Proso millet
L.
is a warm season grass with a growing season of 60-100 days. It is a highly nutritious cereal grain used for human consumption, bird seed, and/or ethanol production. Unique ...characteristics, such as drought and heat tolerance, make proso millet a promising alternative cash crop for the Pacific Northwest (PNW) region of the United States. Development of proso millet varieties adapted to dryland farming regions of the PNW could give growers a much-needed option for diversifying their predominantly wheat-based cropping systems. In this review, the agronomic characteristics of proso millet are discussed, with emphasis on growth habits and environmental requirements, place in prevailing crop rotations in the PNW, and nutritional and health benefits. The genetics of proso millet and the genomic resources available for breeding adapted varieties are also discussed. Last, challenges and opportunities of proso millet cultivation in the PNW are explored, including the potential for entering novel and regional markets.
5-Enolpyruvylshikimate-3-phosphate synthase (EPSPS) is the sixth and penultimate enzyme in the shikimate biosynthesis pathway, and is the target of the herbicide glyphosate. The EPSPS genes of ...allohexaploid wheat (Triticum aestivum, AABBDD) have not been well characterized. Herein, the three homoeologous copies of the allohexaploid wheat EPSPS gene were cloned and characterized.
Genomic and coding DNA sequences of EPSPS from the three related genomes of allohexaploid wheat were isolated using PCR and inverse PCR approaches from soft white spring "Louise'. Development of genome-specific primers allowed the mapping and expression analysis of TaEPSPS-7A1, TaEPSPS-7D1, and TaEPSPS-4A1 on chromosomes 7A, 7D, and 4A, respectively. Sequence alignments of cDNA sequences from wheat and wheat relatives served as a basis for phylogenetic analysis.
The three genomic copies of wheat EPSPS differed by insertion/deletion and single nucleotide polymorphisms (SNPs), largely in intron sequences. RT-PCR analysis and cDNA cloning revealed that EPSPS is expressed from all three genomic copies. However, TaEPSPS-4A1 is expressed at much lower levels than TaEPSPS-7A1 and TaEPSPS-7D1 in wheat seedlings. Phylogenetic analysis of 1190-bp cDNA clones from wheat and wheat relatives revealed that: 1) TaEPSPS-7A1 is most similar to EPSPS from the tetraploid AB genome donor, T. turgidum (99.7 % identity); 2) TaEPSPS-7D1 most resembles EPSPS from the diploid D genome donor, Aegilops tauschii (100 % identity); and 3) TaEPSPS-4A1 resembles EPSPS from the diploid B genome relative, Ae. speltoides (97.7 % identity). Thus, EPSPS sequences in allohexaploid wheat are preserved from the most two recent ancestors. The wheat EPSPS genes are more closely related to Lolium multiflorum and Brachypodium distachyon than to Oryza sativa (rice).
The three related EPSPS homoeologues of wheat exhibited conservation of the exon/intron structure and of coding region sequence, but contained significant sequence variation within intron regions. The genome-specific primers developed will enable future characterization of natural and induced variation in EPSPS sequence and expression. This can be useful in investigating new causes of glyphosate herbicide resistance.
Microspore culture is used to generate completely homozygous plants in a single generation, thereby reducing cost and time required for the production of doubled haploid (DH) plants for breeding and ...genetic studies. Many factors are known to influence green plant recovery including composition of regeneration media, donor plant genotype, microspore developmental stage, and pretreatment conditions. The objectives of this study were to: (i) develop an improved regeneration medium for wheat microspore culture and (ii) determine the optimal pretreatment conditions and regeneration media combination for increasing green plant recovery rates. Four wheat cultivars, two pretreatment methods (0.4 M mannitol at 4°C and solution B containing 0.3 M mannitol with inorganic components at room temperature), and five regeneration media were tested. Green plant recovery rates from each treatment combination were analyzed using the Proc Logistic model in SAS. Regeneration medium fortified with ascorbic acid produced the highest number of green plants across the different pretreatment conditions, regeneration media, and cultivars tested. Pretreating wheat (Triticum aestivum L.) spikes with 0.4 M mannitol at 4°C followed by embryoid induction and regeneration in a medium fortified with ascorbic acid resulted in the recovery of the highest number of green plants. This high-efficiency method may prove useful for producing DH populations for wheat improvement efforts.
With 1 figure and 4 tables ABSTRACT: Grain protein concentration (GPC) impacts the end‐use quality of products made from flour extracted from wheat (Triticum aestivum L.) grain; therefore, it is a ...high priority in wheat improvement efforts. Recently, researchers determined that the Gpc‐B1 gene increases the rate of senescence in wheat, consequently increasing GPC. The objective of this study was to incorporate the Gpc‐B1 gene into regionally adapted hard red spring wheat cultivars ‘Tara 2002’ and ‘Scarlet’ to evaluate the impact of this gene under irrigated and rainfed production conditions. Three isogenic derivates with and three without Gpc‐B1 were evaluated in replicated field trials in Pullman, WA, in 2006 and 2007 in a split‐plot design, with genotype and production system as the main‐ and subplot factors, respectively. Increased senescence rates (1.8 days earlier; P = 0.03) were only detected for Tara 2002 isolines with the Gpc‐B1 gene in 2007 when averaged across irrigation conditions. Increased GPC (0.5%; P = 0.01) was only detected in Tara 2002 isolines with the gene in 2006, although no increases in senescence were detected. Significant (P < 0.01) decreases in grain weight were detected in both years for all isolines, whereas grain yields of the isolines did not differ significantly (P = 0.14). Significant (P < 0.02) differences in mineral content in Scarlet isolines also were identified. Differences in environmental conditions appear to impact the expression of the Gpc‐B1 gene, which may limit its utility as a breeding strategy for increasing GPC for spring wheat cultivars produced in regions with short growing seasons.
Glyphosate is a broad-spectrum herbicide used for the control of weeds in glyphosate-resistant crops. Glyphosate inhibits 5-enolpyruvyl shikimate 3-phosphate synthase, a key enzyme in the synthesis ...of aromatic amino acids in plants, fungi, and bacteria. Studies with glyphosate-resistant wheat have shown that glyphosate provided both preventive and curative activities against Puccinia striiformis f. sp. tritici and Puccinia triticina, which cause stripe and leaf rusts, respectively, in wheat. Growth-chamber studies demonstrated wheat rust control at multiple plant growth stages with a glyphosate spray dose typically recommended for weed control. Rust control was absent in formulation controls without glyphosate, dependent on systemic glyphosate concentrations in leaf tissues, and not mediated through induction of four common systemic acquired resistance genes. A field test with endemic stripe rust inoculum confirmed the activities of glyphosate pre- and postinfestation. Preliminary greenhouse studies also demonstrated that application of glyphosate in glyphosate-resistant soybeans suppressed Asian soybean rust, caused by Phakopsora pachyrhizi.
The necrotrophic root pathogens Rhizoctonia solani AG-8 and R. oryzae cause Rhizoctonia root rot and damping-off, yield-limiting diseases that pose barriers to the adoption of conservation tillage in ...wheat production systems. Existing control practices are only partially effective, and natural genetic resistance to Rhizoctonia has not been identified in wheat or its close relatives. We report the first genetic resistance/tolerance to R. solani AG-8 and R. oryzae in wheat (Triticum aestivum L. em Thell) germplasm 'Scarlet-Rz1'. Scarlet-Rz1 was derived from the allohexaploid spring wheat cultivar Scarlet using EMS mutagenesis. Tolerant seedlings displayed substantial root and shoot growth after 14 days in the presence of 100-400 propagules per gram soil of R. solani AG-8 and R. oryzae in greenhouse assays. BC₂F₄ individuals of Scarlet-Rz1 showed a high and consistent degree of tolerance. Seedling tolerance was transmissible and appeared to be dominant or co-dominant. Scarlet-Rz1 is a promising genetic resource for developing Rhizoctonia-tolerant wheat cultivars because the tolerance trait immediately can be deployed into wheat breeding germplasm through cross-hybridization, thereby avoiding difficulties with transfer from secondary or tertiary relatives as well as constraints associated with genetically modified plants. Our findings also demonstrate the utility of chemical mutagenesis for generating tolerance to necrotrophic pathogens in allohexaploid wheat.
Life skills, including conflict management, flexibility in response to change, and effective communication, are critical to success in college and career. Most university administrators and employers ...believe that students should learn foundational life skills in college, but for the most part universities do not explicitly teach these skills as part of the general undergraduate education experience. The goal of the present study was to examine whether personal development can be effectively fostered in a general education course. It reports on a theory-based course designed to increase leadership, adaptive coping skills, and mental well-being. It also demonstrates through a quasi-experiment that participation in this course is related to social and psychological outcomes such as increased adaptability to change and social integration. These skills will support students in being successful in college and beyond.
Damage caused by Hessian fly, Mayetiola destructor (Say), was quantified in spring wheat, Triticum aestivum L., trials near Pendleton and Moro, OR, during 2001 and 2002. Five field experiments were ...established to examine genetic resistance to Fusarium crown rot, Fusarium pseudograminearum (O’Donnell & Aoki), and economic damage by lesion nematode, Pratylenchus neglectus (Rensch, 1924) (Filipjev Schuurmanns & Stekhoven, 1941) and Pratylenchus thornei (Sher & Allen, 1941). Hessian fly became the dominant factor affecting grain yield in four experiments. Genotypes carrying the H3-resistance gene had grain yields 66 and 68% higher than susceptible genotypes in cultivar trials during 2001 and 2002, respectively. Yield reductions were detected when Hessian fly infestation rates exceeded 50% plants during 2001 and 15% plants (8% tillers) during 2002. In two trials during 2001, in-furrow application of aldicarb (Temik) at planting improved yields of four Hessian fly-susceptible cultivars by 72 and 144% (up to 1,959 kg/ha) and yields of one Hessian fly-resistant cultivar by 2 and 3%. Resistant cultivars and aldicarb improved grain quality as much as two market grades during 2001. The value of increased grain production with Hessian fly-resistant cultivars in four field experiments ranged from $112 to $252/ha, excluding price incentives for improved market quality. Yield reduction due to combined damage from Hessian fly and either Fusarium crown rot or lesion nematode was additive. This report seems to be the first quantitative yield loss estimate for Hessian fly in spring wheat in the semiarid environment of the inland Pacific Northwest.
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