Edamame (Glycine max (L.) Merr.), a specialty soybean prized for its nutritional value and taste, has witnessed a surge in demand within the U.S. However, subpar seedling stands have hindered its production potential, necessitating increased inputs for farmers. This study aims to uncover potential physiological factors contributing to low seedling emergence in edamame. We conducted comprehensive assessments on thirteen prominent edamame genotypes alongside two food-grade and two grain-type soybean genotypes, focusing on germination and emergence speed in both laboratory and field settings. Additionally, we employed single electrical conductivity tests and identified and quantified seed leachate components to distinguish among soybean types. Furthermore, using a LabField™ simulation table, we examined seed emergence across a wide soil temperature range (5°C to 45°C) for edamame and other soybean types. All seeds were produced under the same environmental conditions, harvested in Fall 2020, and stored under uniform conditions to minimize quality variations. Our findings revealed minimal divergence in emergence percentages among the seventeen genotypes, with over 95% germination and emergence in laboratory conditions and over 70% emergence in the field. Nonetheless, edamame genotypes typically exhibited slower germination speeds and higher leachate exudates containing higher soluble sugars and amino acids. Seed size did not significantly impact total emergence but was negatively correlated with germination and emergence speed, although this effect could be mitigated under complex field conditions. Furthermore, this study proposed differences that distinguish edamame from other soybean types regarding ideal and base temperatures, as well as thermal time. The finds offer valuable insights into edamame establishment, potentially paving the way for supporting local edamame production in the U.S.

Edamame (Glycine max (L.) Merr.) is a specialty soybean newly grown in the United States that has become the second most widely consumed soy food (25,000–30,000 tons annually). Poor crop establishment caused by soilborne diseases is a major problem limiting edamame production in the U.S. This study investigated 24 edamame cultivars/lines to determine their response to three soilborne pathogens causing seed rot and seedling damping off, including Rhizoctonia solani, Sclerotium rolfsii, Pythium irregulare, and Xanthomonas campestris pv. glycines, a seedborne pathogen that caused severe outbreaks of bacterial leaf pustules in mid-Atlantic regions in 2021. The hypothesis was that resistant variations existed among the genotypes, which could be used for production and future breeding efforts. The results reveal that all genotypes were affected, but partially resistant varieties could be clearly recognized by a significantly lower disease index (p < 0.05), and no genotype was resistant to all four diseases. Newly developed breeding lines showed overall higher disease resistance than commercial cultivars, particularly to R. solani and P. irregulare. This study found genetic variability in edamame, which can be helpful in breeding for resistance or tolerance to early-season diseases. The result will promote domestic edamame production and further strengthen and diversify agricultural economies in the U.S.

Vegetable seed production is critical to the success of an enterprise. The seeds produced must satisfy customer demands with the right quantities and quality of seed when needed. High-quality vegetable seeds must be germinable and exhibit high levels of vigor. The vegetable seed business is global. Seed crops must meet legal requirements in both the exporting and importing countries, labelling laws, laws protecting against the spread of diseases, insects, and weeds, be free of inert matter, while meeting standards for germinability. This chapter discusses best regions of the world for producing vegetable seeds, contracting with qualified growers, agronomic practices, optimizing pollination, considerations for growing biennial seed crops, monitoring seed development during production, pest management, and coordinating harvests.

Plant geneticists develop new vegetables cultivars using diverse technologies to combine beneficial traits into novel cultivars. After new genotypes are developed, evaluated, and deemed to express stable novel characteristics, they are given to seedsmen, the professionals in an organization in charge of mass-producing commercial quantities of seed, postharvest conditioning of seed in preparation for sale, and the application of seed treatments to enhance germination performance prior to sale. F-1 hybrid seed production strategies and benefits are explained. This chapter reviews sources of genetic variation and how novel genes can be combined using traditional and molecular breeding technologies to develop new cultivars. CRISPR, Agrobacterium, and ballistic genetic manipulation technologies are described and compared along with common terminology used to describe molecular biology.

Arthraxon hispidus is an introduced, rapidly spreading, and newly invasive grass in the eastern United States, yet little is known about the foundational biology of this aggressive invader. Germination responses to environmental factors including salinity, pH, osmotic potential, temperature, and burial depth were investigated to better understand its germination niche. Seeds from six populations in the Mid-Atlantic US germinated 95% with an average mean time to germination of 3.42 days of imbibition in the dark at 23°C. Germination occurred across a temperature range of 8-37°C and a pH range of 5-10 (≥83%), suggesting that neither pH nor temperature will limit germination in many environments. Arthraxon hispidus germination occurred in high salinity (342 mM NaCl) and osmotic potentials as low as -0.83MPa. The NaCl concentration required to reduce germination by 50% exceeded salinity concentrations found in soil and some brackish water saltmarsh systems. While drought adversely affects A. hispidus, 50% germination occurred at osmotic potentials ranging from -0.25 to -0.67 MPa. Given the climatic conditions of North America, drought stress is unlikely to restrict germination in large regions. Finally, emergence greatly decreased with burial depth. Emergence was reduced to 45% at 1-2 cm burial depths, and 0% at 8 cm. Emergence depths in concert with adequate moisture, germination across a range of temperatures, and rapid germination suggests A. hispidus' seed bank may be short-lived in moist environments, but further investigation is warranted. Given the broad abiotic tolerances of A. hispidus and a widespread native range, A. hispidus has the potential to germinate in novel territories beyond its currently observed invaded range.

Vegetable soybean or edamame is a specialty soybean (Glycine max (L.) Merr.). Unlike grain-type soybean (mainly for oil and source of protein in animal feeds), edamame pods are harvested at a green and immature stage, and beans are consumed by humans as a vegetable. While originally from China, edamame has recently gained much-increased popularity and expanded market needs in the US. However, domestic edamame production is limited in the US because at least 70% of the edamame consumed is imported. Poor seed germination and seedling emergence are one of the major problems in US edamame production. This review focuses on the introduction of edamame, a high-value niche crop, and its low emergence issue in production. Here, we provide a comprehensive exploration of the factors that influence edamame germination and emergence, including the intrinsic factors related to seeds (seed and seedling characteristics), and extrinsic factors related to the biotic (soil/seed-borne diseases) and abiotic (seedbed physical components as well as their interaction with climate) stresses. This information will help farmers and plant breeders to better understand the causes of the poor edamame emergence and may provide a foundation for improved field management of edamame, to increase production of this valuable specialty crop.

The sweet-basil (Ocimum basilicum L.) fruit/pericarp produces mucilage that engulfs the fruit and seed within minutes of hydration. Seed mucilage is produced by plant species that have adapted to arid, sandy soils. This study was conducted to determine how basil-seed mucilage improves ecological fitness. A second objective was to find ways to remove mucilage, which may interfere with commercial planting. Basil fruit/seeds were examined using light and environmental scanning electron microscopy. Columnar structures of basil mucilage rapidly unfolded from the pericarp upon initial hydration. Dilute hydrochloric acid removed the mucilage, which decreased the water content four-fold but did not inhibit seed germination in a laboratory test. Nondestructive Fourier-transform mid-infrared (FTIR) spectroscopy confirmed that the mucilage was primarily composed of hemicellulose that anchored the basil seed to resist movement. The fully hydrated seeds approached zero water potential, so the mucilage did not interfere with hydration. The seeds that were planted in growing media with mucilage had from 12 to 28% higher seedling emergence and survival percentages after 10 days than seeds without mucilage. Basil-fruit/seed mucilage provides a reservoir of loosely bound water at high water potential for seed germination and early seedling development, thus improving survivability under low moisture.

Extreme cold plays a key role in the range boundaries of plants. Winter survival is central to their persistence, but not all structures are equally susceptible to frost kill and, therefore, limiting to distributions. Furthermore, we expect intraspecific variation in cold tolerance both within and among tissue types. In a laboratory setting, we determined freezing tolerances of two overwintering propagule types – seeds and rhizomes – of the globally invasive Johnsongrass ( Sorghum halepense ), testing apparent emergence and electrolyte leakage as a proxy for cell death. We used 18 genotypes from agricultural and non-agricultural habitats spanning the climatic extremes occupied by Johnsongrass in the US. Single node rhizome fragments had an average LT90 of -5.1 °C with no significant variation based on home climate or ecotype. Seeds frozen at -85 °C suffered a decline in germinability to 10% from 25% at 22 °C. Population origin did not affect seed response to any temperature. However, non-agricultural seeds germinated more and faster than agricultural seeds from the coldest climates, with a reversed relationship among warmest origin seeds. Regardless of ecotype, seeds from the cold/dry and wet/warm sectors of Johnsongrass’s range germinated more and faster. Drastic differences in cold tolerance between seeds and rhizome and evidence for seeds’ local adaptation to land use and climate suggest that its spread is likely limited by winter rhizome survival, as well as adaptability of germination behavior to longer winters. These findings shed light on Johnsongrass’ dispersal dynamics and help identify future avenues for mechanistically understanding its range limitation.

Low tunnels (LTs) enhance vegetative growth and production in comparison with open field, but it is not known whether nitrogen (N) requirements and use efficiency increase or decrease for optimal crop performance. Therefore, the purpose of this study was to determine differences in N requirement, uptake, and use efficiency in basil grown under LTs compared with open field. The experimental design each year was a split plot with four replications. The main effect (plots) was N fertilizer application rate (0, 37, 74, 111, 148, and 185 kg·ha−1) and the secondary effect (subplots) was production system (LTs covered with spun-bonded rowcover vs. open field). Plant height and stem diameter were greater under LT than open field; however, they were unaffected by N fertilizer rate. Total fresh and dry weight increased with LT by 61% and 58% and by 50% and 48% in 2017 and 2018, respectively. Optimum N rates for fresh weight (98% of peak yield) were 124 and 104 kg·ha−1 N under LT and open field, respectively. Leaf N concentration decreased under LT, but total plant N uptake increased because of increased dry weight. Without fertilization, soil available N use efficiency (SNUE) for dry weight increased by 45% and 66% in 2017 and 2018, respectively. Mixed results were obtained for N fertilizer use efficiency (NFUE) in response to N rate. In conclusion, LT increased summer production of sweet basil, total plant N uptake, and SNUE.

Pepper (Capsicum annuum), as a warm-season crop, germinates poorly under wet and cold soils due in part to seed fungal diseases. The objective of this study was to test whether seed treatment with chitosan improved low temperature germination by increasing chitinase and glucanase activities. Pepper seeds were imbibed in 0.01, 0.05, 0.1, 0.3, and 0.5 % chitosan solutions, 1 % acetic acid, 1 % Benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole] fungicide, or hydroprimed in distilled water for comparison with dry-untreated seeds. After treatment, all seeds were slowly dried back to their original moisture content and evaluated for germination percentage, mean time to germination (MTG), seedling growth in a warm germination test and for seedling emergence in a standard cold test. Chitinase and glucanase activities were also measured for seeds after treatment and for germinating seedlings. Seeds treated with chitosan or hydroprimed germinated faster with decreased MTG compared to untreated seeds germinated at 25 degrees C and produced longer seedlings with greater fresh weights. Treatment of seeds with chitosan significantly improved final germination percentage by 8% in the second lab experiments (>= 90 %). Seed treatment with chitosan or hydropriming improved seedling emergence in the cold test by 29 %. Seed treatment with chitosan increased chitinase and glucanase activities in both seeds and seedlings compared to untreated seeds. In conclusion, treatment of pepper seeds with chitosan improved seed germination under wet and cold conditions, which might be due to the induction of systemic acquired resistance in seeds by increasing chitinase and glucanase activities. Greater chitinase and glucanase activities in chitosan-treated seeds might protect seedlings from fungal diseases under cold conditions.

Low tunnels covered with spun-bonded fabric (row covers) provide season extension for vegetable production and also afford a physical barrier against airborne insects and other non-soil pests. Brussels sprouts, Brassica oleracea L. group Gemmifera (Brassicaceae), is a popular vegetable in local markets in Virginia; however, unprotected field production is severely affected by insect pest infestation. This study's objective was to determine the level of protection low tunnels provide against insect infestation and leaf herbivory injury. The experiment was conducted at the Virginia Tech Eastern Shore Agricultural Research and Extension Center in Painter, Virginia. The experimental design was split-plot with polyethylene soil mulches (white or black) as whole plot factors and production systems (low tunnel or open field) as subplot factors. In this study, low tunnels reduced insect infestation and chewing herbivory leaf injury to Brussels sprouts. Compared to an unprotected open field, infestations of lepidopteran insects and harlequin bug, Murgantia histrionica (Hahn) (Hemiptera: Pentatomidae) were reduced on plants under low tunnels. However, aphids (Hemiptera: Aphidae) infestation occurred under low tunnels in fall. There was no effect of color mulches (white or black) and no interaction between tunnel and mulch color on insect infestation and chewing injury. Fewer insect infestations and feeding injury indicate that low tunnels can be an effective management tool for sustainable vegetable production.

Low phytic acid (LPA) soybean [Glycine max (L.) Merr] genotypes reduce indigestible PA in soybean seeds in order to improve feeding efficiency of mono- and agastric animals, but often exhibit low field emergence, resulting in reduced yield. In this study, four LPA soybean varieties with two different genetic backgrounds were studied to assess their emergence and yield characters under 12 seed treatment combinations including two broad-spectrum, preplant fungicides (i.e., ApronMaxx (mefenoxam: (R,S)-2-[(2,6-dimethylphenyl)-methoxyacetylamino]-propionic acid methyl ester; fludioxonil: 4-(2,2-difluoro-1,3-benzodioxol-4-yl)-1H-pyrrole-3-carbonitrile) and Rancona Summit (ipconazole: 2-[(4-chlorophenyl)methyl]-5-(1-methylethyl)-1-(1H-1,2,4-triazol-1-ylmethyl) cyclopentanol; metalaxyl: N-(methooxyacetyl)-N-(2,6-xylyl)-DL-alaninate)), osmotic priming, and MicroCel-E coating. Two normal-PA (NPA) varieties served as controls. Both irrigated and non-irrigated plots were planted in Blacksburg and Orange, Virginia, USA in 2014 and 2015. Results revealed that three seed treatments (fungicides Rancona Summit and ApronMaxx, as well as Priming + Rancona) significantly improved field emergence by 6.4–11.6% across all genotypes, compared with untreated seeds. Seed priming was negatively associated with emergence across LPA genotypes. Seed treatments did not increase the yield of any genotype. LPA genotypes containing mips or lpa1/lpa2 mutations, produced satisfactory emergence similar to NPA under certain soil and environmental conditions due to the interaction of genotype and environment. Effective seed treatments applied to LPA soybeans along with the successful development of LPA germplasm by soybean breeding programs, will increase use of LPA varieties by commercial soybean growers, ultimately improving animal nutrition while easing environmental impact.

Tobacco mosaic virus (TMV) is an extensively studied RNA virus known to infect tobacco (Nicotiana tabacum) and other solanaceous crops. TMV has been classified as a seedborne virus in tobacco, with infection of developing seedlings thought to occur from contact with the TMV-infected seed coat. The mechanism of TMV transmission through seed was studied in seed of the K 326 cultivar of flue-cured tobacco. Cross pollinations were performed to determine the effect of parental tissue on TMV infection in seed. Dissection of individual tobacco seeds into seed coat, endosperm, and embryo was performed to determine TMV location within a seed, while germination tests and separation of the developing seedling into seed coat, roots, and cotyledons were conducted to estimate the percent transmission of TMV. A reverse-transcriptase quantitative PCR (RT-qPCR) assay was developed and used to determine TMV concentrations in individual seed harvested from pods that formed on plants from TMV-infected and noninfected crosses. The results showed maternal transmission of TMV to tobacco seed and seedlings that developed from infected seed, not paternal transmission. RT-qPCR and endpoint PCR assays were also conducted on the separated seed coat, endosperm, and embryo of individual seed and separated cotyledons, roots, and seed coats of individual seedlings that developed from infected tobacco seed to identify the location of the virus in the seed and the subsequent path the virus takes to infect the developing seedling. RT-qPCR and endpoint PCR assay results showed evidence of TMV infection in the endosperm and embryo, as well as in the developing seedling roots and cotyledons within 10 days of initiating seed germination. To our knowledge, this is the first report of TMV being detected in embryos of tobacco seed, demonstrating that TMV is seedborne and seed-transmitted in flue-cured tobacco.