bluuebunny/crossref_metadata_2025 huggingface dataset:
Intersubspecies Hybrids and Their Progeny in Brassica campestris
Authors: McGrath J. Mitchell , Quiros Carlos F.
Published: January 2019

Morphology and fertility were characterized for 22 intersubspecies hybrids within B. campestris L. Nine subspecies, representing crop types from different geographical areas, were used as pollen donors on three different seed parents. Stability of scored morphological characters was divided into four classes based on their appearance in F1 hybrids; i) constant (present in all hybrids when the character was present in one of the parents, e.g., enlarged hypocotyl, divided leaf), ii) variable (present in some hybrids when the character was present in parent types, e.g., petiole color, pubescence), iii) novel (appearing in hybrids but not present in parents, e.g., anther tip spot, self-compatibility), and iv) reciprocal differences. Constant characters are assumed to have a strong genetic component, variable characters may result from heterozygosity in parents, an allelic series, or polygenic inheritance, and novel characters may arise through mutation or altered gene or physiological interactions. Reciprocal crosses revealed morphological components controlled by the maternal parent, and were most striking in pak-choi (ssp. chinensis) by turnip [ssp. rapifera (Metzg.) Sinsk.] hybrids. Pollen and seed fertility of hybrids was generally reduced when Indian oilseeds [ssp. dichomata (Roxb.) Olsson; ssp. trilecularis (Roxb.) Olsson] were used as parents. Inheritance of the enlarged hypocotyl character was tested in one F2 population. Segregation of the enlarged hypocotyl trait was consistent with a hypothesis of a dominant Mendelian locus. Various novel characters appeared in this F2 population that were not evident in the parents of the hybrid, some of which also showed Mendelian segregation. Genetic differentiation of nuclear or plastid genomes may account for these observations.
In Vitro Propagation of Virginia Pine from Cotyledons
Authors: Saravitz Carole H. , Blazich Frank A. , Amerson Henry V.
Published: January 2019

Adventitious shoots developed on cotyledons of Virginia pine (Pinus virginiana Mill.) excised from seeds subjected to H2O2 treatment for 3, 6, or 9 days and cultured on media containing 0.5 to 10 mg BA/liter. Shoot regeneration was greatest (42 shoots per embryo) on cotyledons from seeds treated with H2O2 for 6 days and placed on medium containing BA at 10 mg·liter-1. Excised shoots elongated on medium lacking BA. Following elongation, shoots were placed on media containing IBA at 0 to 40 mg·liter-1 for 14 days followed by transfer to the same medium lacking auxin. Without IBA treatment, rooting was 3%, and increased to 50% for 5 to 40 mg·liter-1. Rooted shoots averaged 2.0 roots per shoot without auxin incorporation, 3.3 roots when treated with 5 mg IBA/liter, and the number of roots increased linearly with increased IBA concentration up to 40 mg·liter-1 (4.5 roots). Plantlets were transferred to growing medium and acclimated successfully to greenhouse conditions. Chemical names used: N- (phenylmethyl)-1 H- purine-6-amine (BA), 1 H- indole-3-butyric acid CBA).
Using Canopy Temperature Measurements to Evaluate Drought Tolerance of Potato Genotypes
Authors: Stark Jeffrey C. , Pavek Joseph J. , McCann Ian R.
Published: January 2019

Field studies were conducted in 1986 and 1987 to evaluate the potential of using canopy temperature measurements to evaluate the relative drought tolerance of potato genotypes. In both years, 14 potato genotypes representing a relatively wide range of Solarium tuberosum L. germplasm were grown under well-watered [irrigation ≈100% potential evapotranspiration (ET) and stressed (irrigation ≈40% to 50% potential ET) coditions. Irrigation differences were imposed with a line source irrigation system. Canopy temperatures of the 14 genotypes were measured between 0900 and 1430 hr on 7 clear days during tuber bulking. A general linear relationship between canopy minus air temperature (ΔT) and air vapor pressure deficit (VPD) was determined for each year by regressing all ΔT data onto corresponding VPD values. The relative sensitivity of each genotype to changes in VPD was determined by regressing observed ΔT values onto the estimated ΔT from the general equation for that year. Genotypes with higher than average temperatures under well-watered conditions were generally less sensitive to changes in VPD than those with lower than average temperatures. Warmer genotypes under well-watered conditions were also generally less susceptible to drought than cooler genotypes. Thus, ΔT measurements from well-watered plots can be effectively used to assess the relative drought tolerance of potato genotypes.
Fruit and Hormones Influence Flowering of Apple. II. Effects of Hormones
Authors: McLaughlin Joann M. , Greene Duane W.
Published: January 2019

Combination postbloom sprays of BA at 50 mg·liter-1 and daminozide at 2000 mg·liter-1 were made to limbs of `Early McIntosh' apple (Malus domestics Borkh.) where all of the flowers were either removed before full bloom or allowed to remain. BA and fruit removal increased return bloom, whereas daminozide bad no effect. No treatment had a consistent effect on spur leaf area. Repeat sprays of GA4+7 to `Delicious' apple trees at full bloom (FB) +5, FB + 14, and FB +22 days reduced appendage development and flower bud formation on spurs. One spray of GAd+7 at 150 mg·liter-1 at FB +42 days reduced appendage formation and the percentage of flowering spurs but not as effectively as earlier repeat sprays of GA4+7 at 50 mg·liter-1 When BA at 150 mg·liter-1 was combined with the GA at FB +42 days, appendage formation was increased but the reduction in flowering was not reversed. One BA spray at 50 mg·liter-1 at FB +22 days to `McIntosh' trees increased the number of appendages formed in spurs, but return bloom was not influenced. Chemical names used: (N -phenylmethyl) -1 H -purine-6-amine (BA); butanedioic acid mono (2, 2-dimethylhydrazide) (daminozide); gibberellins A4 and A7 (GA4+7).
Growth, Yield, and Fruit Weight of Spur-bound `Delicious' Apple Trees following Spur-pruning and BA Plus GA4+7 Application
Authors: Marini Richard P. , Sowers Donald
Published: January 2019

Twenty-eight-year-old `Starkrimson Delicious' and 10-year-old `Fullred Delicious' apple (Malus domestics Borkh.) trees were spur-pruned in 1986 and 1987 and/or treated with 500 mg BA + GA4+7/liter in 1986 in an attempt to improve spur growth and increase fruit weight. All treatment combinations generally failed to improve yield or fruit size. BA + GA4+7 reduced yield and fruit weight and increased the number of pygmy fruit in 1986, but had little effect on fruiting or vegetative growth for 3 years after treatment. Spur-pruning reduced spur density in 1986 and 1987 and increased yield, but not fruit weight, in 1987. Although spur-pruning improved spur length, spur bud diameter, leaf area per spur, and leaf dry weight per spur, fruit weight was not improved. Chemical names used: N-(phenylmethyl)-1H -purine-6-amine [benzyladenine (BA)]; gibberellin (GA4+7).
A Tentative Model to Describe the Respiration of Stored Apples
Authors: Andrich G. , Fiorentini R. , Tuci A. , Zinnai A. , Sommovigo G.
Published: January 2019

Using mathematical equations that describe the 02 mass-transfer and the enzymatic oxidation of the organic substrates of apples (Malus domestica Borkh.), we developed a kinetic model to correlate fruit respiration rate with environmental oxygen partial pressure (PO2. The kinetic determinations were carried out at room temperature using apples stored at 3 to 4C for 11 to 19 weeks. Results show that: 1) the calculated value of the Michaelis-Menten constant related to the enzymatic oxidation of the respiratory substrate (Km = 2.1 ± 0.5.10-5 mol·kg-1) is close to that reported in the literature for cytochrome-c oxidase; 2) the located range of PO2 levels where 02 becomes the limiting factor in the respiration process (near 2.6 kPa at T = 20.5 ± lC) is close to those usually used on a commercial scale for controlled atmosphere storage.
Responses of Closely Related Bush Blue Lake Snap Bean Cultivars to Increasing Concentrations of Ozone
Authors: Eason G. , Reinert R.A.
Published: January 2019

Eight Bush Blue Lake type snap bean (Phaseolus vulgaris L.) lines and cultivars with similar genetic backgrounds were container-grown to green-pod maturity in open-top field chambers while being exposed to chronic doses of 03 for 7 hours·day-1 for 42 consecutive days. Treatments included charcoal-filtered air, nonfltered air, and 0.02, 0.04, or 0.08 ppm O3 added to nonfiltered air. Visible injury was estimated during the 2nd week of exposure and compared to the green pod yield data. The presence of four yield response groups, as determined via regression analysis, indicated the presence of variation for 03 sensitivity in the germplasm pool, but all eight lines were O3 - sensitive with yield losses at 03 levels exceeding a 7-hour daily mean of 0.085 ppm. Foliar injury may be a good indicator of general yield loss; however, estimates of visible injury lack the precision necessary to distinguish subtle differences among a collection of O3-sensitive snap bean lines.
The Impact of Phytophthora Root Rot on Water Extraction from Soil by Roots of Field-grown Processing Tomatoes
Authors: Ristaino J.B. , Duniway J.M.
Published: January 2019

Processing tomatoes (Lycopersicon esculentum Mill.) grown in field plots with soil infested with or free of Phytophthora parasitic Dastur. were furrow-irrigated for 4 to 8 hours every 14 days (normal irrigation), for 4 to 8 hours every 28 days (less frequent irrigation), or for 4 to 8 and 24 hours on alternate irrigations every 14 days (prolonged irrigation). Disease developed more rapidly and symptom severity was greater in inoculated plants that received prolonged irrigation, whereas disease onset was delayed in inoculated plants that were irrigated less frequently. Water extraction by tomato roots from well-irrigated and noninfested soil was usually greatest at shallow depths and decreased with depth. When disease was increasing and soil moisture was high, diseased plants extracted less total water from all depths and significantly less water at shallow depths. Plants in the drier soil profiles extracted the greatest amounts of water at depths below 90 cm, and diseased plants irrigated less frequently showed reductions in water extraction at shallow depths later in the season. Tomato root systems appeared to compensate for moderate levels of root disease at shallow depths by extracting more water from deeper in the profile.
Regression Models Describing Rosa hybrida Response to Day/Night Temperature and Photosynthetic Photon Flux
Authors: Hopper Douglas A. , Hammer P. Allen
Published: January 2019

A central composite rotatable design was used to estimate quadratic equations describing the relationship of irradiance, as measured by photosynthetic photon flux (PPF), and day (DT) and night (NT) temperatures to the growth and development of Rosa hybrida L. in controlled environments. Plants were subjected to 15 treatment combinations of the PPF, DT, and NT according to the coding of the design matrix. Day and night length were each 12 hours. Environmental factor ranges were chosen to include conditions representative of winter and spring commercial greenhouse production environments in the Midwestern United States. After an initial hard pinch, 11 plant growth characteristics were measured every 10 days and at flowering. Four plant characteristics were recorded to describe flower bud development. Response surface equations were displayed as three-dimensional plots, with DT and NT as the base axes and the plant character on the z-axis while PPF was held constant. Response surfaces illustrated the plant response to interactions of DT and NT, while comparisons between plots at different PPF showed the overall effect of PPF. Canonical analysis of all regression models revealed the stationary point and general shape of the response surface. All stationary points of the significant models were located outside the original design space, and all but one surface was a saddle shape. Both the plots and analysis showed greater stem diameter, as well as higher fresh and dry weights of stems, leaves, and flower buds to occur at flowering under combinations of low DT (≤ 17C) and low NT (≤ 14C). However, low DT and NT delayed both visible bud formation and development to flowering. Increased PPF increased overall flower stem quality by increasing stem diameter and the fresh and dry weights of all plant parts at flowering, as well as decreased time until visible bud formation and flowering. These results summarize measured development at flowering when the environment was kept constant throughout the entire plant growth cycle.
Nodule Distribution among Root Morphological Components of Field-grown Cowpeas
Authors: Kahn Brian A. , Stoffella Peter J.
Published: January 2019

Field experiments were conducted in 1985 at Fort Pierce, Fla., and Bixby, Okla., to quantify and describe the distribution of nodules among root morphological components of cowpea [Vigna unguiculata (L.) Walp.]. Plants of `Knuckle Purplehull', `Mississippi Cream', and `White Acre' were sampled by cultivar on separate dates at three growth stages: pre-anthesis, seed initiation, and harvest, when most pods were dry. Root masses were partitioned into adventitious, basal, lateral, and taproot components. Nodules were removed from roots, grouped according to root morphological component of origin, and weighed. No linear correlation was found between the weight of a particular root morphological component and the nodule weight associated with that component. Total root weight and total nodule weight also were not strongly correlated. Nodule weights usually were lower at harvest than at earlier stages of ontogeny, especially for nodules from taproots. Although ≈70% of the root mass was in the taproot and its associated laterals at both locations, the taproot per se was not the primary locus of nodulation. Instead, most nodules generally were located on the basal and lateral roots. When percentage distribution of total nodule weight was examined, neither growth stage nor cultivar was found to affect nodulation of basal or lateral roots.
Changes in Xylem Constituents in Response to Rest-breaking Agents Applied to Apple before Budbreak
Authors: Cutting J.G.M. , Strydom D.K. , Jacobs G. , Bellstedt D.U. , Van Der Merwe K.J. , Weiler E.W.
Published: January 2019

Xylem sap was vacuum-extracted weekly from 1-year-old apple shoots from trees treated with dinitro-o-cresol (DNOC) oil, hydrogen cyanamide, or untreated controls. Sampling began 1 week before treatment and continued until 2 weeks after budbreak had occurred in the control trees. Sorbitol, calcium, magnesium, potassium, and zeatin-type cytokinin concentrations were determined by enzymatic, atomic absorption, and immunoassay methods, respectively. The rest-breaking treatments resulted in earlier and more intense budbreak. Xylem sap cytokinin concentrations increased rapidly in response to the rest-breaking chemicals and peaked just before or at budbreak. The rapid increase in cytokinin was closely followed by increases in calcium and magnesium concentrations in the sap. Potassium concentration appeared to be unaffected by rest-breaking treatment. Sorbitol levels dropped rapidly as a result of the rest-breaking treatments and appeared to be used rapidly in budbreak and early bud growth.
Postanthesis Flower and Fruit Abscission in `Manzanillo' Olive
Authors: Rapoport H.F. , Rallo L.
Published: January 2019

The dramatic postanthesis flower and fruit abscission in olive was found to consist of two distinct but overlapping phases for ovaries following the abscission of imperfect flowers. Imperfect flower abscission peaked 8 days after full bloom (FB), while perfect flower and fruit abscission was greatest between 13 to 15 days after FB. Ovary abscission, expressed as percent ovaries abscising per day (relative abscission rate), peaked 15 and 21 days after FB. The first ovary abscission phase includes fertilized and unfertilized ovaries. The second phase occurs once early fruit growth is in progress, suggesting a possible role for substrate competition.
Honey-bee-mediated Cross- versus Self-pollination of `Sharpblue' Blueberry Increases Fruit Size and Hastens Ripening
Authors: Lang Gregory A. , Danka Robert G.
Published: January 2019

To study self- and cross-pollination effects on fruit development in southern highbush (mainly Vaccinium corymbosum L.) blueberries, `Sharpblue' plants were caged with honey bees (Apis mellifera L.) and other `Sharpblue' or `Gulfcoast' plants at anthesis. Ratios of pollinizer: fruiting flowers ranged from 2.1 to 4.5. Cross-pollination increased fruit size by ≈14% and seed count by 27% but did not influence fruit set. Overall, seed count decreased by 58% during the 30 days of harvest, but this did not directly affect fruit size. Seed count appeared to influence earliness of ripening as much as it influenced fruit size. Cross-pollination increased the harvest percentage of early-ripening fruits by ≈140% and of premium market fruits (those ≥ 0.75 g) by 13% and decreased the percentage of small fruits by 66%. Consequently, a 43% increase in premium early market crop value (nearly $5000/ha) resulted from optimizing `Sharpblue' cross-pollination.
Inhibition of Softening by Polyamine Application in `Golden Delicious' and `McIntosh' Apples
Authors: Kramer George F. , Wang Chien Yi , Conway William S.
Published: January 2019

Pressure infiltration of `Golden Delicious' and `McIntosh' apples (Malus domestica Borkh.) with polyamides resulted in an immediate increase in firmness. `Golden Delicious' apples were 2.7 N (0.25 mM spermidine) to 6.7 N (1.0 mM spermine) firmer, while `McIntosh' apples were 2.2 N (0.25 mM spermidine) to 5.3 N (1.0 mM spermine) firmer than the water-treated control. During 28 weeks of storage at 0C, the differences between the polyamine-treated and water-treated apples were even larger. Similar results were observed with a 3% Ca treatment, but the Ca treatment reduced the rate of softening to a greater extent than did the polyamine treatments in `Golden Delicious'. Polyamides increased the endogenous levels of the polyamides infiltrated; however, the levels declined rapidly with time in storage. Both polyamine and Ca inhibited the development of chilling injury symptoms (brown core) in `McIntosh'. The influence of polyamines on ethylene production was negligible in both cultivars. The Ca treatment, however, inhibited ethylene evolution in `Golden Delicious'. Polyamides, thus, may affect apple softening through rigidification of cell walls rather than through interactions with ethylene metabolism.
Primary Bud Hardiness of Four Genotypes of Grapes in Arkansas
Authors: Bourne Timothy F. , Moore J.N. , George Milon F.
Published: January 2019

Four interspecific grape hybrids (Vitis spp.) developed in Arkansas were evaluated for primary bud hardiness by differential thermal analysis. Buds from two locations were analyzed over 2 years for acclimation, midwinter hardiness, and deacclimation. In addition, effects of two training systems on cold hardiness of buds were evaluated in one location. The buds of the two genotypes with the greatest component of V. vinifera in their ancestry acclimated more slowly than did the other genotypes. Ultimate midwinter bud hardiness was greater in the genotypes possessing less V. vinifera than other parentage. No effect on cold hardiness due to training system was noted. No natural winter freeze damage was observed on any of the genotypes in the period of observation.
Regeneration from Sweetpotato Protoplasts and Assessment of Growth Conditions for Flow-sorting of Fusion Mixtures
Authors: Perera Srini C. , Ozias-Akins Peggy
Published: January 2019

Petiole protoplasts of the sweetpotato [Ipomoea batatas (L.) Lam.] cultivars Red Jewel and Georgia Jet formed cell walls within 24 hours and divided in 2 to 3 days. Pretreating enzyme solutions with activated charcoal increased the viability and division frequency of protoplasts. Culture of protoplast-donor plants in a medium containing STS did not affect plant growth, protoplasm yield, or viability, but did increase the division frequency. Culture of protoplasts for 24 hours in a medium containing DB, a cell wall synthesis inhibitor, or staining of protoplasts with FDA did not significantly affect division frequency. The division frequency of protoplasts cultured in liquid medium was significantly higher than that of protoplasts cultured in agarose-solidified medium. Cell cycle analysis of petioles and freshly isolated protoplasts showed that the latter has a significantly higher proportion of nuclei in G1 phase. Protoplasts did not initiate DNA synthesis or mitosis within the first 24 hours of culture. Low-frequency regeneration of shoots from protoplast-derived callus was accomplished on MS medium containing 1.0 mg ldnetin/liter when preceded by MS medium modified to contain only (in mg·liter-1) 800 NH4NO3, 1400 KNO3, 0.5 2,4-D, 0.5 kinetin, and 1.0 ABA. Roots produced from protoplast-derived callus formed adventitious shoots after 4 weeks on MS medium containing 2% sucrose, 0.02 mg kinetin/liter and 0.2% Gelrite. Secondary shoot formation from regenerated roots will be a more effective means of obtaining plants from protoplasts than direct shoot regeneration from callus. Chemical names used: silver thiosulfate (STS): 2.6-dichlorobenzonitrile (DB); fluorescein diacetate (FDA): 2.4-diacetate (FDA); 2.4 dichlorophenoxyacetic acid (2,4-D); abscisic acid (ABA).
Photosynthesis and Leaf Water, Carbohydrate, and Hormone Status during Rooting of Stem Cuttings of Acer rubrum
Authors: Smalley T.J. , Dirr M.A. , Armitage A.M. , Wood B.W. , Teskey R.O. , Severson R.F.
Published: January 2019

Leaf water status, carbohydrate levels, net photosynthesis, stomatal conductance, ABA, dihydrozeatin riboside (DHZR), and trans-zeatin riboside (ZR) levels were determined in a greenhouse during rooting of stem cuttings of Acer rubrum L. `Red Sunset' taken on 3 Sept. 1987 and 28 May 1988. Leaf water status deteriorated before rooting and improved after root emergence. Leaf carbohydrate concentrations (glucose, sucrose, total soluble sugars, and total carbohydrates) increased until rooting and decreased after rooting, while changes in starch concentrations were trendless. ABA levels increased after insertion of cuttings into the rooting medium, but decreased before rooting. No correlation between timing of rooting and concentrations of the cytokinins ZR or DHZR was observed. Photosynthetic rates during rooting were higher for the Sept. 1987 cuttings and did not decrease to the compensation point as did those for May 1988 cuttings. Low photosynthetic rates and stomatal conductance of the cuttings during rooting were associated with water stress. The relationship between photosynthetic rates of such cuttings and cytokinin (CK) or ABA content was unclear. Chemical names used: [S-(Z,E]-5-(1-hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl)-3-methyl-2, 4-pentadienoic acid (abscisic acid, ABA); 2-methyl-4-(1H-purin-6-ylamino)-2-buten-1-ol (zeatin, Z).
Application of DNA Fingerprints for Identification and Genetic Analysis of Avocado
Authors: Lavi U. , Hillel J. , Vainstein A. , Lahav E. , Sharon D.
Published: January 2019

Application of four DNA fingerprint probes to avocado (Persea americana Mill.) resulted in identification of various cultivars, characterization of the three avocado races, and a genetic analysis of family structure. Genomic DNA from 14 cultivars was probed with four DNA fingerprint probes. Three of the probes gave well-resolved bands. The individual-specific patterns obtained for each cultivar validate the use of this technique for definitive cultivar characterization, with the probability of obtaining a similar pattern for two different cultivars being 2 × 10-9. DNA mixes representing either Mexican, Guatemalan, or West-Indian avocado races were hybridized with the DNA fingerprint probes, and a band pattern characteristic for each race was obtained. Progeny of a cross between the cultivars Ettinger and Pinkerton were analyzed. Their DNA fingerprints revealed one pair of linked bands and another band allelic to one of them. The application of these observations to identification, evolutionary studies, and breeding is discussed.
Field Performance of Micropropagated, Own-rooted Peach Trees
Authors: Hammerschlag F.A. , Scorza R.
Published: January 2019

Four peach [Prunus persica (L.) Batsch] scion cultivars, `Jerseyqueen', `Redskin', `Suncrest', and `Sunhigh', that were propagated by tissue culture techniques and by bud-grafting onto `Lovell' seedlings, were compared at Kearneysville, W.Va., and at Beltsville, Md. At Kearneysville, total fruit production was higher for tissue-cultured (TC) trees when compared with budded trees in the first 3 years of fruiting, whereas trunk diameter increases were generally larger for budded trees. In the following year, fruit production was similar for both TC and budded trees, although trunk diameter increases continued to be larger for budded trees. At Beltsville, fruit production was significantly higher for TC trees in 1987, the first fruiting season, but the same for both in the second season. Trunk diameter increases were larger for budded trees both years. Differences in tree growth and productivity in the early years of orchard establishment appeared to be related to the size of plants that were planted. Budded trees, which were smaller than TC trees at planting, increased in size faster than TC trees but were less productive. Crop efficiency was cultivar-specific, but differences among cultivars was less if trees were TC propagated. These results suggested that based on yield and growth, own-rooted TC trees should be an acceptable tree type for commercial orchards.
Organogenesis in Carnation
Authors: Frey Les , Janick Jules
Published: January 2019

Shoot regeneration in carnation (Dianthus catyophyllus L.) was influenced by genotype, explant source, and plant growth regulator balance. Plants were regenerated from petals, calyxes, nodes, internodes, and leaves, but only petals, calyxes, and nodes were regenerative from all three cultivars examined (`Scania', `Improved White Sire', `Sandra'). Maximum proliferation was achieved with petals on Murashige and Skoog medium supplemented with 0.05 μm TDZ and 0.5 μm NAA. Shoot initiation originated from cells near vascular regions and perhaps from epidermal cells in petals and via organogenic callus from other explants. There was no evidence of chimeral separation from petals or callus, but somaclonal variants (3.3%) were observed involving petal hue and plant dwarfness. Unstable color patterns were observed in tissue-cultured regenerants of `Scania' and `Improved White Sire' similar in type and frequency to propagules derived from cuttings; none were observed for tissue-cultured or cutting-derived plants of `Sandra'. Chemical names used: N-pheny1-N′-l,2,3 -thiadiazol-5-ylurea [thidiazuron (TDZ)]; 1-napthaleneacetic acid (NM).
Effect of Seed Size and Cultivar on Emergence and Stand Establishment of Broccoli in Crusted Soil
Authors: Heather D.W. , Sieczka J.B.
Published: January 2019

Greenhouse and field experiments were conducted in 1988 and 1989 to determine the effect of seed size and cultivar on seedling emergence through crusted soil for several hybrid broccoli cultivars (Brassica oleracea ssp. italica). Seed was separated into four sizes (2.0, 1.8, 1.6, and 1.4 mm in diameter) for the greenhouse investigations, and soil crusting was achieved using a crusting resin. In 1989, field experiments using three seed sizes (small = 1.4 to 1.6 mm, medium = 1.7 to 1.9 mm, and large = 2.0 to 2.2 mm in diameter) were planted at the Long Island Horticultural Research Laboratory in a Riverhead sandy loam that crusted readily following rainfall. Seedling emergence data from the greenhouse and field studies indicate that seed size and cultivar significantly affect emergence and stand establishment. Seedling stand, dry weight, and final yield significantly increased as seed size increased for both cultivars in the field experiments. The emergence of `Mariner' generally was significantly better than that of `Greenlady' for each seed size. Seed of `Greenlady' also weighed significantly less than that of `Mariner' within each seed size tested.
Intercultivar Differences in Quality and Postharvest Life of Pomegranates Influenced by Partial Drying
Authors: Al-Kahtani Hassan A.
Published: January 2019

Eleven pomegranate (Punica granatum L.) cultivars were first evaluated, dried for 9 days at 20C and 47% relative humidity (RH), 30C and 33% RH, and 40C and 25% RH before storage at 20 ± 2C and 47% RH. `Taifi-A' was given the highest scores for sensory evaluation. `Kab El-Jameel' contained significantly more edible portion and more juice, and had lower pH and higher acidity than any other cultivar. The highest vitamin C content was found in `Taifi-A', `Red Balady', and `Mellasi'. Drying at 40C and 25% RH seriously damaged the pomegranates. `De-Jativa, `Molar', `Succary', and `Taifi-R' softened on the 4th day of drying and were more sensitive to drying conditions than the others. Drying at 30C and 33% RH and at 20C and 47% RH did not appear to have visually deleterious effects on the internal portion of the fruit, but the edible portion was slightly inferior to that of fresh (refrigerated) fruits, particularly those dried at 30C and 33% RH. The juices of most dried fruits had higher pH, acidity, and total soluble solids content, but less vitamin C than fresh fruits. Fruits dried at 30C and 33% RH or 20C and 47% RH remained acceptable at 20 ± 2C and 47% RH for up to 3 months or more, depending on the cultivar. Fungal decay (Aspergillus niger. Tiesh. and some Penicillum spp. were found) appeared only in fruits previously dried at 20C and 47% RH. Partial drying of pomegranates maybe useful for processed juice products.
Nitrogen and Sulfur Interaction Influences Net Photosynthesis and Vegetative Growth of Pecan
Authors: Hu Hening , Sparks Darrell
Published: January 2019

Seedlings of pecan [Carya illinoensis (Wangenh.) C. Koch] grown in perlite culture were treated with N and S in a 5 × 5 factorial in a randomized complete block design to determine the effect of N, S, and N × S interaction on vegetative growth and photosynthesis. Nitrogen and S deficiency symptoms occurred when leaf N and S were < 25 and 1.4 mg·g-1 dry weight, respectively. Photosynthesis was reduced when combined leaf N and S exceeded 35 and 3.7 mg·g-1 dry weight, respectively; growth was reduced when leaf N and S were > 34 and 3.7 mg·g-1 dry weight, respectively. Photosynthesis and growth increased with N supply, but depended on leaf N: S ratio. In plants without visible N or S deficiency, a N: S ratio of ≈9. is proposed to be near the optimum for maximum growth. Comparison of leaf N, S, and the N: S ratio with similar analyses in selected orchards suggests that pecan productivity will increase from S application under field conditions. We conclude that the interaction” of N and S imposes stringent controls on leaf N and S, photosynthesis, and growth.
Initial Growth of Seedlings of Flame Azalea in Response to Day/Night Temperature
Authors: Malek Asiah A. , Blazich Frank A. , Warren Stuart L. , Shelton James E.
Published: January 2019

Seedlings of flame azalea [Rhododendron calendulaceum (Michx.) Torr] were grown for 12 weeks under long-day conditions with days at 18, 22, 26, or 30C for 9 hours in factorial combination with nights at 14, 18, 22, or 26C for 15 hours. Total plant dry weight, top dry weight, leaf area, and dry weights of leaves, stems, and roots were influenced by day and night temperatures and their interactions. Dry matter production was lowest with nights at 14C. Root, leaf, top, and total dry weights were maximized with days at 26C in combination with nights at 18 to 26C. Stem dry weight was maximized with days at 26 to 30C and nights at 22C. Leaf area was largest with days at 18 and 26C in combination with nights at 18 or 26C. Within the optimal, day/night temperature range of 26 C/18-26C for total plant dry weight, there was no evidence that alternating temperatures enhanced growth. Shoot: root ratios (top dry weight: root dry weight) were highest with days at 18 and 30C. Leaf area ratio (total leaf area: total plant dry weight) was highest and specific leaf area (total leaf area: leaf dry weight) was largest when days and nights were at 18C and were lower at higher temperatures. Regardless of day/night temperature, leaf weight ratio (leaf dry weight: total plant dry weight) was higher than either the stem weight ratio (stem dry weight: total plant dry weight) or root weight ratio (root dry weight: total plant dry weight). Net leaf photosynthetic rate increased with day temperatures up to 30C.
Low Temperatures Induce Rough Blossom-end Scarring of Tomato Fruit during Early Flower Development
Authors: Barten J.H.M. , Scott J.W. , Kedar N. , Elkind Y.
Published: January 2019

To identify the stage of flower development sensitive to low temperature-induced rough blossom-end scarring (RBS) in tomato (Lycopersicon esculentum Mill.), short-term low-temperature treatments (1, 3, and 5 days continuously at 10C or 6, 9, and 12 days at 18/10C day/night) were applied to young, flowering plants and to plants at the six-leaf stage. Flowers were tagged at anthesis over 4 weeks and the growth stage of the flowers at the beginning of the treatments was determined in days relative to anthesis. The blossom-end scar index (BSI), a measure for blossom-end scar size relative to fruit size, and number of locules were recorded for mature fruits. In three experiments, 5 days at 10C or 6 days at 18/10C, applied during early flower differentiation, induced RBS in mature fruits. For each of the three cultivars tested `Horizon', Waker', and `Solar Set'), flower buds were most sensitive from 26 to 19 days before anthesis. In this experiment, RBS induction was not caused by an increase in the average number of locules per fruit. A short period of sensitivity during very early flower development explains the variation in RBS among seasons and within plants encountered in field situations. This study also presents a standard induction technique for further investigation of physiological and morphological backgrounds of the disorder and possible genotype screening.
An Induced Mutant for Blue Flowers in Common Bean That Is Not Allelic to V or Sal and Is Linked to Fin
Authors: Bassett Mark J.
Published: January 2019

A mutation for blue (methyl-violet) flower color was induced by gamma irradiation of dry seed in common bean (Phaseolus vulgaris L.). Inheritance and allelism tests demonstrated that the mutation is controlled by a single recessive gene that is not allelic with Sal or V. The gene symbol blu is proposed for this mutant. Linkage was detected between blu and Fin, which controls the change from indeterminate to determinate plant habit. Three linkage estimates ranged from 19 to 35 cM, but the large variability (homogeneity x2 = 45.32) precludes making a conclusive combined estimate of linkage. The tentative combined estimate of linkage is 27 cM.
Changes in Amino Acid Composition Associated with Tolerance to Partial Desiccation of Celery Somatic Embryos
Authors: Saranga Yehoshua , Rhodes David , Janick Jules
Published: January 2019

Tolerance to partial desiccation and amino acid composition of celery (Apium graveolens L. cv. SB 12) somatic embryos were investigated under various culture durations and with exogenous application of 1 μm ABA, proline, and/or γ -aminobutyrate (GABA). ABA consistently increased tolerance to partial desiccation and elevated proline and GABA content of embryos. The changes in tolerance to partial desiccation associated with changes in culture duration (optimum 9 to 10 days) correlated with embryo proline content. Exogenous proline increased embryo proline content and tolerance to partial desiccation. Exogenous GABA increased embryo GABA content and tolerance to partial desiccation only when applied in combination with proline. Chemical name used: abscisic acid (ABA).
Micropropagation of Juvenile and Adult Flowering Ash
Authors: Arrillaga Isabel , Lerma Victoria , Segura Juan
Published: January 2019

A protocol for in vitro propagation in flowering ash (Fraxinus ornus L.) has been developed. Shoot apices or nodal segments from aseptically grown seedings or shoot apices from adult trees were used as initial explants. Highest shoot multiplication rates were obtained when the explants were cultured for 30 days in liquid Rugini induction medium supplemented with BA followed by 30 days on solidified Rugini multiplication medium without growth regulators. Regenerated shoots were rooted on Heller medium containing auxins alone or in combination with BA. Rooting percentages up to 71% (juvenile material) or 50% (adult material) were obtained in the presence of NAA and BA, and were not improved by treating the basal end of the shoots with concentrated NAA solutions. Following conventional procedures, regenerated plants were transferred to soil with more than 80% success. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); 1-naphthaleneacetic acid (NAA).
A Low-pressure, Trunk-injection Method for Introducing Chemical Formulations into Olive Trees
Authors: Navarro C. , Fernández-Escobar R. , Benlloch M.
Published: January 2019

A low-pressure injection method for introducing chemical formulations into trees is presented. The apparatus consists of a plastic injector and a tube providing a pressure of 60 to 80 kPa, which is below the injurious level for the xylem. The efficiency of the method was determined by injecting PTS, a marker of apoplastic flux dye solutions, and rubidium chloride into young trees, main scaffolds, or tree trunks. The depth of the hole drilled) and the number of injections necessary to distribute the solutions was also determined. The injected solutions moved mainly upward through the older rings of the xylem, suggesting that uptake is directly controlled by the transpiration rate. A single injection was enough to distribute solutions in scaffolds with a diameter of 8 cm, but two injections were necessary for 17-cm-diameter trunks. According to the results, the injection method was effective in introducing chemicals into olive (Olea europaea L.) trees. The method is easy to use, safe and economical and does not involve special equipment. Chemical name used: trisodium, 3-hydroxi-5,8,10-pyrenetrisulfonate (PTS).
Modification of Petunia Seedling Carbohydrate Partitioning by Irradiance
Authors: Graper David F. , Healy Will
Published: January 2019

Petunia × hybrida Villm. `Red Flash' plants received either 10 or 20 mol·day-1 photosynthetic photon flux (PPF) in growth chambers at: 175 μmol·m-2·s-1 for 16 hours, 350 μmol·m-2·s-1 for 8 or 16 hours, or 350 μmol·m-2 s-1 for 8 hours plus 8 hours of incandescent photoperiod extension (5 μmol·m-2·s-1 PPF). The irradiation components of peak, total, and duration were examined. Doubling total PPF increased total carbohydrate (CHO) production by 60%, seedling dry weight (DW) by 30%, rate of seedling growth by 25%, and acid invertase activity by 50% compared to the other treatments, once the seedlings had reached the two-leaf stage. Seedlings receiving 20 mol·day-1 PPF partitioned 14% more CHO into ethanol soluble sugars rather than starch, which may explain the increase in relative growth rate observed with supplemental irradiance treatments. Extending the photoperiod for 8 hours with 5 μmol·m-2·s-1 PPF reduced total CHO production by 50% compared to the same treatment without photoperiodic lighting. Treatment with 350 μmol·m-2·s-1 for 8 hours resulted in the highest O2 evolution (8.8 μmol O2/min per dm2). Increasing the photoperiod from 8 to 16 hours gave the lowest rate of O2 evolution (4.5 μmol O2/min per dm2). Previous reports of the importance of photosynthetic period in controlling partitioning between starch and sugars may have simply observed a decreasing rate of starch accumulation due to increased total PPF.
Phosphorus Nutrition and Selection against Leaf Chlorosis Related to Powdery Mildew Resistance in Cucumber
Authors: Groot Steven P.C. , Zijlstra Sierd , Jansen Johannes
Published: January 2019

Powdery mildew-resistant (PMR) cultivars of cucumber (Cucumis sativus L.) grown in greenhouses in the Netherlands during winter show chlorosis on the full-grown leaves of the main stem. The symptoms are yellowing and occasional necrosis between the main veins of the leaves, resembling symptoms of P toxicity. Severity of the chlorosis may vary from one winter to another. Variation is also observed in the severity of the symptoms between cultivars and individual plants of a cultivar. High P nutrition results in an increase of the severity of chlorosis and provides a better discriminating environment for the selection of PMR genotypes that are less susceptible for leaf chlorosis.
Parents and Mating Systems Affect the Transfer of Gynoecious Flowering to Chinese Monoecious Cucumbers
Authors: Zhang Qi , Gabert August C. , Baggett James R.
Published: January 2019

Monoecious cucumber (Cucumis sativus L.) parents with high, medium, and low percentage of nodes with distillate flowers had a stronger effect on the percentage of gynoecious plants in F1 and F2 progenies than did degree of gynoecious expression in incompletely gynoecious parents. Highest percentages of gynoecious plants were obtained by using both gynoecious and monoecious parents with the highest level of distillate flowering tendency. According to our data, monoecious parents with a low percentage of distillate flowering nodes should be avoided when gynoeciousness is transferred to monoecious cultivars. Self-pollination of gynoecious F2 plants, requiring induction of staminate flowers by chemical treatment, was more effective in obtaining a high percentage of gynoecious plants in F3 progenies than selfing predominately gynoecious plants, or sibmating predominately gynoecious plants.
Biomass and Fruit Production for the Prickly Pear Cactus, Opuntia ficus-indica
Authors: de Cortázar Victor Garcia , Nobel Park S.
Published: January 2019

Productivity of irrigated prickly pear cactus [Opuntia ficus-indica (L.) Miller] was studied over 3 years in central Chile using two planting densities. A low-density planting (0.25 plants/m2), traditionally favored for fruit production, had maximal fruit productivity in the 2nd year (6 Mg dry weight/ha per year). A high-density planting (24 plants/m2), which assured almost full interception of incident solar radiation, led to an extremely high shoot dry-weight productivity (50 Mg·ha-1·year-1) in the 2nd year and maximal fruit productivity (6 Mg·ha-1·year-1) in the 3rd year. Cladode dry weight tended to increase with cladode surface area. However, fruit production did not occur until the dry weight per cladode exceeded the minimum dry weight for a particular cladode surface area by at least 33 g. The year-to-year variation in fruit production apparently reflected variations in such excess dry weight and, hence, in the storage reserves of individual cladodes.
Inheritance of Shortened Fruit Maturation in the Cherry Tomato Cornell 871213-1 and Its Relation to Fruit Size and Other Components of Earliness
Authors: Kemble Joseph M. , Gardner Randolph G.
Published: January 2019

The heritability of shortened fruit maturation (SFM) period in Cornell 871213-1, an inbred cherry tomato [Lycopersicon esculentum var. cerasiforme (Dunal.) A. Gray] line, was estimated from a greenhouse experiment. Cornell 871213-1 was crossed with the cherry tomato line NC 21C-1. Mean fruit maturation period (FMP) (days from anthesis to the breaker stage of fruit color) was 40.8 days for NC 21C-1 and 32.0 days for Cornell 871213-1. Parental, F1, F2, and backcross generations all differed in mean FMP and yielded, estimates of broad- and narrow-sense SFM heritabilities of 72% and 40%, respectively, on a single-plant basis. A test for midparent heterosis showed significance. Genetic control of SFM was quantitative in nature and highly dominant. A field study of an F2 population developed from the cross Cornell 871213-1 × NC 84173, the latter a large-fruited tomato line (Lycopersicon esculentum Mill.), gave a mean FMP of 48.4 and 31.2 days for NC 84173 and Cornell 871213-1, respectively. The F1 and F2 generations had FMP of 33.1 and 34.7 days, respectively. The parents, F1, and F2 generations all differed in FMP. Parental, F1, and F2 generations yielded an estimate of broad-sense SFM heritability of 64% on a single-plant basis. F3 progenies from selected F2 s were grown in a greenhouse, and F3-F2 regression analysis gave a narrow-sense SFM heritability of 39%. Parental means differed from each other and from the F1 and F2 means for period from sowing to anthesis, fruit weight, and locule number. F1 and F2 means did not differ for any trait and were far below the midparent values, approaching Cornell 871213-1 for each trait except for the number of days from sowing to anthesis. Significant correlations existed in the F2 generation between FMP and fruit weight (0.61) and between fruit weight and locule number (0.69). Significant correlations existed between selected F2s and their F3 progeny for FMP (0.53), fruit weight (0.78), and days from sowing to anthesis (0.78). In the F3 generation, a significant correlation occurred between FMP and fruit weight (0.48). F3-F2 regression and realized heritabilities were used as two estimates of narrow-sense heritability (29% and 31%, respectively) for days from sowing to anthesis.
Multiple Propagation Effects on Genetic Estimates of Rooting for Western Hemlock
Authors: Pounders Cecil T. , Foster G. Sam
Published: January 2019

Analysis of clonal variation for two rooting traits of western hemlock [Tsuga heteterophylla (Raf.) Sarg.] clones indicated that realized genetic gain would be improved by more effective partitioning and reduction of environmental differences associated with clones. Interactions between clones and multiple propagation dates were significant, but clone rank changes between dates were minor. Number of meted cuttings per plot (RC) and number of main roots per cutting (MR) were more highly correlated genetically (1.06) than phenotypically (0.36). Broad-sense heritabilitiesHx2 = 0.62 and Hx2 = 0.79 for RC and MR, respectively) and predicted genetic gain from clonal selection were moderately high. Both the percentage of rooted cuttings and root system quality could be rapidly improved by the clonal selection procedures used.
Modeling Chilling Influence on Cumulative Flowering: A Case Study Using `Tifblue Rabbiteye Blueberry
Authors: NeSmith D.S. , Bridges D.C.
Published: January 2019

A Weibull distribution function was used to develop a model for estimating cumulative flowering and the distribution of flowering of `Titblue' rabbiteye blueberry (Vaccinium Ashei Reade) as a function of growing degree days (GDD) following exposure to chilling temperatures for 300 to 1200 hours. Controlled chilling and flowering conditions were imposed on blueberry plants to obtain data for model development. Once developed, the model was validated using independent data sets from the literature. Given information concerning chilling and historical GDD, the model can be used to predict the onset of flowering, cumulative flowering, total number of flowers, and flower frequency at discrete intervals. The techniques developed likely will be applicable to a range of fruit species in which chilling influences flowering habit.