ASHS 2025 Conference

Puakenikeni (Fagraea berteroana) is a popular flower in lei making in Hawaii, especially during graduation season and mothers day, which coincide with the flowering period. Most of the propagation is done via air layers, to promote early flowering. Propagation via rooted cuttings has been reported in the literature, however, there are is no information in regards to best practice, and it is a common question asked to the the University of Hawaii at Manoa Cooperative Extension Services. This trial used different powder rooting hormones to compare their effectiveness in propagating semi hardwood cuttings of puakenikeni. Cuttings were dipped in the rooting hormone, and the lower 2 inches of each cutting was inserted in a mix of 50% perlite and 50% vermiculite and placed in a mist bench for 2 months. Three treatments were compared (no rooting hormone, and 0.1%, 0.3% and 0.8% IBA). A total of 80 cutings were used, or 20 cuttings per treatment. After two months the control treatment with no rooting hormone had only 10% rooting. The 0.1% IBA and 0.3% IBA had 30% and 10% rooted cuttings, respectively. The 0.8% IBA treatment had 85% rooting success. Results from this trial indicate that a rooting hormone with 0.8% IBA should be used when rooting semi hardwood cuttings of puakenkeni (Fagraea berteroana). Future trials may be performed to compare other concentrations and types of rooting hormones (powder, liquid and gel), in order to achieve higher rooting percentage rates.

A forum for discussion of potential collaborations with regards to plant growth and culture – i.e. propagation, root growth, water management, weed control, PGRs, plant nutrition, etc.

In this study, we evaluated the germination rates of twenty native plant species and their response to cold stratification as well as four chemical solution treatments—water (control), gibberellic acid, smoke water, and gibberellic acid with smoke water. Seeds were evaluated and counted twice a week. Of the twenty evaluated species, sixteen had germination rates over 3%, or 1 seed out of 30. Stratification increased germination by 54% when compared to the control. For chemical treatments, gibberellic acid and gibberellic acid with smoke water were significantly different from the control and increased germination by an average of 47% and 48%, respectively. Six species showed a response to chemical treatment and stratification. Four species showed a response to chemical treatments only, and four species showed a response to stratification only. No growth defects were discovered upon further evaluation after sowing the seed. This study suggested that the combination of stratification with smoke water and/or gibberellic acid has a significant effect on seed germination yield of some native perennials.

Commercial spinach (Spinacia oleracea L.) production is underrepresented in hydroponic production due to inconsistent germination rate, uniformity, and percentage. Seed treatments to enhance germination require tedious decoating of the pericarp or priming with synthetic chemicals. This study was carried out to investigate the effects of plasma activated water (PAW) on spinach seed germination. PAW is generated by applying cold atmospheric plasma to water, resulting in a multitude of direct and indirect chemical reactions at the interface. PAW is rich in reactive nitrogen and oxygen species, and it has been shown to enhance several agricultural processes including seed germination. Seeds of spinach were primed for a set period of time in distilled water (control) or PAW and germinated in petri dishes. After 14 d, seeds that had been primed in PAW for any length of time germinated with greater percentage than control (74.6% and 66.1%, respectively). Optimal priming in PAW was found to be 6 h, yielding a study high germination percentage of 80%. Additionally, seeds primed with PAW improved mean germination time compared to control conditions. This study demonstrates the effectiveness of PAW as a useful tool in seed priming to improve germination.

Kratom (Mitragyna speciosa), a tropical evergreen tree indigenous to Southeast Asia, has gained attention in recent years due to its potential as a natural medicine for pain management and its ability to alleviate symptoms associated with opioid withdrawal. These properties indicate that kratom could be a promising candidate for drug development aimed at addressing the opioid epidemic. Despite growing interest in kratom’s therapeutic applications, its domestic cultivation remains limited, and investigations on vegetative propagation methods are unavailable. The traditional propagation technique, i.e., rooting stem cuttings in greenhouse settings with misting systems, has resulted in inconsistent success and varying quality. To address these challenges and improve propagation efficiency, this study evaluated the use of an aeroponic system to root kratom cuttings in controlled environments under various conditions. Stem cuttings were cultured in aeroponic devices under three photoperiods provided by light-emitting diode (LED) lights in environmentally controlled rooms. Rooting percentages reached 87, 88, and 90% in six weeks under 10-, 14-, and 24-hr photoperiods, respectively. Cuttings rooted three days earlier under 24-hr compared to those rooted at 10- and 14-hr photoperiods. On the other hand, the 14-hr photoperiod led to the highest root dry mass,109% and 14% greater than the 10- and 24-hr treatments, respectively. Furthermore, propagules rooted under 14-hr photoperiod had the highest total root length, 92% and 33% greater than those rooted under 10- and 24-h photoperiods. Additionally, the 14-hr photoperiod significantly enhanced root projected area, surface area, root volume, and number of root forks by 82, 81, 80, and 124%, respectively compared to those rooted under the 10-hr photoperiod, although these enhanced parameters were not statistically different from those rooted under 24-hr photoperiod. Our results showed that photoperiod generally had little effect on rooting percentages, shoot growth (e.g. new leaf number and new leaf area), average root diameter, and number of root tips and crossings; higher rooting quality was produced under 14-hr photoperiod. These findings provide valuable insights for improving rooting of this novel medicinal plant.

Stratified substrates may offer some advantages in containerized plant production, but their function in the propagation environment has not been extensively studied. We tested unrooted cutting root develop and plug stability with four herbaceous species [Agastache × ‘Sunrise Red Improved’, Cuphea hyssopifolia 'Maria' (Floriglory®), Gaillardia ×grandiflora 'Eclipse' (Lunar®), and Salvia ×jamensis 'Ignition Purple' (VIBE®)] in stratified propagation substrates. We used small, round pots to mimic a liner cell (top diameter 63.2 mm, depth 61.2 mm, volume 140 cm3 ). The control was a commercial propagation mix. We created top and middle-stratified treatments, using amendments of coarse perlite, fine coconut shell biochar, and parboiled rice hulls. The top-stratified treatments had 3 cm of an amendment material on top, with the control substrate underneath. The middle-stratified treatment contained the control on the top and bottom, with a 2-cm layer of amendment in the middle. We tested the species in separate experiments, with 7 replications each, in an approximately 30 day experiment. We repeated the experiments in a second cycle. At harvest, we assigned each cutting a plug integrity rating on a 0 to 5 scale: 0 = no visible roots, unstable, 1 = minimal roots, one or two roots visible, unstable, 2 = moderate roots, more than two roots but large spaces with no roots, partially unstable, 3 = acceptable roots, many roots with only small gaps, stable, 4 = optimum roots, many roots with full coverage, stable. Most of the stratified substrates had lower ratings than the control (P < 0.05). The top stratified rice hull treatment had a lower mean rating than the control for every plant in every cycle. Cuphea and Gaillardia with middle perlite stratification were not significantly different than the control in both cycles, while all top stratified mixes had significantly lower ratings than the control for Cuphea. Root growth in stratified substrates was similar to the control in the majority of cases. Cuphea cuttings had lower total root length (mm) than the control in all top stratification treatments and the middle perlite treatments in both cycles (P < 0.05). Some non-significant trends in the data repeated in both cycles, showing repeating patterns between the stratification treatments. Stratified substrates generally had lower plug integrity than the control, with few significant root growth effects.

Achimenes are rhizomatous gesneriads that can be used as flowering houseplants or grown in hanging baskets and mixed containers. Achimenes are typically asexually propagated from scaly rhizomes. The potential exists to propagate from leaf cuttings, however, there is limited published information on this propagation method. Thus, a leaf cutting study was initiated to further investigate the effects of indole-3-butyric acid (IBA) and propagation time on root development, plantlet, and rhizome production. We tested three Achimenes cultivars, ‘Charm’, ‘Apricot Glow’, and ‘Pink Cloud’. A total of 96 leaf-cuttings per cultivar were obtained from pre-flowering plants. Leaves were treated with one of four treatments; control (water), 1,000, 3,000, and 8,000 ppm of powder rooting hormone and were propagated under mist for a period of 3, 6, or 9 weeks. Data collection included root fresh and dry weights, plantlet number (stolons that emerged above the media surface), and rhizome development. In addition, root development was qualitatively evaluated on a scale from 1 = no rooting to 5 = prolific rooting. Propagation time significantly impacted each variable for all cultivars (p < 0.0001). Root ratings showed that all cultivars had ratings of 5 at 6 and 9 weeks, significantly higher than at 3 weeks. Generally, root dry weights significantly increased with increased propagation times. The interaction between rooting hormone and propagation time was significant for ‘Charm’ and ‘Apricot Glow’ for plantlet production. Increased plantlets were observed as both hormone concentration and propagation time increased, although not always significantly. ‘Apricot Glow’ leaf cuttings treated with 1,000 ppm and propagated for 9 weeks produced the most plantlets (1.6), however, plantlet number was not significantly different between hormone concentrations. Rhizome development significantly increased as propagation time increased for all cultivars (p < 0.0001). Rhizome number of all three cultivars significantly increased by double or triple for cuttings grown for 9 weeks compared to the 3 weeks. Our findings suggest that rooting hormones are negligible in enhancing propagation of Achimenes leaf cuttings for the cultivars evaluated. Propagation duration has a greater impact on growth and development than treatment concentrations. In this study, minimal differences in growth and development were observed after 6 weeks. This suggests that the ideal propagation period is within 3 and 6 weeks. Additional leaf cutting research is warranted to evaluate subsequent growth and development of Achimenes plants.

Northern berry crops including blueberry (Vaccinium spp.), lingonberry (V. vitis-idaea L.), cranberry (V. macrocarpon Ait.), cloudberry (Rubus chamaemorus L.) and huckleberry (V. membranaceum Douglas ex Torr.) are native to the North. Their health promoting role in anti-oxidant, anti-inflammatory, anti-ulcer and anti-tumor activities is due to their high contents of bioactive components. Although conventional methods of berry crop propagation are successful, for producing a large number of disease-free high quality plants, in vitro propagation (micropropagation) is more desirable. With the introduction of in vitro culture techniques, it is widely used to produce the true-to-type plants for year around multiplication. Propagation in vitro, using semi-solid and liquid media in different bioreactor systems, has advanced a multi-billion dollar industry in various crop plants globally. However, stresses during in vitro culture can provoke a range of genetic and epigenetic variabilities in the genome of the micropropagules leading to somaclonal variation. These variations (genetic or epigenetic) in micropropagated berry crops that include increased shoot and rhizome growth, berry production and/or antioxidant properties, might be useful for early establishment and berry production to the northern growers. This review updates the propagation technologies used in northern berry crops along with the evaluation of clonal fidelity and somaclonal variation in micropropagated plants. The existing gap in literature will be covered.

Prairie willow (Salix humilis) is a compact shrub willow native throughout the eastern United States. Aside from its desirable habit, attractive flowers and foliage, and pervasive ecological associations, prairie willow demonstrates profound adaptability in its native range, offering potential for urban green infrastructure applications. The dwarf variety (S. humilis var. tristis) is particularly favorable for horticultural applications due to its pronounced short stature. However, prairie willow exhibits a unique recalcitrance to traditional asexual propagation techniques commonly employed with willows. Tissue culture, a highly effective means for propagating recalcitrant woody plants, has not been explored for prairie willow. Given its potential horticultural value, tissue culture serves as a promising alternative for commercializing this taxon. This study explored the impact of four concentrations (0mg/L, 0.1mg/L, 1mg/L, and 10mg/L) of the common shoot-inducing hormone BAP (6-benzylaminopurine, a cytokinin) on initial growth in culture. Plant material was harvested from actively growing softwood tissue on a greenhouse-grown stock plant of the dwarf variety (USDA-GRIN accession AMES35806) and was trimmed to 1-2cm single-node explants (N=80, n=20). Sterilization involved an initial rinse in tap water with Tween-20, followed by a 30-second soak in 70% ethanol, a 5-minute soak in 0.9% sodium hypochlorite, and intermittent 5-minute rinses in sterile distilled water. Explants were stuck in 15mL falcon tubes with 4mL of media (2.41g/L woody plant media 30g/L sucrose 7g/L agar BAP). Culture tubes were placed on a light rack (18.3°C) with continuous light (40 watt fluorescent) and monitored weekly. The number of expanded buds and contamination rates were recorded. Contamination rates were low (12.5%), indicating successful sterilization. Development was slow across all treatment groups, suggesting the need for stock plant rejuvenation before propagule harvest. However, days to bud break indicated that 0.1mg/L BAP may result in the quickest shoot proliferation. Percentages of explants with expanded buds by week 5 were 13% (0mg/L), 68% (0.1mg/L), 41% (1mg/L) and 6% (10mg/L). All explants in 10mg/L exhibited browning and necrosis by week 5, while all but 5% of explants in 0mg/L remained green despite limited bud expansion. Future trials will investigate rejuvenation and alternative cytokinins to generate a complete protocol for introducing prairie willow into tissue culture. This research supports the integration of this versatile plant into commercial production, enhancing the ornamental plant palette for challenging urban landscapes.

Roses seeds (achenes) have a reputation of being challenging to germinate due to physiological and minor physical dormancy. The effect of gibberellins (GA) on rose seed germination has generally been neutral or negligible. Soaking rose seeds in cellulase before stratification has been documented to improve germination in some roses, likely due to degrading the outer covering around the embryo to allow for better imbibition. This experiment uniquely combines cellulase with GA to ascertain if there would be a stronger effect of GA if reaching the embryo was a limitation. A full factorial was used with a two-day duration of either dry seed, a 0.5% cellulase soak, or reverse osmosis (RO) water soak followed by a one-day soak of 200ppm GA3, 200ppm GA4 7, 200ppm GA4 7 plus 6-benzyladenine as Promalin®, or RO water. Rosa arkansana was chosen due to it being challenging to germinate. Four replications of 100 seeds each for each of the 12 treatments were prepared and mixed with 80cc of moist peat moss. All treatments were given a common warm stratification (8 weeks room temperature) and cold stratification (12 weeks 4C) followed by constant 10C in a growth chamber. Germination was recorded and germinated seedlings removed three times while at 10C at 5-week intervals. Promalin® led to slightly faster germination at week 5, but by week 10 GA treatments were not significantly different than the water control. Cellulase and RO water pre-GA soaks were not significantly different than each other at any time interval and by week 15 both were significantly better than the dry seed treatment. This data suggests the importance of having well hydrated seeds going into stratification, a neutral effect of GA on germination of this species, suggests 6-benzyladenine may slightly speed along germination, and that cellulase may not significantly improve water penetration over a sufficient imbibition duration.

Native four o’clocks (Mirabilis spp.) are drought-tolerant perennials native to North America, valued for their vibrant flowers and ecological contributions, including pollinator support and soil stabilization. Despite their ornamental appeal and value in ecological restoration, their use in horticulture has been limited due to propagation challenges such as low seed availability, poor germination, and complex dormancy requirements. Micropropagation, the production of new plants from small tissue sections under sterile conditions using artificial media and controlled environments, presents a promising solution to these limitations. It offers a reliable method to produce large quantities of native Mirabilis for conservation and nursery applications. In 2021, an effective micropropagation protocol was developed for the rare North American species Mirabilis macfarlanei. Building on this success, the current project evaluated the applicability of this protocol to three additional native species: Mirabilis greenei, Mirabilis laevis var. villosa, and Mirabilis laevis var. crassifolia. Single-node cuttings were surface sterilized with 20% bleach and cultured on Driver and Kuniyuki Walnut (DKW) medium supplemented with 4 µM 6-benzylaminopurine (BA). All three species were successfully established in vitro and proliferated. Growth parameters, including average number of shoots, shoot length, and shoot dry weight, were compared between DKW with 4 µM BA and Murashige and Skoog (MS) medium with the same BA concentration. For M. greenei, shoot proliferation was similar between MS and DKW (5.7 and 5.8 shoots, respectively). M. laevis var. villosa and M. laevis var. crassifolia produced more shoots on MS medium (10.6 and 4.5) than on DKW (7.8 and 3.9). All species exhibited higher shoot dry weights on MS medium, while shoot lengths were comparable across treatments. Rooting success varied among species. The rooting medium developed for M. macfarlanei (DKW supplemented with 0.5 mg/L indole-3-acetic acid [IAA], 0.5 mg/L naphthaleneacetic acid [NAA], and 0.15 mg/L Sequestrene® 138) was effective only for M. greenei. However, M. laevis var. villosa and M. laevis var. crassifolia rooted better on MS medium containing 1 µM NAA and 0.15 mg/L Sequestrene® 138. Rooted plantlets of all three species were successfully acclimatized in rockwool, with M. laevis var. villosa and M. laevis var. crassifolia flowering under greenhouse conditions.

Bush bean is a popular vegetable as it is high in fiber, vitamins, minerals, and antioxidants. Assessment of the physiological quality of bush bean seeds is essential for ensuring better crop performance and yield, and the controlled deterioration technique is a reliable and practical tool for this purpose. The objective of this study was to determine the seed quality of two bush bean varieties using the controlled deterioration technique. Two bush bean varieties (Jhar Sheem-1 and Jhar Sheem-2) were induced with 12%, 16%, and 20% moisture levels for 0, 4, 8, and 16 days. Seed quality factors, such as, germination percentage, abnormal seedlings percentage, dead seed percentage, soil emergence percentage, root and shoot lengths, and dry matter content, were evaluated. In this study, 24 treatments were arranged as completely randomized design with 3 replications. Both varieties showed an identical performance at 12% moisture in 0 days of the aging period, but prominent differences were noticed at a highly deteriorated level of the factors. The percentage of normal seedlings declined to 85.34% in Treatment-24 (Jhar Sheem-2 at 20% moisture level with a 16-day aging period) compared to Treatment-1 (Jhar Sheem-1 at 12% moisture level with no aging period). Meanwhile, seedling abnormality increased by 22.00% in Treatment-11 (Jhar Sheem-1 at 20% moisture level with an 8-day aging period) relative to Treatment-1. Conversely, root and shoot dry matter were 93.06% and 28.62% lower, respectively, in Treatment-24 than Treatment-1. Moreover, highly remarkable (1%) relations were traced among all the traits, ranging from -0.466 (seed dry matter x abnormal seedling) to 0.983 (normal seedling x root length). Another finding was that among all the values about normal seedlings (i.e., the germination percentage); their affiliation with the soil emergence was prominent, i.e., 0.983. Thus, the outcomes revealed that the controlled deterioration test was highly effective in assessing the physiological conditions of the varieties. According to the vigor and quality performance, bush bean Variety-1 (Jhar Sheem-1) can be used as a parent for hybridization programs to produce superior inherent quality. Future investigations can be conducted to find more acceptable temperature and moisture trait limits among other bush bean varieties.

The University of California Riverside (UCR) rootstock breeding program has selected five advanced avocado (Persea americana Mill.) rootstocks for their resistance to Phytophthora Root Rot (PRR), a major disease affecting avocados worldwide. Another significant threat to avocado trees is laurel wilt (LW), caused by the fungus Harringtonia lauricola. To date, laurel wilt has been reported in 12 states, but has only infected avocado trees in Florida, where it has killed approximately 290,000 trees worth an estimated $95 million. It is anticipated that laurel wilt will eventually spread to California, the leading avocado production region in the U.S., as well as to Mexico and South America, where the largest world-wide avocado production occurs. For the UCR experimental PRR-resistant rootstocks to be successful in the long term after their commercial release, they should positively influence the LW resistance of ‘Hass’ and other scions. In this study, we tested the LW susceptibility and physiological responses of ‘Donnie,’ ‘Hass,’ ‘Gem,’ and ‘Reed’ scions grafted onto UCR advanced clonal rootstocks PP35, PP40, PP42, PP45, and PP80 under climate-controlled greenhouse conditions. All scions were also grafted and tested on ‘Waldin’ seedling rootstock, which is the primary avocado rootstock used in South Florida. Trees of each scion/rootstock combination were either inoculated with H. lauricola or with deionized water as a control. There were six single-plant replicates per treatment for each scion/rootstock combination, arranged in a completely randomized design. Visual disease symptoms were evaluated on a scale of 1 to10 (1= no symptoms, 10 = severe symptoms) every 3 to 4 days from the time of inoculation until the trees were harvested. Physiological variables, including leaf gas exchange (net CO2 assimilation, stomatal conductance, and transpiration), were also measured. At the end of the experiment, all plants were harvested, and the presence or absence of H. lauricola was confirmed by plating stem sections on CSMA (cycloheximide-streptomycin malt agar) medium. Although all scion/rootstock combinations were susceptible to LW, there were differences in susceptibility among combinations. The combinations ‘Hass’/PP45, ‘Gem’/PP40, ‘Gem’/PP80, ‘Hass’/Waldin’, and ‘Gem’/’Waldin’ exhibited the greatest tolerance to LW, as indicated by fewer external symptoms and less reduction in leaf gas exchange variables compared to the other combinations tested. Therefore, these more LW-tolerant scion/rootstock combinations have potential for planting in areas where both PRR and LW diseases occur. The most tolerant combinations identified in this study continue to be evaluated under field conditions for horticultural characteristics and yields in Florida.

Improving stem cutting propagation of grapevine species holds immense importance with the growing interest in grapevine cultivation in the region. Propagating these plants from stem cuttings can be a challenging endeavor. As a result, this research initiative seeks to address this issue by exploring methods to enhance the success rate of stem cutting propagation. By developing more efficient and reliable techniques, nurseries can increase their ability to supply grapevines to local growers, which not only expands the availability of grapevines in the market but also plays a pivotal role in bolstering the wine industry in Mississippi. By facilitating the growth of this industry, improved grapevine propagation methods contribute to economic development, agricultural diversification, and ultimately benefiting the local economy and wine enthusiasts. Hardwood and semi-hardwood cuttings of four bunch grape varieties: ‘Miss Blanc’, ‘MidSouth’, ‘Norton’ and ‘Mamont Noir’ were subjected to 10 hormone treatments of indole-3-butyric acid (IBA) alone and in combination with ascorbic acid. These treatments were applied as a basal quick dip. Sixty days after treatment, rooting percentage, growth index (new shoots), cutting quality (0-5, with 0 = dead and 5 = transplant-ready cutting), total root number, average root length (of three longest roots), and root quality (0-5, with 0=no roots and 5=healthy, vigorous root system) data were collected. Of the four varieties trialed, ‘Miss Blanc’ performed the best with the greatest rooting percentage of 95% as a hardwood cutting and ‘Mamont Noir’ performed the best as a semi-hardwood cutting with the greatest rooting percentage of 100%. ‘MidSouth’ and ‘Norton’ will both require further research to assess the best rooting option for these varieties.

Tea (Camellia sinensis) has the potential to be cultivated as a commercial crop in the United States, but growers need access to clean plant material. The wholesale value of tea in the United States was $13.6 billion in 2022, yet less than 100 acres of tea are currently grown here. Tissue culture can be a means to provide disease-free and genetically identical plants. Three experiments were carried out using explants, which are 2.5 cm stems with single, active nodes from the young shoots of 28-year-old ‘Minto Pacific’ plants. Experiment 1 tested chemo- and thermotherapy: 40 explants were placed in Murashige and Skoog (MS) medium supplemented with 2, 4-dioxo-hexahydro-1-3-5 triazine (2 mL/L), aspirin (1.4 mL/L), and ribavirin (1.5 mL/L). Explants were placed in a growth chamber at 25 ± 1 ℃ on a 16-h photoperiod for 4 to 5 weeks, then subcultured and placed in an incubator for an additional 4 to 5 weeks set at 32 to 35℃ on the high end/light period and 28 to 30℃ on the low end/dark period (alternating every 4 h). All explants were either contaminated or dead, potentially due to high temperatures, by the end of this 8 to 10 week cycle. Experiment 2 evaluated use of meristems, which were excised from axillary buds of the aforementioned young shoots of 28-year-old ‘Minto Pacific’ plants and placed on MS media supplemented with 6-benzylaminopurine (1 mL/L) and gibberellic acid (0.5 mL/L). Explants were placed in a growth chamber at 25 ± 1 ℃ on a 16-h photoperiod. Of the 10 meristems, there was no contamination, but only one meristem has survived long-term (5 months). With Experiment 3, explants (n=26) were soaked in 4% v/v Plant Preservative Mixture (PPM) for 2 h, then transferred to MS medium, before being placed in a growth chamber at 25 ± 1 ℃ on a 16-h photoperiod. Contamination and physiological disorders developed over time, leaving only one visually healthy explant after 5 months. The effect of PPM as a soak or a growth medium-additive needs to be further investigated through additional experiments.

This interactive workshop will introduce attendees to the history, science, and industry opportunities related to grafting perennial tree fruits, nuts, and vines. It will be accompanied by a hands-on demonstration and time for attendees to practice with real-time feedback. A liability waiver will be required for participants who wish to handle grafting knives.

Speakers:

• Dr. Rachel Spaeth, post doc Research Horticulturist currently serving as the Interim Curator of Prunus, National Clonal Germplasm Repository, UC Davis, CA
• Dr. John Preece, Supervisory Research Leader of the USDA-ARS National Clonal Germplasm Repository Davis, CA