value as cereal grains, wheat (Triticum aestivum L.) and triticale (× Triticosecale Wittmack) are important cool-season annual forages and cover crops. Yearling steer (Bos taurus) performance was compared in the spring following autumn establishment as for age cover crops after soybean [Glycine max (L.) Merr.] grain harvest. Replicated pastures (0.4 ha) were no-till seeded in three consecutive years into soybean stubble in autumn, fertilized, and grazed the following spring near Ithaca, NE, USA. Each pasture (n = 3) was continuously stocked in spring with four yearling steers (380 ± 38 kg) for 17, 32, and 28 d in 2005, 2006, and 2007, respectively. In 2005, average daily gain (ADG) for steers grazing triticale exceeded the ADG for wheat by 0.31 kghd<sup>-1</sup>d<sup>-1</sup>. In 2006, wheat ADG exceeded that for triticale by 0.12 kghd<sup>-1</sup>d<sup>-1</sup>. In 2007, steers grazing wheat lost weight, while steers grazing triticale gained 0.20 kghd<sup>-1</sup>d<sup>-1</sup>. Based on the 3-year average animal gains valued at $1.32 kg<sup>-1</sup>, mean net return ($ ha<sup>-1</sup> yr<sup>-1</sup>) was $62.15 for triticale and $22.55 for wheat. Since these grazed cover crops provide ecosystem services in addition to forage, grazing could be viewed as a mechanism for recovering costs and adds additional value to the system. Based on this 3-year grazing trial, triticale was superior to wheat and likely will provide the most stable beef yearling performance across years with variable weather for the western Cornbelt USA.
文摘Kernel texture(grain hardness) is a fundamental and determining factor related to wheat(Triticum spp.) milling, baking and flour utilization.There are three kernel texture classes in wheat: soft and hard hexaploid(T.aestivum), and very hard durum(T.turgidum subsp.durum).The genetic basis for these three classes lies with the Puroindoline genes.Phenotypically, the easiest means of quantifying kernel texture is with the Single Kernel Characterization System(SKCS), although other means are valid and can provide fundamental material properties.Typical SKCS values for soft wheat would be around 25 and for durum wheat≥80.Soft kernel durum wheat was created via homeologous recombination using the ph1b mutation, which facilitated the transfer of ca.28 Mbp of5 DS that replaced ca.21 Mbp of 5 BS.The 5 DS translocation contained a complete and intact Hardness locus and both Puroindoline genes.Expression of the Puroindoline genes in durum grain resulted in kernel texture and flour milling characteristics nearly identical to that of soft wheat, with high yields of break and straightgrade flours, which had small particle size and low starch damage.Dough water absorption was markedly reduced compared to durum flour and semolina.Dough strength was essentially unchanged and reflected the inherent gluten properties of the durum background.Pasta quality was essentially equal-to-or-better than pasta made from semolina.Agronomically, soft durum germplasm showed good potential with moderate grain yield and resistance to a number of fungal pathogens and insects.Future breeding efforts will no doubt further improve the quality and competitiveness of soft durum cultivars.
文摘Dear Editor,Genome editing has been widely applied in nuclei but not so in organelles such as the mitochondria and chloroplasts.The challenge for organelle genome editing is the limited accessibility of editing reagents to the compartments of organelles(Zhu et al.,2020).Recently,fusion proteins of cytidine deaminase domain(DddAtox)and transcription activator-like effectors(TALEs)have been developed for DNA base editing in mitochondria of human cells and mice(Mok et al.,2020;Lee et al.,2021).
基金supported by USDA-ARS In-House Project 2090-21000-033-00Dlowa State University Crop Bioengineering Center seed grantsupported by the USDA-ARS SCINet Postdoctoral Fellowprogram.
文摘Dear Editor,Pan-genomes with high quality de novo assemblies are shifting the paradigm of biology research in genome evolution,speciation,and function annotation(Shi et al.,2023).An all-vs.-all comparison across assemblies potentially overcomes the limitation of mapping short reads to a single assembly in cataloging polymorphisms,especially large insertions and deletions(indels)contributing to phenotypic variations through altering gene structure or expression(Chen et al.,2021).
