bluuebunny/crossref_metadata_2025 huggingface dataset:
Louisiana Select—Plant Promotion, Marketing, and Recommendation Efforts for the Nursery and Landscape Industry
Authors: Owings Allen D.
Published: February 2019

The LSU Agricultural Center and Louisiana Nursery and Landscape Association initiated an ornamental plant promtion, marketing, and recommendation program in 1996. Called `Louisiana Select', this program is intended to actively promote outstanding ornamental plants to Louisiana's gardening consumers. In addition, it provides county agents and industry professionals information on plants that should be recommended. The selection committee consists of an extension horticulturist, two county agents, a landscape contractor, a wholesale greenhouse grower, a wholesale woody ornamental producer, and two representatives from retail garden centers. Plants are usually promoted in the spring and fall of each year. Plants previously named as Louisiana Select recipients include `New Orleans Red' (Red Ruffle) coleus, mayhaw, `Henry's Garnet' virginia sweetspire, `Homestead Purple' perennial verbena, `Telstar' dianthus, bald cypress, `New Gold' lantana, `Confetti' lantana, `Trailing Purple' lantana, `Dallas Red' lantana, `Silver Mound' lantana, `Lady in Red' salvia, `New Wonder' scaevola, `Goldsturm' rudbeckia, and `Foxy' fox-glove. A theme (“Fall is for Planting Native Trees”) has also been promoted. Point of purchase signs promoting the Louisiana Select program and individual plants are made available to garden centers. Significant sales increases ranging from 300% to 2500% have been reported for seelcted plants with annual bedding plants and perennial flowers enjoying the greater sales volume increases.
East Texas Bedding Plant Pack and Garden Performance Trials: Master Gardeners, A Web-site and Publishable Data
Authors: Pemberton H. Brent , Roberson William E.
Published: February 2019

The East Texas Bedding Plant Pack and Garden Performance Trials are performed as an interaction between the plant material source companies, the plant producer companies, volunteers, and retail consumers. The Overton Trial Site is located near a concentration of bedding plant growers ($80 million annual wholesale value) which is part of the close to $500 million in ornamental plant production in northeast and north central Texas, about half of the state industry value. The spring and fall trials consist of two phases. The greenhouse phase consists of assessing production performance for use by the crop production industry. Crops are usually finished in packs (36 cells per flat), but larger size containers are used as needed according to species. Height control is a major issue and specific issues have been addressed. This is one way that publishable data can be generated by these trials. The garden phase consists of assessing garden performance in a replicated field setting at the Overton site. Garden performance is also assessed for many of the entries at sites at the Dallas Arboretum and Botanical Garden and the Texas A&M Univ. Agricultural Research and Extension Center at Dallas. An integral part of the trials are the volunteers who, as members of the Smith County Master Gardener Association, donate hundreds of hours of labor to the seeding, transplanting, and garden establishment phases of the trials. In addition, a web site has been initiated as the only practical way to share the data and hundreds of images that are generated each trial season.
Evaluation of Sweetpotato Cultivars to Root-knot Nematodes
Authors: Cervantes J.C. , Davis D.L. , Yencho G.C.
Published: February 2019

This study was conducted to determine whether the type of pot used for the evaluation affected the resistance response of the sweetpotato plants, and to assess the resistance response to different root-knot nematode species. Five sweetpotato [Ipomoea batatas (L.) Lam] cultivars, `Beauregard', `Exce'l, `Jewel', `Hernandez', and `Porto Rico', were screened for M. incognita (race 3), Meloidogyne arenaria (race 2), and M. javanica, in both 10-cm-side, square pots and 4-cm-diameter, cone pots. Gall index, necrosis index, and number of nematode eggs per gram of root were used to estimate nematode-resistance reaction. Mean of all indices between the 2 pot types were not significantly different (α = 0.05). Gall and necrosis indices were not correlated in any of the cultivars. Resistance response depended on cultivars and nematode species for all variables analyzed. `Beauregard' was the most susceptible to Meloidogyne. `Hernandez' and `Excel' were found to be the most resistant cultivars to the Meloidogyne species.
An Evaluation of Summer Cover Crops for Use in Vegetable Production Systems in North Carolina
Authors: Creamer Nancy G. , Baldwin Keith R.
Published: February 2019

Summer cover crops can produce biomass, contribute nitrogen to cropping systems, increase soil organic matter, and suppress weeds. Through fixation of atmospheric N2 and uptake of soil residual N, they also contribute to the N requirement of subsequent vegetable crops. Six legumes {cowpea (Vigna unguiculata L.), sesbania (Sesbania exaltata L.), soybean (Glycine max L.), hairy indigo (Indigofera hirsutum L.), velvetbean [Mucuna deeringiana (Bort.) Merr.], and lablab (Lablab purpureus L.)}; two nonlegume broadleaved species [buckwheat (Fagopyrum esculentum Moench) and sesame (Sesamum indicum L.)]; and five grasses {sorghum-sudangrass [Sorghum bicolor (L) Moench × S. sudanense (P) Stapf.], sudangrass [S. sudanense (P) Stapf.], Japanese millet [Echinochloa frumentacea (Roxb.) Link], pearl millet [Pennisetum glaucum (L). R. Br.], and German foxtail millet [Setaria italica (L.) Beauv.)]}, were planted in raised beds alone or in mixtures in 1995 at Plymouth, and in 1996 at Goldsboro, N.C. Biomass production for the legumes ranged from 1420 (velvetbean) to 4807 kg·ha-1 (sesbania). Low velvetbean biomass was attributed to poor germination in this study. Nitrogen in the aboveground biomass for the legumes ranged from 32 (velvetbean) to 97 kg·ha-1 (sesbania). All of the legumes except velvetbean were competitive with weeds. Lablab did not suppress weeds as well as did cover crops producing higher biomass. Aboveground biomass for grasses varied from 3918 (Japanese millet) to 8792 kg·ha-1 (sorghum-sudangrass). While N for the grasses ranged from 39 (Japanese millet) to 88 kg·ha-1 (sorghum-sudangrass), the C: N ratios were very high. Additional N would be needed for fall-planted vegetable crops to overcome immobilization of N. All of the grass cover crops reduced weeds as relative to the weedy control plot. Species that performed well together as a mixture at both sites included Japanese millet/soybean and sorghum-sudangrass/cowpea.
Pest Damage to Pecan is Affected by Irrigation, Nitrogen Application, and Fruit Load
Authors: Wood Bruce W. , Reilly Charles C.
Published: February 2019

Orchard trees of pecan [Carya illinoinensis (Wangenh.) K. Koch] were subjected to combinations of cultural practices inducing differential physiological states so as to assess the potential for culture-related impact on damage to trees by key arthropod pests. Leaf N concentration, leaf water status, and crop load all affected foliar damage by black pecan aphids [BPA; Melanocallis caryaefoliae (Davis)] and pecan leaf scorch mite [PLSM; Eotetranychus hicoriae (McGregor)], as well as second-flush shoot growth. Damage to first-flush foliage in the late season by BPA generally diminished as leaf water status and leaf N concentration increased, but intensified with a reduction in crop load. Conversely, foliage damage by PLSM increased with elevated leaf water status and N concentration, but was unaffected by crop load. First- and second-order interactions for all combinations of cultural treatments conferring differential physiological states affected damage by pests and induction of second-flush shoot growth. Arthropod-induced defoliation on trees receiving highly favorable cultural practices—those producing high leaf N, high leaf water availability, and low crop load—was greater than on trees receiving minimal or lesser cultural inputs. Thus, cultural practices influencing leaf water status, N status, or crop load potentially act and interact to produce both desirable and undesirable side-effects on damage incurred by certain arthropod pests and therefore merit consideration in efforts to develop improved integrated pest management strategies.
Path Analysis of the Correlation between Fruit Number and Plant Traits of Cucumber Populations
Authors: Cramer Christopher S. , Wehner Todd C.
Published: February 2019

The relationships between fruit yield and yield components in several cucumber (Cucumis sativus L.) populations were investigated as well as how those relationships changed with selection for improved fruit yield. In addition, the correlations between fruit yield and yield components were partitioned into partial regression coefficients (path coefficients and indirect effects). Eight genetically distinct pickling and slicing cucumber populations, differing in fruit yield and quality, were previously subjected to modified half-sib family recurrent selection. Eight families from three selection cycles (early, intermediate, late) of each population were evaluated for yield components and fruit number per plant in four replications in each of two testing methods, seasons, and years. Since no statistical test for comparing the magnitudes of two correlations was available, a correlation (r) of 0.7 to 1.0 or –0.7 to –1.0 (r2 ≥ 0.49) was considered strong, while a correlation of –0.69 to 0.69 was considered weak. The number of branches per plant had a direct positive effect on, and was correlated (r = 0.7) with the number of total fruit per plant over all populations, cycles, seasons, years, plant densities, and replications. The number of nodes per branch, the percentage of pistillate nodes, and the percentage of fruit set were less correlated (r < |0.7|) with total fruit number per plant (fruit yield) than the number of branches per plant. Weak correlations between yield components and fruit yield often resulted from weak correlations among yield components. The correlations among fruit number traits were generally strong and positive (r ≥ 0.7). Recurrent selection for improved fruit number per plant maintained weak path coefficients and correlations between yield components and total fruit number per plant. Selection also maintained weak correlations among yield components. However, the correlations and path coefficients of branch number per plant on the total fruit number became more positive (r = 0.67, 0.75, and 0.82 for early, intermediate, and late cycles, respectively) with selection. Future breeding should focus on selecting for the number of branches per plant to improve total fruit number per plant.
A Stenospermocarpic, Seedless Vitis vinifera × Vitis rotundifolia Hybrid Developed by Embryo Rescue
Authors: Ramming David W. , Emershad Richard L. , Tarailo Ronald
Published: February 2019

Hybridizations between seedless Vitis vinifera L. genotypes and V. rotundifolia (Michx.) were made specifically to introgress the seedless trait into the disease-resistant background of V. rotundifolia. The seedless, gynoecious P79-101 was hybridized with three V. rotundifolia parents, producing a total of 102 ovules. From these ovules, 44 embryos developed, producing 20 plants. Isozyme analyses and morphological traits confirmed that 19 of the plants were hybrids. Sixteen were planted in an experimental vineyard at California State Univ. Fresno. One seedling, C41-5, produced seedless fruit that appeared to be stenospermocarpic based on fruit and aborted seed size. Fruit weight was slightly less than that of `Thompson Seedless' (stenospermocarpic) and at least twice that of parthenocarpic fruit of `Black Corinth' and C41-7, a seeded hybrid with many parthenocarpic fruit. Aborted seeds of C41-5 were larger than, but not significantly different from, those of `Thompson Seedless', while parthenocarpic fruit from `Black Corinth' and C41-7 had aborted seeds that were smaller than those of C41-5. Seed weight of C41-7 averaged almost 10 times that of aborted C41-5 seeds. This is the first report of a stenospermocarpic, seedless hybrid of V. vinifera × V. rotundifolia.
Relationship between Nitrate Leaching under Turf and Nitrate Uptake by Turfgrasses
Authors: Pote John W. , Basu Chhandak , Jiang Zhongchun , Sullivan W. Michael
Published: February 2019

Leaching-induced N losses have been shown to be minimal under turfgrasses. This is likely due to superior ability of turfgrasses to absorb nitrate. No direct evidence for this theory has been reported. The present study quantified nitrate leaching under miniature turf and nitrate uptake by individual turfgrass plants, and established the relationship between nitrate leaching loss and nitrate uptake rate. Seedlings of six Kentucky bluegrass (Poa pratensis L.) cultivars, `Blacksburg', `Barzan', `Connie', `Dawn', `Eclipse', and `Gnome', were planted individually in polystyrene containers filled with silica sand. The plants were irrigated with tap water or a nutrient solution containing 1 mm nitrate on alternate days and mowed to a 5-cm height once each week for 25 weeks. Nitrate leaching potential was then determined by applying 15 to 52 mL of nutrient solutions containing 7 to 70 mg·L-1 nitrate-N into the containers and collecting leachate. After the leaching experiment, plants were excavated, roots were washed to remove sand, and the plants were grown individually in containers filled with 125 mL of a nutrient solution containing 8.4 mg·L-1 nitrate-N. Nitrate uptake rate was determined by monitoring nitrate depletion at 24-hour intervals. Leachate nitrate-N concentration ranged from 0.5 to 6 mg·L-1 depending on cultivar, initial nitrate-N concentration, irrigation volume, and timing of nitrate-N application. Significant intraspecific difference in nitrate uptake rate on a root length basis was observed. Nitrate uptake rate on a per plant basis was significantly (P ≤ 0.05) and negatively correlated (r = -0.65) with nitrate leaching loss. The results provide strong evidence that superior nitrate uptake ability of turfgrass roots could reduce leaching-induced nitrate-N losses.
Residents' Opinions on the Value of Street Trees
Authors: Gorman James , Swasey James E.
Published: February 2019

This research sought to determine if there was a difference of opinions regarding street trees depending on whether or not residents had a street tree planted directly in front of their house. Six hundred seventy-six residents of State College, Pa., responded to a structured questionnaire regarding their opinions of benefits and annoyances of street trees. Results of this research show that there were statistically significant differences of residents' opinions depending on whether or not there was a street tree planted in front of their residence.
A Comparative Study of Onion Maggot “Delia Antiqua” Monitoring Techniques
Authors: Kline Wesley , Haag Scott , Ghidiu Gerald
Published: February 2019

Onion maggots have reduced green onion and leek production in southern New Jersey for at least the last 80 years. Growers routinely apply soil insecticides at planting and spray for larvae and adult flies during the season. Two monitoring methods are available for determining adult fly activity. New York researchers have demonstrated that cone traps can be used. Two traps are placed near onion fields and checked for adult flies twice per week to determine peak fly emergence. Ontario researchers use yellow sticky cards for monitoring onion maggot flies in the onion fields. Three 10 × 15-cm cards are placed on each side of the field and are checked twice per week. An experiment was conducted in New Jersey to determine which system is more reliable and easier for consultants and growers to use. Two cone traps were placed at the edge of one onion field and yellow cards were placed in another field on four farms. The traps were checked twice per week from 29 Mar. to 22 Oct. Both monitoring methods tracked the adult flights, but the average number of flies captured was higher on the sticky cards. Ease of use is important if either system will be used as a monitoring tool. Sticky cards are more difficult to maintain since they must be replaced at least every 2 weeks. Since fields are irrigated or cultivated every week in southern New Jersey, the cards become covered with soil, reducing effectiveness. Also, it is more difficult to determine male and female flies on sticky cards.
Root Severance at Harvest Increases Embolism and Decreases Sap Flow of Field-grown Acer rubrum L.
Authors: Knight Patricia R. , Harris J. Roger , Fanelli Jody K.
Published: February 2019

Root severance during field harvesting alters the water status of a tree, resulting in water stress and reduced post-transplant growth. Two experiments, using Acer rubrum L. (red maple), determined the influence of root severance at harvest on sap flow and xylem embolism. Trees 1.5–1.8 m tall (4 years old) were utilized in the first experiment, and trees 1.2–1.5 m tall (2 years old) were utilized in the second. Sap flow sensors were installed on the 4-year-old trees prior to root severance and remained on the trees until 1 week after harvest. Within 1 day after root severance sap flow was reduced and remained lower than nontransplanted (control) trees for the remainder of the experiment. Leaf stomatal conductance (Cs) of transplanted trees 1 week after root severance was lower than that of control trees, but leaf water potentials (ψ) were similar. In the second experiment, sap flow was reduced relative to control trees within 2 h after root severance. Although Cs was reduced 4 hours after root severance, ψ was not. Embolism increased within 24 hours of root severance. These results indicate that root severance quickly induces increased levels of embolism, which is associated with reduced sap flow.
Yield, Time of Maximum CO2 Exchange Rate, and Leaf-area Index of `Clemson Spineless' Okra Are Affected by Within-row Spacing
Authors: Whitehead W.F. , Singh B.P.
Published: February 2019

A 2-year field study was conducted to determine the effects of within-row spacing (WRS) on CO2 exchange rate (CER), leaf-area index (LAI), and yield of okra [Abelmoschus esculentus (L.) Moench]. Okra cultivar Clemson Spineless was seeded at WRS of 8, 16, 24, 32, 40, and 48 cm in a randomized complete-block design replicated three times. CER and LAI were measured five times at about biweekly intervals between first flowering and final harvest. Fruits were harvested three times weekly for 7 weeks. There was no year-to-year variation in CER or LAI. Plants at 8 cm WRS attained maximum CER by 56 days after planting (DAP), while all other spacings took longer. CER at all WRS declined after 85 DAP. In 8 and 16 cm WRS, maximum LAI developed by 56 DAP, but 69 DAP were required at all other spacing. Depending on the spacing, LAI regressed linearly or cubically on DAP. Fruit number/plant (FNP), fruit fresh and dry weight/plant (FFW and FDW), and fresh and dry fruit yield/ha (FFY and DFY) were greater in 1991 than in 1990 as a result of more favorable weather during 1991. There was a linear increase in FNP, FFW, and FDW as WRS increased. Conversely, FFY and DFY were highest at 8 cm and decreased linearly in 1990 and quadratically in 1991 as WRS increased. Results of this study suggest that okra plants reach maximum CER and LAI earlier and produce higher fruit yield per unit area when spaced close together in the row.
Taro Responses to Excess Copper in Solution Culture
Authors: Hill Steven A. , Miyasaka Susan C. , Yost Russell S.
Published: February 2019

Cupric sulfate pentahydrate (CuSO4·5H2O) has been proposed for use in Hawaii as a molluscicide to control golden apple snail (Pomacea canaliculata Lamarck) infestations of taro [Colocasia esculenta (L.) Schott]. Two hydroponic, greenhouse studies were conducted to determine the effects of solution Cu2+ levels on taro growth, the solution Cu2+ toxicity threshold, and useful diagnostic indicators of Cu toxicity. In the first experiment, taro cultivars Lehua maoli and Pololu were grown at nine levels of Cu2+ ranging from 0.5 to 25.0 μm. In the second experiment, `Lehua maoli' was grown at six levels of Cu2+ ranging from 0.25 to 2.5 μm. Significant (P ≤ 0.05) toxic effects included reduced dry matter production, leaf area, and root length: root dry weight ratio, and both impaired photosynthesis and a generalized reduction of cation accumulation in leaf blade tissue. The solution Cu2+ toxicity threshold (based on 90% of relative total dry weight) for young taro plants was 1.2 μm. Because Cu does not accumulate in leaf blade tissues with increasing solution Cu2+ levels, leaf Cu concentration cannot be used as a diagnostic indicator of Cu toxicity in taro.
Resistance to European Corn Borer in Processing Sweet Corn
Authors: Gardner Jeffrey , Hoffmann Michael P. , Smith Margaret E.
Published: February 2019

Trials were conducted in 1997 and 1998 to determine if there is a range of resistance to European corn borer [Ostrinia nubilalis (Hübner)] (ECB) in commercially available processing sweet corn (Zea mays L.). Twelve processing corn cultivars were tested in 1997 and 18 cultivars in 1998. About 40 first instar larvae of colony-reared ECB were used to infest plants in both whorl and silking stages of growth. At harvest, plants infested at the whorl stage were evaluated for numbers of larvae and larval tunnels, and length of larval tunnels. Plants infested at the silking stage were evaluated for number of larvae per ear and were rated for ear damage using a 9-point scale. Resistance rankings among cultivars were consistent between years and between silk- and whorl-infested plants. We conclude that there is a substantial range of resistance already present in processing sweet corn cultivars, and that resistance is probably a combination of both exclusion and suppression of feeding. Our findings have two immediate uses: incorporation into existing IPM programs and incorporation of identifiable resistance bearing cultivars into a long-term breeding program for resistance to ECB in sweet corn.
Phenotypic Variation for Downy Mildew Resistance among Inbred Broccoli
Authors: Wang Min , Farnham Mark W. , Thomas Claude E.
Published: February 2019

Downy mildew, caused by Peronospora parasitica (Pers. Fr.) Fr., is one of the most economically important diseases of broccoli (Brassica oleracea L. Italica group). Previous studies have shown that resistance to downy mildew in broccoli is dependent on plant age with seedling resistance being independent of mature-plant resistance. The objectives of this study were to: 1) determine if valid evaluations for downy mildew resistance can be conducted at both the cotyledon and the three to four true-leaf stages on the same plants of a given broccoli entry; 2) determine if doubled-haploid (DH) lines derived from the resistant hybrid `Everest' also exhibit resistance to downy mildew and if so, characterize the resistance phenotype(s) in these lines; and 3) determine if identified resistant DH lines exhibit resistance to isolates of P. parasitica acquired from different geographic regions of the United States. Twenty-three DH broccoli inbreds and two commercial hybrids were evaluated for reaction at different developmental stages to infection by P. parasitica in a controlled environment. Results showed that broccoli plants can be evaluated for downy mildew resistance in a two-stage process. Inoculation at the cotyledon stage did not offer any cross-protection or otherwise influence the expression of reaction phenotype (RP) when the same plants were subsequently inoculated at the three to four true-leaf stage. Three different RPs to infection by P. parasitica were identified in DH inbreds. These were: 1) susceptibility at both the cotyledon stage and the true-leaf stage; 2) resistance at both the cotyledon and true-leaf stage; and 3) susceptibility at the cotyledon stage but resistance at the true-leaf stage. There was no effect of two pathogenic isolates from different geographic regions on RP of DH broccoli inbreds. Selection of plant resistance to downy mildew at the cotyledon stage will effectively identify plants with high levels of resistance at subsequent developmental stages.
Aflatoxin Production among Almond Genotypes Is Not Related to Either Kernel Oil Composition or Aspergillus flavus Growth Rate
Authors: Gradziel Thomas , Mahoney Noreen , Abdallah Ashraf
Published: February 2019

Genetic differences were observed in levels of aflatoxin production following controlled inoculations of California almonds [Prunus dulcis (Mill.) D.A. Webb, syn. P. amygdalus, Batsch.; P. communis (L.) Arcangeli, non Huds.]. Genetic variation was also observed in kernel oil composition, and in susceptibility to Aspergillus flavus Speare as indicated by rate of mold expansion on the surface of cut kernels. Several almond lines resulting from the introgression of peach [P. persica (L.) Batsch] germplasm had very low aflatoxin levels relative to commercial cultivars tested. Peach-derived almond breeding lines and cultivars also produced some of the highest oil quality as determined by the proportion of oleic acid, and by the oleic to linoleic acid balance. The proportion of linoleic acid to total oil ranged from 16% to almost 30%. No correlations were detected between aflatoxin production in inoculated almond kernels and either kernel oil composition or mold growth rate on injured kernel tissue.
Browning Inhibition of Fresh-cut `Anjou', `Bartlett', and `Bosc' Pears
Authors: Buta J. George , Abbott Judith A.
Published: February 2019

Treatments to inhibit browning and maintain quality of fresh-cut `Anjou', `Bartlett', and `Bosc' pears (Pyrus communis L.) were developed. Slices of `Anjou', `Bartlett', and `Bosc' pears (firmness 22, 36, and 22 N, respectively) were dipped in solutions of 4-hexylresorcinol, isoascorbic acid, N-acetylcysteine, and potassium sorbate prior to storage in air for up to 14 days at 5 °C. Inhibition of browning without loss of firmness and with no microbial growth was achieved for the three cultivars for 14 d. Inhibition of browning during 14 d storage at 5 °C was not affected by initial firmness (21-52 N) of `Anjou' pear slices.
DNA Extraction from Several Cacti
Authors: Mondragon-Jacobo Candelario , Doudareva Natalia , Bordelon Bruce P.
Published: February 2019

A method for extraction of high quality DNA from four Opuntia sp. and other cacti using a hexadecyltrimethylammonium bromide (CTAB) method is described. These plants typically contain high levels of mucilages, complex polysaccharide compounds that bind water, thus preventing DNA extraction by common miniprep methods. The method involves adjusting the amount of tissue used according to species and age, followed by processing in an extraction buffer to separate coarse material. Extended centrifugation and digestion time in a separation buffer with CTAB (2%) was used. Exposing tissue to both buffers maintained polysaccharides in solution and allowed easier recovery of the aqueous phase that contains the DNA. We found that 5-8 g were needed to obtain up to 153 μg·g-1 of DNA from tender tissue. Old tissue yielded 26% less. Extraction of DNA from 5-g samples of tender tissue of the ornamental cacti Stenocereus sp., Cleistocactus sp., and Echinocereus sp. was successful. For these species, average yields ranged from 25 to 53 μg per sample. The DNA obtained was suitable for polymerase chain reaction (PCR) amplification, producing clear, distinctive, and reproducible banding patterns useful for a variety of applications.
Cultivar Pollinizer Does Not Affect Almond Flavor
Authors: Dicenta F. , Martínez-Gómez P. , Ortega E. , Duval H.
Published: February 2019

The effect of pollinizer on sweet or bitter almond flavor was studied by tasting the seeds obtained from 32 crosses between sweet, bitter, and slightly bitter parents. Out of eight female parents, two were homozygous sweet (`Del Cid' and `Aï'); two were heterozygous sweet (`Marcona' and `Nonpareil'); one heterozygous with an almost undetectable slightly bitter flavor (`Ferrastar'); two heterozygous slightly bitter (`Garrigues' and `Marie Dupuy'); and one bitter homozygous (`S3067', self-compatible clone obtained in CEBAS). Each cultivar was hand-pollinated with four male cultivars: one homozygous sweet (`Ramillete'), one heterozygous sweet (`Atocha'), one heterozygous slightly bitter (`Garrigues'), and one homozygous (`S3067'). Since `Garrigues' is self-incompatible, the cross `Garrigues' × `Garrigues' was replaced by `Garrigues' × `S3065' (slightly bitter clone obtained in CEBAS). Tasting of the seeds resulting from each cross resulted in the complete absence of any influence of pollinizer on flavor, which only depended on the female parent.
Orchard Cooling with Overtree Sprinkler Irrigation to Improve Fruit Color of `Delicious' Apples
Authors: Iglesias I. , Graell J. , Echeverría G. , Vendrell M.
Published: February 2019

The influence of supplemental sprinkler irrigation on fruit color of `Oregon Spur Delicious' (Trumdor) apples (Malu×domestica Borkh.) was evaluated in the area of Lleida (NE Spain) over a 3-year period. Cooling irrigation was applied for 2 hours daily for 25-30 days preceding the harvest. Three treatments were evaluated: 1) control without overtree sprinkler irrigation; 2) sprinkler irrigation applied at midday; and 3) sprinkler irrigation applied at sunset. Fruit color was significantly affected by the cooling irrigation and also by the weather of the particular year. Increased red color and higher anthocyanin content resulted from sprinkler irrigation, especially when applied at sunset. At harvest, anthocyanin content was correlated with a*/b* and hue angle, suggesting that the colorimeter measurements could provide a nondestructive estimate of anthocyanin content.
Response of Potted Peach Trees to Pruning and Grass Competition
Authors: Tworkoski Thomas
Published: February 2019

Peach [(Prunus persica (L.) Batsch., `Rutgers Redleaf'] trees were grown for two seasons in a greenhouse with three pruning treatments (none, shoot tips removed, and half the shoots removed) and three grass treatments (no grass competition; perennial ryegrass, Lolium perenne L., `Linn'; and tall fescue, Festuca arundinacea Schreb, `Kentucky 31'). Competing grass reduced shoot growth, leaf area, and weight of fine roots in shallow soil, but did not affect the growth response to pruning. Regrowth from pruned trees was such that the shoot: root ratio was restored to that of unpruned trees. Leaf water potential, stomatal conductance, and photosynthesis had decreased markedly by 48 hours after irrigation ceased in trees without competition (larger trees) and to a similar level by 96 hours in trees with competition (smaller trees). Apparently, the reduced leaf area of peach trees grown with grass competition delayed water stress. Leaf abscisic acid levels were not directly affected by grass competition but increased as leaf water potential decreased. Grass competition modified morphology and reduced tree size, but did not affect shoot growth following pruning.
Trellising System and Cane Density Affect Yield and Fruit Quality of Red Raspberry
Authors: Heuvel Justine E. Vanden , Proctor John T.A. , Sullivan J. Alan
Published: February 2019

Trellising and cane density treatments were applied to vigorous raspberry (Rubus idaeus L.) cv. Titan plants in Southern Ontario to determine their effects on yield, yield potential, and canopy microclimate during the 1997 and 1998 seasons. The trellising treatments compared were hedgerow (control), V-trellis, and single-sided shift-trellis (shift-trellis). Cane densities (9, 16, 23, and 30 canes/m2) were established before budbreak each season. The treatments significantly affected yield and yield components. Path analysis indicated that interrelationships among yield components were significantly affected by trellising system. In the second season, plants trained on the V-trellis yielded more than did those in a hedgerow system, while those trained on a shift-trellis had the lowest yield because of a smaller fruiting framework. Fruit quality was lower on the shifttrellis than in the other two systems. These differences were related to light penetration into the three canopies. While an optimum cane density was not found for any system, the maximum cane density (30 canes/m2) produced the highest yields. Yield potential per cane decreased as cane density increased; however, the increase in cane number compensated for this decrease, resulting in an increase in total yield per unit area. Fruit quality also decreased as cane density increased, but cane density did not affect canopy microclimate.
Growth Promotion of Highbush Blueberry by Fungal and Bacterial Inoculants
Authors: de Silva Amal , Patterson Keith , Rothrock Craig , Moore James
Published: February 2019

The highbush blueberry cultivar Bluecrop was inoculated with potential plant growth-promoting (PGPR) candidates, including bacterial inoculants Pseudomonas fluorescens (Migula) (strains Pf 5, PRA 25, 105, or 101), Bacillus pumilus (Mayer and Gottheil) (strain T4), Pseudomonas corrugata (Roberts and Scarlett) (strain 114), and fungal isolates Gliocladium virens (Miller et al., Von Arx) (strain Gl.21) and Trichoderma harzianum (Rifai) (strain T 22). Addition of G. virens to pasteurized soil increased leaf area and the number of leaves produced in a 4-month growth period, as well as shoot content of P, Zn and Cu in 1997. Treatment with P. fluorescens Pf 5 increased leaf area and stem diameter. In nonpasteurized soil, plants inoculated with G. virens had greater leaf area, stem diameter, shoot and root dry weight, and more leaves per plant. These results demonstrate the potential of G. virens for increasing growth when used to inoculate blueberry plants in the nursery or at transplanting.
Improving the Prediction of Processing Bean Maturity Based on the Growing-degree Day Approach
Authors: Jenni Sylvie , Bourgeois Gaétan , Laurence Hélène , Roy Geneviève , Tremblay Nicolas
Published: February 2019

Four snap bean (Phaseolus vulgaris L.) cultivars, Goldrush, Teseo, Labrador, and Flevoro, were grown in irrigated fields of southern Quebec between 1985 and 1998. Data on phenology collected from these fields were used to determine which base temperature would best predict time from sowing to maturity. The optimal base temperature was 0 °C for `Goldrush', `Teseo', and `Labrador' and 6.7 °C for `Flevoro'. Adjusting different base temperatures for intermediate developmental stages (emergence, flowering) did not improve the prediction model. All years for a given cultivar were then used to determine the base temperature with the lowest coefficient of variation (CV) for predicting the time from sowing to maturity. A common base temperature of 0 °C was selected for all cultivars, since `Flevoro' was not very sensitive to changes in base temperature. This method improved the prediction of maturity compared with the conventional computation growing-degree days (GDD) with a base of 10 °C. For the years and cultivars used in this study, calculating GDD with a base of 0 °C gave an overall prediction of maturity of 1.7, 1.5, 2.0, and 1.4 days based on average absolute differences, for `Flevoro', `Goldrush', `Teseo', and `Labrador', respectively.
Phosphorus Source Affects Phosphorus Leaching and Growth of Containerized Spirea
Authors: Godoy Arleen , Cole Janet C.
Published: February 2019

Commercially propagated `Halward's Silver' spirea (Spiraea nipponica Maxim.) bareroot cuttings and cuttings with substrate around the roots (plugs) were transplanted into 3.8-L containers and fertilized with various P fertilizers to determine the effect of fertilizer source on P leaching and plant growth. The following fertilizer treatments were applied: 1) 100% of the recommended rate of P from controlled-release fertilizer (CRF), consisting of 22N-2.6P-10K; 2) 100% of P from triple superphosphate (TSP, 0N-20P-0K) with N and K provided by 22N-0P-10K CRF; and 3) 50% of P from CRF, consisting of 22N-1.3P-10K, plus 50% of P from TSP (CRF/TSP). The most P leached from cuttings transplanted as plugs or bareroot and fertilized with TSP, while the least P leached from cuttings transplanted as plugs and fertilized with CRF or CRF/TSP. Plants fertilized with CRF/TSP generally had larger root dry weights than did plants fertilized with CRF or TSP. Plants fertilized with CRF had the smallest stem dry weights. Shoot-to-root (S/R) ratio was largest in plants transplanted as plugs in substrate amended with TSP, but cuttings transplanted bareroot into CRF-amended substrate had the highest S/R ratio and the lowest stem P concentration. Incorporation of CRF/TSP into the container substrate can reduce P leaching compared with incorporation of TSP, and can increase root and stem dry weights of plants transplanted as plugs compared with incorporation of CRF.
Fresh Market Tomato Yield and Soil Nitrogen as Affected by Tillage, Cover Cropping, and Nitrogen Fertilization
Authors: Yaffa Sidat , Singh Bharat P. , Sainju Upendra M. , Reddy K.C.
Published: February 2019

Sustainable practices are needed in vegetable production to maintain yield and to reduce the potential for soil erosion and N leaching. We examined the effects of tillage [no-till (NT), chisel plowing (CP), and moldboard plowing (MP)], cover cropping [hairy vetch (Vicia villosa Roth) vs. winter weeds], N fertilization (0, 90, and 180 kg·ha-1 N), and date of sampling on tomato (Lycopersicon esculentum Mill.) yield, N uptake, and soil inorganic N in a Norfolk sandy loam in Fort Valley, Ga. for 2 years. Yield was greater with CP and MP than with NT in 1996 and was greater with 90 and 180 than with 0 kg·ha-1 N in 1996 and 1997. Similarly, aboveground tomato biomass (dry weight of stems + leaves + fruits) and N uptake were greater with CP and MP than with NT from 40 to 118 days after transplanting (DAT) in 1996; greater with hairy vetch than with winter weeds at 82 DAT in 1997; and greater with 90 or 180 than with 0 kg·ha-1 N at 97 DAT in 1996 and at 82 DAT in 1997. Soil inorganic N was greater with NT or CP than with MP at 0- to 10-cm depth at 0 and 30 DAT in 1996; greater with hairy vetch than with winter weeds at 0- to 10-cm and at 10- to 30-cm at 0 DAT in 1996 and 1997, respectively; and greater with 90 or 180 than with 0 kg·ha-1 N from 30 to 116 DAT in 1996 and 1997. Levels of soil inorganic N and tomato N uptake indicated that N release from cover crop residues was synchronized with N need by tomato, and that N fertilization should be done within 8 weeks of transplanting. Similar tomato yield, biomass, and N uptake with CP vs. MP and with 90 vs. 180 kg·ha-1 N suggests that minimum tillage, such as CP, and 90 kg·ha-1 N can better sustain tomato yield and reduce potentials for soil erosion and N leaching than can conventional tillage, such as MP, and 180 kg·ha-1 N, respectively. Because of increased vegetative cover in the winter, followed by increased mulch and soil N in the summer, hairy vetch can reduce the potential for soil erosion and the amount of N fertilization required for tomato better than can winter weeds.
Resistance to the Fruit Infection Phase of Mummy Berry Disease in Highbush Blueberry Cultivars
Authors: Stretch A.W. , Ehlenfeldt M.K.
Published: February 2019

Sixty-eight highbush blueberry (Vaccinium corymbosum L.) cultivars and selections were evaluated over 3 years for their resistance to the fruit infection phase of mummy berry disease [Monilinia vaccinii-corymbosi (Reade) Honey]. Average incidence of fruit infection under test conditions was 34.3% in 1995, 14.4% in 1996, and 27.9% in 1997, with significant differences occurring among clones in all 3 test years. Several cultivars exhibited consistent resistance to mummy berry fruit infection across all years of testing. `Northsky', `Reka', `Northblue', `Cape Fear', `Bluegold', `Puru', and `Bluejay' were among the most resistant, and `Atlantic', `Berkeley', `Herbert', and `E-176' were among the most susceptible. The consistent resistant reaction of certain cultivars indicates that they may be suitable as parents for introducing resistance into a breeding program. No significant correlation was observed between blighting resistance and fruit infection resistance.
Reduction of Ethylene-induced Physiological Disorders of Carrots and Iceberg Lettuce by 1-Methylcyclopropene
Authors: Fan X. , Mattheis J.P.
Published: February 2019

Whole carrots (Daucus carota L.) and midrib tissues of iceberg lettuce (Lactuca sativa L.) were treated with 42 μmol·m-3 MCP, then exposed to ethylene. Exposure to 42 μmol·m-3 ethylene at 10 °C increased isocoumarin content ≈40-fold in both peel and pulp of nontreated carrots within 4 days, but treatment with MCP for 4 hours at 20 °C before exposure to ethylene prevented isocoumarin accumulation. Ethylene-induced acidity loss and respiration rate increase in carrots were also prevented by MCP treatment. Ethylene treatment (126 μmol·m-3) of lettuce at 6 °C had induced russet spotting >5% to 10% of the midrib tissue by day 3 and 30% to 35% by day 9, while pretreatment with MCP for 4 hours at 6 °C prevented development of russet spotting. The results indicate that ethylene-induced physiological disorders and quality loss in carrots and iceberg lettuce can be prevented by MCP treatment prior to exposure to ethylene. Chemical name used: 1-methylcyclopropene (MCP).
Discovery of a New Self-incompatibility Allele in Apple
Authors: Matsumoto Shogo , Kitahara Kentaro
Published: February 2019

A polymerase chain reaction (PCR)-based method for identifying the S-alleles in the Asian pear [Pyrus pyrifolia (Burm) Nak.] was applied to apple (Malus ×domestica Borkh.) cultivars. With minor modifications in one of the primers, the fragments from S-genes (S-RNases) with introns were amplified from total DNA of apple cultivars possessing S2-, S3-, S5-, S7-(=Sd-), S9-(=Sc-), Sf- and Sg-allele genotypes. S-genes within S24-(=Sh-) and S26-alleles were also amplified. The PCR amplification step of this method appears to be useful for preliminary investigation of apple S-genotypes, especially for species or cultivars of unknown origin or history. Using the primers, which are a part of a new S-allele, the Se-allele encoding Se-RNase with an intron in the Se-allele was amplified. We cloned the cDNA of Se-RNase, and developed a PCR-restriction fragment length polymorphism (RFLP) analysis method for Se-allele identification. S-allele genotypes of seven apple cultivars were investigated.
A Monogenic Recessive Gene, fw, Conditions Flower Doubling in Nicotiana alata
Authors: Zainol Rozlaily , Stimart Dennis P.
Published: February 2019

A double-flower form of Nicotiana alata Link & Otto was characterized genetically as a monogenic recessive trait expressed when homozygous. Reciprocal crosses demonstrated no maternal effect on expression of double flowers. A single dominant gene expressed in the homozygous or heterozygous state caused the single-flower phenotype. The symbol fw is proposed to describe the gene controlling double-flower phenotype.
Relationships Among Day of Year of Drop, Seed Number, and Weight of Mature Apple Fruit
Authors: Ward Daniel L. , Marini Richard P. , Byers Ross E.
Published: February 2019

Preharvest fruit drop of apple [Malu×domestica (L.) Borkh.] can cause significant crop losses, but factors controlling date of individual fruit drop are unknown. In three types of experiments, we investigated the relationships among seed number/fruit, fruit weight, and day of year of drop. By shading in mid-May and stigma excision before bloom, we induced variability in seed number. Dropped fruit were weighed, and their seeds were counted daily from late August until all fruit had dropped. Nontreated trees were studied similarly. Regression analyses were used to assess relationships among day of drop, fruit weight, and seed number/fruit. Substantial variation in day of drop of individual fruit was not explained by seed number of the fruit in these experiments with `Smoothee Golden Delicious', `Redchief Delicious', and `Commander York'.
Evaluating Hairy Vetch Residue as Nitrogen Fertilizer for Tomato in Soilless Medium
Authors: Sainju Upendra M. , Rahman Syed , Singh Bharat P.
Published: February 2019

The ability of hairy vetch (Vicia villosa Roth) residue (100 g/plant) to supply N and to increase yields of tomato (Lycopersicon esculentum Mill.) was compared with that of N fertilization (0, 4.1, and 8.2 g/plant N) in a medium containing a mixture of 3 perlite: 1 vermiculite in a greenhouse and a lathhouse. Hairy vetch residue did not interact with N fertilization in affecting tomato yield and medium N concentration. In the greenhouse, leaf dry weight, leaf and stem N uptake, total (fruit + stem + leaf + root) dry weight and N uptake of tomato, and NH4+ and inorganic N concentrations in the medium at transplanting were significantly greater with than without residue. In the lathhouse, fruit number, fresh and dry yields and N uptake, leaf, stem, and root dry weights and N uptake, root length, total dry weight and N uptake of tomato, and NH4+, NO3-, and inorganic N concentrations in the medium at transplanting, and inorganic N at harvest were greater with than without residue. Nitrogen fertilization increased fruit number, fresh and dry yields and N uptake, stem, leaf, and root dry weights and N uptake, root length, and total dry weight and N uptake. The residue was as effective in increasing fresh fruit yield, total dry weight, and N uptake as was 4.4 to 7.9 g/plant of N fertilizer. Tomato yield and N uptake per unit amount of N supplied was greater for the residue than for N fertilization, suggesting that hairy vetch residue can be effectively used as N fertilizer for tomato production.
Temperature Effects on Interspecific Hybridization between Gladiolus ×grandiflora and G. tristis
Authors: Takatsu Yasumasa , Kasumi Masakazu , Manabe Toru , Hayashi Mikio , Inoue Eiichi , Marubashi Wataru , Niwa Masaru
Published: February 2019

Interspecific hybridization between a modern cultivar of Gladiolu×grandiflora hort. (2n = 60) and the wild species G. tristis L. (2n = 30) was made to introduce characteristics of the wild species into the cultivated one. Gladiolus ×grandiflora is a summer-flowering species, and G. tristis flowers in winter. The effect of storage temperature on pollen viability was tested, as long-term storage of pollen was necessary to facilitate crossing these two species. Pollen of G. tristis could be stored at -20 °C for ≈1 year, and was more practical than storage at -80 °C. Air temperature affected pollen tube growth, fertility, and fruit set in the cross between G. ×grandiflora and G. tristis, and low temperatures (15 to 20 °C) were best. The morphological data and flow cytometric analysis showed that the F1 plants were hybrids between G. ×grandiflora and G. tristis.
Heat Tolerance of Kentucky Bluegrass as Affected by Trinexapac-ethyl
Authors: Heckman Neil L. , Horst Garald L. , Gaussoin Roch E. , Young Linda J.
Published: February 2019

Heat accumulation during storage of sod may reach lethal temperatures within 4 days, decreasing sod quality. Treatment with trinexapac-ethyl reduces heat accumulation during sod storage. However, heat tolerance of grasses treated with trinexapacethyl has not been documented. Our objectives were to: 1) determine the lethal temperatures for Kentucky bluegrass (Poa pratensis L.); and 2) identify the effect of a single application of trinexapac-ethyl on heat tolerance. Experimental design was a randomized complete block with three replications and a two (trinexapac-ethyl vs. control) × two (cultivars) factorial arrangement of treatments. Ten days after chemical treatment, Kentucky bluegrass sprigs were exposed to heat stress for 4 days in a temperature gradient block under low vapor pressure deficit. Treatment with trinexapac-ethyl at 0.23 kg·ha-1 reduced heat tolerance. Temperature needed to kill 50% of the population was 35.5 °C for treated vs. 36.1 °C for nontreated grass. Trinexapac-ethyl is in the same chemical family as the cyclohexanedione herbicides that interfere with lipid syntheses in grasses. This may be a reason for the slight decrease in heat tolerance. The practical value of trinexapac-ethyl treatment in reducing heat accumulation during storage of sod may be partially negated by a decrease in heat tolerance. Chemical name used: [(4-cyclopropyl-α-hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid methyl ester] (trinexapac-ethyl).