bluuebunny/crossref_metadata_2025 huggingface dataset:
Tomato and Nightshade (Solanum nigrum L. and S. ptycanthum Dun.) Effects on Soil Water Content
Authors: McGiffen Milton E. , Masiunas John B. , Huck Morris G.
Published: January 2019

Field and greenhouse experiments were conducted to determine the response of eastern black nightshade (Solanum ptycanthum), black nightshade (S. nigrum), and tomato (Lycopersicon esculentum Mill. cv. Heinz 6004) to water stress and the effect of nightshade-tomato competition on soil water content. In the greenhouse, plants were exposed to three water regimes induced by watering either daily, weekly, or biweekly. Water deficit caused a similar decrease in height, weight, and leaf area in all three species. There was more than a 50% reduction in height when the plants were watered biweekly compared with daily watering. Water stress caused a shift in biomass from shoots to roots in all three species. Black nightshade and tomato produced thinner leaves in response to water deficit. Companion field experiments were conducted during the 1989 and 1990 growing seasons in Urbana, Ill. Eastern black nightshade and black nightshade were transplanted at densities of 0.8, 1.6, 3.2, and 4.8 plants/m2, 5 days after tomatoes were transplanted. These nightshade densities caused significant reductions in soil water content. In 1989, only the highest density of either nightshade species reduced topsoil water content. In 1990, all densities of nightshade, except the two lowest densities of black nightshade, reduced topsoil water content. Eastern black nightshade consistently had a greater effect on tomato yield than black nightshade. Tomato yields averaged over both years were 17,000 and 8,000 kg·ha-1 at the highest (4.8 plants/m*) density of black and eastern black nightshade, respectively. The decrease in soil moisture from high densities of nightshade could not account for the reduced yields.
Stock Plant Etiolation, Shading, and Banding Effects on Cutting Propagation of Carpinus betulus
Authors: Maynard Brian K. , Bassuk Nina L.
Published: January 2019

In a study of stock plant etiolation and stem banding, stem cuttings of upright European hornbeam (Carpinus betulus L. `Fastigiata') were taken at 2-week intervals over 4 months following budbreak and rooted under intermittent mist for 30 days. Percent rooting and root counts declined with increasing cutting age. Stock plant etiolation and stem banding increased percent rooting and root counts throughout the study, with the combination of both treatments yielding the best rooting. In nontreated stems, > 75% rooting was achieved only within 4 weeks of budbreak. Etiolation and stem banding resulted in rooting ≥ 75% up to 3 months after budbreak. In two shading studies, stock plants were grown in a glass greenhouse under 0%, 50%, 75%, or 95% shade, or initially etiolated (100% shade) for 1.5 days. Cuttings were taken after 2.5 and 60 days and treated with IBA concentrations ranging from 0 to 4.9 mm before rooting under intermittent mist for 30 days. Percent rooting increased proportionally to the degree of shading, with a maximum response at 95% shade. Cuttings taken at 60 days were less responsive to etiolation and shading than those harvested at 25 days. Auxin concentration interacted with shading to yield, at 95% shade and 3.7 mm IBA, the highest rooting percentage and the greatest root counts and lengths. Light exclusion by etiolation, stem banding, or shading can extend the cutting propagation season by increasing rooting responses and increasing the sensitivity of stem cuttings to exogenously applied auxin. Chemical name used: 1H-indole-3-butyric acid (IBA).
Chilling Requirement of Pecan
Authors: Smith Michael W. , Carroll Becky L. , Cheary Becky S.
Published: January 2019

`Dodd' pecan seedlings [Carya illinoinensis (Wangenh.) K. Koch] were chilled at 6C for 0 to 1800 hours in 300-hour intervals and percent budbreak and days to budbreak recorded. Chilling duration required for ≥ 50% budbreak was 900 hours. Chilling > 900 hours increased budbreak percentage and reduced time to budbreak. `Dodd' seedlings chilled at 1, 5, or 9C for 0 to 2500 hours in 500-hour intervals had more lateral budbreak after 1000 hours of chilling at SC than at 1 or 9C. When chilling hours ranged from 1500 to 2500, 1C increased budbreak of the first lateral bud compared with 5 or 9C. As chilling was increased from 1000 to 2500 hours, the days to budbreak declined, and the uniformity of budbreak increased.
Salinity and Supplemental Calcium Influence Growth of Rabbiteye and Southern Highbush Blueberry
Authors: Wright Glenn C. , Patten Kim D. , Drew Malcolm C.
Published: January 2019

`Tifblue' and `Brightwell' rabbiteye blueberries (Vaccinium ashei Reade.) were subjected to 0, 25, or 100 mM Na+, as Na2SO4 or NaCl, and 0, 1, 3, or 10 mM supplemental Ca2+, primarily as CaSO4, in an irrigated sand culture in the greenhouse. Additionally, the effect of NaCl on `Sharpblue' southern highbush blueberry (primarily V. corymbosum L.) was examined. For unsalinized plants, fastest growth occurred in plants not receiving supplemental Ca2+. Root and shoot growth were depressed as salinity increased in plants lacking additional Ca2+. With 100 mM Na+ as Na2SO4. `Tifblue' root and shoot dry weight increases were only 37% and 25%, respectively, of the increase of unsalinized controls, while with 100 mM Na+ as NaCl, the corresponding shoot and root dry weight increases were only 38% and 43%, respectively. `Brightwell' plants reacted similarly to `Tifblue' in salinity treatments with Na2SO4 and NaCl, but `Sharpblue' plants were more severely affected by 100 mM NaCl than were the rabbiteye cultivars. In no case did addition of Ca2+ have any ameliorative effect on either the dry weight of roots of plants exposed to 25 or 100 mM NaCl or on the shoot growth of plants exposed to NaCl. The inability of Ca2+ to counter Cl- entry or toxicity may account for the lack of amelioration. In contrast, additional Ca2+ did improve shoot growth of plants exposed to Na2SO4. For `Tifblue' plants supplied with 25 mM Na+ as Na2SO4, growth increased by almost 25% in the presence of 10 mM Ca2+, while for `Tifblue' plants treated with 100 mM Na+ as Na2SO4, growth was more than three times greater in plants supplied with 1 mM Ca than in those not given any Ca2+. Growth increase was primarily due to increased leaf area and number. Low (1 mM) concentrations of Ca2+ were more effective in ameliorating the effects of 100 mM Na+ as Na2SO4 than were 3- and 10-mM Ca2+ supplements, possibly because higher Ca2+ additions lead to metabolic damage in these calcifuge Vaccinium species.
Imbibition of Water by Rockwool-Peat Container Media Amended with Hydrophilic Gel or Wetting Agent
Authors: Elliott George C.
Published: January 2019

Water retention at effective water-holding capacity (EWHC) and container capacity (CCAP) were measured in four rockwool-peat potting media amended with a wetting agent and/or a hydrophilic gel in pots 12 cm tall containing 445 cm3 medium, and irrigated by capillary mat, flood-and-drain, trickle emitter, or overhead sprinkler. Water retention was measured by weighing. Irrigation was continued until EWHC (i.e., net water retention when no weight increase could be obtained by further irrigation) was reached. CCAP (i.e., net water retention following saturation and free drainage) was measured at the end of each experiment. Irrigation method and medium amendments significantly affected EWHC. Rank order of irrigation treatments was sprinkler ≥ trickle > flood and drain ≥ mat. Hydrophilic gel increased both EWHC and CCAP, while the wetting agent increased EWHC but decreased or had no effect on CCAP. Significant interactions of gel and wetting agent were observed in some media. EWHC was less than CCAP, and EWHC was better correlated with CCAP with trickle emitter and overhead sprinkler irrigation than with capillary mat and flood-and-drain irrigation.
Modeling Nutrient Uptake in Chrysanthemum as a Function of Growth Rate
Authors: Willits D.H. , Nelson P.V. , Peet M.M. , Depa M.A. , Kuehny J.S.
Published: January 2019

The results of six experiments conducted over 3 years were analyzed to develop a relationship between nutrient uptake rate and growth rate in hydroponically grown Dendranthema ×grandiflorum (Ramat.) Kitamura, cv. Fiesta. Plants subjected to two levels of CO, and three levels of irradiance in four greenhouses were periodically analyzed for growth and the internal concentration of 11 mineral elements. The resulting data were used to determine relative accumulation rate and relative growth rate, which were included in linear regression analyses to determine the dependence of uptake on growth. The regression equations were significant, with a slight trend toward nonlinearity in some elements. This nonlinearity seems to be related to the aging of the plant and suggests a process in the plant capable of controlling uptake rate, perhaps as a result of changes in the rate of formation of different types of tissues.
Mode of Action of Benzyladenine When Used as a Chemical Thinner on Apples
Authors: Greene Duane W. , Autio Wesley R. , Erf Jeffrey A. , Mao Zhongyuan Y.
Published: January 2019

BA thinned apple (Malus domestica Borkh.) fruits when applied to either the leaves or the fruit, although it was much more effective when applied to the leaves. BA increased fruit size independent of its effects on reducing crop load, but only when applied directly to the fruit. When applied to one of two fruit in a cluster, BA had no influence on abscission, fruit size, or fruit characteristics of the adjacent nontreated fruit. BA reduced fruit flesh Ca only on treated fruit and the response was inversely proportional to the increase in fruit size. More than 60% of the BA applied to a fruit was absorbed during 24 hours, and this amount was considerably larger than penetration through either the abaxial or adaxial leaf surface. BA treatments that thinned also increased ethylene production linearly in both leaves and fruit 24 hours after application, but the magnitude of increase was not considered large enough to be the primary cause for thinning. BA thinned spurs with two or three fruit more than spurs with one fruit, and it did not selectively thin to just one fruit per cluster. Chemical name used: N-(phenylmethyl)-1H-purine-6-amine [benzyladenine (BA)].
Soluble Silicon Sprays Inhibit Powdery Mildew Development on Grape Leaves
Authors: Bowen Pat , Menzies Jim , Ehret David , Samuels Lacey , Glass Anthony D.M.
Published: January 2019

The effect of root or leaf applications of soluble Si on severity of grape (Vitis vinifera L.) powdery mildew [Uncinula necator (Schwein) Burrill] was determined. On potted plants, root-feeding at 1.7 mm Si had no effect on disease severity, but foliar sprays at 17 mm Si substantially reduced the number of mildew colonies that developed on inoculated leaves. Scanning electron micrographs showed that, on Si-sprayed leaves, hyphae did not develop in areas where thick Si deposits were present on the leaf surface; and where surface deposits were not present, Si was translocated laterally through the leaf and surrounded the appressoria. Leaves on plants that were fed Si via roots showed a similar deposition of Si surrounding the appressoria. On water-sprayed leaves and leaves from untreated plants, internal deposition of Si was more variable and generally less than on Si-sprayed or root-fed plants. Conidia germination and germtube development on agar media were weakly promoted by the presence of Si. Reduced severity of grape mildew by Si sprays may be partly due to a physical barrier to hyphal penetration and to a resistance response involving the lateral movement of Si and its deposition within the leaf at fungal penetration sites.
Meristem Ontogenetic Age as the Controlling Factor in Long-day Floral Initiation in Poinsettia
Authors: Evans Michael R. , Wilkins Harold F. , Hackett Wesley P.
Published: January 2019

The poinsettia [Euphorbia pulcherrima (Willd. ex. Klotzsch)] is a short-day plant (SDP) for floral initiation that will also initiate floral structures (cyathia) under long days (LD) after the apical meristem produces a cultivar-dependent number of nodes (long-day node number). Leaf removal, root restriction, and air layering failed to affect the long-day node number (LDNN) of the apical meristem. Repeated rooting of shoots, which resulted in the removal of nodes, did not affect the total number of nodes initiated by the apical meristem before floral initiation, although the number of nodes intact on the plant at the time of floral initiation was reduced. Reciprocal grafting of axillary buds of `Eckespoint Lilo' and `Gutbier V-14 Glory' plants did not affect the LDNN of the grafted meristem since the LDNN was the same as for nongrafted buds of the same cultivar. Further, grafting axillary buds from different positions along the main axis that differed in LDNN did not affect the LDNN of the grafted meristems. On the basis of these results, it was concluded that LD floral initiation in poinsettia is a function of the ontogenetic age of the meristem and that the LDNN represents a critical ontogenetic age for floral initiation to occur under LD.
Size and Carbohydrate Content of Ears of Baby Corn in Relation to Endosperm Type (Su, su, se, sh2)
Authors: Bar-Zur A. , Schaffer A.
Published: January 2019

Ear size and quality traits of various types of maize (Zea mays L.) (Su, su, se, sh2) used as baby corn were evaluated in field experiments. Ear size increased with time (0 to 6 days) after silking. Optimal stage for harvest was at silking for most cultivars and 6 days after silking for the prolific mini-corn cultivars. Sugar content of baby corn ears of all genotypes consisted primarily of glucose and fructose, with only low levels of sucrose. There was no significant increase in sugar content attributable to the su, se, or sh2 genes compared with Su, thus indicating there is no reason to use sweet corn types instead of the higher-yielding Su types. Total soluble sugar content of the genotypes ranged from ≈20 to 30 mg·g-1 fresh weight. Starch and water-soluble polysaccharide (WSP) concentrations in the Su cultivars, which were higher than those in the other endosperm types studied, decreased slightly from 0 to 6 days after silking. However, WSP concentrations were low and not likely to affect quality. Crispness, determined by organoleptic tests, decreased with time of harvest and differed among genotypes.
Chilling and Heating Model for Pecan Budbreak
Authors: Sparks Darrell
Published: January 2019

Chilling and heating effects on budbreak of pecan [Carya illinoinensis (Wangenh.) K. Koch] trees were examined by linear regression analyses from experimental data and from records of budbreak dates over a wide geographic range. The results demonstrate that budbreak in pecan is under the interactive control of heating and of chilling. Heat required for budbreak varies inversely with chill accumulation, and budbreak may occur with no chilling once sufficient heat accumulates. Variability in budbreak increases dramatically when there are fewer than ≈ 100 chilling degree days. Heating degree days with daily minima <2.2C are inefficient; 3.9C is the most efficient heating and chilling base. At base 3.9C and the daily minimum heating temperature of 2.2C, heating degree days required for budbreak of a composite of cultivars can be predicted from chilling degree days over a wide geographic range by the relationship, Log Y = 2.7190-0.0216 √X.
Chilling of Endodormant Peach Propagules: I. Seed Germination and Emergence
Authors: Frisby James W. , Seeley Schuyler D.
Published: January 2019

We compared peach [Prunus persica (L.) Batsch cv. Johnson Elberta] seed germination (G) and seedling emergence (E) after various stratification (St) treatments. Treatments were arranged in factorial combinations of five St durations (20 to 60 days) at eight constant temperatures (0 to 18C) in a completely randomized design followed by repeated measures during forcing time. G and E were recorded every 5 days during forcing. Seed St at 0 to 10C and 0 to 14C promoted G and E, respectively. G and E increased with longer St treatments at promoting temperatures. There was a weak correlation between G and E averaged over the forcing measurements (r2 = 0.54). The best correlation was between E after 15 days and G after 10 days (r2 = 0.83). The results indicate that G and E in peach are not identical indicators of endodormancy (ED) release and should not be used interchangeably. Forcing times must be considered when making comparisons between G and E.
Chilling of Endodormant Peach Propagules: II. Initial Seedling Growth
Authors: Frisby James W. , Seeley Schuyler D.
Published: January 2019

We observed initial peach [Prunus persica (L.) Batsch] seedling growth after endodormant (ED) seeds (`Johnson Elberta') had been stratified for five durations (20 to 60 days) at eight constant temperatures (0 to 18C). Seedling growth increased and became more normal when seeds were stratified for longer durations at chilling temperatures. Stratification (St) at 0 to 6C (especially 2C) produced seedlings with more abnormal growth than St at higher temperatures (8 to 10C) at intermediate St durations (30 to 50 days). Growth of the primary stem increased with additional St (0 to 14C). Abnormal (epinastic) leaf development decreased following longer St treatments at 4 to 14C. Lateral shoot growth increased initially, then decreased after longer treatments at low temperatures (0, 4, and 6C) and decreased after St at higher temperatures (8 to 10C).
Chilling of Endodormant Peach Propagules: IV. Terminal Shoot Growth of Cuttings, Including Gibberellic Acid Treatments
Authors: Frisby James W. , Seeley Schuyler D.
Published: January 2019

Cuttings from peach (Prunus persica (L.) Batch cv. Johnson Elberta) trees were subjected to five chilling durations (20 to 76 days) at seven temperatures (0 to 14C) and five concentrations of gibberellic acid [GA, (0.0 to 1 mm)]. There was a significant increase in terminal shoot length with longer chilling treatments. Cuttings treated at 2 to SC had the longest shoots, and shoot length decreased, in order, following treatment at 10, 0, and 14C. Treatment with the highest concentration of GA, resulted in the longest terminal shoots. Interactions between GA and chilling durations indicated that either higher concentrations of GA, or longer chilling treatments increased terminal shoot growth. Thus, endogenous promoters, like GA, are evidently produced or released during chilling. Sensitivity to GA, was also important. Chemical name used: Gibberellic acid (GA3).
Solute Accumulation in Leaves of a Fragaria chiloensis and a F. virginiana Selection Responds to Water Deficit Stress
Authors: Zhang Baolin , Archbold Douglas D.
Published: January 2019

The effect of water deficit stress on the foliar solute concentration of Fragaria chiloensis Duch. cv. `BSP14' (FC) and F. virginiana Duch. cv. `NCC85-13V (FV) was studied to assess solute contribution to osmotic adjustment. Plants were stressed for three wilting cycles by withholding water until incipient wilting, followed by a recovery period. The length of each cycle for the FC selection was J-fold that for the FV selection. Wilting of FC plants occurred at a leaf water potential (ψ) 1.1 MPa lower, a leaf osmotic potential (ψπ) 0.45 MPa lower, and a relative water content (RWC) 14% lower than for FV plants. Leaf ψπ at full turgor (ψπ100) was reduced in the FC selection from 0.11 to 0.27 MPa but not in the FV selection. Water deficit stress increased the total foliar soluble carbohydrate (TSC) concentration from 1.4- to 2.4-fold for FC during each cycle. Glucose and fructose were the primary carbohydrates, comprising >50% of the TSC. Leaf starch concentration decreased appreciably to 4% to 6% of nonstressed (control) levels for FC during each cycle. In the FC selection, the TSC: starch ratio was considerably higher, 30- to 50-fold, in stressed than in control plants. No consistent changes in solute or starch concentration were observed in the FV selection. Total free amino acid concentration increased from 1.8- to 2.7-fold in FC plants in response to stress. Proline accumulation was not detected. The solutes, TSC and amino acids, accounted for <40% of the measured ψπ100 in control plants, although the average contribution of these solutes to the measured leaf ψπ100 increased to 40% or more in stressed FC plants. However, the stress-induced increase in solute concentration fully accounted for the reduction of leaf ψπ100 in the FC selection plants.
Changes in the Physico-chemical Properties of Peach Fruit Pectin during On-tree Ripening and Storage
Authors: Fishman M.L. , Levaj B. , Gillespie D. , Scorza R.
Published: January 2019

Radius of gyration (size), intrinsic viscosity, molecular weight, percentage of galacturonate, and percentage of neutral sugars were measured for chelate-soluble (CSP) and alkaline-soluble (ASP) pectins extracted from the cell walls of melting flesh (MF) and nonmelting flesh (NMF) peach [Prunus persica (L.) Batsch]. Weight percentage of cell walls, pectin content, and firmness were measured also. Peaches were extracted at 20, 21, and 22 weeks after flowering (WAF) and after various lengths of shelf storage at 25 ± 2C for the peaches picked at 21 WAF. Weight percentage of cell walls and firmness decreased markedly between the 21st and 22nd WAF; and between the 3rd and 6th day of storage for MF peaches as compared to NMF peaches. During these same periods, there were marked drops in the pectin content and the uronide content for MF as compared to NMF peaches. Size and intrinsic viscosity dropped markedly for CSP of MF peaches in comparison with NMF peaches during these same periods, whereas the molecular weight of CSP and ASP increased in MF peaches over that measured for NMF peaches. These results suggested that α -D-galacturonase (E.C. 3.2.1.15) was involved in softening only in the latter stages of ripening MF peaches. Further, cell wall polymers containing long thin pectin aggregates were destroyed, whereas cell wall polymers containing short thick pectin aggregates remained.
The Effect of Germicides on the Longevity of Cut Flowers
Authors: Jones Rodney B. , Hill Megan
Published: January 2019

The effect of DICA (50 mg·liter-1), BCDMH (12 mg available chlorine/liter), and HQC (250 mg-liter]) on the longevity of 14 popular cut flower species was assessed. Longevity was significantly extended in: Rosa hybrida L. `Gabrielle' and Scilla campanulata L. Squill. by all germicides; Lilium parkmannii L. `Nepal', Gerbera jamesonii L. `Mercy', and Narcissus tazetta L. `Fortune' by DICA and BCDMH; Gypsophila paniculata L. `R22' by DICA and HQC; and Freesia hybrida Eckl. ex Klatt `White Bergunden' by BCDMH. No effect on longevity was found in Dendranthema grandiflora (Ramat) Kitamura. `Horim', Dianthus caryophyllus L. `Medea', Dianthus barbatus L., Iris hollandica L. `Pearl', and Gerbera jamesonii L. `Double Delight'. Longevity was significantly reduced by DICA in Alstroemeria aurantiaca L. `Mona Lisa' and Tulipa hybrida L. `Apeldoorn'. Analysis of microbial concentrations showed that proliferation was effectively controlled by DICA and BCDMH, but not by HQC. Levels of up to 106 cfu·ml-1 were detected in water, indicating that species not affected by germicides can tolerate these microbial quantities. Fresh weight and solution uptake data indicated that germicides acted primarily by improving solution uptake. Longevity was significantly reduced in R. hybrida `Gabrielle' and D. caryophyllus `Medea' flowers placed in solutions containing high counts of microorganisms (>108 cfu·ml-1) isolated from D. caryophyllus or R. hybrida. Chemical names used: 1-bromo-3-chloro-5,5-dimethylhydantoin (BCDMH); sodium dichloroisocyanuric acid (DICA); 8-hydroxyquinoline citrate (HQC).
Water Deficits and Environmental Factors Affect Photosynthesis in Leaves of Cucumber (Cucumis sativus)
Authors: Janoudi Abdul K. , Widders Irvin E. , Flore James A.
Published: January 2019

Cucumber plants were cultured in a greenhouse and subjected to either well-watered or water deficit conditions that reduced leaf water potential to-0.6 MPa. Leaf gas exchange measurements were conducted using an open gas exchange system. Carbon dioxide assimilation (A) attained saturation at a photon flux density (PFD) of 1000 μmol·m-2·s-1 (400-700 nm). There were no significant differences in A at ambient temperatures between 16 and 34C. Water use efficiency decreased rapidly with increasing vapor-pressure deficits to 2.5 kPa. Water stressed plants had lower stomata1 conductances and CO2 assimilation rates. The decrease in A was only partially due to stomata1 closure. The A vs. intercellular CO (Ci) relationship for stressed leaves revealed a change in the CO, compensation point, and that nonstomatal factors were contributing to the decrease in A in stressed plants. Thus, feedback inhibition of A may have occurred through photoassimilate accumulation. The concentrations of sucrose and raffinose were higher, and the concentration of stachyose was lower in leaves of stressed than of well-watered plants.
Creation of New Flower Colors in Ornithogalum Via Interspecific Hybridization
Authors: Griesbach R.J. , Meyer F. , Koopowitz H.
Published: January 2019

Embryo rescue was successfully applied to develop hybrids between Ornithogalum dubium Houtt. (short inflorescence with orange flowers) and O. thyrsoides Jacq. (tall inflorescences with white flowers]. Meiosis in these hybrids showed abnormalities such as univalents, laggards, and bridges. The F, hybrids were partially fertile, and F2 and BC1 progeny were produced. The backcross hybrids segregated for flower color and, inflorescence traits and introgressed seedlings with orange pigmented flowers on tall inflorescences were obtained in the population.
High-frequency Somatic Embryogenesis from Quiescent Seed Cotyledons of Cucumis melo Cultivars
Authors: Gray D.J. , McColley D.W. , Compton Michael E.
Published: January 2019

A protocol for high-frequency somatic embryogenesis in Cucumis melo L. was developed using `Male Sterile A147 as a model cultivar. Basal halves of quiescent seed cotyledons were cultured on embryo induction (EI) medium containing concentration ranges of the auxin 2,4-D and the cytokinins BA, Bin, TDZ, or 2iP before transfer to embryo development (ED) medium. Medium with 2,4-D at 5 mg·liter-1 and TDZ at 0.1 mg·liter-1 was superior, with 49% of explants responding and an average of 3.3 somatic embryos per explant (6.8 somatic embryos per responding explant). More explants produced embryos when incubated on EI medium for 1 or 2 weeks (30% and 33%) than for 3 or 4 weeks or with no induction. However, 2 weeks was 2.9 times better than 1 week in terms of number of embryos per explant. One week of initial culture in darkness, followed by a 16 hour light/8 hour dark photoperiod, produced more responding explants (26%) than two or more weeks in darkness or no dark period at all; but 1 and 2 weeks of darkness resulted in a similar number of embryos per explant (2.1 and 2.8). Sucrose concentration in EI and ED media had a highly significant effect on embryo induction and development. EI medium with 3% sucrose resulted in more embryogenic explants than EI medium with 1.5% or 6% sucrose. However, treatments with 3% sucrose in EI medium and 3% or 6% sucrose in ED medium produced significantly more embryos per explant (8.5 and 11.9) than other treatments. Treatments did not affect embryo induction directly and regeneration per se but, instead, frequency and efficiency of somatic embryo development. The optimal treatments were tested with 51 other commercial varieties. All varieties underwent somatic embryogenesis, exhibiting a response of 5% to 100% explant response and 0.1-20.2 embryos per explant. Chemical names used: N-(phenylmethyl)-lH-purin-6-amine (benzyladenine or BA); N-(2-furanylmethyl)-lH-purin-6-amine (kinetin or BIN); N-phenyl-N'-1,2,3-thiadiazol-5-ylurea (thidiazuron or TDZ); N-(3-methyl-2-butenyl)-lH-purin-6-amine (2iP); (2,4-dichlorophenoxy) acetic acid (2,4-D).
Growth and Fruiting Responses of `Redchief Delicious' Apple Trees to Heading Cuts and Scaffold Limb Removal
Authors: Marini Richard P. , Barden John A. , Sowers Donald
Published: January 2019

Three-year-old `Campbell Redchief Delicious'/MM.111 [Malus domestica (Borkh.)] trees were subjected to a factorial arrangement of annual pruning treatments (removal of excess scaffold limbs vs. no removal, heading the terminal extension shoot on scaffold limbs vs. no heading) plus a treatment involving gradual removal of excess scaffold limbs. Six years after treatments were initiated, pruning treatment did not influence tree height or trunk size. Tree spread was greatest for nonheaded trees. Although yield, yield efficiency, and gross returns were reduced by either type of pruning, there was significant interaction between limb removal and heading. Compared to no limb removal or heading, limb removal plus heading reduced cumulative gross returns by ≈ $12,800/ha.
Relative Growth Rate and its Relationship to Compositional Changes of Nonstructural Carbohydrates in the Mesocarp of Developing Peach Fruits
Authors: Pavel E.W. , DeJong T.M.
Published: January 2019

Dry weights of whole fruit and of different fruit tissues, such as the mesocarp (with exocarp) and the endocarp (with seed), were accumulated on early (`Spring Lady'), midseason (`Flamecrest'), and late-maturing (`Cal Red') peach [Prunus persica (L.) Batsch] cultivars during the 1988 growing season. Seasonal relative growth rate (RGR) patterns of whole fruit showed two distinct phases for `Flamecrest' and `Cal Red'; however, `Spring Lady' did not exhibit two distinct RGR phases. The shift from phase I to phase II of the whole fruit RGR curve was related to an intersection of mesocarp and endocarp RGR curves, indicating a change of physiological sink activities in those fruit tissues in the later-maturing cultivars, but not in the early cultivar. Nonstructural carbohydrate compositional changes in concentration or content were similar in the three peach cultivars. Sucrose accounted for most of the seasonal increase in mesocarp nonstructural carbohydrate concentration. A sudden rise of sucrose was associated with the phase shift of the fruit RGR curves of the midseason and late-maturing cultivars, but not of the early maturing cultivar; however, in the early maturing cultivar, mesocarp compositional carbohydrate changes and, particularly, the sucrose increase, indicate that the physiological processes normally associated with the two phases exist in very early maturing fruit but are not associated distinctly with two separate RGR phases.
Irrigation Method and Rowcover Use for Strawberry Freeze Protection
Authors: Hochmuth George J. , Locascio Salvadore J. , Kostewicz Stephen R. , Martin Frank G.
Published: January 2019

Three irrigation treatments (none, drip, and sprinkler) and eight rowcover treatments were evaluated for their capacity to provide freeze protection for strawberries (Fragaria ×ananassa Duch.) in a split-plot factorial field experiment. The period under study included 20 freeze events, two events with minima of -9.5C and -10.0C. With no freeze protection, up to 93% of the flowers were damaged by freezes. Among sprinkler-irrigated plants, an average of only 10% flowers were damaged due to the freezes. Heavy-weight rowcovers (polyethylene blanket and polypropylene, 30 and 50 g·m-2, respectively) protected strawberry flowers as well as sprinkler irrigation to -4.4C. Early yield (December-January) from unprotected plants was negligible. Early yields from plants protected with a 3.2-mm polyethylene blanket or a 50 g·m-2 polypropylene cover were equal to yields obtained with sprinkler-protected plants. Combinations of sprinkler and certain rowcover treatments provided for better fruit production than either treatment alone. Drip irrigation alone provided no protection from freezes. All strawberry plants recovered from freeze damage and total-season yields were similar with all irrigation methods and rowcovers.
Calcium (45Ca) Mobility in Chicory Root (Cichorium intybus L.) as Affected by the Anionic Composition of the Nutrient Solution during Forcing
Authors: Fouldrin Karine , Limami Anis , Lamaze Thierry
Published: January 2019

During forcing, the witloof chicory taproot produces an etiolated bud, the chicon. The axis of this organ often is brown as a consequence of a disorder associated with a localized Ca deficiency. The effect of the main anions (NO3-, Cl-, SO42) in the nutrient solution on Ca (45Ca) absorption and translocation in the chicon was investigated. Although the amount of Ca that accumulated in the chicon was not affected by nutrient solution composition, Ca (45Ca) mobility was modified. The amount of radioactivity in the chicon increased slightly when the main anion in the solution was sulfate and decreased markedly when the main anion was chloride, compared to nitrate. Calculations of the specific radioactivity of Ca reaching the chicon and in root tissue suggest that, when slowed down, Ca transport consists of a homogeneous flow in all root tissues, whereas, in other cases, Ca moves along a preferential pathway, such as the xylem vessels. Modifying the anionic composition of the nutrient solution to avoid a localized Ca deficiency is discussed.
Firmness and Decay of Apples following Postharvest Pressure Infiltration of Calcium and Heat Treatment
Authors: Sams Carl E. , Conway William S. , Abbott Judith A. , Lewis Russell J. , Ben-Shalom Noach
Published: January 2019

Heating `Golden Delicious' apples (Malus domestica Borkh.) for 4 days at 38C or pressure-infiltrating them with a 4% CaCl2 solution reduced decay and maintained fruit firmness during 6 months of storage at 0C. Heating reduced decay caused by Penicillium expansum Link ex Thorn by ≈30%, while pressure infiltration with CaCl2 reduced decay by >60%. Pressure infiltration with CaCl2 after heating reduced decay by ≈40%. Pressure infiltration maintained firmness best (>84 N), as measured with a manually driven electronic fruit-firmness probe, followed by heat and CaCl2 (76 N), heat alone (71 N), and no treatment (control) (60 N). Force vs. deformation (FD) curves from a puncture test with a fruit-firmness probe mounted in a universal testing machine showed that fruit heated before storage were firmer than all nonheated fruit, except those pressure-infiltrated with 4% CaCl2. However, FD curves also showed that apples pressure-infiltrated with 4% CaCl2 differed quantitatively from apples in all other treatments, including those heated.
Anatomy of Adventitious Root Formation in Microcuttings of Malus domestica Borkh. `Gala'
Authors: Harbage James F. , Stimart Dennis P. , Evert Ray F.
Published: January 2019

Anatomical events of adventitious root formation in response to root induction medium, observing changes during induction and post-induction stages, were made with microcuttings of `Gala' apples. Shoot explants on root induction medium containing water, 1.5 μm IBA, 44 mm sucrose, or 1.5 μm IBA + 44 mm sucrose after 4 days of treatment averaged 0, 0.2, 2.2, and 11.9 meristemoids per microcutting, respectively. Meristemoids formed in response to sucrose were confined to leaf gaps and traces. Time-course analysis of root induction with 1.5 μm IBA + 44 mm sucrose over 4 days revealed that some phloem parenchyma cells became densely cytoplasmic, having nuclei with prominent nucleoli within 1 day; meristematic activity in the phloem was widespread by 2 days; continued division of phloem parenchyma cells advanced into the cortex by 3 days; and that identifiable root primordia were present by 4 days. Cell division of pith, vascular cambium, and cortex did not lead to primordia formation. Meristematic activity was confined to the basal 1 mm of microcuttings. Time-course analysis of post-induction treatment revealed differentiation of distinct cell layers at the distal end of primordia by 1 day; primordia with a conical shape and several cell layers at the distal end by 2 to 3 days; roots with organized tissue systems emerging from the stem by 4 days; and numerous emerged roots by 6 days. Root initiation was detectable within 24 hours and completed by day 4 of the root induction treatment and involved only phloem parenchyma cells. Chemical names used: 1 H -indole3-butryic acid (IBA).
Hydrogen Cyanamide Advances Pecan Budbreak and Harvesting
Authors: Wood Bruce W.
Published: January 2019

Dormant season sprays of hydrogen cyanamide applied to pecan [Carya illinoinensis (Wangenh.) K. Koch] trees advanced budbreak, flowering, and shuck dehiscence. Hydrogen cyanamide was applied to dormant branches at ≈60, 45, 30, and 15 days before normal vegetative budbreak at rates of 0, 120, 240, 480, and 960 mm (corresponding to ≈0%, 0.5%, 1%, 2%, and 4%, solutions for 3 years). Depending on treatment, hydrogen cyanamide advanced budbreak by as much as 17 days, female and male flower maturity by up to 15 days, and nut ripening by as much as 14 days without reducing nut yield or causing phytotoxicity. Hydrogen cyanamide applied at 480 to 960 mm ≈60 days before expected budbreak possibly may be used commercially to advance ripening, manipulate time of pollen dispersal, and substitute for chilling when pecan is grown in mild environments.
Ontogeny and Sulfur Fertility Affect Leaf Sulfur in Short-day Onions
Authors: Randle W.M. , Bussard M.L. , Warnock D.F.
Published: January 2019

Five short-day onion (Allium cepa L.) cultivars grown with high (4.0 meq S/liter) and low (0.1 meq S/liter) S fertility were evaluated for ontogenetic changes in leaf S concentration and the association between leaf S concentration and final bulb pungency as reflected by pyruvate formation. Cultivars differed in leaf S concentration at each of eight sampling dates during growth and development, but the pattern of leaf S accumulation among cultivars was similar. Leaf S concentration increased during early plant development while in a nonbulbing photoperiod, but decreased as bulbing progressed to maturity with high and low S fertility. The decline in leaf S concentration during bulbing was more severe with low than with high S fertility. Leaves that were left to dry on the mature bulb lost most of their S, especially with 0.1 meq S/liter, a result that could have implications in final bulb flavor intensity. Correlations generally were poor between leaf and final bulb S concentration or pungency.
Incidence of Physical Damage on Peach and Nectarine Skin Discoloration Development: Anatomical Studies
Authors: Crisosto Carlos H. , Johnson R. Scott , Luza Juvenal , Day Kevin
Published: January 2019

Skin discoloration (SD) formation in peach [Prunus persica (L.) Batsch] and nectarine [Prunus persica (L.) Batsch, var. nectarine] was related to physical damage (abrasion) to the fruit during fruit handling (harvest and hauling operations) within the orchard and during transport to the packinghouse. Vibration and rubbing treatments increased SD formation indicating that tissue damage is involved in SD formation. Anatomical studies comparing sound and SD-injured tissues done by scanning electron and light microscopy indicated that very-low-intensity physical damage could induce brown and/or black spots because of cell disruption in the epidermal and hypodermal layers. The fact that injury was specific to the exocarp tissues (cuticle, epidermis, and hypodermis), and that mesocarp tissue located below the exocarp cells remained sound and turgid, indicated that abrasion injury is associated with SD. Similar types of visible and anatomical injury characteristics were induced by a rubbing treatment, demonstrating that physical abrasion damage affecting just exocarp cells was enough to induce SD:
Flowering, Vegetative Growth, Yield, and Fruit Quality in Muskmelons under Saline Conditions
Authors: Mendlinger Samuel , Fossen Michael
Published: January 2019

The muskmelon (Cucumis melo L.) cultivars Topmark, Galia, No. 1, and BG-84-3 (BG) were examined in a field test for the influence of increased salt concentration (700, 2500, 5000, 7500, and 10,000 ppm) on flower production, vegetative growth, yield, and fruit quality. Increased salinity did not affect the number or timing of staminate and pistillate flowers produced. Increased salinity significantly and to the same extent reduced vegetative growth in the four cultivars. Increased salinity did not affect the number of fruit produced in the four cultivars but reduced mean fruit weight in three. Mean fruit weight and yield of `BG' were not reduced; i.e., `BG' was salt tolerant. Increased salinity increased the soluble solids concentration and slightly improved fruit appearance of all cultivars.
Interaction of Two Genes, Fcr and Fcr2, with the t Allele in Common Bean that Restores Color to Flowers
Authors: Bassett Mark J.
Published: January 2019

Plant Introduction (PI) accession 507984 of common bean (Phaseolus vulgaris L.) has partly colored seed coats and either pure white flowers or light laelia flowers. Crosses were made with white-flowered plants of PI 507984: white-flowered plant #1 × the genetic stock t ers ers2 BC2 5-593 and white-flowered plant #2 × recurrent parent dry bean breeding line 5-593. Inheritance was studied in the F1, F2, and F3 of the former cross and the F1 and F2 of the latter cross. PI 507984 (white flower, plant #1) × t ers ers2 BC2 5-593 gave F1 plants with colored flowers and partly colored seeds. The F2 gave a 9:7 segregation ratio (colored flowers to white flowers), and the genetic model proposed is that flower color is restored in the presence of t/t by two complementary genes, Fcr and Fcr-2. That model was confirmed by F3 progeny tests of 21 F2 parents with colored flowers. The cross PI 507984 (white flower, plant #2) × 5-593 gave an F2 segregation ratio of 9:3:4 (bishops-violet: light laelia: white flowers), indicating that the white-flowered PI 507984 has vlae masked by t. Analysis of all the data suggests that PI 507984 is heterogeneous at Fcr and Fcr-2, having all three possible homozygous genotypes, viz., either light laelia flowers from vlae t Fcr Fcr-2 or white flowers from vlae t Fcr fcr-2 or vlae t fcr Fcr-2. The flower color restoration gene in 5-593 is arbitrarily assigned the symbol Fcr. Great variability occurs in partly colored seeds of PI 507984 due to the environment in which the seed was produced.
Severity of Tomato Blossom-end Scarring is Determined by Plant Age at Induction
Authors: Wien H.C. , Turner A.D.
Published: January 2019

Tomato plants were induced to produce fruit with abnormally large blossom-end scars (catfaces) by exposing them to 16/10C (day/night) for 2 weeks, starting at the six-leaf stage. Fruit of the second and third, but not the first, cluster showed catface symptoms. To identify the initial period of susceptibility to catfacing, `Revolution' tomatoes were greenhouse-grown for 34,48, or 62 days and induced to catface by a gibberellic acid (GA) foliar spray (43 μM) when transplanted to the field. Catfacing was significantly increased by GA sprays (23% vs. 11% of all fruit in 1989, 22% vs. 8% in 1990). There was a highly significant interaction between plant age and catfacing, with high levels for young and medium-aged, but lower levels for old GA3-treated transplants. The early-maturing `Revolution' is susceptible to catfacing from ≈25 to 60 days after sowing. Marketable yields were highest for young and medium-aged plants in 1989 and 1990, respectively. Old plants were checked in growth after being transplanted and produced lowest yields. Avoiding catfacing by using old transplants has doubtful practical value.
Path Analysis of Tomato Yield Components in Relation to Competition with Black and Eastern Black Nightshade
Authors: McGiffen Milton E. , Pantone Dan James , Masiunas John B.
Published: January 2019

Path analysis is a statistical method for determining the magnitude and direction of multiple effects on a complex process. We used path analysis to assess 1) the impact of black nightshade(Solarium nigrum L.) or eastern black nightshade(Solarium ptycanthum Dun.) competition on the yield components of `Heinz 6004' processing tomato (Lycopersicon esculentum Mill.) and 2) the relationship between tomato yield components and total and marketable yield. Either black or eastern black nightshade was interplanted with tomatoes at population densities from 0 to 4.8/m2. Path analysis revealed that increasing weed population density led directly to fewer green and total fruit per plant, two components of marketable yield. However, the percentage of culls per plant and fruit weight were not affected by nightshade population density. Using correlation coefficients alone would have lead to the erroneous conclusion that the percentage of culls did not affect marketable yield; our path analysis demonstrated that decreasing the percentage of culls through breeding or cultural practices will strongly affect marketable yield. The total number of fruit was the most important yield component in determining total and marketable yields per plant. Breeding and management practices that maximize fruit set, increase maturity at harvest, and decrease the percentage of culls would be expected to increase marketable yield.
Changes in Polyamine Content during Dormancy in Flower Buds of `Anna' Apple
Authors: Wang Shiow Y. , Faust Miklos
Published: January 2019

Polyamine, putrescine, spermidine, and spermine contents were determined during endodormancy in the buds of low-chilling-requiring `Anna' apples (Malus domestics Borkh.). Putrescine, spermidine, and spermine contents increased greatly in buds when their chilling requirement was satisfied. Polyamine biosynthetic inhibitors α -difluoromethylarginine (DFMA) or α -difluoromethylornithine (DFMO) reduced bud break and bud growth in concert with decreased polyamine titers. DFMO or DFMA did not inhibit bud break when it was applied to buds after they received the full chilling requirement. DFMO was more inhibitory than DFMA. The polyamine requirement was much higher for bud growth and bud development than during differentiation and bud break.
Mineral Composition of Young Rabbiteye and Southern Highbush Blueberry Exposed to Salinity and Supplemental Calcium
Authors: Wright Glenn C. , Patten Kim D. , Drew Malcolm C.
Published: January 2019

`Tifblue' and `Brightwell' rabbiteye blueberry (Vaccinium ashei Reade) and `Sharpblue' southern highbush blueberry (primarily V. corymbosum) were treated with 0, 25, and 100 mm Na+ as Na2SO4 or NaCl, and 0, 1, 3, and 10 mm supplemental Ca2+ in sand culture in the greenhouse. For rabbiteye plants salinized with Na2SO4, leaf Na+ concentrations increased 54-fold and the percentage of total plant Na+ found in the leaves increased from 9% to 63% with increasing external Na+. Calcium supplementation reduced the Na+ concentrations in leaves by up to 20%. Leaf Ca2+ concentrations increased with Ca2+ supplementation, but accounted for a decreasing percentage of the total Ca2+ found in the plant, since root Ca2+ concentrations were much higher. Root Na+ concentrations increased with increasing Na+ treatments to a smaller extent than in the leaves and were also reduced by Ca2+ supplements. Potassium concentrations in leaves and roots decreased with increasing Na+ treatment levels, particularly in roots, where K+ concentration was about half at 100 mm Na+ (as Na2SO4.) Leaf Na+ concentrations were up to two times greater when Na was supplied as NaCl compared to Na2SO4. For plants salinized with NaCl, leaf Na+ levels increased to 1.1% and did not decrease when supplemental Ca2+ was applied. Leaf Cl- concentrations also increased greatly with NaCl, reaching >1.0% (dry weight basis.). Root Cl- concentrations also increased with increasing salinity and were not affected by Ca2+ supplements. Ca2+ supplementation led only to a greater Ca2+ concentration in leaves and roots, but this did not alter Na+ concentrations. Nutrient concentrations in `Sharpblue' leaves, stems, and roots were greater than those of the rabbiteye cultivars, but were influenced by salinity and Ca2+ in essentially the same way. Excess Na+, Cl-, or both, together with lowered K+, were likely the cause of extensive leaf necrosis and may be indicative of a lack of a mechanism to control Na+ influx into blueberry leaves.