bluuebunny/crossref_metadata_2025 huggingface dataset:
Seed Piece Spacing Influences Yield, Tuber Size Distribution, Stem and Tuber Density, and Net Returns of Three Processing Potato Cultivars
Authors: Love Stephen L. , Thompson-Johns Asunta
Published: February 2019

Seed piece spacing is an important economic consideration in the production of potatoes (Solanum tuberosum L.). The optimum spacing varies with cultivar and intended market. A study was designed to determine the influence of seed piece spacing on yield, tuber size distribution, net returns, and stem and tuber density of three processing potato cultivars. Seed tubers of cultivars Russet Burbank, Frontier Russet, and Ranger Russet were planted 8, 15, 23, 31, 46, 61, 76, or 91 cm apart at two locations in 1988 and 1989. Total, marketable (U.S. No. 1), and midsize (226–452 g tubers) yield, tuber size distribution, net profits from a representative processing contract, and stem and tuber density (number per meters of row) were determined. All three cultivars achieved highest total yields at the narrowest (8 cm) spacing. Maximum marketable and midsize (226–452 g) yield occurred between 15 and 31 cm, depending on the cultivar. Size distribution shifted from a predominance of small tubers at narrow spacings to a predominance of large tubers at wide spacings, and the rate of shift was cultivar-dependent. `Russet Burbank' showed a broad range of optimal spacing for net returns, with a maximum in the range of 23 to 46 cm. Optima for `Frontier Russet' and `Ranger Russet' were between 15 and 46 cm. Of the four tuber measurements, midsize yield appeared to be best for determining optimum spacing. Marketable yield was also a useful measurement. All three cultivars gave maximum midsize yields at a stem density of 10.5 to 12.1 per meter of row and a tuber density of 23.9 to 24.9 per meter of row. Tuber density showed some promise as a predictor of optimum seed piece spacing for new cultivars.
Carbon and Nitrogen Budgets in Spring and Fall Tomato Crops
Authors: Andersen Peter C. , Rhoads Fred M. , Olson Steven M. , Hill Kristen D.
Published: February 2019

Carbon and nitrogen budgets were determined for `Colonial' (spring) and `Equinox' (fall) tomato (Lycopersicon esculentum Mill.) plants grown on raised beds with black polyethylene mulch and supplied with preplant-N at 0, 67, 134, 202, or 269 kg·ha–1. For both spring and fall experiments, we quantified the partitioning of dry matter, N, and C, and determined marketable and total yield. In the spring study, the concentration of N in leaves, stems, and in total plants increased linearly with level of N fertilization, whereas a quadratic relationship described the amount of N contained in the fruit (maximum with 202 kg·ha–1). Quadratic relationships occurred between rate of fertilization and leaf weight, stem weight, total plant weight, marketable yield, and total yield in the spring study, with maximum values at 134 or 202 kg·ha–1 rates of N fertilization. In the fall crop, fewer significant relationships occurred between dependent variables and rate of N fertilization, and coefficients of determination tended to be much lower than in the spring study. The fraction of N in leaves, stems, and roots (fall study only) was influenced by N fertilization. Effects of N fertilization on the fraction of C partitioned to any plant part was either nonsignificant or significant at P = 0.05. Total yield was related to N fertilization in a quadratic manner, but marketable yield was significantly affected only in the spring study. In both studies, increasing the rate of N fertilization reduced the C: N linearly for all tissues. In all cases, the quantity of N partitioned to vegetative tissue was at least 65% of that partitioned to the fruit, and the quantity of C in the plant was at least 74% of that in the fruit. In conclusion, although N fertilization above 202 kg·ha–1 generally increased the concentration and total amount of N in vegetative tissues, it did not increase yield. Also, the highest rate of N fertilization (269 kg·ha–1) resulted in a much lower efficiency of applied N [defined as: (N plant + N fruit)/N applied], and a much higher level of residual soil nitrate-N.
Fertilizer Concentration Affects Growth and Nutrient Composition of Subirrigated Pansies
Authors: van Iersel Marc
Published: February 2019

Ebb- and-flow irrigation is an economically attractive subirrigation method that reduces labor costs and eliminates runoff from greenhouses. The effects of fertilizer concentration on growth of subirrigated pansy (Viola ×wittrockiana Gam.) and the leachate electrical conductivity (EC) and pH were quantified, using two growing media. Leachate EC increased as the EC of the fertilizer solution increased from 0.6 to 3.6 dS·m–1 (70 to 530 mg·L–1 N). The leachate EC was fairly constant over time when the EC of the fertilizer solution was 0.6 dS·m–1, while it increased throughout the experiment at higher fertilizer concentrations. MetroMix 300 leachate consistently had a higher EC than did MetroMix 500. Leachate pH of both growing media was similar throughout the growing season. The pH decreased over time and was lower with higher fertilizer concentrations. Optimal plant growth occurred with a fertilizer EC of 1.2 or 1.8 dS·m–1, and a leachate EC between 1.5 and 4 dS·m–1. Increasing the concentration of the fertilizer solution resulted in increased shoot tissue levels of P and Mn and decreased tissue levels of K, Mg, and Na. The results of this study indicate that pansy is not very sensitive to the EC of the growing medium and can be grown successfully in a closed subirrigation system.
Benzaldehyde as a Soil Fumigant, and an Apparatus for Rapid Fumigant Evaluation
Authors: Wilson Charles L. , Solar Jose M. , El Ghaouth Ahmed , Fravel Deborah R.
Published: February 2019

An apparatus was developed for the rapid and facile evaluation of soil fumigants in a controlled manner using small volumes of soil. The apparatus consisted of a manifold to which were attached six canisters containing a loamy sand soil (adjusted to –100 kPa soil water potential). The soil was infested with either conidia of Fusarium oxysporum or Trichoderma harzianum; sclerotia of Sclerotinia minor; ascospores of Talaromyces flavus; vermiculite colonized with Pythium aphanidermatum; or beet (Beta vulgaris L., cv. Detroit Red) seed colonized with Rhizoctonia solani. Using nitrogen gas (N2) as a carrier gas, either N2 or N2 plus benzaldehyde was passed continuously through the soil for 24, 48, or 72 hours. At all three exposure times, benzaldehyde + N2 reduced viability of R. solani and S. minor, and reduced populations of P. aphanidermatum and T. harzianum. Populations of F. oxysporum were reduced after 48 and 72 hours of exposure to benzaldehyde, whereas populations of T. flavus were reduced only after 72 hours of exposure. Fumigation with benzaldehyde + N2 for 24 hours did not affect soil pH 1 week after exposure, but fumigation for 48 or 72 hours temporarily lowered pH from an average of 6.86 to 5.57 and 5.32, respectively. The biocontrol fungus, T. flavus, was less sensitive to benzaldehyde than the pathogens or the biocontrol fungus, T. harzianum. Thus, combining T. flavus with benzaldehyde to enhance biocontrol may be possible.
A New S-allele in Apple, `Sg', and Its Similarity to the `Sf' Allele from `Fuji'
Authors: Matsumoto Shogo , Kitahara Kentaro , Komori Sadao , Soejima Junichi
Published: February 2019

S-allele genotypes of nine apple (Malus ×domestica Borkh.) cultivars were identified using S-allele–specific polymerase chain reaction (PCR)–restriction fragmentlength polymorphism (RFLP) analysis. A new S-allele, Sg, was proposed to be present in `American Summer Pearmain', `Indo', `Kitanosachi', and `Meku 10'. This allele is very similar to Sf at the nucleotide sequence (92%) and deduced amino acid sequence (94%) levels.
Adventitious Shoot Formation on Excised Hypocotyls of Antirrhinum majus L. (Snapdragon) In Vitro
Authors: Schroeder Kenneth R. , Stimart Dennis P.
Published: February 2019

Hypocotyls from Antirrhinum majus L. were excised at 2 weeks of age from seedlings grown under a 16-hour photoperiod or continuous darkness. Explants were cultured on modified Murashige-Skoog (MS) medium containing 0, 0.44, 2.22, 4.44, 8.88, or 44.4 μm BA to investigate adventitious shoot formation. Excised hypocotyls from eight commercial cultivars, three inbred lines, and an F1 hybrid between two of the inbreds were cultured on MS medium containing 2.22 μm BA to assess genotypic effects on adventitious shoot formation. The influence of seedling age was assessed by excising hypocotyls from seedlings at 6, 10, 14, 18, 22, 26, or 30 days. Optimal conditions for adventitious shoot formation on excised hypocotyls included: seedling growth in a lighted environment, use of hypocotyls from 10-day-old seedlings, and culture on medium containing 2.22 μm BA for 3 weeks. Under these conditions, up to a 5-fold improvement in number of shoots per hypocotyl over previous studies was achieved. Adventitious shoot formation was genotype-dependent and appeared to be a dominant trait. Chemical name used: N6-benzyladenine (BA).
Impact of Overseeding Bermudagrass with Various Amounts of Perennial Ryegrass for Winter Putting Turf
Authors: Mazur A.R. , Rice J.S.
Published: February 2019

Research was conducted to determine the influence of the rate of seeding perennial ryegrass (Lolium perenne L.) over bermudagrass [Cynodon dactylon (L.) Pers × C. transvaalensis Burtt-Davy] on both the establishment of the ryegrass and the quality of bermudagrass golf greens. Increasing seeding rate from 90 to 180 g·m–2 resulted in more rapid establishment and a linear increase in turf quality. Turf density, as measured by leaf number, displayed linear and quadratic responses to seeding rates, with higher rates producing the greatest leaf numbers. Leaf width declined linearly with seeding rate, suggesting higher putting quality, as did tillers per plant. Spring transition to bermudagrass was slowed at high (150–180 g·m–2) seeding rates, with significantly more ryegrass present in late May. Emergence and growth of bermudagrass were suppressed longer at the higher overseeding rates. We conclude that the choice of seeding rate for ryegrass is a compromise between rapid development of, and maintenance of, quality turf vs. early smooth transition to bermudagrass in the spring.
Boron Requirement of Young `Sharwil' Avocado Trees
Authors: Miyasaka Susan C. , Million Jeff B. , Hue Nguyen V. , McCulloch Charles E.
Published: February 2019

Possible boron (B) deficiency symptoms were observed on avocado (Persea americana Mill. `Sharwil') grown in Kona, Hawaii. To determine the B requirement of young, `Sharwil' avocado trees, two greenhouse experiments were conducted. In a soil study, seven B treatments (0, 3.7, 11, 22, 44, 89, and 178 mg·kg–1 soil fines) were applied to 1-year-old grafted `Sharwil' avocado trees grown for 13 weeks in a Tropofolist soil. Due to the low and variable fractions of soil fines in this rocky soil, extractable soil B concentration did not appear to be a good predictor of B requirements by avocados. Adequate foliar B concentrations in `Sharwil' avocado trees based on dry weight and area of new leaves ranged from 37 (±3) to 65 (±4) and from 31 (±10) to 78 (±13) mg·kg–1 (dry-weight basis), respectively. (Means are followed by standard errors of the mean in parentheses.) In a hydroponics study, 6-month-old grafted `Sharwil' avocado trees were supplied with four levels of B (0, 1, 10, and 100 μm). At 11 months after B treatment initiation, leaves with deformed margins and a “shot-hole” appearance were first observed at a solution level of 0 μm B. At 14 months after B treatment initiation, foliar B concentrations that were associated with 12% to 14% incidence of deformed leaves ranged from 9.8 to 13.5 mg·kg–1 (dry-weight basis). Although `Sharwil' avocados are reportedly susceptible to B deficiency, foliar B concentrations required for adequate growth and those associated with B deficiency symptoms are similar to those for other cultivars.
Performance of Five Turfgrasses under Linear Gradient Irrigation
Authors: Qian Y.L. , Engelke M.C.
Published: February 2019

Determining the appropriate level of irrigation for turfgrasses is vital to the health of the turfgrass and the conservation of water. The linear gradient irrigation system (LGIS) allows long-term assessment of turf performance under continuous irrigation gradients from excess to no irrigation. The objectives of this study were to: 1) evaluate the minimum irrigation requirements and relative drought resistance of `Rebel II' tall fescue (Festuca arundinacea Schreb.), `Meyer' zoysiagrass (Zoysia japonica Steud.), `Tifway' bermudagrass [Cynodon dactylon (L.) Pers.], `Prairie' buffalograss [Buchloe dactyloides (Nutt.) Engelm], and `Nortam' St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze]; and 2) evaluate the long-term effects of irrigation levels on turf persistence, weed invasion, and disease incidence for the five selected turfgrasses under field conditions. Turf was sodded under LGIS with an irrigation gradient ranging from 120% Class A pan evaporation (Ep) to natural precipitation, along a 20-m turf area. Evaluation during the summers of 1993–96 indicated that grasses differed in drought resistance and persistence under variable irrigation regimes. Irrigation (Ep) required to maintain acceptable turf quality for respective grasses was `Rebel II' (67%), `Meyer' (68%), `Nortam' (44%), `Tifway' (35%), and `Prairie' (26%). Higher dollar spot (Sclerotinia homoeocarpa Bennett) infection was observed at 115% Ep irrigation regime in `Tifway' bermudagrass, whereas gray leaf spot [Pyricularia grisea (Hebert) Barr] was observed only at 10% Ep irrigation regime in St. Augustinegrass plots. An outbreak of brown patch (Rhizoctonia solani Kuehn.) occurred in Sept. 1996 in St. Augustinegrass plots receiving irrigation at >80% Ep.
Physiological Responses of Diverse Tall Fescue Cultivars to Drought Stress
Authors: Huang Bingru , Gao Hongwen
Published: February 2019

Drought is among the most limiting factors for turfgrass growth. Understanding genetic variations and physiological mechanisms in turfgrass drought resistance would facilitate breeding and management programs to improve drought resistance. The experiment was designed to investigate shoot physiological responses of six tall fescue (Festuca arundinacea Schreb.) cultivars representing several generations of turfgrass improvement to drought stress. Grasses were grown in well-watered or drying (nonirrigated) soil for 35 days in the greenhouse. Net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), relative water content (RWC), and photochemical efficiency (Fv/Fm) declined during drought progression in all cultivars, but the time and the severity of reductions varied with cultivar and physiological factors. The values of Pn, RWC, gs, and Tr decreased significantly for `Rebel Jr', `Bonsai', and `Phoenix' when soil water content declined to 20% after 9 days of treatment (DOT) and for `Houndog V', `Kentucky-31', and `Falcon II' when soil water content dropped to 10% at 15 DOT. A significant decrease in Fv/Fm was not observed in drought-stressed plants until 21 DOT for `Rebel Jr', `Bonsai', and `Phoenix' and 28 DOT for `Houndog V', `Kentucky-31', and `Falcon II'. The decline in Pn resulted mainly from internal water deficit and stomatal closure under mild drought-stress conditions. After a prolonged period of drought stress (35 DOT), `Falcon II', `Houndog V', and `Kentucky-31' maintained higher Pn than did `Rebel Jr', `Bonsai', and `Phoenix', which could be attributed to their higher Fv/Fm. This study demonstrated variation in drought resistance among tall fescue cultivars, which was related to their differential responses in photosynthetic capacity and water relations.
Timing of Gibberellin4+7 + Benzyladenine Sprays Influences Efficacy against Foliar Chlorosis and Plant Height in Easter Lily
Authors: Ranwala Anil P. , Miller William B.
Published: February 2019

The effects of Promalin® [PROM; 100 mg·L–1 each of GA4+7 and benzyladenine (BA)] sprays on leaf chlorosis and plant height during greenhouse production of ancymidol-treated (two 0.5-mg drenches per plant) Easter lilies (Lilium longiflorum Thunb. `Nellie White') were investigated. Spraying with PROM at early stages of growth [36 or 55 days after planting (DAP)] completely prevented leaf chlorosis until the puffy bud stage, and plants developed less severe postharvest leaf chlorosis after cold storage at 4 °C for 2 weeks. When PROM was sprayed on plants in which leaf chlorosis had already begun (80 DAP), further leaf chlorosis was prevented during the remaining greenhouse phase and during the postharvest phase. PROM caused significant stem elongation (23% to 52% taller than controls) when applied 36 or 55 DAP, but not when applied at 80 DAP or later. The development of flower buds was not affected by PROM treatments. Although PROM sprays applied at 55 DAP or later increased postharvest flower longevity, earlier applications did not. Chemical names used: N-(phenylmethyl)-1H-purine 6-amine (benzyladenine, BA); α-cyclopropyl-α-(p-methoxyphenyl)-5-pyrimidinemethanol (ancymidol).
Colorado Potato Beetle Resistance in Somatic Hybrids of Diploid Interspecific Solanum Clones
Authors: Jansky Shelley , Austin-Phillips Sandra , McCarthy Corine
Published: February 2019

The Colorado potato beetle (CPB) is a major insect pest that is controlled mainly through the use of pesticides. Development of potato clones with multiple forms of host plant resistance may provide a stable alternative or supplemental form of CPB control. Tetraploid hybrids were developed by somatic fusion of diploid interspecific Solanum clones with different forms of resistance to CPB. Hybrids were created between a clone containing leptine glycoalkaloids and four clones producing glandular trichomes. One fusion produced vigorous hybrids that were analyzed for CPB resistance traits. Somaclonal variation among hybrids was detected for trichome density and resistance to feeding by adult and larval beetles. Somatic hybrids were less resistant than the parents in adult feeding preference trials, but several were more resistant than either parent in larval feeding trials. Future studies are needed to determine whether clones producing both glandular trichomes and leptines express resistance that is more stable than that of clones with only one resistance factor.
Differences in Pod Calcium Concentration for Eight Snap Bean and Dry Bean Cultivars
Authors: Quintana J.M. , Harrison H.C. , Nienhuis J. , Palta J.P. , Kmiecik K.
Published: February 2019

This study was designed to compare snap and dry beans (Phaseolus vulgaris L.) for pod Ca concentration, and to identify genetic resources that might be useful in breeding programs directed to increase Ca concentration in bean pods. Pods from eight snap bean and eight dry bean cultivars were evaluated for Ca concentration during 1995 and 1996 at Hancock, Wis. A randomized complete-block design was utilized with three replications in 1995 and six in 1996. Beans were planted in June and hand-harvested in August for both experiments. Soil Ca at planting time was 580 mg·kg–1 in 1995 and 500 mg·kg–1 in 1996. No additional Ca was added. Plots consisted of 10 plants each. At harvest, a pooled sample of 10 to 15 size no. 4 pods was collected from each plot. Atomic absorption spectrophotometry was used to determine Ca content. Significant differences (P ≤ 0.01) were detected among and within bean types (dry and snap). Although bean type × year interaction was nonsignificant, a strong year effect was observed (P ≤ 0.01). Snap beans (4.6 ± 0.7 mg·g–1 dry weight) had significantly higher pod Ca concentration than did dry beans (4.2 ± 0.6 mg·g–1 dry weight). Within snap beans, `Checkmate' had the highest pod Ca concentration (5.5 ± 0.3 mg·g–1 dry weight) and `Nelson' the lowest (3.8 ± 0.3 mg·g–1 dry weight). Within dry beans, `GO122' had the highest (5.1 ± 0.4 mg·g–1 dry weight) and `Porrillo 70' the lowest pod Ca concentration (3.6 ± 0.3 mg·g–1 dry weight). Six cultivars had pod Ca concentrations significantly (P ≤ 0.01) higher than the overall mean (4.4 ± 0.3 mg·g–1 dry weight).
Growth and Development of Young Apple Fruits Following Applications of Ethephon Plus Carbaryl for Thinning
Authors: Ward Daniel , Marini Richard P.
Published: February 2019

In three experiments, apple trees (Malus ×domestica Borkh.) were sprayed, when fruits were 20 to 30 mm in diameter, with a combination of ethephon (800 mg·L-1) and carbaryl (600 mg·L-1) to induce abscission of all fruits on the tree. Two days after treatment (DAT), most treated fruits stopped or slowed increasing in diameter, fruit water potential was less negative, and starch accumulation was less than for nontreated fruits. Cellulase activity appeared in the abscission zone by 4 DAT. Fruit growth cessation following treatment was probably due to inadequate assimilate supplied to the fruit, but assimilate flow slowed before cellulase activity was apparent in the abscission zone. Chemical names used: 2-chloroethyl phosphonic acid (ethephon); 1-naphthyl (N-) methylcarbamate (carbaryl).
Quantitative Magnetic Resonance Imaging of Satsuma Mandarin Fruit during Growth
Authors: Clark Christopher J. , Richardson Annette C. , Marsh Ken B.
Published: February 2019

Whole-fruit proton magnetic resonance (MR) imaging was performed on satsuma mandarin (Citrus unshiu Markovich cv. Miho Wase) during a 15-week period commencing 10 weeks after anthesis and continuing to maturity, and at 6 weeks after anthesis the following season. Images with long repetition times (>1600 ms) and short echo times (20 ms) provided the clearest details of anatomical changes in the peel (flavedo, albedo) and vascular system, while those with similar repetition times but longer echo times (120 ms) were best for viewing juice sac morphology within pulp segments. At 6 weeks after anthesis, images of fruits of slightly different physiological ages highlighted rapid changes in the vascular bundles and albedo tissue at this stage of development. Variation in the relaxation measurements, T1 and T2, was determined from quantitative MR images of the juice sacs in equatorial slices, and images of expressed juice from whole fruit. Seasonal measurements of T1 determined in situ (1760 ms) were significantly greater than those in juice (1413 ms). By contrast, there was no mean seasonal difference between in situ T2 measurements (360 ms) and those for juice (332 ms). No associations between trends in the MR data and total soluble solids, pH, titratable acidity, and sugar and organic acid composition of the juice were established. Cell structure is identified as a hindrance in the use of quantitative MR imaging for probing compositional changes in solution in serial imaging studies.
Paclobutrazol Distribution following Application to Two Media as Determined by Bioassay
Authors: Million Jeff B. , Barrett James E. , Nell Terril A. , Clark David G.
Published: February 2019

A broccoli (Brassica oleracea var. botrytis L.) seedling bioassay was used to measure paclobutrazol activity and distribution in two growing media following drench or subirrigation applications. The bioassay exhibited a saturation-type response curve for paclobutrazol concentrations up to 1000 μg·L-1 in solution and 100 μg·L-1 in the media. The concentration of paclobutrazol required to achieve one-half of the maximum observed bioassay activity was 3-fold as high in bark-based commercial potting medium as in a peat-based medium. Less than 2% of applied paclobutrazol leached out during the drench application despite the collection of up to 50 mL of leachate per 120 mL of the solution (1000 μg·L-1) that was applied per 15-cm pot. Immediately following drench application, paclobutrazol concentrations in both media were highest in the uppermost 2.5 cm and decreased downward. By 3 weeks after treatment, drench-applied paclobutrazol had moved into lower depths. Distribution of paclobutrazol was limited to the bottom 2.5 cm of media when applied as a subirrigation soak. Chemical name used: (±)-(R*,R*)-β-[(4-chlorophenyl)methyl]-α-(1,1-dimethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
Strategies for Mycorrhizal Inoculation of Six Annual Bedding Plant Species
Authors: Koide Roger T. , Landherr Lena L. , Besmer Ylva L. , Detweiler Jamie M. , Holcomb E. Jay
Published: February 2019

We inoculated six common annual bedding plant species with the vesicular-arbuscular mycorrhizal fungus Glomus intraradices Schenck & Smith using two fertilizer P concentrations (3 or 15 μg·mL-1) and three inoculation timings (inoculation at sowing, at transplanting, or at both times). The plant species used were: Salvia splendens F. Sellow ex Roem. & Schult. cv. Firecracker Rose; Impatiens walleriana Hook. f. cv. Sun and Shade Royal Red; Tagetes patula L. cv. Girls Golden; Petunia ×hybrida Hort. Vilm.-Andr. cv. Freedom Blue; Coleus ×hybridus Voss. cv. Jazz Salmon; and Viola ×wittrockiana Gams. cv. Majestic Giant White. In general, Coleus, Petunia, and Viola were colonized more than were Impatiens, Tagetes, and Salvia. Inoculation at sowing required less inoculum than either of the other methods. Moreover, it was generally as effective in promoting colonization as double inoculation, and was often more effective than inoculation at transplanting. Mycorrhizal colonization was significantly reduced by the higher P concentration. The use of Myconate®, a water-soluble form of the flavonoid formononetin, significantly stimulated colonization in Salvia.
Yield Response of Watermelon to Planting Density, Planting Pattern, and Polyethylene Mulch
Authors: Sanders Douglas C. , Cure Jennifer D. , Schultheis Jonathan R.
Published: February 2019

One or two plants per hill of `Prince Charles' and `Royal Jubilee' watermelon were grown with drip fertigation at five in-row spacings, with or without polyethylene mulch, in four location × year combinations (environments). Rows were 1.5 m apart and in-row spacings were 45, 60, 90, 120, and 150 cm. `Royal Jubilee' yielded more than `Prince Charles' in all environments, and the highest yields were associated with low percent culls and high fruit numbers per hectare. Highest yields of marketable fruits (≥4.5 kg/melon) were obtained using polyethylene mulch and areas per plant between 0.4 and 0.9 m2. Average weight per melon, however, was ≥9 kg only at areas per plant >0.9 to 1.0 m2. Unless there is a market for small fruits (≥4.5–9 kg), optimum area per plant was ≈1.0 m2. Results for one plant per hill at one in-row spacing were similar to those for the alternative planting pattern of two plants per hill at half the in-row spacing, thus supporting the feasibility of using the more economical alternative planting pattern.
Root Characteristics and Seed Yields of Cowpeas Grown with and without Added Nitrogen Fertilizer
Authors: Kahn Brian A. , Schroeder Judith L.
Published: February 2019

Field experiments were conducted in Oklahoma in 1993 and 1994. Cowpeas [Vigna unguiculata (L.) Walp.] were grown using either noninoculated seed and 23 kg·ha–1 of preplant nitrogen (N) fertilizer (conventional) or Rhizobium-inoculated seed and no preplant N fertilizer (reduced input). Sample plants were excavated at first pod set and analyzed for nodulation and root morphology. Additional plants were harvested at the green-shell stage to determine seed yield and plant N concentration. Conventional and reduced input cowpeas did not differ in dry weight of root mass components, total root dry weight, shoot dry weight, shoot: root ratio, nodule distribution among root morphological components, total nodule fresh weight, plant N concentration, or green-shell seed yield. Most of the nodule fresh weight generally was associated with nodules on the basal and lateral roots. Results indicate that cowpea root characteristics are not necessarily altered by the presence or absence of added N fertilizer at a given location.
Carbon Dioxide–induced Changes in Color and Anthocyanin Synthesis of Stored Strawberry Fruit
Authors: Holcroft Deirdre M. , Kader Adel A.
Published: February 2019

Anthocyanin concentrations increased in both external and internal tissues of `Selva' strawberries (Fragaria ×ananassa Duch.) stored in air at 5 °C for 10 days, but the increase was lower in fruit stored in air enriched with 10 or 20 kPa CO2. Flesh red color was less intense in CO2 storage than in air storage. Activities of phenylalanine ammonia lyase (PAL) and UDP glucose: flavonoid glucosyltransferase (GT) decreased during storage, with decreases being greater in both external and internal tissues of strawberry fruit stored in air + 20 kPa CO2 than in those kept in air. Activities of both PAL and GT in external tissues of strawberries stored in air + 10 kPa CO2 were similar to those in fruit stored in air, while enzyme activities in internal tissues more closely resembled those from fruit stored in air + 20 kPa CO2. Phenolic compounds increased during storage but were not affected by the storage atmosphere. The pH increased and titratable acidity decreased during storage; these effects were enhanced in internal tissues by the CO2 treatments, and may in turn have influenced anthocyanin expression.
Using the Streif Index as a Final Harvest Window for Controlled-atmosphere Storage of Apples
Authors: DeLong John M. , Prange Robert K. , Harrison Peter A. , Schofield R. Andrew , DeEll Jennifer R.
Published: February 2019

A final harvest window (FHW), expressed as Streif Index coefficients [firmness/(percentage soluble solids concentration × starch index)], was developed for identifying maximum fruit quality for strains of `McIntosh', `Cortland', and `Jonagold' apples (Malus ×domestica Borkh.) following 8 months of controlled-atmosphere (CA) storage. The Streif Index was calculated during nine preharvest (twice per week) intervals and four weekly harvests over three seasons. The relationship between Streif Index (dependent variable) and day of year (independent variable) of the preharvest and harvest samples was then derived by negative first-order linear regression equations that had parameter estimate (b1) probability values ≤0.0001 for all of the strains. Apples from the four harvest periods were stored in standard CA storage for 8 months and then subjected to a 7-day shelf-life test at 0 °C followed by 5 days at 20 °C. Poststorage quality data were categorized and combined to produce an overall fruit quality rating scale. For each strain, the final harvest (i.e., day of year) was identified as that which directly preceded at least a 10% drop in the poststorage fruit quality rating compared with the first harvest rating. The FHW, expressed as Streif Index coefficients via the regression of Streif Index (Y) on day of year (X), was then calculated as the 3-year final harvest mean with the upper and lower window limits being determined by the standard deviation of the mean. The lower to upper FHW boundaries ranged from 4.18 to 5.34, 4.12 to 5.46, 4.51 to 5.68, 5.23 to 5.99, and 1.38 to 2.34 for Redmax, Marshall and Summerland `McIntosh', Redcort `Cortland' and Wilmuta `Jonagold', respectively. The practical utility of the Streif Index method lies in the ease with which apple fruit maturity at harvest can be evaluated for its suitability for long-term CA storage.
Storage of Flowering Dogwood (Cornus florida L.) Pollen
Authors: Craddock J.H. , Reed S.M. , Schlarbaum S.E. , Sauve R.J.
Published: February 2019

A series of experiments was conducted with flowering dogwood (Cornus florida L.) to evaluate in vitro pollen germination both prior to and following storage at various temperatures. For all experiments, pollen was germinated on an agar-solidified medium containing 20% sucrose. Collection method had a significant effect on germination of `Cherokee Chief', `Cherokee Princess', and `Cloud 9' pollen. Pollen obtained from anthers that had been collected prior to dehiscence and allowed to air-dry for 24 hours had a higher germination rate than did pollen that had undergone a desiccation treatment. None of the treated pollen tested, however, had a germination rate >25% of that of freshly collected pollen. The deleterious effect of dehydration could not be reversed by rehydration. Pollen germination was tested after 1, 4, 7, and 108 days at 5, –20, and –196 °C. Pollen stored at –196 and at –20 °C had a better germination rate than that stored at 5 °C. Germination was not significantly affected by length of storage, nor was there any significant temperature × length of storage interaction.
Performance of Turkey Litter Compost as a Slow-release Fertilizer in Containerized Plant Production
Authors: Kraus Helen T. , Warren Stuart L.
Published: February 2019

An experiment was conducted to develop a protocol for using compost in nursery crop production. Five rates of inorganic fertilizer (0, 1, 2, 3, and 4 g N) and two irrigation volumes (600 and 900 mL per 3.8-L container) were evaluated for their effects on Rudbeckia fulgida Ait. `Goldsturm' and Cotoneaster dammeri Schneid. `Skogholm' growth in a pine bark substrate amended with composted turkey litter (CTL). Additions of ≥2 g N per container for cotoneaster and ≥1.0 g N for rudbeckia were required to produce growth equivalent to that of plants in a control treatment that simulated typical production by a grower in the southeastern United States. Phosphorus, Ca, and Mg contents of cotoneaster and rudbeckia plants grown in CTL-amended substrates with no fertilizer added (0 g N) were similar to or greater than that of the control. Phosphorus concentrations in the substrate solutions were higher in all CTL-amended substrates than in the control regardless of fertilizer addition. This suggests that P released from CTL had a greater impact than P added with fertilizer. The greatest nutrient value of CTL may be as a P source and a replacement for dolomitic limestone and micronutrients in container-grown plant production.
Virus Assessment of Ajuga reptans Cultivars Reveals Alfalfa Mosaic, Tobacco Streak, and Cucumber Mosaic (CMV) Viruses, and a CMV Satellite RNA
Authors: Fisher J.R. , Nameth S.T.
Published: February 2019

Ajuga reptans L. is an herbaceous ornamental mint grown in borders or as a groundcover, and is commonly propagated vegetatively and by seed. Three hundred and fifty-six A. reptans samples were obtained from growers in Washington, Michigan, Iowa, and Ohio, and screened for alfalfa mosaic virus (AMV), tobacco streak ilarvirus (TSV), cucumber mosaic cucumovirus (CMV), tomato aspermy cucumovirus (TAV), tomato spotted wilt tospovirus (TSWV), impatiens necrotic spot tospovirus (INSV), tobacco mosaic tobamovirus (TMV), potato virus × potexvirus (PVX), and 80 potyviruses, using direct antibody sandwich (DAS) and indirect enzyme-linked immunosorbent assay (ELISA). Viral-associated double-stranded ribonucleic acid (dsRNA) analysis was used to detect an apparent satellite (sat) RNA, and northern hybridization using a digoxigenin (DIG) labeled (S) CARNA-5 cDNA probe was used to confirm the identity of the apparent satRNA. No incidences of TAV, TMV, TSWV, INSV, PVX, or potyviruses were detected. CMV was detected in 11%, AMV in 22.2%, TSV in 3.7%, and mixed infections of CMV and AMV in 1.1% of the samples. SatRNA was detected in 36 A. reptans `Royalty', two `Rainbow', and two `Burgundy Glow' samples by dsRNA analysis, and confirmed by hybridization in 29 `Royalty' and one `Burgundy Glow' samples. Sixteen A. reptans `Royalty' seedlings grown from seed harvested from CMV-infected plants were tested by ELISA for CMV, AMV, and TSV. All were positive for CMV, and two were positive for a mixed infection of CMV and AMV. SatRNA was detected in all 16 seedlings by RT-PCR.
194 The Relationships among Preceding Air Temperatures, Cold Hardiness, and Water Content of Concord Grape Canes from Fall to Early Spring
Authors: Jiang H. , Howell G.S.
Published: February 2019

Biweekly cold hardiness and water content were measured on 1-year-old field cuttings of bearing Concord grapevines at the Horticultural Teaching and Research Center at MSU from Sept. 1998 to Apr. 1999. Cold hardiness index LT50 (temperature at which 50% of the sample was killed) was determined by three viability tests after laboratory controlled sub-freezing treatments. Weather data were obtained from the MSU agricultural weather automatic system. Average maximum and minimum air temperatures of 1, 3, 5, and 7 days prior to each field sampling were regressed against the LT50 of the tissues. Our results suggested that: 1) Tmin1 (minimum air temperature of the preceding 1 day of each sampling) had the most significant correlation with LT50 and cane water content among all air temperatures analyzed. 2) While cane water content was significantly related to its bark water, the water content of periderm and pith did not. 3) When comparing the effects of Tmin1 and bark water content on cane LT50 together, bark water had significant higher coefficient of determination (R2). This research provided additional information about the mechanisms of plant dormancy and cold hardiness.
242 Fruit Quality Parameters of Various Apple Scion/Rootstock Combinations
Authors: Siswanto Usman , Matta Frank B.
Published: February 2019

A study of spur-type apple scion cultivars on semi-dwarf and dwarf apple rootstocks was conducted to evaluate and identify suitable scion/stock combination for Mississippi. Fruit weight varied among scion/stock combinations. `Royal Gala' on MM111 and MM106 and `Ultra Gold' on MM106 yielded the heaviest fruit. `Jon-A-Red' on Mark produced the lightest fruit. Fruit length diameter ratio (L/D) was the highest for `Blushing Golden' on M7A and MM111, and `Ultra Gold' on MM111. The L/D ratio of `Royal Gala' was not affected by rootstock. Scion cultivars on M7A and M26 tended to have more red fruit than on the remaining rootstocks. `Ultra Gold' on M26 and `Braeburn' on Mark and MM111 had the firmest fruit. Overall, trees on M7A and Mark rootstock tended to produce firm fruit. Juice pH was significantly affected by scion-stock combination. In general, `Royal Gala', regardless of rootstock, had the highest juice pH, whereas `Ultra Mac' and `Jon-A-Red' produced the lowest pH. `Blushing Golden' on MM111 and `Royal Gala' on M26 had the highest soluble solids concentration (SSC). Soluble solids concentration of scion cultivars on MM106 did not differ.
289 Effect of Swine Effluent on Yields of Plasticulture-grown Vegetables
Authors: Cushman K. , Snyder R. , Horgan T. , Bufogle A.
Published: February 2019

Five fertilizer treatments, three of which included swine effluent alone or in combination with commercial fertilizers, were evaluated for plasticulture production of vegetables. Effluent and/or soluble fertilizers were delivered through drip irrigation tubing to their respective treatments. Four experiments were conducted at two locations: 1) spring tomatoes followed by pumpkin at Verona, Miss., 2) spring tomatoes followed by zucchini at Pontotoc, Miss., 3) fall tomato at Verona, and 4) fall tomato at Pontotoc. In all four experiments, representing six crops, yields from treatments receiving swine effluent were equal to or greater than yields from treatments receiving preplant fertilizers and/or commercially available soluble fertilizers. There were also no significant differences among treatments in relative number of marketable fruit. Leaf tissue analysis of the tomato crops showed no significant differences among treatments in N content. For some experiments, there were significant differences for other elements. These results showed that swine effluent was an effective nutrient source for plasticulture production of vegetable crops when compared to preplant and soluble fertilizers. These results also showed that the alkaline pH (about 7.8) and high level of ammonium nitrogen of swine effluent (>95 % of N content) did not adversely affect vegetable yield or marketability.
608 Super-elevated CO2 Concentrations Reduce Growth of Radish and Lettuce
Authors: Wheeler R.M. , Mackowiak C.L. , Yorio N.C. , Ruffe L.M. , Stutte G.W.
Published: February 2019

Radish (Raphanus sativus cv. Giant White Globe) and lettuce (Lactuca sativa cv. Waldmann's Green) plants were grown for 25 days in growth chambers at 23 °C, ≈300 μmol·m-2·s-1 PPF, and 18/6 photoperiod, and four CO2 concentrations: 400, 1000, 5000, and 10,000 μmol·mol-1. Average total dry mass (g/plant) at the 400, 1000, 5000 and 10,000 μmol·mol-1 treatments were 6.4, 7.2, 5.9, and 5.0 for radish and 4.2, 6.2, 6.6, and 4.0 for lettuce. Each species showed an expected increase in yield as CO2 was elevated from 400 to 1000 μmol·mol-1, but super-elevating the CO2 to 10,000 μmol·mol-1 resulted in suboptimal growth. In addition, many radish leaves showed necrotic lesions at 10,000 μmol·mol-1 by 17 days and at 5000 μmol·mol-1 by 20 days. These results are consistent with preliminary tests in which radish cvs. Cherry Belle, Giant White Globe, and Early Scarlet Globe were grown for 16 days at 400, 1000, 5000, and 10,000 μmol·mol-1. In that study, `Giant White Globe' produced the greatest total dry mass at 1000 (3.0 g/plant) and 5000 μmol·mol-1 (3.0 g/plant), and the least at 10,000 μmol·mol-1 (2.2 g/plant). `Early Scarlet Globe' followed a similar trend, but `Cherry Belle' showed little difference among CO2 treatments. Results suggest that super-elevated CO2 can depress growth of some species, and that sensitivities can vary among genotypes.
Plant Propagation Methods Course Developed for Delivery on the World Wide Web
Authors: Peffley Ellen B. , Lombard Kevin , McKenney Cynthia , Durham Richard
Published: February 2019

A plant propagation course was developed for delivery on the World Wide Web. Plant Propagation Methods is one of two foundation courses required of students with either a major or minor in horticulture. The course is accessed via the Texas Tech Univ. Horticulture website, www.pssc.ttu.edu. The delivery software is Web-CT Tutorial and access is password protected. The course has been offered two semesters, Fall 1999 and Spring 2000. Overall, student evaluations have been very favorable. The ratings for the first time offering were a 100% excellent rating was given for stimulating student interest and concepts pointed out; 67% excellent rating for effectiveness of the course, presents challenging ideas, stresses important points, uses visual materials, defines new terms, and provides an overview/objective. Students gave an overall rating of good for the organization of the course. The only negative response by the students was that they said the class was very hard because it was not in a structured classroom setting.
Exotherm Characteristics and Cold Hardiness Mechanisms within the Buds of Some Deciduous Fruit Trees
Authors: Ding Pinghai , Gu Sanliang
Published: February 2019

Exotherm characteristics of dormant apple, pear, peach, plum, grape, persimmon, and black walnut buds were investigated from late autumn to early spring. Differential thermal analysis indicated differences in the high-temperature exotherm (HTE) and low-temperature exotherm (LTE) among the fruit species and sampling dates. According to exotherm characteristics and cold hardiness, the species tested could be divided into two groups, those without LTE (apples and pear) and those with LTE (grape, persimmon, black walnut, peach, and plum). The latter group with LTE could be further categorized into two subgroups, those possessing three stages of hardiness development (peach and plum group) and those with five stages of hardiness development (grape, persimmon, and black walnut). In the peach and plum group, HTE and no LTE could be detected in the first and last stages when bud water content was >55%. In the second stage, both HTE and LTE could be detected when bud water content was between 40% and 50%. In the grape, persimmon, and black walnut group, the first stage with only HTE was from bud formation to deep supercooling initiation when bud water content was >52%. The second stage with both HTE and LTE was when bud water content was between 40% and 48%. The third stage when only LTE could be detected and bud water content was usually <40%. The fourth stage was from HTE reappearance to LTE disappearance before bud swell. The fifth stage was from LTE disappearance to when only HTE could be detected. No detection of LTE in the buds of apple and pear and no detection of HTE in the buds of grape, persimmon, and black walnut were both closely associated with water status in the buds.
Plant Development Services, Inc., Collaborates with Plant Originators in the Evaluation and Introduction of New Ornamental Plants
Authors: Berry Jim , Coker Aimee
Published: February 2019

Plant Development Services, Inc. (PDSI), was organized in 1996 for the purpose of research, development and the marketing of new innovative landscape plants. PDSI focuses on discovery, evaluation and production of new clones that are superior in horticultural qualities to current ones in our industry. Some superior horticultural traits that PDSI looks for are disease and insect resistance, heat and cold tolerance, superior foliage, form, or flower, ease of propagation and cultivation, and marketability. All new ornamental plant introductions orginate from small producers, private breeders, or from our own research. PDSI offers new plant discoveries a place and method of evaluation, legal protection services, production and marketing. Our method of evaluation includes propagation and cultivation and can take varying lengths of time to complete. On an average, it can take 3 to 5 years of evaluation before final selections are made. Once we have a high confidence level on a particular variety we enter them into university trials. We also offer public gardens these new plants for public exposure and evaluation. This has given us valuable feedback on the performance of these new cultivars in different areas of the country. This exposure has also turned into promotion. As people notice these new plants established and performing well in landscapes, they become confident to try the plants on their own, often talking about them and sometimes writing about them. If a plant is patented, the patent belongs to the breeder and typically PDSI is the managing partner making decisions on royalties, promotion, production, and licensing. Royalties fund our program and are paid on a per plant basis, not per size.
Regeneration of Ornamental Cherry (Prunus) Taxa from Mature Stored Seed
Authors: Hokanson Karen E. , Pooler Margaret R.
Published: February 2019

Callus formation and adventitious shoot regeneration in vitro from mature stored seed were evaluated in eight ornamental cherry (Prunus) taxa: P. campanulata Maxim., P. maackii Rupr., P. sargentii Rehd., P. serrula Franch., P. serrulata Lindl., P. subhirtella Miq., P. virginiana L., and P. yedoensis Matsum. Several portions of the embryo (cotyledons and hypocotyl sections) and nine combinations of growth regulators (BA, 2,4-D, IBA, NAA, and TDZ) were compared. Effects of embryo portions and growth regulator treatments were generally small within taxa, but shoot formation differed among taxa. About 20% to 50% of the embryos from P. virginiana and P. serrula and ≈5% to 30% of those from P. maackii produced shoots. The other taxa generally did not produce shoots. Regeneration from mature stored seed in the responsive taxa represents a potential system for genetic transformation. Chemical names used: 6-benzyladenine (BA); 2,4-dichlorophenoxyacetic acid (2,4-D); indole-3-butyric acid (IBA); α-naphthaleneacetic acid (NAA); thidiazuron (TDZ).