bluuebunny/crossref_metadata_2025 huggingface dataset:
Ethylene Evolution from Detached Apple Spurs in Response to Chemical Thinners
Authors: McArtney Steven J.
Published: February 2019

Ethylene evolution from detached fruiting apple spurs was measured after application of various bloom and post-bloom thinning agents. Ethylene evolution from fresh detached spurs of `Splendor' apple trees increased one day after application of a bloom thinning spray of ethephon or NAA, and remained higher than rates of ethylene evolution by detached spurs from unsprayed control trees for 6 (NAA) or 10 (ethephon) days. Both ethylene evolution and fruit abscission during the initial drop period were higher on trees treated with ethephon compared to NAA, however final fruit set was similar for these two treatments. Ethylene evolution was significantly higher following NAA application onto `Fuji' trees compared with NAAm, but final fruit set was reduced by a similar amount (≈20%) for both of these materials. Application of BA to `Pacific Rose™' apple trees when the average diameter of spur fruit was either 4 mm (6 days after full bloom) or 7 mm (12 days after full bloom) resulted in a significant increase in the rate of ethylene evolution and also reduced final fruit set. When application of BA was delayed until the average diameter of spur fruit was 14 mm (24 days after full bloom) neither the rate of ethylene evolution or final fruit set was affected. Although an increase in the rate of ethylene evolution was a prerequisite for thinning in the present experiments, the magnitude of this increase was not related to the final thinning efficacy. Chemical names used: benzyladenine (BA); 2-chloroethyl phosphonic acid (ethephon); naphthaleneacetic acid (NAA); naphthalene acetamide (NAAm).
Phytotoxicity of Selected Insecticides on Greenhouse-grown Herbs
Authors: Cloyd Raymond A. , Cycholl Nina L.
Published: February 2019

A greenhouse study was conducted from Oct. 1999 through Feb. 2000, and Mar. 2001 through Apr. 2001, to determine the potential phytotoxic effects of selected insecticides on Spanish lavender (Lavandula stoechas L.), oregano (Origanum vulgare L. `Santa Cruz'), rosemary (Rosmarinus officinalis L.), St. Johnswort (Hypericum perforatum L. `Topaz'), wolly thyme (Thymus vulgaris L. `Wolly'), and nutmeg thyme (Thymus vulgaris L. `Nutmeg'). Insecticides used for the study were Beauveria bassiana Strain GHA, pyrethrin [+ piperonyl butoxide (PBO)], azadirachtin, potassium salts of fatty acids, two rates of cinnamaldehyde, paraffinic oil, and capsaicin. Visual observations of phytotoxicity were made 7 days after the final application. Pyrethrin, potassium salts of fatty acids, and both rates of cinnamaldehyde were consistently more phytotoxic than the other insecticides. Despite the phytotoxic effects from some of the insecticides, new growth that emerged following treatments compensated for the initial damage, and the herbs were still saleable.
Inheritance of Resistance to Colletotrichum acutatum Simmonds on Runners of Garden Strawberry and its Backcrosses
Authors: Giménez Gustavo , Ballington James R.
Published: February 2019

Two half diallel mating designs were conducted to study the inheritance of resistance to Colletotrichum acutatum Simmonds on runners of strawberry. The main design included six genotypes representing a range of responses to the pathogen: `Chandler' (very susceptible); FL 87-210 (tolerant); MS/US 541 (very resistant); NC 92-01 (Fragaria chiloensis Duch.) (resistant); NCH 87-10 (tolerant-susceptible); and NCC 89-39 (susceptible). The cross `Chandler' × MS/US 541 was absent. The secondary test included `Chandler' and selections FL 87-210 and NC 85-01 (Fragaria virginiana Duch.) (very resistant) as parents. Griffing's methods 4 and 2, model I, were used to test for combining ability in the main and secondary tests, respectively. General combining ability and specific combining ability were highly significant in all analyses. This study indicated that nonadditive effects are more important than additive effects in the inheritance of resistance of runners to anthracnose. The frequency distribution of lesion lengths within progenies suggests that resistance to C. acutatum on runners is quantitative. Therefore, breeding for resistance should be accomplished using progeny testing followed by individual selection within progenies.
Low Temperature Storage of Almond Pollen
Authors: Martínez-Gómez P. , Gradziel T.M. , Ortega E. , Dicenta F.
Published: February 2019

Pollen of the California almond cultivars Nonpareil, Ne Plus Ultra, Sonora, and Peerless was evaluated for viability following storage over 12 months at 4, 0, -20, and -80 °C. The proportion of viable pollen exceeded 80% for all cultivars and for all temperatures evaluated after 2 months of storage. Following 12 months of storage at 4 °C, germination decreased to 8% for `Nonpareil', 10% for `Ne Plus Ultra', 50% for `Sonora', with no germination observed for `Peerless'. Storage at sub-freezing temperatures maintained pollen viability above 70% in `Nonpareil', `Ne Plus Ultra', and `Sonora' and above 40% in `Peerless'. Cultivars differed significantly in their tolerance to low temperature pollen storage. Within cultivars, differences in pollen germination following storage at 0, -20, or -80 °C were nonsignificant.
Improving Cut Flower Production of Balloon Flower
Authors: Halevy Abraham H. , Shlomo Eitan , Ziv Ofra
Published: February 2019

Experiments aiming to adapt the perennial balloon flower (Platycodon grandiflorus) as a commercial cut flower crop were conducted for 4 years under various growing conditions: four controlled-temperature rooms at two photoperiods in a phytotron, heated and unheated greenhouses, and a saran net-house (15% shade). Best flower yield was obtained following crown cooling for 12 weeks at 2 to 4 °C. Platycodon is a day-neutral plant, but produce more flowering stems under long days. Flower initiation and development is enhanced with increased growing temperature from 17/12 °C (day/night) to 27/22 °C. At very high temperatures (32/24 °C), however, only a few flowers are formed. Best quality stems were produced at 12 to 14 °C night temperature. At higher night temperatures, flowering stems were thin and weak. Gibberellin treatments to the crowns and the plants did not affect flowering time. Chemical name used: gibberellin (GA3).
Comparing Three Solutions for Extracting Western Flower Thrips from Coleus Shoots
Authors: Warnock Daniel F. , Loughner Rebecca
Published: February 2019

Western flower thrips [Frankliniella occidentalis (Pergande)] are small-bodied insects that prefer tight spaces such as flower buds and young leaves. Western flower thrips (WFT) pose sampling problems when compared with larger insects commonly found in plant canopies. Techniques to wash insects from plant canopies exist; however, plant type, plant age, and spatial distribution of insects within the canopy impact the efficacy of sampling. An experiment was designed to determine if 75% ethyl alcohol (EtOH), 0.1% detergent solution, or deionized water effectively wash WFT from the foliage of six coleus [Solenostemon scutellarioides (L.) Codd] genotypes inoculated with 32 adults and larvae. The number of WFT recovered after filtration through three mesh sizes varied between blocks and extraction solutions. The mean number of thrips recovered from coleus shoots with 75% EtOH solution, 0.1% detergent solution, or deionized water was 6.7, 8.4, or 0.8, respectively. The number of thrips recovered did not vary by coleus genotype, indicating the extraction solutions were equally effective on smooth leaf or curly leaf type plants. The 75% EtOH extraction solution is recommended for subsequent experiments.
Browning and Dieback of Distal Parts of Fruit-bearing Strands in Date Palms
Authors: Abdul-Baki Aref A. , Wilson Clyde , Brown George E. , Carrera Lidia M. , Aslan Sam , Cobb Sam , Burke Tim
Published: February 2019

The mineral concentration of bearing `Mejhool' date palm (Phoenix dactylifera L.) trees was investigated with the objective of identifying the cause of browning and dieback of distal parts of the fruit-bearing strands. Tissue analyses of leaves, fruits, healthy and dead portions of fruit-bearing strands indicated that tissue browning and dieback appeared to be associated with a high concentration of certain mineral elements. A comparison of mineral concentration between healthy and dead tissue of the fruit-bearing strands showed no significant increase in K, Cu, B, Zn, and Na, but very high increases in the concentrations of P, Ca, Mg, S, Mn, and Fe. The levels of P, Ca, Mg, S, Mn, and Fe in the distal part of the fruit-bearing strand over a 3-year average were 5, 18, 12, 3, 11, and 2 times, respectively, higher than those in the healthy, proximal part of the strand. Mineral concentrations of leaves and mature fruits were determined for comparison with those in fruit-bearing strands.
The Vegetative Response of 'Concord' Grapevines to Soil pH
Authors: Bates Terence R. , Dunst Richard M. , Taft Theodore , Vercant Michael
Published: February 2019

One- and 2-year-old 'Concord' (Vitis labruscana L.) grapevines were used to study the effect of soil pH on vegetative growth and nutrition. Ninety-eight, own-rooted, 'Concord' grapevines were planted in 94.6-L pots containing vineyard soil adjusted to seven soil pH levels ranging from 3.5 to 7.5. After the first growing season, seven vines from each soil pH treatment were randomly selected, destructively harvested, and measured for root and shoot growth. The remaining 49 vines over-wintered in the pots, were defruited in year two, and were destructively harvested at the end of the second growing season. There was a reduction in root biomass below soil pH of 4.5 and a greater reduction in shoot biomass leading to a higher root: shoot ratio. There were no significant differences in vegetative growth of young 'Concord' vines from a soil pH of 5.0-7.5. However, there was a trend toward lower shoot biomass and higher root: shoot ratio at the highest soil pH level. Phylloxera nodosities on roots were present in equal densities at all soil pH values. However, the negative impact of phylloxera on vine dry mass was greater on vines under nutrient stress at the highest and lowest pH treatments than on those with adequate nutrition at the mid-range soil pH values.
Post-symptom Sprays of Prohexadione-calcium Affect Fire Blight Infection of 'Gala' Apple on Susceptible or Resistant Rootstocks
Authors: Schupp J.R. , Rosenberger D.A. , Robinson T.L. , Aldwinkle H. , Norelli J. , Porpiglia P.J.
Published: February 2019

Three studies were conducted to evaluate the effect of post-infection sprays of prohexadione-calcium on the severity of naturally occurring fire blight infections on 3- and 4-year-old 'Gala' apple trees on blight-susceptible or blight-resistant rootstocks. Although post-infection prohexadione-calcium reduced the dry weight of fire blight strikes removed by pruning in one commercial orchard site, this treatment did not reduce mortality of young 'Gala' trees on M.9 or M.26 rootstocks, and did not reduce the incidence of scion or rootstock cankers on any of the rootstocks tested. We conclude that post-infection treatment with prohexadione-calcium is of no practical value in reducing fire blight symptoms on apple. Our results suggest that resistant apple rootstocks will be very valuable in increasing orchard survival in a fire blight epidemic.
Field Evaluations of Novel Chloronicotinyls and Insect Growth Regulators against the Greenhouse Whitefly on Strawberry
Authors: Bi J.L. , Toscano N.C. , Ballmer G.R.
Published: February 2019

The efficacy of two novel chloronicotinyls and two novel insect growth regulators against the greenhouse whitefly [Trialeurodes vaporariorum (Westwood)] on summer-planted strawberries was evaluated in field experiments. Imidacloprid applied in soil 3 weeks after planting decreased whitefly adult numbers by 58% to 90%, first and second instars by 78% to 93% up to 56 days postapplication, and third and fourth instars by 42% to 86% up to 77 days postapplication, whereas thiamethoxam applied similarly reduced adults by 58% to 80%, first and second instars by 78% to 93% up to 6 weeks posttreatment, and third and fourth instars by 48% to 80% up to 10 weeks after initial application, compared to nontreated controls. Imidacloprid applied in soil immediately prior to planting further suppressed numbers of whiteflies by 71% to 83% (adults), 58% to 74% (first and second instars), and 52% to 74% (third and fourth instars), in comparison with the same compound applied through drip irrigation lines 4 weeks after planting. Buprofezin and pyriproxifen applied 6 weeks after planting reduced numbers of adult whiteflies by 25% to 81% and 40% to 73%, respectively; first and second instars by 61% to 92% and 51% to 100%, respectively; and third and fourth instars by 45% to 100% and 37% to 87%, respectively, on most sampling dates up to 7 weeks postapplication. The potential roles of these insecticides in integrated greenhouse whitefly management programs are discussed.
Seed Transmission of Acidovorax avenae subsp. citrulli in Cucurbits
Authors: Hopkins D.L. , Thompson C.M.
Published: February 2019

Prevention of the introduction of bacterial fruit blotch of watermelon, caused by Acidovorax avenae subsp. citrulli, into the transplant house or field is the most effective control strategy. Watermelon seedlots currently are screened for A. avenae subsp. citrulli, but other cucurbits, often grown in the same transplant house or field, generally are not as carefully monitored. In 1997 and 1999 field tests, cultivars of watermelon, muskmelon, honeydew melons, acorn squash, butternut squash, yellow squash, zucchini squash, cucumber, and pumpkin were evaluated for foliar and fruit susceptibility to bacterial fruit blotch and for seed transmission of A. avenae subsp. citrulli. The bacterium was introduced into the field on infected watermelon transplants or by misting a bacterial suspension onto fruit of the cucurbits. Foliar and fruit symptoms were more extensive in the watermelon, muskmelon, and honeydew melons than in the other cucurbits. In greenhouse grow-out assays, seed transmission of A. avenae subsp. citrulli was detected in every cucurbit in at least one of the two seasons, even though there were no fruit symptoms in some of them. Thus, any cucurbit crop plant should be considered a potential source for the introduction of A. avenae subsp. citrulli into the transplant house or field.
Inefficient Transmission of Citrus Tristeza Virus from Grapefruit by Single Brown Citrus Aphids
Authors: Lin Youjian , Brlansky R.H. , Powell Charles A.
Published: February 2019

Six severe and six mild Florida isolates of citrus tristeza virus (CTV) were used to evaluate the transmission efficiency of the virus from grapefruit seedlings by single brown citrus aphids (Toxoptera citricida Kirkaldy) (BrCA) from colonies initiated by aphids obtained from citrus groves in Fort Pierce, Fla. The transmission rate to 2120 receptor plants [`Mexican' lime (Citrus aurantifolia)] from grapefruit by single BrCA was 1.5%. Single BrCA transmitted four of the six severe isolates and three of the six mild isolates of CTV. The average transmission rate of severe isolates was 1.8%, higher than that (0.9%) of mild isolates. Severe isolate Y-7 had the highest transmission rate among six severe isolates, 3.6%. Mild isolate Y-23 had the highest transmission rate among the mild isolates, 3.0%. The transmission rates of CTV by alatae, apterae, or nymphs of BrCA were 1.5%, 1.5%, and 1.0%, respectively. The results suggested that BrCA is an inefficient vector of CTV when the source plant is grapefruit.
Postharvest Handling of Cut Campanula medium Flowers
Authors: Bosma Theresa , Dole John M.
Published: February 2019

Various postharvest treatments were evaluated for effect on longevity and quality of cut Campanula medium L. `Champion Blue' and `Champion Pink' stems. Stems stored at 2 °C either wet or dry had no difference in vase life or percent flowers opened; however, flowers stored dry had a slightly greater percentage of senesced flowers at termination. Increasing storage duration from 1 to 3 weeks decreased vase life. Stems pretreated for 4 hours with 38 °C floral solution (deionized water amended to pH 3.5 with citric acid and 200 mg·L-1 8-HQC) or a 1-MCP pulse followed by a 5% sucrose pulse solution produced the longest vase life (10.3 or 10.4 days, respectively). Flowers opening after treatments commenced were paler than those flowers already opened and a 24-hour pretreatment with 5% or 10% sucrose did not prevent this color reduction. Stems had an average vase life of only 3.3 days when placed in floral vase foam but lasted 10.0 days without foam. Optimum sucrose concentration was 1.0% to 2.0% for stems placed in 22 °C floral vase solution without foam and 4% for stems placed in foam. High (110 μmol·m-2·s-1) or low (10 μmol·m-2·s-1) light levels did not affect postharvest parameters, but the most recently opened flowers were paler under low light conditions than under high light conditions. Chemical names used: 8-hydroxyquinoline citrate (8-HQC); 1-methylcyclopropene (1-MCP).
Plant Regeneration from Anther-derived Embryos of Apple and Pear
Authors: Kadota Masanori , Han Dong-Sheng , Niimi Yoshiji
Published: February 2019

Anthers of six apple [Malus ×domestica (L.) Borkh.], three Japanese pear (Pyrus pyrifolia N.) and two European pear (Pyrus communis L.) scion cultivars were cultured. Callus formation occurred from anthers of all cultivars and androgenic embryogenesis was observed from all except P. pyrifolia `Kosui' and P. communis `La France'. Regeneration of adventitious shoots from anther-derived embryos was shown from all apple cultivars and P. pyrifolia `Shinko'. Many of these shoots did not grow or died on half-strength Murashige and Skoog medium (1962) with 4.4 μm BA and 0.5 μm IBA, whereas several shoots of apple `Starking Delicious' grew to plantlets. Chromosome counts of shoot apical cells of four clones derived from embryos of `Starking Delicious' showed that three clones were diploids and one clone comprised diploid and haploid shoots, suggesting that at least one clone originated from a microspore. Chemical names used: 3-indolyl-butyric acid (IBA); N6-benzyladenine (BA).
Estimation of Fruit Grade Weights Based on Fruit Number and Total Fruit Weight in Cucumber
Authors: Shetty Nischit V. , Wehner Todd C.
Published: February 2019

In many cases, measurement of cucumber fruit weight in small research plots involves more labor and resources than just counting the number of fruit per plot. Therefore, plant breeders are interested in an efficient method for estimating fruit weight per grade (early, marketable, and cull) based on fruit number and total fruit weight. We evaluated the cucumber germplasm collection of 810 plant introduction accessions (supplied by the U.S. Dept. of Agriculture, Regional Plant Introduction Station at Ames, Iowa) along with seven check cultivars for yield. Correlations were calculated for all pairs of fruit number and fruit weight combinations for each grade. In general, the lowest correlations were observed between the fruit weight of each grade (early, marketable, and cull) and total fruit weight or number per plot. High correlations were observed for fruit weight and fruit number within each grade (early, marketable, and cull). An efficient method for estimating fruit weight per hectare of early, marketable, and cull grades is to count total, early, and cull fruit, then measure total fruit weight. Our results showed that the fruit weight of each grade (early, marketable, and cull) was best estimated using the fruit number of that grade (early, marketable, and cull) along with the total fruit weight and total fruit number.
Genetic Assessment of Watermelon Germplasm using the AFLP Technique
Authors: Che Ke-peng , Liang Chun-yang , Wang Yue-guang , Jin De-min , Wang Bin , Xu Yong , Kang Guo-bing , Zhang Hai-ying
Published: February 2019

Amplified fragment length polymorphism (AFLP) analyses were used to assess genetic diversity among 30 genotypes of watermelon [Citrullus lanatus (Thunb.) Mansf.] representing a broad genetic base, including breeding lines and commercial germplasm. Eight AFLP primer combinations selected from 64 primer combinations were polymophic. The polymorphism was 13.0% to 31.9% within the 28 cultivars examined, and 45.3% to 64.2% among all the genotypes. Each genotype could be successfully distinguished based on AFLP scoring. Cluster grouping of accessions based on the AFLP analysis was consistent with that from classification by pedigrees and ecotypes.
Using Self-compatible Inbreds of Broccoli as Seed Producers
Authors: Farnham Mark W. , Harrison Howard F.
Published: February 2019

The discovery that broccoli (Brassicaoleracea L., Italica Group) sprouts contain high levels of sulforaphane, a constituent that may provide chemoprotection against certain carcinogens, has stimulated much interest in seed production of this crop. Studies were undertaken to determine the potential for producing broccoli seed using self-compatible selections from open-pollinated (OP) populations or doubled-haploid (DH) programs. In all outdoor and greenhouse trials, three OP selections and seven DH lines produced selfed seed, but seed weight per plant and number per plant varied significantly among the entries. In all environments there were individuals with relatively high (i.e., >3 g/plant) production that were significantly different from low (i.e., <2 g/plant) producers. The relative productivity of some lines varied greatly between experiments, which indicates that seed production of particular genotypes is affected differently by environmental conditions. This indicates the importance of identifying lines that are high producers of selfed seed across different environments. Two OP cultivar-derived lines (USVL102 and USVL104) and two DH lines (USVL062 and USVL093) were identified that consistently produced relatively high yields in greenhouse and screen cage trials. These lines are good candidates for evaluating seed production in field tests and as possible sources of seed for sprouting.
Uniconazole Application to Container Medium Surface Prior to Planting Bedding Plants
Authors: Barrett J.E. , Schoellhorn R.K. , Bartuska C.A. , Clark D.G. , Nell T.A.
Published: February 2019

Uniconazole was applied as a spray to the surface of container media prior to planting bedding plant plugs. This medium spray was compared to a standard whole-plant spray applied 2 weeks after planting. For petunia (Petunia ×hybrida Vilm.) and coleus (Solenostemon scutellarioides L.) the efficacy of the medium spray was similar to the whole-plant spray. However, for impatiens (Impatiens wallerana Hook. f.) and vinca [Catharanthus roseus (L.) G. Don.] the medium spray had greater efficacy than the whole-plant spray. Increased concentrations of uniconazole in the medium spray decreased plant height; however, the effect of higher concentrations was greater in a medium with out pine bark compared to a medium with pine bark as a component. In the above experiments, uniconazole was applied in a volume of 200 mL·m-2. In a test where spray volume varied, there was a negative linear relationship between plant height and spray volume. Chemical name used: (E)-(+)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ane-3-ol (uniconazole).
Performance of 'Ponkan' Mandarin on Seven Rootstocks in Southern Brazil
Authors: Stenzel Neusa M.C. , Neves Carmen S.V.J. , Gomes José C. , Medina Cristiane C.
Published: February 2019

This study reports the performance (yield, tree size, and fruit quality) of 'Ponkan' mandarin (Citrus reticulata Blanco) on seven rootstocks, evaluated for 11 years under Southern Brazil conditions. Trees on C13 citrange had higher cumulative yield for seven harvests than those on trifoliate orange. Cleopatra mandarin, rough lemon, Rangpur lime, Sunki mandarin, and Volkamer lemon rootstocks maintained their values at an intermediate position and did not present any significant difference regarding C13 citrange, and trifoliate orange. Trees on C13 citrange and on trifoliate orange exhibited the lowest alternate bearing index. Cleopatra mandarin induced the greatest canopy volume, but it was not significantly different from Sunki mandarin and rough lemon. The smallest trees were those on Volkamer lemon and trifoliate orange. The highest yield efficiency came from trees on C13 citrange and the smallest on Cleopatra mandarin. Rootstocks did not significantly affect fruit weight.
Photoperiodic Effects on Vegetative and Reproductive Growth of Vaccinium darrowi and V. corymbosum Interspecific Hybrids
Authors: Spann Timothy M. , Williamson Jeffrey G. , Darnell Rebecca L.
Published: February 2019

Experiments were conducted with V. darrowi and two cultivars of southern highbush blueberry, `Sharpblue' and `Misty,' to test whether V. darrowi and cultivars derived from it are photoperiodic with respect to flower bud initiation. Plants of each cultivar were grown under three different photoperiod treatments [long days (LD) = 16-hour photoperiod; short days (SD) = 8-hour photoperiod; and short days + night interrupt (SD-NI) = 8-hour photoperiod with 1-hour night interrupt] at constant 21 °C for 8 weeks. Vegetative growth was greatest in the LD plants of both cultivars. Flower bud initiation occurred only in the SD treatments, and the lack of flower bud initiation in the SD-NI treatment indicates that flower bud initiation is a phytochrome mediated response in Vaccinium. Previously initiated flower buds on the V. darrowi plants developed and bloomed during the LD treatment, but bloom did not occur in the SD and SD-NI treatment plants until after those plants were moved to LD. These data indicate that flower bud initiation in both V. darrowi and southern highbush blueberry is photoperiodically sensitive, and is promoted by short days, while flower bud development is enhanced under long days.
Response of Shallots to Mulching and Nitrogen Fertilization
Authors: Woldetsadik Kebede , Gertsson Ulla , Ascard Johan
Published: February 2019

Two field experiments were conducted with shallot (Allium cepa var. ascalonicum Baker) on heavy clay soil to evaluate growth and yield response to mulching and nitrogen fertilization under the subhumid tropical climate of eastern Ethiopia during the short and main rainy seasons of 1999 with rainfalls amounting to 240 and 295 mm, respectively. The treatments included wheat straw, clear and black plastic mulches, and an unmulched control, each with nitrogen rates of 0, 75, or 150 kg·ha-1. Straw and black plastic mulches increased soil moisture while clear plastic reduced it considerably. Weed control was best with black and clear plastics in the short season and with black plastic or straw mulch in the main season. Both plastic mulches elevated soil temperature, especially clear plastic, which also caused most leaf tip burn. Yield increased nearly three-fold with the black plastic mulch in the short season and by one fourth in the main season compared to the bare ground. The straw and clear plastic mulches increased yield during the short sea son, but slightly reduced yield in the main season. The growth and yield of shallot were related to the weed control and soil moisture conservation efficiency of the mulches. Mulching did not alter the dry matter and the total soluble solids contents of the bulbs. Nitrogen fertilizer increased leaf numbers, plant height, mean bulb weight, bulb dry matter, and total soluble solids while reducing marketable bulb number, but did not significantly affect yield, leaf tip burn, or weed abundance.
Solution Electrical Conductivity and Ratio of Nitrate to Other Nutrients Affect Accumulation of Nitrate in Hydroponic Lettuce
Authors: Gent Martin P.N.
Published: February 2019

Solution electrical conductivity (EC) and the supply of nitrate in proportion to other elements (nitrate supply ratio) should effect tissue composition of lettuce (Lactuca sativa L.) grown in hydroponic solution. These parameters were varied in several series of successive plantings in greenhouses in the northeast United States. In 1996, when the treatments differed only in EC, 0.65 and 0.9 dS·m-1, but not in nitrate supply ratio, leaf tissue had more nitrate and total reduced-N and lettuce grew faster in the solution with higher EC. Over four series of plantings in 1997 and 1998, the nitrate supply ratio of a low-N treatment was only 60% of that for a high-N treatment, and EC was varied from 1.2 to 2.0 dS·m-1. In 1997 and 1998, tissue nitrate was lower in the low-N treatment only when EC was less than in the high-N treatment. However, under irradiance greater than 10 MJ m-2 per day, the lower EC also slowed growth. Stepwise regression over data from all experiments showed leaf nitrate was primarily a function of EC, and a term that described the interaction between irradiance and EC. Due to selective uptake by the plants, the ratio of elements in the recirculating solution differed from the ratio in which they were supplied. Under irradiance less than 10 MJ m-2 per day and solution EC greater than 1.5 dS·m-1, nitrate accumulated in solution to a concentration greater than expected from simple dilution of the concentrates. Tissue nitrate was also related to solution nitrate, increasing by 0.08-0.09 mg·g-1 dry weight per 1 mg·L-1 increase in solution nitrate. To prevent a rise in tissue and solution nitrate under low irradiance, both solution EC and nitrate supply ratio had to be reduced by about one-third, compared to the conditions required for rapid growth under high irradiance.
Enhanced Production of Brassica oleracea Transplants Using Bed Solarization and Metam Sodium
Authors: McGovern R.J. , Harper F. , Douglas C. , Thompson T.L.
Published: February 2019

Experiments at two commercial farms in Bermuda tested the effectiveness of solarization of narrow beds alone and together with metam sodium (MS) to enhance in-field production of broccoli (Brassica oleracea L. var. botrytis L.) and kale (B. oleracea L. var. acephala DC.) transplants. Soil treatments of clear, low-density polyethylene (LDPE) mulch (25 μm), white LDPE mulch (25 μm) plus MS (702 L·ha-1), and clear mulch plus MS were compared to bare soil. Mulches were applied and MS incorporated through rototiller cultivation 20 cm deep into 1.2-m-wide, flat seed-beds in the last week of June 1995. Mulches were maintained for 8 weeks. Either Broccoli `Pirate' or kale `Blue Curled Scotch' were seeded into transplant beds in Warwick and Devonshire parishes, respectively. Stand data was obtained for broccoli and kale 25 and 35 days, respectively, after seeding. Transplants were rated for root infection and biomass at 11 days (broccoli) or 31 days (kale) after seeding. In general, solarization was as effective as MS in suppression of soilborne pathogens of broccoli and kale plants. An additive effect on plant biomass was observed when solarization and MS were combined. All treatments significantly increased the establishment of broccoli plants and decreased root infection by Rhizoctonia solani in both crops. The incidence of Fusarium sp. was significantly decreased by all treatments in kale roots, and in broccoli by MS alone and in combination with solarization. Shoot fresh weight was significantly increased in kale by all treatments and in broccoli by solarization plus MS.
Resistance to Geminivirus Mixed Infections in Mexican Wild Peppers
Authors: Anaya-López J.L. , Torres-Pacheco I. , González-Chavira M. , Garzon-Tiznado J.A. , Pons-Hernandez J.L. , Guevara-González R.G. , Muñoz-Sánchez C.I. , Guevara-Olvera L. , Rivera-Bustamante R.F. , Hernández-Verdugo S.
Published: February 2019

Screening for resistance to mixed infections with pepper huasteco virus (PHV) and pepper golden mosaic virus (PepGMV) was carried out on plants representing wild pepper accessions collected in different states of México. One accession collected in Yucatán (BG-3821) corresponded to Capsicum chinense Jacq., and three collected from Michoacán (BG-3818), Tamaulipas (BG-3820), and Sinaloa (BG-3819) were identified as C. annuum L. Forty-eight plants were initially inoculated with a 1:1 mix of PHV and PepGMV DNAs by a biolistic method. Those plants that did not show typical symptoms after the biolistic method, were inoculated by grafting. Half of the plants (24) were highly susceptible, while the other half expressed different degrees of resistance. Of the resistant individuals, eight plants were asymptomatic and viral DNA of both viruses was detected in low levels. Two individuals showed delayed symptoms 34 days after symptom expression in the control plants. This delay was correlated with an increase in PHV DNA levels when plants became symptomatic. The remaining 14 plants showed symptom remission in newly developed leaves at 31 days postinoculation, and this asymptomatic effect was correlated diminished PHV DNA within the plants. Our results suggest that the resistance shown by some individuals to geminivirus mixed infections (PHV and PepGMV) is likely due to constrains in viral movement.
Increased Rooting of 'Norton' Grape Cuttings Using Auxins and Gibberellin Biosynthesis Inhibitors
Authors: Keeley Kathryn , Preece John E. , Taylor Bradley H.
Published: February 2019

Hardwood and softwood cuttings of Vitis aestivalis Michx. 'Norton' were rooted under intermittent mist in a series of experiments using cuttings collected from two local vineyards. Hardwood cuttings treated in late March responded in a similar manner to KIBA and KNAA. Although there was little increase in the percentage rooting above 22.29 mm KIBA or 20.72 mm KNAA (5000 mg·L-1 of either auxin), root number (but not root length) increased linearly on cuttings treated with up to 44.58 mm KIBA or 41.44 mm KNAA (10000 mg·L-1 auxin). Cuttings treated with 10000 mg·L-1 auxin produced up to 4 times more roots than the nontreated controls. The gibberellin biosynthesis inhibitors CCC and PAC had little effect on either hardwood cuttings or softwood cuttings that were harvested, treated and placed in the propagation bench in June. However, when softwood cuttings were collected in August, the most roots were found on cuttings treated with 50.6 mm CCC or 0.85 μm PAC. Although all hardwood cuttings were collected at the same time and stored under refrigerated conditions, rooting percentage increased as storage time increased, especially on the nontreated control cuttings. When the cuttings were stored for the longest time (six weeks), KIBA no longer caused more roots per cutting. Chemical names used: potassium salt of indole-3-butyric acid (KIBA), potassium salt of α-naphthaleneacetic acid (KNAA), chlormequat chloride (CCC), paclobutrazol (PAC).
Planting Date Effects on Stand Establishment and Yield of Chile Pepper
Authors: Bevacqua Robert F. , VanLeeuwen Dawn M.
Published: February 2019

Chile pepper (Capsicum annuum L.) yields are highly variable and are strongly influenced by disease and weather. The goal of two field experiments was to evaluate crop management factors, especially planting date, that could contribute to improved and more consistent crop production. Current practice in New Mexico is to direct seed the crop from 13 to 27 Mar. In the first experiment, chile pepper was direct seeded on three planting dates, 13, 20, and 27 Mar. 2000, without or with a fungicide treatment of pentachloronitrobenzene and mefenoxam for the control of damping off. The results indicate planting date had no effect on stand establishment or yield. Fungicide treatment, significantly reduced stand, but had no effect on yield. In the second experiment, chile pepper was direct seeded on six planting dates, 13, 20, 27 Mar. and 3, 10, 17, Apr. 2001, with or without an application of phosphorus fertilizer, P at 29.4 kg·ha-1, banded beneath the seed row. During the growing season, this experimental planting suffered, as did commercial plantings in New Mexico, from high mortality and stunting due to beet curly top virus, a disease transmitted by the beet leafhopper. The results indicate planting date had a significant effect on crop performance. The best stand establishment and highest yield were associated with the earliest planting date, 13 Mar. This date also resulted in the least viral disease damage. Phosphorus fertilizer had no effect on stand establishment or yield. Chemical names used: pentachloronitrobenzene (PCNB); (R)-2-[(2,6-dimethylphenyl)-methoxyacetylamino]-propionic acid methyl ester (mefenoxam).
Relationship of Alternate Bearing Intensity in Pecan to Fruit and Canopy Characteristics
Authors: Wood Bruce W. , Conner Patrick J. , Worley Ray E.
Published: February 2019

Alternate bearing is a major economic problem for producers of pecan nuts [Carya illinoinensis (Wangenh.) K. Koch], yet a fundamental understanding of alternate bearing remains elusive. Nut yields (over a period of up to 78 years) from a commercial-like orchard of 66 cultivars was used to calculate alternate bearing intensity (I). Best-fit regression analysis indicates no association between I and fruit ripening date (FRD) or nut volume; although, there was moderate association with post-ripening foliation periods (PRFP) in that I tends to decrease as the length of the PRFP decreases. Multiple regression models indicated that FRD and nut volume were poor predictors of I: however, PRFP possessed significant inverse predictive power. Late-season canopy health, as measured by percentage of leaflet retention, decreased as FRD approached early-season ripening. Late-season photoassimilation rate was high er on foliage of trees with late FRDs than those with mid- or early-season ripening dates. These data provide new insight into the complex nature of alternate bearing in pecan and provide evidence for modifying the existing theories of alternate bearing of pecan.
Population Density and Nitrogen Fertility Effects on Tomato Growth and Yield
Authors: Wahle Elizabeth A. , Masiunas John B.
Published: February 2019

Greenhouse hydroponics and field experiments were conducted to determine how nitrogen (N) fertilizer treatments affect tomato (Lycopersicon esculentum Mill.) growth, yield, and partitioning of N in an effort to develop more sustainable fertilization strategies. In a hydroponics study, after 4 weeks in nitrate treatments, shoot dry weight was five times greater at 10.0 than at 0.2 mm nitrate. An exponential growth model was strongly correlated with tomato root growth at all but 0.2 mm nitrate and shoot growth in 10 mm nitrate. Root dry weight was only 15% of shoot biomass. In field studies with different population densities and N rates, height in the 4.2 plants/m2 was similar, but shoot weight was less than in the 3.2 plants/m2. At 12 weeks after planting, shoot fresh weight averaged 3.59 and 2.67 kg/plant in treatments with 3.2 and 4.2 plants/m2, respectively. In 1998, final tomato yield did not respond to N rate. In 1999, there was a substantial increase in fruit yield when plants were fertilized with 168 kg·ha-1 N but little change in yield with additional N. Nitrogen content of the leaves and the portion of N from applied fertilizer decreased as the plants grew, and as N was remobilized for fruit production. Both studies indicate that decreasing N as a way to reduce N loss to the environment would also reduce tomato growth.
Effects of Cane Number on Yield Components in 'Chester Thornless' Blackberry on the Rotatable Cross-Arm Trellis
Authors: Takeda Fumiomi , Hummell Ann K. , Peterson Donald L.
Published: February 2019

Mature 'Chester Thornless' blackberry plants were trained to the rotatable cross-arm (RCA) trellis to determine the effect of retaining two, four, or six primocanes on plant productivity. Retention of only the two oldest primocanes and generally the most vigorous primocanes per plant yielded 14.1 kg of fruit compared to 17.1 kg per plant in which as many as six primocanes were retained. Increasing the number of canes did not result in significant yield increase (P = 0.09) because the primocanes trained in late-June and July produced only a few, and, in some cases, no lateral branches. Thus, retaining only those canes that become trainable early in the season decreased labor inputs and allowed primocane training to be completed prior to the onset of harvest. As a result, the effort to train and retain only those primocanes that reach the trainable height before mid-June may be advantageous to minimize labor costs, but will not effect plant productivity.
Basal Medium and Sucrose Concentration Influence Regeneration of Easter Lily in Ovary Culture
Authors: Ramsay Jodie L. , Galitz Donald S. , Lee Chiwon W.
Published: February 2019

Influences of culture media and sucrose concentrations on plant regeneration from Easter lily (Lilium longiflorum L. cv. Ace) ovary tissues were investigated. Pistils excised from unopened flower buds (3-5 cm long) were sectioned and cultured on either B-5 medium or Murashige and Skoog (MS) medium containing 2%, 5%, or 10% sucrose, with 1 mg·L-1 2,4-D and 2 mg·L-1 BA. Callus formation was most prolific on MS medium containing 5% sucrose. Shoot differentiation was higher on MS medium than on B-5 medium. Rooted plants were transferred into soil medium and grown in a greenhouse. Root tip smears showed that 35% of the regenerated plants showed a variation in chromosome numbers from 10 to 25 per cell, while the rest of the regenerants showed the normal 2n = 2x = 24 chromosomes per cell. The mixoploid condition also existed in different root cells of the same regenerated plant. Chemical names used: 2,4-dichlorophenoxyacetic acid (2,4-D); 6-benzylaminopurine (BA).
Role of Sugar in the Vase Solution on Postharvest Flower and Leaf Quality of Oriental Lily 'Stargazer'
Authors: Han Susan S.
Published: February 2019

Individual 'Stargazer' flowers lasted about 4.5 to 5 days and weighed ≈14 g. Addition of 2% sugar into the vase solution neither affected the longevity nor the size of the flowers but significantly enhanced anthocyanin content and, thus, the intensity of petal color. Defoliation of Oriental lilies, the common practice of retail florists, did not affect the opening, longevity, and size of the open flowers, but did result in lighter-color petals when placed in a solution without sugar. Addition of sugar to the vase solution counteracted the adverse effects of defoliation on petal color. Sugar in the vase solution did not overcome the increased bud blasting and the reduced longevity and size of flowers induced by cold storage. However, it enabled more flowers to open fully, which, without sugar, remained only partially open. Excised bud experiments revealed that bud size of 6.1 cm and 7.0 cm were critical for opening of non-cold-stored and cold-stored buds, respectively. Unlike other cut flower species in which flowers for long-term storage or long-distance transport are harvested at a tighter-bud stage than those intended for the local market, in 'Stargazer', harvesting of stems where the smallest bud is >7.0 cm would be critical in reducing cold-storage-induced bud blasting.
Frequency of Vascular Nodules in the Fruit of 'Gala' × 'Splendour' Hybrids and Other Apple Cultivars
Authors: McIvor Ian , Lang Alexander , Lane W. David , Jameson Paula E.
Published: February 2019

The new apple (Malus ×domestica Borkh.) cultivar Sciros™, resulting from a cross of 'Gala' with 'Splendour', is marketed internationally from New Zealand. A characteristic of this cultivar is the presence of dense, dark green or black nodules in the fruit cortex, located in close proximity to the five sepal vascular bundles. Nodules are visible as green spots beginning about 40 days after bloom and they continue to develop, reaching a length of up to 8 mm at fruit maturity, although there is considerable variation in their size. Large vascular nodules often develop dark brown centers and reduce the visual quality of the fruit flesh. The frequencies of vascular nodules in 61 'Gala' × 'Splendour' hybrids from New Zealand and British Columbia, Canada, were examined. These ranged from a mean of 0 to 12.1, depending on the hybrid. Thirteen hybrids were in the high frequency class (2.76-12.1), 28 in the low frequency (0.04-1.86), and 20 were without nodules. The mean nodule frequency in Sciros™ was 12.1 nodules per fruit, the highest of all hybrids examined. Our survey of 44 other cultivars confirmed the occurrence of vascular nodules in 'Gala' and 'Splendour', with mean vascular nodule frequency of 1.9 and 0.5 nodules per fruit, respectively. Nodules were also found in 'Newtown Pippin' (frequency 0.8), and in a 'Newtown Pippin' × 'Granny Smith' hybrid (frequency 0.1).
Self-fertility and Time of Stigma Receptivity in Styrax japonicum
Authors: Reed Sandra M.
Published: February 2019

The objectives of this study were to evaluate self-fertility and to determine the effectiveness of pollinations made over a 4-day period in Japanese snowbell, S. japonicum Sieb. & Zucc. Pollen germination and pollen tube growth were observed in stained styles following cross- and self-pollinations made from 1 day before to 2 days after anthesis. One month after pollination, fruit set averaged 40% in cross-pollinations and 14% in self-pollinations. Two months later, about one-third of the fruit resulting from cross-pollinations had aborted and only one fruit remained from the self-pollinations. This study demonstrated that stigmas of S. japonicum are receptive for at least 4 days and that flowers should be emasculated prior to making controlled cross-pollinations.
Planting Date and Plant Density Affect Yield of Pungent and Nonpungent Jalapeño Peppers
Authors: Russo V.M.
Published: February 2019

There is little known about how cultural methods affect yields of nonpungent jalapeño peppers (Capsicum annuum L.). Seedlings of the nonpungent jalapeño peppers `Pace 103', `Pace 105', `Pace 108', `Dulce', and `TAM Sweet2', as well as the pungent jalapeño peppers `Delicias' and `TAM Jalapeño1', used for comparison, were grown in a greenhouse with either one or two seedlings per cell in transplant trays. Transplanting to the field was in mid-April and mid-June of 2000 and 2001. In-row spacing was 0.46 m between transplanting sites. Density was varied by placing either one or two seedlings at a transplant site with resultant plant densities of 24,216 or 48,432 plants/ha. Marketable and cull yields, on a per hectare basis, were determined. In both years there were more fruit produced, and higher yields (25+% greater), at the higher plant density, especially for the mid-April planting. The exception for the mid-April planting date was `TAM Jalapeño1', which was not different at the two densities. If the increased income from higher yield can compensate for the cost of producing two seedlings in each transplant tray cell, then this technique should be employed when these types of peppers are used in early plantings.