Brief Summary of Minutes of Annual Meeting

The 2017 meeting of the W3168 group followed a different format than usual because it was held in conjunction with one of the major committee-sponsored activities: the 12^th Triennial Conference of the International Society for Seed Science. This conference was organized by Prof. Kent Bradford in collaboration with members of W3168 who contributed both logistical and scientific support. As a consequence, the formal meeting of the committee only addressed general business issues since all the scientific activity was incorporated into the conference. The business meeting was held on Sunday, 10 September in the morning. 

The meeting was presided by Pablo Jourdan and called to order at 8:00 a.m. Following introduction of those present, the committee heard from Megan Haidet who recently joined NIFA from the BLM-SOS program. Megan has a strong interest in seeds and was very keen to participate in this meeting. Megan detailed various activities and initiatives at NIFA that may bear close relationship to seeds and the expertise of the committee. She indicated the possibility of using seeds of native species as a possible focus for research. Megan informed the group that NIFA is initiating a series stakeholder-wide listening sessions, seeking input on the challenges confronting agricultural systems in the broadest sense. She encouraged the group to participate and share any concerns about support for seed-centric research and development at NIFA

A discussion, led by Kent Bradford, followed on the proposal by Henk Hilhorst, editor of Seed Science and Technology to publish a special edition of the journal focused on short reviews on seed topics – these may or may not be related to the specific topics presented at the conference. W3168 members were encouraged to approach Henk about possible topics of interest.

The structure of the committee was also a topic of extensive discussion, emphasizing the concern about dwindling membership and the need to attract and encourage younger scientists to the group. Suggestions were made to reach out to more seed scientists at the Forest Service as well as at Botanic Gardens and Arboreta; however, since the group depends on Experiment Station support, it is going to be challenging to attract members from non-USDA-supported entities. It was also mentioned that there may be weed scientists with potential interest in the committee and we must make a greater effort to reach out to this group. One possible venue for expanding the membership is to work more closely with the seed-related sections of the Tri-Societies; these include C4 (seed production and technology), C7 (molecular biology) and C8 (plant genetic resources). Chris Walters, a member of W3168, is current chair of the C4 group and she will be approached to seed closer integration between the C4 section and W3168. 

A general concerned expressed by the committee is the continued decline in the specialization on seeds. There are few seed science courses at universities; there is a dearth of seed technologists. There is also concern that national review panels for grant proposals often lack knowledge of seeds and thus consider seed-centric research as less relevant. It was also noted that seed companies are really about breeding and not about seeds per-se, even though their principal products is seeds! Many problems related to seeds could be prevented if in breeding new cultivars, more attention is paid to seed attributes and quality early on. 

The leadership of the W3168 was established by consensus as follows: Secretary – Ramin Yadegary; Vice Chair (next meeting host) – Sabry Elias; President (chair of the next meeting): Robert Geneve. The next meeting is tentatively scheduled for summer of 2018 in Corvallis, OR. A focus for the 2018 meeting will be addressing the committee objectives in anticipation of the next re-write of the project. It was suggested that we also consider our 2019 meeting in conjunction with the Agronomy meetings to be held in mid-november in San Antonio. 

Although the scientific component of the meeting was part of the conference, there was a general discussion about different interests of the group such as seed germination studies specifically focused on the emergent controlled-environment production systems. There was also an interesting discussion about large-scale organic production research for corn, taking advantage of a mutation that provides enhanced seed vigor. A response to the lack of seed scientists could be the development of training grant proposals and it was suggested we make this an important topic for our next meeting. 

The meeting was adjourned at 11:30 a.m. 

A major accomplishment of the committee for this reporting period (through 9/30/2017) was organizing and co-hosting the 12^th Triennial Conference of the International Society for Seed Science with the Seed Biotechnology Center (SBC) of the University of California, Davis. Organizing this conference was one of the principal proposed activities for the W3168 committee. The conference was held September 10-15 in Monterey, CA. Taking place in the U.S. for the first time since 1989, the conference brought 180 attendees from 24 different countries and enabled top international seed scientists to share research findings and interact with the U.S. and California seed industry. According to conference organizer, W3168 member, and SBC’s Director Dr. Kent Bradford “The International Society for Seed Science is the sole professional and scientific organization dedicated to the scientific study of seed biology, technology, quality, ecology and conservation. Seed scientists play a critical role in enabling high crop yields, in providing high quality seeds for crop propagation and establishment, in controlling weeds and in preserving ecological diversity. In addition, more than 90% of global crop genetic resources are stored as seeds. Thus, seed science is a key component of agriculture’s goal of sustainably feeding the global population.” W3168 members were part of the scientific committee, assisted in raising funds to support undergraduate and graduate student participation, chaired all sessions, and presented numerous talks.

The accomplishments of researchers in individual states is presented below:
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Objective 1 - Identifying key factors involved in the enhancement or loss of seed quality. Seed development through post-harvest losses in storage. Specific topics include seed development, desiccation tolerance, and aging in storage 
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AZ (Yadegari): Our goal is to understand the regulatory mechanisms that underlie accumulation of storage proteins and starch during mid to late stages of endosperm development in maize. During the past year, we have developed a series of datasets related to the expression and function of Opaque-2 (O2), a bZIP transcription-factor protein that is known to regulate zein genes encoding the major seed storage proteins in maize endosperm. Our studies have uncovered the genes that are regulated directly or indirectly regulated by O2. Analysis of these gene sets indicate a broad role for O2 in endosperm metabolism and basic differentiation. A series of experiments to address this hypothesis are currently underway. <p>

CA (Bradford): We developed analysis methods to utilize single-seed respiratory data obtained through the ASTEC Q2 instrument in population-based threshold models. This quantitative analysis of the respiratory characteristics of seed populations enables labor-efficient monitoring of seed quality and new insights into seed germination, vigor, enhancement and aging. We worked with a seed technology company in 2016-2017 to test its applicability to corn (Zea mays) vigor testing and subsequent seed performance in the field. This could be a generally applicable vigor test, and efforts are being made to scale up the analysis system for greater throughput. <p>

Elevated seed moisture content due to insufficient drying is the major cause of seed deterioration, particularly in humid environments. When applied to food grains and commodities, drying and packaging (termed the “dry chain”) has the potential to greatly reduce postharvest loss and improve food safety by preventing accumulation of fungal toxins (e.g., aflatoxin) in storage. We have reviewed this field and written a review of strategies to dry and package seeds and dry commodities, particularly in humid regions (in review). We have developed a number of tools and methods to monitor seed/commodity moisture content and use desiccant-based drying followed by hermetic packaging to preserve viability/quality. <p>

FL (Perez): We evaluated the seed viability of the endangered Euphorbia deltoidea ssp. deltoidea. We collected data on the number of seeds from three populations that responded positively to biochemical viability assays. The majority of E. deloidea ssp. deltoidea seeds were filled and apparently fully developed. However, seed viability across populations did not exceed about 5%. Thus, we learned that populations of E. deloidea ssp. deltoidea display low seed viability. However, a seed developmental study would be helpful in determining viability and germination ability. <p>

KY (Downie): Working with colleagues from the Federal University of Sao Paulo, Jaboticaba, Brazil, we have investigated the probable cause of poor seed vigor in reciprocal hybrids of Zea mays (maize; Santos et al. 2017). This was in collaboration with a Brazilian subsidiary of Syngenta whose breeding lines these were. Occasionally, reciprocal crosses produce hybrid seeds with dramatically different seed vigors. This was the case in these two different breeding pairs from Syngenta. In both instances, a possible cause of the poor quality could be linked to greater amounts of reducing sugars in the maize kernels. <p>

The debate concerning whether raffinose or raffinose family oligosaccharides (RFO) assist seed viability or vigor has raged since the discovery of these soluble sugars. Using Zea mays (maize) as a model we have demonstrated that raffinose biosynthetic capacity enhances seed vigor (Li et al. 2017, provisional). We continue to use maize as a model using sugar feeding and mutagenesis to try and understand the implications of soluble sugar amount, identity, and balance on seed vigor. <p>

OH (Jourdan): The Ornamental Plant Germplasm Center’s seed research efforts emphasize areas that relate to seed quality, germination, and long-term storage of North American native wild species. We have been working primarily with seeds of perennial species of Phlox that are presenting significant challenges in terms of production, germination and potential for storage. After 3 years of intensive effort we have finally produced enough seed of different species to undertake more systematic studies on parameters that define seed quality, assessment of viability, and efficient germination systems. We have optimized the Tetrazolium test to get some indication of seed viability without relying on germination, as seeds have what appear to be non-deep physiological dormancy and require 2-3 months cold stratification for germination. A major problem is the extensive fungal contamination that is found in these seeds, even after surface-sterilization and/or treatment with various fungicides. The seeds are endospermic and the seed coverings appear to provide excellent substrate for fungal growth. Isolated embryos of most species germinate readily on 1% agar. However, the seeds do not respond to Gibberellic acid treatment by faster germination. We know the GA does get through the seed coverings as embryos isolated from seeds imbibed in 1000 ppm GA show the typical hyper-elongation of internodes. Thus, alternative treatments of whole seeds must be sought to expedite germination tests without the lengthy stratification period. Our progress to date has been possible through the interaction with W3168 colleagues such as Drs. Downie, Geneve, and Taylor who have provided helpful advice and suggested important experiments.

OR (Nonogaki): The genes, which were identified by RNA sequencing (RNA-seq) of NCED6 (nine-cis epoxycarotenoid dioxygenase 6: ABA biosynthesis gene)-inducible lines (described in the previous report), were characterized into details. DELAY OF GERMINATION1 (DOG1)-LIKE 4 (DOGL4), which was identified as an outstanding ABA-regulated gene by RNA-seq, has been particularly focused on during this reporting period. DOGL4-inducible lines have been created using the Plant Gene Switch System (PGSS) and another round of RNA-seq was performed. The sequencing results revealed that DOGL4 is a master regulator of seed storage proteins and has great potential to enhance quality of seeds as the final products in agriculture. An intergenic long non-coding RNA (lincRNA), which was also upregulated by NCED6 induction (termed N6LINCR1), was characterized. For N6LINCR1, a manuscript has been accepted and in press. The DOGL4 manuscript is being prepared in collaboration with the seed biology group at Wageningen University in the Netherlands. <p>

VA (Welbaum): We are studying fundamental aspects of Acidovorax citrulli-cucurbit interactions (bacterial fruit blotch) to elucidate the bacterial determinants that mediate host preferential association towards different cucurbits. The specific objectives of this research are to: (1) to investigate the susceptibility of different cucurbit species to group I and II strains of A. citrulli under field conditions during seed production; (2) to assess the contribution of type III effectors and other virulence factors to A. citrulli virulence and host preference in cucurbit fruit tissues and seeds; and (3) to characterize the mechanism of action of selected type III effectors. The work has provided evidence demonstrating the optimization of a new assay based on surface inoculation of detached melon fruits. We are providing insights into the mechanisms involved in host preferential association in the A. citrulli-cucurbit pathosystem, and developing new strategies for bacterial fruit blotch management through improved screening techniques. <p>

Objective 2 - Eliminating seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment. Pre-mature sprouting in cereals and other species and the identification dormancy mechanisms to manipulate germination. 
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CA (Bradford): In work conducted in collaboration with the West Coast Metabolomics Center at UC Davis and funded by the American Seed Research Foundation, we characterized the metabolites and storage compounds present in dry and imbibed lettuce (LACTUCA SATIVA) seeds. Several hundred compounds were identified, including small molecules and metabolites, phospholipids and triacylglycerol storage lipids. In addition, we assessed the effects of high temperature and ABA on germination, respiration and metabolites. The work provides a view into how temperature stress can affect respiration and storage reserve mobilization in seeds. This work is described in the PhD dissertation of D. Ardura (2017) and is in preparation for publication. <p>

Seeds of many species are photoblastic, or require light in order to germinate. This can create problems for seed performance, such as for pelleted seeds that require prior hydration and exposure to light in order to germinate. We identified a quantitative trait locus (QTL) associated with dark inhibition of germination in lettuce (LACTUCA SATIVA). Within this QTL is a gene encoding LsGA2ox2. Through gene expression and transgenic experiments, we demonstrated that this gene is a likely candidate gene for this QTL. When it is expressed, GA2ox2 enzyme inactivates gibberellin and prevents germination. Conserved SNPs in its promoter disrupt an ABA-responsive element, transfer of which is sufficient to control germination in the dark. This work is described in the dissertation of M. Niroula (2017) and is in preparation for publication. <p>

OR (Nonogaki): This project had developed a technology, which imposes hyperdormancy through enhanced ABA production and prevents precocious seed germination, such as preharvest sprouting (PHS). As a next step, the germination recovery strategy through expression of ABA counteracting genes, such as GA biosynthesis gene or NCED RNAi was proposed (see previous report). Another germination recovery strategy, through a chemical biology approach, was tested in this reporting period. Application of 3′-hexylsulfanyl-ABA (AS6), an ABA antagonist, was sufficient to recover germination from our inducible hyperdormant seeds. While ABA biosynthesis was still enhanced in the hyperdormant seeds, AS6 caused temporal ABA insensitivity in seeds, which released deep dormancy. These results demonstrate that chemical biology approaches have great potential to eliminate constraints for seed production and germination in agriculture. Combination of hyperdormancy and germination recovery will establish a comprehensive technology for PHS prevention for cereals. <p>

• SD (Gu): Completed cloning and molecular characterization of the seed dormancy loci qSD12. This was a continuous project funded by NSF grants. All candidate genes were confirmed by complementation for function of seed dormancy. Data from a series of research will be released as publications late this to early the next year. <p>
• Completed an initial experiment to evaluate effects of seed dormancy genes on seedbank longevity. A set of 16 isogenic lines of rice for 4 seed dormancy loci were evaluated for primary dormancy under controlled conditions and also evaluated for seed survivability in soil of a rice field for 7 months from early October to later April the next year. A significant, moderate level of correlation was detected between seed dormancy and seedbank longevity. All these four genes have main and epistatic effects on seed survivability in soil. This would be the first time that relates seed dormancy genes with seedbank longevity. 
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Objective 3 - Enhancing seed vigor and germination in agronomic and other species for improved stand establishment. The emphasis of this objective is on post-harvest technologies. 
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CA (Bradford): Seed priming (hydration and drying) is used to enhance seed germination and improve stand establishment. We conducted research on seed priming treatments to understand why such treatments can shorten seed longevity and tested some post-priming treatments reported to restore much of the lost storage potential. While we could easily demonstrate a loss of tomato (Solanum lycopersicum) seed storage longevity after priming, none of the post-priming treatments we tested were effective in restoring longevity (Li, 2017). 
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FL (Perez): Germination ability of Euphorbia deltoidea ssp. deltoidea was also investigated at various simulated seasonal temperatures. Next, we studied the germination response of Linum arenicola. Finally, we investigated the germination ecology of developing Harperocallis flava seeds. All study species are rare and listed as endangered. We collected data pertaining the germination ability of: a) L. arenicola seeds following exposure to a series of constant and simulated seasonal temperatures and b) H. flava seeds following exposure to conditions of low relative humidity and simulated seasonal temperatures. Germination of L. arenicola seeds was delayed for up to 16 days and final percentage varied between 0-4% at simulated winter, spring, and summer temperatures. However, germination increased to about 33% at simulated fall temperatures. In contrast, germination was comparably rapid at constant temperatures. Germination commenced by day 1 under these conditions. Final germination ranged between 28 and 38%, with most germination taking place at constant 29°C. Seeds of H. flava are viable and appear under-developed. Germination is induced at all seasonal temperatures. However, more rapid and complete germination was observed at simulated winter temperatures. Final germination ranged from 5% at simulated summer temperatures to 77% at simulated winter temperatures. Seeds of H. flava germinated to about 24-80% following exposure to 0.5 to 90% relative humidity. 4) Key outcomes or other accomplishments realized – We learned that germination of L. arenicola seeds appears inhibited at alternating temperatures. However, germination progresses rapidly under constant temperatures. Alternatively, seeds of H. flava may possess morphological dormancy and, contrary to anecdotal evidence, have a high capacity for germination. Seeds appear to display some tolerance to high levels of desiccation, which would be an advantage in terms of ex situ conservation. However, testing the desiccation tolerance of mature seeds may provide further insight related to storage under genebank standards. 
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KY (Downie): In so far as Arabidopsis thaliana is a “native species” somewhere on the planet, we have reported on a gene, previously misannotated, that enhances the completion of seed germination of seeds when overexpressed (Majee et al. 2017). The product produced from the gene of interest somehow plays a role in phytochrome-mediated light signaling in both the completion of germination and hypocotyl elongation. 
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KY (Geneve): The audience for this project includes private and public seed technologists, seed producers and seed scientists. During the reporting period, invited presentations related to this project were made at the 12^th International Society for Seed Science: Seeds as Systems meeting in Monterey, California and the International Plant Propagator’s Society meeting in Tzaneen, South Africa. As a result of these meetings, a review manuscript was submitted to Seed Science Research describing the importance of water gap complexes for controlling physical seed dormancy as well as a proceedings paper related to the impact of seed technology on germination of commercially important horticultural crops. 
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MT (Stougaard): Falling numbers tests were performed on a set of 18 private spring wheat varieties that are typically marketed in the Pacific Northwest. Entries included materials from Syngenta, Monsanto, Limagrain and Winfield United. Two public varieties from Montana State University were included for comparison. Falling numbers were high and all entries avoided dockage this year. The average falling number for the nursery was 426 seconds. Egan had the highest falling number at 470 while Vida had the lowest at 362. 
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A separate experiment was conducted to determine the effect of plant population of falling numbers. Six spring wheat varieties were planted at four densities as a complete factorial treatment design. Egan, Expresso, Solano, Soren, Tyra and Vida were planted at densities of 172, 258, 344, and 430 plants/m². High temperatures and drought typified this season. Falling numbers were high and averaged 396 seconds. The main effect of variety was significant. Egan had the highest at 460 while Tyra had the lowest at 364 seconds. Although falling numbers varied among varieties, the main effect of plant density was nonsignificant and had no effect on the results. 
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NY (Taylor): A novel method was developed of using plant-derived protein hydrolysates as seed coating materials. The objective of this study was to develop seed coating formulations using soy flour, a sustainable, inexpensive, and green source, as a biostimulant using broccoli as the model system. A 10% suspension of soy flour was used as the seed treatment binder in all coatings. The solid particulate filler was composed of mixtures of soy flour, cellulose, and diatomaceous earth, together termed as SCD. All SCD components were homogenized in water, then dried and ground to a fine particle size <106 mm. The SCD coatings were applied with rotary pan seed coating equipment at 25% of the seed weight. Increasing the proportion of soy flour increased the seed coating strength and also the time for the coating to disintegrate after soaking in water. As a result, the seed coatings reduced the percentage germination and the germination rate compared with the nontreated control. However, the 10-day-old seedling root and shoot growth showed significant improvement for all SCD coating treatments compared with controls. Plant growth and development was also measured after 30 days in the greenhouse. Fresh weight (FW) and dry weight (DW), leaf area, plant height, leaf development, Soil-Plant Analyses Development (SPAD) index (chlorophyll measurement), and nitrogen (N) per plant were all greater from coatings with 30%, 40%, and 50% soy flour than the noncoated control. Nitrogen, from the soy flour applied in the seed coatings, ranged from 0.024 to 0.073 mg per seed, while the enhanced N per plant ranged from 1.7 to 8.5 mg. The coating treatment with 0.063 mg N per seed resulted in the greatest plant leaf area and highest N content. Nitrogen applied in the seed coating only accounted for 1% to 2% of the enhanced N in the plants, indicating the soy flour acted as a biostimulant rather than a fertilizer. 
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Systemic seed treatment uptake into soybean and corn seeds during imbibition has not been investigated over a broad range of application rates. The objectives of this study were to investigate application dosage rates on uptake, to assess the role of the seed coat on uptake and determine the dosage for greatest uptake efficiency. The model fluorescent tracer compound, coumarin 120, 7-Amino-4-methylcoumarin was applied as a seed treatment in the range of 0.01 to 20.0 mg g^-1 seed to study the dose effects on seed uptake of corn lines ‘OH7B’ and ‘B73’, and soybean varieties ‘TMG 312RR’, ‘IAR 1902’, and a blacked-seeded ‘V12-1223’. The uptake by two lines of corn seeds and three varieties of soybean seeds showed a dose dependent process that was described by an exponential model of Y = (r² ³ 0.93), where y₀ is the uptake limit. In general, there was a large increase in seed uptake as dosage increased, followed by a saturated state at higher dosages. The uptake limit (y₀) differed between the two corn lines and the three soybean varieties. The maximum uptake efficiency or recovery of applied coumarin 120 was at 0.1 mg g^-1. The pericarp/testa of both corn lines and the testa of black-seeded soybean variety ‘V12-1223’, attenuated the uptake in comparison with decoated seeds of each line/variety. Results from this study have implications on the effect of application rate on seed treatment efficacy and phytotoxicity. 
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Systemic uptake of organic compounds from roots to leaves follows a Gaussian distribution in relation to the lipophilicity, as measured by the log Kow. Quantification of compound uptake with different lipophilicity, and applied as a seed treatment that diffused through the seed coat into the embryo during imbibition has not been reported. The objective of this investigation was to quantify the uptake of nonionic compounds in soybean (Glycine max) and corn (Zea mays). A series of fluorescent piperonyl amides were synthesized and a novel combinatorial pharmacokinetic technique was developed that provided a range of compounds from log Kow 0.02 to 5.7. Seeds were treated with a mixture of amides, imbibed and compounds chemically extracted and quantified by HPLC using a fluorescence detector. The maximum uptake efficiency of the applied amide mixture from whole soybean and corn seeds was 67% at log Kow 2.9, and 43% at log Kow 3.4, respectively. The critical partition coefficient for uptake for both species was <4.2 log Kow. Seeds were dissected and separated as soybean embryo and testa, and corn internal tissues (embryo + endosperm) or seed covering layers (pericarp + testa), and >75% of the amides were found in the soybean embryo or corn internal tissues compared to the covering layers at log Kow <4.2. The distribution of amides showed that corn seed covering layer had similar hydrophilic/lipophilic properties as internal tissues, while soybean tissues had different hydrophilic/lipophilic properties. Collectively, the Gaussian uptake pattern for systemic uptake into plants was not found for either seed species. 
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TX (Leskovar): Plant growth regulators (PGRs) can positively regulate seed germination and/or root growth and development. Research with PGRs in onion showed ethephon to be beneficial in increasing seedling root surface area but reduced root length. The addition of IAA and/or tZ could potentially control the reductions in root length and diameter in response to ethephon, while combining tZ and ACC can increase root length. Another study assessed the impact of lignite-derived humic substances (HS) on pepper transplant root traits, shoot growth and physiology exposed to water stress. A new study was initiated to evaluate the grafting technology and physiological mechanisms underlying drought tolerance in tomato grafted plants using different Solanum spp. rootstocks. 
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VA (Welbaum): Standardized germination testing in a laboratory under controlled conditions by placing seeds in rolled paper towels at an optimum temperature. We have developed a new laboratory analysis system called Lab FieldÔ for standardized, realistic seed germination testing in field soils (Welbaum, 2017b). This system provides a more accurate assessment of viability by subjecting seeds to biotic stresses. The Lab FieldÔ was created by welding thin vertical aluminum strips to the face of a thermogradient table while adding micro-irrigation, drainage and LED grow lights, to create a soil environment that can be adjusted to mimic a wide range of field conditions in a laboratory. This allows for realistic seed testing that more accurately predicts how seeds will perform in production fields.

Fast germination and vigorous early seedling growth are essential for establishment of pepper (Capsicum annuum), a warm-season crop that germinates poorly under cold conditions. We have developed a novel seed treatment that exposes seeds to “nano” sized chitin molecules created by hydrolysis of chitosan during controlled seed hydration. Effects of hydropriming, nanochitin, and chitosan treatments on ‘California Wonder’ bell pepper were compared for seed germination percentage and mean time to germination (MTG) in soil at 19, 22, 26 and 30°C on a thermogradient table (Welbaum, 2017b). Treatments with nanochitin or hydropriming reduced MTG to 4.9-5.3 days compared with 5.4-6.7 days for other treatments or untreated seeds at 25°C on blotter paper in a standard germination test. Nanochitin, chitosan, acetic acid or hydropriming treatments enhanced low temperature emergence compared with standard Captan fungicide treated or untreated seeds. Treatments with 0.05% nanochitin or hydropriming improved seedling emergence at 19 to 30°C. Hydroprimed seeds germinated faster with improved emergence similar to nanochitin, but nanochitin also visibly reduced fungal growth on the seeds (Samarah et al., 2016). 
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Impact Statements: 
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Objective 1 - Identifying key factors involved in the enhancement or loss of seed quality. Seed development through post-harvest losses in storage. Specific topics include seed development, desiccation tolerance, and aging in storage 
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AZ (Yadegari): A detailed description of endosperm development will provide a roadmap to develop strategies for enhancing seed quality in maize and related crops. Our analysis of the role of Opaque-2 in endosperm development is expected to identify some key processes that can inform research activities in seed quality and germination in grain seeds. 
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CA (Bradford): A close correlation between single-seed respiration data acquired with the Q2 instrument and germination rates creates an efficient automated method for a seed vigor assay. The Q2 instrument is being modified for scale-up to enable use as a general seed vigor test.

Desiccant-based drying systems enable seed drying even in humid environments. Combined with hermetic packaging, this “dry chain” would largely prevent the rapid loss of viability in warm, humid climates. Similarly, it would prevent damage to stored grains due to molds and insects. Desiccant-based drying systems followed by packaging could have a significant impact on food safety and security in tropical regions. 
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FL (Perez): The impact of our research is that restoration practitioners and seedling producers can better plan and coordinate in terms of seeding activities for restoration and conservation of natural resources. Similarly, conservation practitioners can adapt methods for ex situ activities. We also developed targeted research programs that enhance the wildflower seed industry. 
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KY (Downie): Based on the response from the industry to the publication (Santos et al. 2017), there exists a fair number of parental lines where a cross in one direction produces seed of acceptable quality while the reciprocal cross produces sub-standard seed quality, sometimes, drastically so.

Seed Science; Findings from Sao Paulo State University Broaden Understanding of Seed Science (Reciprocal effect of parental lines on the physiological potential and seed composition of corn hybrid seeds). Agriculture Week, Sep 21, 2017, p.106. 
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We have established that the response of plant seeds to RFO is amazingly complex depending on whether they accumulate raffinose only (maize) or higher order RFO as well (Arabidopsis). This information may explain why there have been very few publications on the effect of over-expression of RAFFINOSE SYNTHASE or other genes whose transcripts product higher order RFOs while the number of publications over-expressing GALACTINOL SYNTHASE abound. In the first instance the influence on soluble sugar profiles and seed vigor were contrary to our expectations while over expression of GALACTINOL SYNTHASE has universally enhanced the amounts of RFOs and positively influenced seed vigor. 
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OH (Jourdan): The most efficient way to capture and conserve genetic diversity of native wild species is through seeds. To achieve this in the 25 or so species of Phlox in the germplasm collection at the OPGC, we must be able to produce or obtain seeds of high quality that have the potential for long term storage. Our studies on seed quality parameters of Phlox are providing information that will help us devise strategies to produce the kinds of seeds that can be stored and thus conserve important genetic diversity. In addition, we can make this diversity available to breeders for the development of new cultivars that can be used in diverse constructed landscapes and provide economic benefits to growers and landscapers. 
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OR (Nonogaki): The discovery of DOGL4 as a master regulator of seed storage proteins and (possibly lipids) provides great potential of crop modification through the manipulation of this gene, which is currently examined in legumes and cereal crops. 
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VA (Welbaum): Research on the epidemiology of bacterial fruit blotch disease has elucidated the A. citrulli virulence genes as well as resistance genes in Cucurbit species. These discoveries will enable novel genetic approaches to control this economically important disease through continuing collaborative research. 
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Objective 2 - Eliminating seed dormancy as a constraint during seed production and germination in agronomic seed production and ecological/biomass seed establishment. Pre-mature sprouting in cereals and other species and the identification dormancy mechanisms to manipulate germination. 
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CA (Bradford): Some seed components, such as raffinose or stachyose, are thought to be involved in seed desiccation tolerance and longevity. How seeds preserve or resynthesize these compounds during hydration and dormancy could reveal mechanisms for seed preservation or elimination of dormancy (e.g., to control weed seed banks). Studies of the metabolism of germinating and dormant seeds are a path to such information. 
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In genetic and transgenic studies, we identified a gene encoding a gibberellin-inactivation enzyme (GA2ox2) as a key regulator of the light requirement for germination of lettuce seeds. As specific sequences in the promoter of this gene were responsible for this effect, gene editing could be used to transfer the ability to germinate in the dark to different varieties and species. 
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OR (Nonogaki): The PHS prevention/germination recovery system has direct impacts on food production when translated to crops species. The system is being introduced to cereal crops through international collaboration. 
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Objective 3 - Enhancing seed vigor and germination in agronomic and other species for improved stand establishment. The emphasis of this objective is on post-harvest technologies. 
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CA (Bradford): Seed priming enhances germination in the short term, but often reduces the potential seed storage life. Studies were proposed to identify the molecular and biochemical basis of this effect and of the restoration of longevity by post-priming treatments. However, we were unsuccessful in identifying effective longevity-restoring treatments. Thus, the search for the basis of this effect will continue. 
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The 12^th Triennial Conference of the International Society for Seed Science enabled international scientists to network with W3168 members and seed industry representatives in California. 
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KY (Downie): Demonstrating that the protein encoded by a gene present in Arabidopsis is responsible for allowing faster completion of germination when overexpressed focused our attention on a region of the Arabidopsis genome that was poorly annotated. Deconvolution of the locus responsible has focused our attention on an F-BOX protein as a positive influence on the completion of seed germination through its presumptive targeting of a negative regulator of seed germination that operates through phytochrome. 
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KY (Geneve): Hemp (Cannabis sativa) is a relatively new crop for U.S. and Kentucky. Cardinal temperatures were established for germination of several potentially important seed cultivars for Kentucky. Optimal germination occurred between 17 and 25C with a lower temperature threshold at 3C and upper limit at 42C. A putative thermal time model was developed that described progress to germination for temperatures between 13 and 30C. These data provide growers with the information required for determining temperature permissive times for optimal spring germination and establishment of hemp. 
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MT (Stougaard): Screening public and private wheat varieties for falling number will allow for the compilation of a data base which will aid producers in selecting the most appropriate cultivar for their area. This will help in avoiding dockage penalties and at the same time increase economic returns. Similarly, understanding how basic cultural practices, such as seeding rates, influence falling numbers will provide additional opportunities to avoid dockage penalties and help to understand the mechanisms affecting seed dormancy. 
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NY (Taylor): A novel seed coating method was developed at Cornell by using soy-flour, a sustainable, inexpensive and green source, as a biostimulant using tomato and broccoli. Seedling shoot length, seedling growth uniformity, seed vigor index and seedling biomass were greater from coated seed than the noncoated control for both crops. Nitrogen applied in the seed coating only accounted for 1%to 2% of the enhanced N in the plants, indicating the soy flour acted as a biostimulant rather than a fertilizer. Plant proteins applied in the seed coating can improve early vegetable crop growth and uniformity. 
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TX (Leskovar): Exogenous PGRs could be useful to enhance germination, root length and surface area of onion seedlings. In addition seed hydro-priming was a simple and viable method to improve onion germination and root traits. These improvements are important since bulb development, uniformity and final size are greatly affected by the time spread of seedling emergence during early establishment. Humic substances applied to soil media rapidly decreased leaf stomatal conductance and transpiration in bell pepper transplants, suggesting that HS transiently ameliorated plants exposed to water stress by reducing moisture losses, which is critical when peppers are established in hot and dry environments.

From the grafted project on Solanum spp. we expect to provide growers with recommendations for best scion/rootstock combinations for use in open field and protected culture in Texas. We also expect to identify rootstocks and germplasm lines with improved biotic and abiotic stress tolerance.

Results from the studies conducted during the project duration on PGRs and humic substances were presented at annual meetings of the Plant Growth Regulator Society of America (Anchorage, AK), Southern Region of the American Society of Horticultural Sciences (Mobile, AL) and Agronomy (Tampa, FL). Similarly, partial results from the tomato grafted projects were presented in trainings, workshops and field days attracting +200 participants that represented small- and large-scale vegetable growers, as well as retailers interested in the production of home-grown tomato in Texas. 
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VA (Welbaum): Our new Lab FieldÔ is being adapted by seed companies to provide a more accurate assessment of seed quality. The Lab FieldÔ system will enable more realistic predictions of how seeds will perform in field soils and help in the development of new treatments to enhance seed vigor and improve field performance. 
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Seed hydropriming enhances germination of pepper seed germination although often reducing the potential seed storage life. Our novel nanochitin treatment appears to naturally increase plant disease resistance by stimulating system natural acquired resistance mechanisms in seeds. Nanochitin treatment will increase seed and seedling disease resistance through preplant seed treatments. Since the treatment uses only natural materials, it may improve plant disease resistance for organic production. 
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Adegbola, Y.A. and Pérez, H.E. 2016. Extensive desiccation and aging stress tolerance characterize Gaillardia pulchella (Asteraceae) seeds. HortScience. 51: 159-163. 
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Amirkhani, M., S. A. G. Avelar, A. R. Quere-Carrillo, and A. G. Taylor. 2016. The effect of film coating on Sideoats grama “Bouteloua curtipendula”. 10^th International Rangeland Congress. Saskatchewan, Canada. 10: 727-729. 
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Amirkhani, M., A. N. Netravali, Huang, W., and A. G. Taylor. 2016. Investigation of soy protein based biostimulant seed coating for broccoli seedling and plant growth enhancement. HortScience: 51(9): 1121–1126. doi: 10.21273/HORTSCI10913-16 
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Amirkhani, M., A. N. Netravali, and A. G. Taylor. 2016. Using sustainable plant based biostimulant resins and fibers for seed coating. Crops & Chemicals USA, Raleigh, NC, USA. 
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Ardura, D. (2017) Mass spectrometry-based metabolomics applied to plant chemotaxonomy and to thermoinhibition of germination in lettuce (Lactuca sativa) seeds. PhD disseratation, University of California, Davis. 
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Avelar, S.A.G., M. Amirkhani, A. G. Taylor. 2016. Upgrading seed quality. Revista Seed News: 20 (3): 8-12. ISSN: 1415-0387. http://store.seednews.inf.br
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Avelar, S.A.G., D. Yang, M. Amirkhani, and A. G. Taylor. 2016. Soybean seed coat permeability: water imbibition rate and fluorescent tracer uptake. Conference Paper. December 2016. American Seed Trade Association (ASTA), Chicago, IL, Volume: 71st Corn & Sorghum Seed Conference, 46th Soybean Seed Conference, Seed Expo. 
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Bewley, JD, Nonogaki H. Seed maturation and germination. Reference Module in Life Sciences, Elsevier, Oxford, accepted. 
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Geneve, R.L., D.F. Hildebrand, T.D. Phillips, M. AL-Amery and S.T. Kester. 2017. Stress influences seed germination in mucilage-producing chia. Crop Science 57:2160-2169. 
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Geneve, R.L., E.W. Janes and S.T. Kester. 2017. Cardinal temperatures and thermal time for seed germination of industrial hemp. Combined Proceedings International Plant Propagators’ Society 66:325-329. 
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Genna, N.G. and Pérez, H.E. 2016. Mass-based germination dynamics of Rudbeckia mollis (Asteraceae) seeds following thermal and ageing stress. Seed Science Research. 26: 231-244. 
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Li, Z. (2017) Seed priming and post-priming treatment effects on germination rates and longevity. MS thesis. University of California, Davis. 
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Majee Manoj, Wu Shuiqin, Salaita Louai, Gingerich Derek, Dirk Lynnette M.A., Chappell Joseph, Hunt Art G., Vierstra Richard, Downie A. Bruce. 2017. A misannotated locus positively influencing Arabidopsis seed germination is deconvoluted using multiple methods, including surrogate splicing. Plant Gene. 10: 74-85. 
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Niroula, M. (2017) Environmental sensitivity of quantitative trait loci for seed germination and flowering time in lettuce (Lactuca sativa L.). PhD dissertation, University of California, Davis. 
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Nonogaki H. 2017. Seed biology updates - highlights and new discoveries in seed dormancy and germination research. Frontiers in Plant Science 8:524. doi: 10.3389/fpls.2017.00524. 
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Nonogaki M, Nonogaki H. 2017. Prevention of preharvest sprouting through hormone engineering and germination recovery by chemical biology. Frontiers in Plant Science 8:90. doi: 10.3389/fpls.2017.00090. 
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Nonogaki M, Nonogaki H. 2017. Germination. In B. Thomas, B. G. Murray, D. J. Murphy eds, Encyclopedia of Applied Plant Sciences, Vol. 1, Waltman M. A.,Academic Press, pp. 509-512. 
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Nonogaki M, Nonogaki H. 2017. Seed dormancy through enhanced ABA biosynthesis and germination recovery by ABA antagonists. Plant Biology 2017 (Honolulu, HI) 
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Nonogaki M, Nonogaki H. 2016. Germination recovery from the NCED-enhanced hyperdorrmant seeds using nitrate-inducible gene switch and chemical biology with an ABA antagonist. 5th Workshop on the Molecular Aspects of Seed Dormancy and Germination (Vancouver, Canada) 
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Nonogaki M. 2016. Strategies to recover germination from PHS-resistant hyperdormant seeds. 13th International Symposium on Preharvest Sprouting in Cereals (Perth, Australia) 
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Nonogaki H. 2016. Prevention of preharvest sprouting through alteration of hormone metabolism, perception and signal transduction. 13th International Symposium on Preharvest Sprouting in Cereals (Perth, Australia) 
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Nonogaki M. 2016. Prevention of preharvest sprouting through hormonal regulation. Preharvest Sprouting Workshop (Kitami, Japan) 
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Sall K, Nonogaki H. 2016. Biochemical function of DELAY OF GERMINATION1-LIKE4 in hormone and cell signaling. 5th Workshop on the Molecular Aspects of Seed Dormancy and Germination (Vancouver, Canada) 
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Sall K, Nonogaki M, Katsuragawa Y, Hendrix D, Dekkers JWD, Bentsink L, Nonogaki H. 2017. DELAY OF GERMINATION1-LIKE4 is a master regulator of reserve accumulation in seeds. Plant Biology 2017 (Honolulu, HI) 
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Sall K, Hendrix D, Sekine T, Katsuragawa Y, Koyari R, Nonogaki H. 2017. Transcriptomics of nine-cis-epoxycarotenoid dioxygenase 6 induction in imbibed seeds reveals feedback mechanisms and long noncoding RNAs. Seed Science Research, accepted. 
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Samarah, N.H., Wang, H. and Welbaum, G.E. 2016 Pepper (Capsicum annuum) seed germination and vigour following nanochitin, chitosan or hydropriming treatments. Seed Sci. & Technol.: 44, 3, 1-15. (http://doi.org/10.15258/sst.2016.44.3.18) 
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Santos, Juliana F., Dirk, Lynnette M.A., Downie, A. Bruce, Sanches, Mauricio F. G. and Vieira, Roberval D. 2017. Soluble sugars, storage proteins and reciprocal effect of parental lines of corn hybrid seeds. Seed Science Research. 27: 206-216. 
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Tao L, Zhang Y, Wang D, Liu Y, Dirk LMA, Downie B, Wang J, Wang G, Zhao T-Y. 2017. Raffinose but not galactinol in Maize directly improves both drought stress-tolerance and seed longevity. Molecular Plant. Provisionally accepted. 
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Welbaum, G.E. 2017a. Chapter 2, Seed production. In book: Editors: Brian Thomas, Brian G Murray and Denis J Murphy. Encyclopedia of Applied Plant Sciences, Vol 1, 2nd Edition, Academic Press, pp.546–552. 
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Welbaum, G.E. 2017b. A Gusseted Thermogradient Table to Control Soil Temperatures for Evaluating Plant Growth and Monitoring Soil Processes Training Video https://www.jove.com/video/54647/a-gusseted-thermogradient-table-to-control-soil-temperatures-for. JOVE DOI: 10.3791/54647
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Wilson, R., D. Culp, K. Nicholson, S. Peterson, and A. Taylor. 2016. Comparison of insecticides and insecticide application methods to protect spring-seeded processing onions from seedcorn maggot and onion maggot damage. Proceedings 2016 National Allium Research Conference, Savannah, GA, 1-3 December. National Onion Association, Greeley, CO 80631
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Zhang L, Lou J, Foley ME, Gu X-Y. 2017. Comparative mapping of quantitative trait loci for seed dormancy between temperate and tropical ecotypes of weedy rice. G3: Genes, Genomics, Genetics 7: 2605-2614 (doi: 10.1534/g3.117.040451) 
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