bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Watertable and Fertilizer Management on Susceptibility of Tomato Fruit to Chilling Injury
Authors: Dodds Georges T. , Trenholm Leif , Madramootoo Chandra A.
Published: January 2019

In a 2-year study (1993-1994), `New Yorker' tomato (Lycopersicon esculentum Mill.) plants grown in field lysimeters were subjected to four watertable depth (WTD) treatments (0.3, 0.6, 0.8, and 1.0 m from the soil surface) factorially combined with 5 potassium/calcium fertilization combinations. Mature-green fruit from four replicates of each treatment were stored at 5C for 21 days, and fruit color was monitored with a tristimulus colorimeter. Fruit were subsequently allowed to ripen at 20C for 10 days, at which time chilling injury was assessed on the basis of delayed ripening and area of lesions. Potassium and calcium applied in the field had no effect on chilling tolerance of the fruit. In the drier year (1993), shallower WTD treatments generally yielded fruit that changed color less during chilling and were more chilling-sensitive based on delayed ripening. In the wetter year, differences in color change and chilling tolerance between WTD, if any, were small. Over both years, lesion area varied with WTD, but not in a consistent manner. Based on these results, we suggest that differences in water availability should be considered when studying tomato fruit chilling.
Separating the Effects of Foliar and Root Salt Uptake on Growth and Mineral Composition of Four Grapevine Cultivars on their Own Roots and on `Ramsey' Rootstock
Authors: Stevens Rob M. , Harvey Gordon , Davies Gerry
Published: January 2019

The effect of foliar salt uptake on potted grapevine growth and ionic composition was investigated in a split plot trial. The main plot was a 2 × 2 factorial consisting of separately irrigating the roots and foliage with nonsaline or saline (25 mm NaCl) solutions. The subplot was a 4 × 2 factorial consisting of four grape (Vitis vinifera) cultivars on their own roots or `Ramsey' (Vitis champini) rootstock. Saline foliar irrigation over 27 weeks reduced total vine growth by 14% while saline root irrigation had no effect. Leaf Na and Cl concentrations were elevated by saline foliar and saline root irrigation. The increases in concentrations with saline foliar irrigation were four times those with saline root irrigation. Leaf K concentration was reduced by saline foliar irrigation and increased by saline root irrigation. With saline irrigation of roots and foliage the Cl and Na levels were highest in the leaves of `Shiraz', but with saline irrigation of only the roots `Sultana' had the higher levels of leaf Cl and `Shiraz' the highest leaf Na. Saline foliar irrigation had no effect on the concentrations of Na, Cl, and K in the roots. In `Sultana', saline foliar irrigation did not affect the leaf concentrations of N, NO3-N, P, Mg, Zn, and Cu. It increased the leaf concentration of Fe, and decreased that of Mn. Rootstock modified the effect of salinity on Fe concentrations. The B concentration was decreased by saline irrigation of either the foliage or the roots, but not by saline irrigation of both. In roots, saline foliar irrigation increased B in own-rooted vines, but not in those on `Ramsey' rootstock.
Role of Calyx Lobes in Gas Exchange and Development of Persimmon Fruit
Authors: Yonemori K. , Itai A. , Nakano R. , Sugiura A.
Published: January 2019

The role of calyx lobes in CO2 exchange in persimmon (Diospyros kaki Thunb.) fruit was investigated during fruit growth and development. Carbon dioxide exchange rates of attached and detached fruit were measured in light and dark conditions in the field after calyx lobes were removed. Calyx lobes were removed at fruit growth stages I and III, which were defined as the period when fruit diameter increases >0.3 mm·d-1 (Zheng et al., 1990). Removing calyx lobes at stage I significantly inhibited fruit growth, while removing them at stage III had no effect on growth. Two weeks after calyx lobes were removed at stage I, CO2 exchange decreased 80% in light and dark conditions compared with the control fruit. The rapid decreases of CO2 exchange rate by calyx lobe removal at stage I were obvious if expressed per fruit or on a fresh weight basis. In contrast, treatment at stage III had no effect on CO2 exchange rate of fruit and no effect on fruit growth. However, when the calyx lobe scars were sealed with Vaseline soon after calyx lobe removal at stage III, an immediate decline in CO2 exchange rate in the dark occurred with simultaneous inhibition of the final swell in fruit growth. A possible relationship between fruit growth potential and gas-exchange capacity is discussed.
Sulfur dioxide-enhanced Phytotoxicity of Ozone to Watermelon
Authors: Eason Gwendolyn , Reinert Richard A. , Simon James E.
Published: January 2019

Three watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] cultivars with different ozone (O3) sensitivities were grown in a charcoal-filtered greenhouse and exposed in continuous-stirred tank reactor chambers to five levels (0, 100, 200, 300, or 400 nL·L-1) of sulfur dioxide (SO2) in the presence (80 nL·L-1) or absence (0 nL·L-1) of ozone (O3) for 4 hours/day, 5 days/week for 22 days. In the presence of O3, SO2 increased foliar injury in all three cultivars, but the impact was greatest for the most O3-sensitive cultivar, `Sugar Baby,' moderate for `Crimson Sweet,' and least for the least O3-sensitive cultivar, `Charleston Gray.' For all cultivars, SO2 intensified O3 suppression of leaf area for the first seven mainstem leaves and of dry weights for aboveground and total plant tissues. Root dry weight was independently suppressed by both pollutants, and the root: top ratio was linearly suppressed by SO2 alone. Sulfur dioxide combined with O3 can be detrimental to crop species such as watermelon. Thus, the potential for SO2 phytotoxicity should not be summarily dismissed, especially in the vicinity of SO2 point sources where O3 co-occurs.
Identifying Molecular Genetic Markers Associated with Seedlessness in Grape
Authors: Striem M.J. , Ben-Hayyim G. , Spiegel-Roy P.
Published: January 2019

Excluding seeded offspring at an early stage could be of great value to the breeder concerned with the development of seedless grapes (Vitis vinifera L.). We used the random amplified polymorphic DNA (RAPD) technique to identify molecular genetic markers, analyzing 82 individuals of a progeny resulting from a cross between `Early Muscat' (seeded) and `Flame Seedless'. Seven variables representing the traits of seedlessness were analyzed: mean fresh weight of one seed, total fresh weight of seeds per berry, perception of seed content, seed size categories evaluated visually, degree of hardness of the seed coat, degree of development of the endosperm, and degree of development of the embryo. Among 160 10mer primers, 110 gave distinct band patterns. Twelve markers yielded significant correlations with several subtraits of seedlessness, mainly with the mean fresh weight of one seed and the total fresh weight of seeds per berry. Multiple linear regression analysis resulted in high coefficients, such as R = 0.779 for fresh weight of seeds per berry, when the seven markers were included as independent variables in the model. Most of the seeded individuals, about 44% of the progeny, could be excluded using a two-step process of marker assisted selection.
Production and Postproduction Performance of Two New Guinea Impatiens Cultivars Grown with Controlled-release Fertilizer and No Leaching
Authors: Haver Darren L. , Schuch Ursula K.
Published: January 2019

The objectives of this study were to determine 1) the minimum controlled-release fertilizer (CRF) rate and the lowest constant medium moisture required to produce the highest quality plants and 2) if this production system affected quality of these plants under two postproduction light levels. Two New Guinea impatiens (Impatiens sp. hybrids) `Illusion' and `Blazon' (Lasting Impressions Series) differing in salt tolerance were grown for 42 days with a CRF at three rates (3.3, 6.6, or 9.9 g/pot) and two medium moisture levels (low or high) without leaching. The high moisture level (tension setpoints of 1 to 3 kPa) and 6.6 g of CRF/pot produced optimum biomass. Low medium moisture (tension setpoints of 4 to 6 kPa) reduced leaf area, leaf number, leaf N content, root, stem, and leaf dry masses as CRF rate increased from low to high for `Illusion'. Similar results in `Blazon' were observed as CRF rates increased from 3.3 to 6.6 g. Biomass decreased no further at the high rate of 9.9 g/pot. Biomass increased in both cultivars under high medium moisture when CRF rates increased from 3.3 to 6.6 g. Biomass of `Illusion' decreased at 9.9 g/pot, although no symptoms of salt sensitivity were observed (i.e., leaf tip burn). `Blazon' maintained a similar biomass when amended with 9.9 or 6.6 g CRF/pot, although electrical conductivity (EC) in the medium was 5.9 dS·m-1 in the upper half and 4.1 dS·m-1 in the lower half of the medium at the end of production. Growth of `Illusion' responded more favorably to postproduction light levels that were similar to those of production regardless of treatment imposed during production. Similar biomass responses occurred for `Blazon' regardless of the postproduction light level.
Changes in the Amounts of the NAD-dependent Sorbitol Dehydrogenase and Its Involvement in the Development of Apple Fruit
Authors: Yamaguchi Hideaki , Kanayama Yoshinori , Soejima Junichi , Yamaki Shohei
Published: January 2019

Seasonal changes in the amounts of the NAD-dependent sorbitol dehydrogenase (NAD-SDH) (enzyme code, 1.1.1.14) protein in developing apple (Malus pumila Mill var. domestica Schneid) fruit were determined by immunoblotting analysis. The amounts of the enzyme protein were very low in young fruit and rose as fruit matured. The weak correlation between enzyme protein and NAD-SDH activity and also the changes in NAD-SDH specific activity suggested that there could be posttranslational modification to the pre-existing enzyme or isoenzyme(s) of NAD-SDH. The changes in the amounts of NAD-SDH protein did not show the same pattern as those in relative growth rate, which is used to express sink activity, especially in young fruit. The role of NAD-SDH on sink activity in apple fruit, therefore, could not be explained simply by the amount and activity of the enzyme. In young fruit, it seems that enzymes other than NAD-SDH would be more directly related with fruit growth.
Effects of Stock Plant Etiolation, Shading, Banding, and Shoot Development on Histology and Cutting Propagation of Carpinus betulus L. fastigiata
Authors: Maynard Brian K. , Bassuk Nina L.
Published: January 2019

New shoot growth of Carpinus betulus L. fastigiata was subjected to stock plant etiolation and stem banding (a 2.5-cm square of Velcro applied to the shoot base) treatments and sampled for histological study at intervals over a 16-week period of shoot development following etiolation. Effects of partial shading on histology of the stem were also investigated. Numerous histological changes were noted with stem development and stock plant treatment. Among these were a reduction in lignification of the secondary xylem and thickness of the periderm, and an increase in the percentage of sclereid-free gaps in the perivascular sclerenchyma with etiolation. Concomitant propagation studies revealed significant etiolation, shading, and banding effects on rooting percentages and root numbers. Rooting capacity was modelled using linear combinations of the widths of nonlignified secondary xylem, cortical parenchyma and periderm, as well as the percentage of gaps in the sclerenchymatic sheath remaining free of sclereids. It is proposed that the development of sclereids in potential rooting sites reduces rooting potential. The exclusion of light during initial shoot development retards sclereid development by up to 3 months following treatment, which correlates well with observed increases in the rooting potential of etiolated stems.
Influence of Light on Grape Berry Growth and Composition Varies during Fruit Development
Authors: Dokoozlian N.K. , Kliewer W.M.
Published: January 2019

Potted `Cabernet Sauvignon' and `Pinot noir' grapevines (Vitis vinifera L.) grown in a sunlit phytotron were used to study the influence of cluster light exposure during various stages of fruit development on berry growth and composition. Clusters grown without light during berry development stages I and II, stage III, or stages I, II, and III, were compared to clusters exposed to light throughout fruit development (control). The temperature of light-exposed and nonexposed fruit was similar. The weights and diameters of berries grown without light during stages I and II, or stages I, II, and III, were similar and significantly lower than those of the control. Fruit softening in both cultivars, as well as the initiation of berry coloration, was delayed when berries were grown without light during stages I and II. Following fruit softening, berries grown without light during stages I, II, and III were lower in sugar than the control. On the final sample date, `Cabernet Sauvignon' berries grown without light during stages I, II, and III were higher in malate compared to the control. `Pinot noir' berries grown without light during stages I and II, or stages I, II, and III, were lower in malate before fruit softening, and higher in malate following fruit softening, than the control. Control berries had greater skin anthocyanins and phenolics compared to the remaining treatments. Berries grown without light during stages I and II, or stage III, were greater in anthocyanins and phenolics than fruit grown without light during stages I, II, and III. Light had no effect on fruit tartrate concentration or juice pH. Light had its greatest impact on fruit development during the initial stages of berry growth. Berry growth was reduced and ripening delayed when fruit were grown without light during stages I and II. Normal fruit development was not fully restored when these fruit were exposed to light during stage III.
Hexanal Vapor Is a Natural, Metabolizable Fungicide: Inhibition of Fungal Activity and Enhancement of Aroma Biosynthesis in Apple Slices
Authors: Song Jun , Leepipattanawit Rujida , Deng Weimin , Beaudry Randolph M.
Published: January 2019

Hexanal vapor inhibited hyphae growth of Penicillium expansum and Botrytis cinerea on potato dextrose agar (PDA) and on apple (Malus domestica Borkh.) slices. After 48 hours exposure to 4.1 μmol·L-1 (100 ppm) hexanal, the hyphae growth of both fungi was about 50% that of untreated controls. At a concentration of 10.3 μmol·L-1 (250 ppm), neither fungus grew during the treatment period, however, some growth of both fungi occurred 120 hours after treatment. At concentrations of hexanal vapor of 18.6 μmol·L-1 (450 ppm) or more, the growth of both fungi ceased and the organisms were apparently killed, neither showing regrowth when moved to air. When fungi were allowed to germinate and grow for 48 hours in hexanal-free air, a subsequent 48-hour exposure to 10.3 μmol·L-1 hexanal slowed colony growth relative to controls for several days and a 48-hour exposure to 18.6 μmol·L-1 stopped growth completely. Concentrations of hexanal that inhibited fungal growth on PDA also retarded decay lesion development on `Golden Delicious' and on `Jonagold' apple slices. Hexanal was actively converted to aroma volatiles in `Jonagold' and `Golden Delicious' apple slices, with hexanol and hexylacetate production strongly enhanced after 20 to 30 hours treatment. A small amount of butylhexanoate and hexylhexanoate production was also noted. Within 16 hours after treatment, no hexanal could be detected emanating from treated fruit. Since hexanal was metabolized to aroma-related volatiles by the fruit slices, the possibility of hexanal being an essentially residue-less antifungal agent seems likely. The possibility of developing a system for treating apple slices with hexanal in modified-atmosphere packages was also examined. The permeability of low-density polyethylene (LDPE) film to hexanal and hexylacetate was, respectively, about 500- and 1000-fold higher than LDPE permeability to O2. The permeability of both compounds increased exponentially with temperature, with hexanal permeability increased 6-fold while hexylacetate increased only 2.5-fold between 0 and 30 °C.
Influence of European Red Mite on Leaf and Whole-canopy Carbon Dioxide Exchange, Yield, Fruit Size, Quality, and Return Cropping in `Starkrimson Delicious' Apple Trees
Authors: Lakso A.N. , Mattii G.B. , Nyrop J.P. , Denning S.S.
Published: January 2019

The hypothesis was tested that effects of late-season European Red Mite (ERM) [Panonychus ulmi (Koch)] injury on apple (Malus domestica Borkh.) fruit development are better explained by carbon physiology than by pest densities. Midseason ERM populations were allowed to develop in mature semi-dwarf `Starkrimson Delicious'/M26 trees with moderately heavy crops, then were controlled with miticides at different mite-day (activity of one mite per leaf for 1 day) levels as estimated by weekly leaf sampling. The range of final mite-days was from 250 to 2100 on individual trees. Seasonal fruit growth patterns were monitored. Diurnal whole-canopy net CO2 exchange rate (NCER) was measured in eight clear flexible balloon whole-canopy chambers on several dates before and after mite infestations. Mite injury reduced fruit growth rates. Leaf and whole-canopy NCER were reduced similarly. Late season fruit growth and final fruit size were correlated with accumulated mite-days, but were better correlated to whole-canopy NCER per fruit. Fruit firmness, color, soluble solids and starch ratings showed no correlation to mite-days. Number of flower clusters per tree and final fruit per tree the following year were not related to accumulated mite-days, but final fruit per tree the following year were better correlated to whole-canopy NCER per fruit. These results generally supported the hypothesis.
The Role of Snails and Ants in Transmitting the Avocado Stem Canker Pathogen, Phytophthora citricola
Authors: El-Hamalawi Zeinab A. , Menge John A.
Published: January 2019

The sugary exudate appearing on bark lesions of Persea americana Miller and Persea indica plants after infection with Phytophthora citricola contained viable oospores and hyphal fragments in the field and in the greenhouse. This sugary exudate was a source of inoculum and dispersal of the pathogen within and between avocado plants. Spraying water onto lesions moved inoculum from the sugary exudate to wounds below. Water from sprinkler irrigation washed propagules into the soil around the plants. Viable propagules of Phytophthora citricola were identified in the feces of snails (Helix aspersa) that had fed on infected bark tissues. When these snails were moved to healthy plants, they made wounds on succulent tissue, and the infectious feces induced cankers. Ants (Iridomyrmex humilis) were attracted to the sugary exudate and also transmitted infectious propagules to wounds on avocado stems and to the soil. Control strategy for the avocado stem canker disease should consider control of vectors.
Phenotypic Variation in Free Folic Acid Content among F1 Hybrids and Open-pollinated Cultivars of Red Beet
Authors: Wang M. , Goldman I.L.
Published: January 2019

The importance of folic acid in the human diet has been recognized in recent years by major increases in government recommended allowances. Red beet (Beta vulgaris L.) is an important vegetable source of folic acid, however little is known about the extent of variation for native folic acid content in red beet germplasm. A total of 18 red beet entries, including 11 hybrids (F1) and seven open-pollinated cultivars (OP), were evaluated for free folic acid content (FFAC) in replicated field experiments during 1993 and 1994. Significant differences among entries were detected in all studies. FFAC ranged from 3.3 to 15.2 μg·g-1 on a dry mass basis. A significant entry × year interaction was detected. Changes in rank of entries between years were minimal among F1 hybrids, while the changes in rank among OP cultivars were large. These data demonstrate significant variability among cultivated red beet germplasm sources for FFAC. Entries with high FFAC may be useful for increasing levels of this vitamin in red beet.
DNA Marker-based Study of Genetic Relatedness in United States Sweetpotato Cultivars
Authors: Prakash C.S. , He Guohao , Jarret Robert L.
Published: January 2019

The polymerase chain reaction (PCR)-based DNA amplification fingerprinting (DAF) approach was used to investigate genetic relationships among 30 U.S. sweetpotato (Ipomoea batatas L. Lam.) genotypes including heirloom cultivars and recent releases. Phenogram, pairwise similarity matrix, and principal coordinate plots were developed based on Jaccard's coefficients using band-sharing data generated by seven octamer primers. All cultivars showed unique fingerprint patterns indicating the utility of DAF in cultivar identification. Many heirloom cultivars such as `Creole' and `Porto Rico' were readily differentiated from recently developed cultivars. Modern cultivars such as `Jewel', `Carver', `Nugget', and `Scarlet' exhibited a high degree of similarity reflecting ancestral relatedness. `Regal' and `Excel', recently developed using a population-based breeding approach, showed greater divergence from all other cultivars. Those cultivars, developed as a result of somatic mutations, exhibited high levels of genetic similarity to their normal-type parents and yet had distinct fingerprint profiles. With few exceptions, genetic relationships derived from DAF data appear to be consistent with available pedigree information.
Photosynthetic Rate, Flowering, and Yield Component Alteration in Hazelnut in Response to Different Light Environments
Authors: Hampson Cheryl R. , Azarenko Anita N. , Potter John R.
Published: January 2019

In hazelnut (Corylus avellana L.), vigorous vegetative growth and traditional orchard practices that include little or no pruning combine to produce a dense, shady canopy. A study designed to quantify the effect of shade on reproduction and photosynthetic rate in this shade-tolerant species was undertaken to assess whether some degree of pruning might improve productivity. Shade cloth was used to exclude 30%, 47%, 63%, 73%, or 92% of ambient sunlight from whole `Ennis' and `Barcelona' trees from mid-May until harvest. Photosynthetic light response curves were obtained for leaves that had developed in full sunlight, deep inside the canopy of unshaded trees, or in 92% shade. Light-saturated net photosynthetic rates were 12.0, 6.1, and 9.3 μmol·m-2·s-1 of CO2 and dark respiration rates were 2.0, 1.1, and 0.7 μmol·m-2·s-1 of CO2, respectively, for the three light regimes. Light-saturated photosynthetic rates of leaves from 30% or 63% shade differed little from the control (0% shade). Area per leaf increased by 49% and chlorophyll concentration (dry weight basis) by 157% as shading increased from 0% to 92%. Shading to 92% reduced specific leaf weight (68%), stomatal density (30%), light compensation point (69%), and dark respiration rate (63%) compared to controls. Female inflorescence density declined by about one-third and male inflorescence density by 64% to 74% in the most heavily shaded trees of both cultivars compared to controls. Shade was more detrimental to yield than flowering: yield per tree dropped by >80%, from 2.9 to 3.4 kg in full sun to 0.6 to 0.9 kg in 92% shade. Shade reduced yield primarily by decreasing nut number and secondarily by decreasing nut size. The incidence of several kernel defects increased as shade increased. Therefore, hazelnut leaves showed considerable capacity to adapt structurally and functionally to shade, but improving light penetration into the canopy would probably increase orchard productivity.
Soil Fumigation, Fruit Production, and Dry Matter Partitioning of Field-grown Strawberry Plants
Authors: Larson Kirk D. , Shaw Douglas V.
Published: January 2019

Bare-rooted `Camarosa' strawberry runner plants were established in a fruit production field on 1 Nov. 1993 using annual hill culture and two preplant soil fumigation treatments: 1) a mixture of 2 methyl bromide: 1 chloropicrin (wt: wt, 392 kg·ha-1) injected into the soil before forming raised planting beds (MBC); or 2) nonfumigation (NF). At about 33-day intervals between mid-January and the end of May, 20 plants were destructively sampled from each treatment to determine leaf dry mass (LDM), crown dry mass (CDM), root dry mass (RDM), and shoot: root dry mass (SRDM) ratios. Plant mortality was <0.2% throughout the study and did not differ with soil treatment. Regardless of sampling date, LDM, CDM, and RDM were greater for MBC plants than for NF plants, although treatment differences were not always significant. During the first 143 days, NF plants allocated a greater proportion of dry matter to roots than to shoots compared to MBC plants, indicating that roots are a stronger sink for photoassimilate in nonfumigated than in fumigated soils. However, there was no difference between treatments in SRDM by the end of the study. Fruit yield and a 10-fruit weight were determined at weekly intervals from mid-January until 23 May 1994. Yield and mean fruit weight of NF plants were 72% and 90%, respectively, of that of MBC plants. For both treatments, about one-half of total fruit production occurred between 144 and 174 days after planting (late March to late April). During that same period, rates of dry matter accumulation in leaf, crown, and root tissues decreased for plants in both treatments, but greatest reductions occurred in NF plants. Chemical name used: trichloronitromethane (chloropicrin).
Effect of Heat Stress on Enzymes that Affect Sucrose Levels in Potato Shoots
Authors: Lorenzen James H. , Lafta Abbas M.
Published: January 2019

Potato (Solanum tuberosum L.) responds to heat stress with a shift in partitioning from tubers to shoots. Enzymes responsible for sucrolysis previously have been used as indicators of sink strength and are likely involved in controlling flow of carbon into developing organs. Changes in activity of enzymes involved in sucrose metabolism were investigated in shoots of two potato cultivars that previously were characterized as susceptible and tolerant to heat stress. Enzyme activity of sucrose synthase (SS) and invertases was determined for mature leaves, young leaves, and stems of plants adapted to 21/19 °C, or after transferring plants to 29/27 °C for 3 days. High temperatures resulted in a nonsignificant increase in activities of SS, acid, and neutral invertase in young growing leaves but not in stems or mature leaves. The combined activity of the two invertases was ≈40 times higher than SS activity in young leaves. There was no temperature genotype interaction with regard to these enzymes in the tissues investigated. A previously reported increase in activity of sucrose-phosphate synthase in mature leaves of plants subjected to high temperature was reversed after these plants were returned to a normal growing temperature.
Paclobutrazol Reduces Some Negative Effects of Salt Stress in Peach
Authors: El-Khashab A.M. Abou , El-Sammak A.F. , Elaidy A.A. , Salama M.I. , Rieger M.
Published: January 2019

One-year-old rooted cuttings of `Nemaguard' peach [Prunus persica (L.) Batsch.] were irrigated with 0, 1000, or 2000 mg·L-1 salts under greenhouse conditions to study the effect of foliar paclobutrazol (PBZ) application on salt stress response. Salinity reduced growth of nontreated plants by ≈60%, but only by ≈30% for PBZ-treated plants. PBZ-treated plants also had less defoliation and fewer leaves per plant showing salt stress symptoms, and had higher rates of leaf gas exchange than nontreated plants. PBZ application generally reduced Na+ and Cl- contents in leaves, roots, and stems, regardless of salt treatment. Furthermore, total Na+ per plant in PBZ-treated plants was about half that found in nontreated plants, although total Cl- per plant was reduced by PBZ in only one of two salt treatments. The data suggested that PBZ promoted salt stress avoidance in peach by reducing the uptake and accumulation of harmful Na+ and Cl- ions in plant tissues.
Iron—Polyphenol Complex Formation and Skin Discoloration in Peaches and Nectarines
Authors: Cheng Guiwen W. , Crisosto Carlos H.
Published: January 2019

The formation of metallo-pigmentation and copigmentation as potential mechanisms of inking formation was investigated in peach and nectarine skin tissues. Cyanidin-3-glucoside, the most abundant anthocyanin in peaches and nectarines, formed very purple ferric complexes with an anthocyanin/iron molar ratio of two. Greenish metallo complexes between ferric ion and chlorogenic acid, caffeic acid, catechin, or epicatechin formed with an phenolic/iron molar ratio of one. The lack of copigmentation pointed out the importance to focus research on the metallo-phenolics reaction. High intensity of dark color formation was developed with cyanidin-3-glucoside, followed by caffeic acid, chlorogenic acid, catechin, and epicatechin on an equal molar basis. Citric acid acted as a strong iron chelator to prevent and reverse the formation of ferric cyanidin-3-glucoside complexes. The variety of dark and light colored spots observed on the surface of peaches and nectarines is explained by the formation of metallo-pigment complexes.
Determining Heat Unit Requirements for Broccoli Harvest in Coastal South Carolina
Authors: Dufault Robert J.
Published: January 2019

The objective of this research was to determine the least variable method to predict the dates of the first and last broccoli (Brassica oleracea L. var Italica) harvests based on heat unit summation using coefficients of variation (cv). The method with the lowest cv for predicting first harvest was to sum, over days from planting to harvest, the difference between the growing season mean (GSM) temperature and a base temperature of 7.2 °C. If the GSM maximum (max) temperature, however, was >26.7 °C, an adjusted max temperature was calculated by first subtracting 26.7 °C from the GSM max temperature and then subtracting the GSM mean temperature. Then the growing degree days (GDDs) were summed by subtracting the base temperature of 7.2 °C from the average of the GSM minimum (min) and adjusted max temperatures. This method produced a cv of 3.96 compared to 4.13 for the standard method of summing over the entire growing season, the mean temperature minus the base temperature of 4.4 °C. The method with the lowest cv for predicting last harvest was to sum, over days from planting to harvest, the difference between the GSM max temperature and a base temperature of 7.2 °C. If the GSM max temperature, however, was >29.4 °C, the base temperature was subtracted from 29.4 °C and not the actual GSM max temperature. This method produced a cv of 3.71 compared to 4.10 for the standard method of summing over the growing season, the mean temperature minus the base of 4.4 °C.
Identifying New Sources of Genes that Determine Cyclic Flowering in Rocky Mountain Populations of Fragaria virginiana ssp. glauca Staudt
Authors: Sakin M. , Hancock J.F. , Luby J.J.
Published: January 2019

The genes that determine cyclic flowering in all commercially grown cultivars of strawberry (Fragaria ×ananassa Duch.) were derived from a single source of F. virginiana ssp. glauca from the Wasatch Mountains in Utah. To broaden the germplasm base of cyclic flowering cultivars, we evaluated the reproductive characteristics of 5 to 10 colonies of F. virginiana ssp. glauca from each of 32 Rocky Mountain sites ranging in elevation from 700 to 2900 m. Populations at high and low elevations had high percentages of putative day neutrals with cyclic flowering (43% to 100%) and hermaphrodites (20% to 80%), although most hermaphrodites were only partially fertile. There was also little association between elevation and crown numbers or flower number per cycle, but the total number of flowers per plant was negatively correlated with elevation. Fruit size was not significantly correlated with fruit number. When the data were subjected to a principal component analysis, two distinct groups were identified: one from the Black Hills of South Dakota and the other from low-elevation sites in Idaho and northwestern Montana. These patterns mirrored previously described patterns based on leaf traits.
Biochemical and Genetic Linkage Analysis of Green Seed Color in Field Pea
Authors: McCallum John , Timmerman-Vaughan Gail , Frew Tonya , Russell Adrian
Published: January 2019

Developmental, environmental, and genetic factors affecting seed color were studied in the progeny of a cross between two white-flowered (aa) green cotyledon (ii) field peas (Pisum sativum L.): the pale large-seeded Marrowfat cultivar Primo and the greener small-seeded Prussian Blue OSU442-15. Changes in chlorophyll and carotenoid content during seed development of the parental genotypes were determined by high performance liquid chromatography analysis. Both cultivars accumulated similar pigment quantities per seed, but pigment loss was greater during maturation of `Primo'. Bleached and unbleached mature seed tissues also were compared for pigment composition. Lutein was the predominant pigment in bleached cotyledons of both cultivars. Only trace amounts of pheophytins were detected in unbleached seed. In both genotypes, chlorophyll A : B ratios were ≈1:1 in seed coats compared to 3:1 in cotyledons. Objective measurements of seed color in terms of luminance (lightness) and chrominance (hue and saturation) were made in YUV color space by video image analysis. Inheritance of seed color was studied in an F2 population derived from the `Primo' × `OSU442-15' cross and inbred descendants. Quantitative trait loci (QTL) for seed color were localized by interval mapping using a linkage map of 199 molecular markers spanning most of the genome and by bulked segregant analysis and selective genotyping. Four genomic regions affecting seed color were detected. A major gene accounting for 61% of the phenotypic variance in seed lightness (Y luminance component) was identified on linkage group V linked to r locus. Another major gene, which accounted for 56% of the phenotypic variance in seed hue (U chrominance component), was mapped to a linkage group containing group III and IV markers. A QTL with smaller effect on seed hue (U and V chrominance components) was detected on linkage group VII. Support for overdominant allelic interaction for a QTL on linkage group I, adjacent to the legumin locus Lg-J, was obtained by selective genotyping of the seed lightness distributional extremes.
Sources of the Bacteria Involved in Vascular Occlusion of Cut Rose Flowers
Authors: van Doorn W.G. , de Witte Y.
Published: January 2019

Cut rose (Rosa hybrida L.) flowers placed in water often wilt prematurely, which is partially due to bacterial accumulation in the stems. Bacterial strains in the stems are mainly pseudomonads and enterobacteria. The possible sources of these organisms were investigated in `Sweet Promise' (trade name Sonia) roses. No bacteria were found in the xylem of intact plants. Cutting the stems with sterile secateurs introduced no bacteria at the cut surface or the stem interior, but cutting with nonsterile secateurs used by rose growers did. The secateurs sampled at rose growers contained Enterobacter agglomerans along with several other bacteria not found inside the xylem of cut flowers but did not contain pseudomonads. Although the plant surface may contain bacteria, freshly cut stems placed in water introduced no bacteria. Bacteria rapidly developed on the cut surface and inside the water-conducting elements when rose stems were placed in tap water, even when the stems had been surface-sterilized. However, there were no bacteria in vase water when the water and the stem surface had been sterilized. Since the stem and the secateurs are not a main source of bacteria inside stems and tap water contains pseudomonads and Enterobacter spp., we conclude that tap water is the main source of the bacteria inside cut rose stems.
Dormancy Release of Purple Nutsedge Tuber Buds by a Single Thermal Pulse
Authors: Sun Wen-Hao , Nishimoto Roy K.
Published: January 2019

The effect of single and daily fluctuating temperature cycles on budbreak of purple nutsedge (Cyperus rotundus L.) tubers was characterized to determine whether the budbreak response was a trigger or rhythmic action. Glasshouse-grown tubers were incubated at 20 °C for 2 weeks, and the nonsprouted tubers were used in experiments. A single 30-minute temperature pulse from 20 to 35 °C caused 80% budbreak, while tubers without the thermal pulse had only 25% budbreak. Increasing the duration of the single 35 °C temperature pulse from 30 minutes to 12 hours did not increase budbreak. Even a 3-minute 35 °C pulse caused 63% budbreak. A single gradual shift (0.02 °C per minute) from 20 to 35 °C was as effective as a rapid shift (0.5 °C per minute) in stimulating budbreak. Nonsprouted tubers preincubated at 25 °C were stimulated to cause budbreak by exposure at 35 °C for 12 hours, but not at 15 °C for 12 hours. A single temperature pulse of at least 10 °C differential (from 20 to 30, 35, or 40 °C) stimulated budbreak, while a 5 °C differential (from 20 to 25 °C) did not; all pulses had the same heat unit (°C > 20 °C × time (minutes) = 3600 °C/minute). These results suggest that budbreak of purple nutsedge tubers responds to high temperature as a trigger action.
Navy Bean Canning Quality: Correlations, Heritability Estimates, and Randomly Amplified Polymorphic DNA Markers Associated with Component Traits
Authors: Walters Kimberly J. , Hosfield George L. , Uebersax Mark A. , Kelly James D.
Published: January 2019

Three populations of navy bean (Phaseolus vulgaris L.), consisting of recombinant inbred lines, were grown at two locations for 2 years and were used to study canning quality. The traits measured included visual appeal (VIS), texture (TXT), and washed drained mass (WDM). Genotype mean squares were significant for all three traits across populations, although location and year mean squares were higher. We found a positive correlation (r = 0.19 to 0.66) between VIS and TXT and a negative correlation (r = -0.26 to -0.66) between VIS and WDM and between TXT and WDM (r = -0.53 to -0.83) in all three populations. Heritability estimates were calculated for VIS, TXT, and WDM, and these values were moderate to high (0.48 to 0.78). Random amplified polymorphic DNA markers associated with quantitative trait loci (QTL) for the same canning quality traits were identified and studied in each population. Marker-QTL associations were established using the general linear models procedure with significance set at P=0.05. Location and population specificity was common among the marker-QTL associations identified. Coefficient of determination (R2) values for groups of markers used in multiple regression analyses ranged from 0.2 to 0.52 for VIS, 0.11 to 0.38 for TXT, and 0.25 to 0.38 for WDM. Markers were identified that were associated with multiple traits and those associations supported correlations between phenotypic traits. MAS would offer no advantage over phenotypic selection for the improvement of negatively associated traits.
Randomly Amplified Polymorphic DNA-based Genetic Linkage Maps of Three Apple Cultivars
Authors: Conner Patrick J. , Brown Susan K. , Weeden Norman F.
Published: January 2019

Genetic linkage maps were created for three apple (Malus ×domestica Borkh.) cultivars using data from two progenies (`Wijcik McIntosh' xNY 75441-67 and `Wijcik McIntosh' xNY 75441-58). The maps consist primarily of randomly amplified polymorphic DNA (RAPD) markers, but also contain six isozyme loci and four morphological markers (Rf, fruit skin color; Vf, scab resistance; Co, columnar growth habit; Ma, malic acid). Maps were constructed using a double pseudotestcross mapping format and JoinMap mapping software. An integrated `Wijcik McIntosh' map was produced by combining marker data from both progenies into a single linkage map. Homologous linkage groups from paternal maps were paired with their counterparts in the `Wijcik McIntosh' map using locus bridges composed of markers heterozygous in both parents of a progeny. The `Wijcik McIntosh' map consists of 238 markers arranged in 19 linkage groups spanning 1206 cM. The NY 75441-67 map contains 110 markers in 16 linkage groups and the NY 75441-58 map consists of 183 markers in 18 linkage groups. The average distance between markers in the maps was ≈5.0 cM.
Inheritance of Biochemical and Morphological Characters Associated with Two-spotted Spider Mite Resistance in Pelargonium ×hortorum
Authors: Grazzini Richard , Walters Donald , Harmon Jody , Hesk David J. , Cox-Foster Diana , Medford June , Craig Richard , Mumma Ralph O.
Published: January 2019

Diploid zonal geraniums (Pelargonium ×hortorum) are able to resist attack by small arthropod pests such as the two-spotted spider mite (Tetranychus urticae Koch) when exudate produced by tall glandular trichomes contains a high percentage of ω5-unsaturated anacardic acids. Trichomes of susceptible plants exude primarily saturated anacardic acids. Inbred mite-resistant and -susceptible geraniums were reciprocally crossed and the F1, F2, and backcross generations were examined for anacardic acid composition and trichome density. Selected F2 plants were bioassayed for resistance to two-spotted spider mites. High concentrations of ω5-unsaturated anacardic acids in resistant plants are conditioned by a single dominant allele. We propose that inheritance of tall glandular trichome density can be controlled by a small number of loci (possibly as few as one) exhibiting codominance. F2, with low densities of tall glandular trichomes and producing ω5-unsaturated anacardic acids, displayed effective resistance to two-spotted spider mites as measured by mite mortality and fecundity. A genetic model for the biosynthesis of anacardic acids is proposed.
Composts from Various Municipal Solid Waste Feedstocks Affect Vegetable Crops. I. Emergence and Seedling Growth
Authors: Roe Nancy E. , Stoffella Peter J. , Graetz Donald
Published: January 2019

The composition of composts derived from municipal solid wastes can affect emergence and seedling growth. Composts consisting of biosolids and yard trimmings [standard compost (SC)] alone or with mixed waste paper (MWP), refuse-derived fuel (RDF), or refuse-derived fuel residuals (RDFR) were evaluated in seedling trays and pots for vegetable crop seedling emergence and growth. In trays, tomato (Lycopersicon esculentum Mill.), cucumber (Cucumis sativus L.), and pepper (Capsicum annuum L.) seedlings emerged faster from a commercial peat-lite mix and from sandy field soil than from the composts. Plants were tallest and shoots were generally heaviest in the peat-lite mix and aged SC and smallest in the field soil. MWP compost generally inhibited early seedling growth more than RDF or RDFR composts. Among the composts, seedlings were tallest and heaviest in SC. In pots, growth of each vegetable was generally greatest in SC, followed by other composts, and lowest in sandy soil. Tomato and pepper seedling emergence was more sensitive to the inhibitory effects of the RDF, RDFR, and MWP composts than cucumber seedling emergence. Fertilizer increased plant growth in each medium except SC, in which cucumber stem diameter was not increased. Adding MWP, RDF, or RDFR to SC generally decreased seedling emergence and growth. The composts prolonged days to emergence and decreased percent emerged seedlings. However, subsequent seedling growth in composts was equal to or greater than seedlings in the peat-lite mix and much greater than those in the sandy field soil.
Growth Response, Nutrient Leaching, and Mass Balance for Potted Poinsettia. I. Nitrogen
Authors: Ku Catherine S.M. , Hershey David R.
Published: January 2019

Single-pinched poinsettias (Euphorbia pulcherrima Willd. ex Klotzsch `V-14 Glory') received 210 mg·L-1 constant N fertigation from Hoagland solution with N sources of 100% NO3-N or 60% NO3-N : 40% NH4-N, P concentrations of 7.8 or 23 mg·L-1, and leaching fractions (LFs) of 0, 0.2, or 0.4. The P fertigation rates did not significantly affect plant growth measurements and N leaching. Shoot dry masses and leaf and bract areas of plants fertigated with 60% NO3-N were 11% to 26% greater than those fertigated with 100% NO3-N. Shoot dry mass at the 0 LF was 27% smaller than those at the 0.4 LF. The total amount of N applied via fertigation was 1.7 g at the 0 LF and 3.3 g at the 0.4 LF. Leachate N concentration ranged from 170 to 850 mg·L-1. Nitrogen recovery was 74% to 91%, and the percentage of fertigation N recovered in leachate ranged from 51% at the 0.2 LF to 74% at the 0.4 LF. With a 0.4 LF and 210 mg·L-1 N fertigation, 15% to 22% of the recovered N was found in the shoots, and 68% to 75% was found in the leachate. Even with a 0.2 LF, >50% of the N recovered was found in the leachate. Premium marketable quality poinsettia were produced with N at 210 mg·L-1 from 60% NO3-N : 40% NH4-N fertigation solution at the 0.4 LF. To reduce N leaching to the environment, good marketable quality poinsettias could be grown at a LF of ≤0.2 with 210 mg·L-1 N fertigation if quality irrigation water is available and if a small reduction in growth is acceptable.
Growth Response, Nutrient Leaching, and Mass Balance for Potted Poinsettia. II. Phosphorus
Authors: Ku Catherine S.M. , Hershey David R.
Published: January 2019

Poinsettias (Euphorbia pulcherrima Willd. ex Klotzsch `V-14 Glory') grown as single-pinched plants and received constant fertigation of Hoagland solution with N at 210 mg·L-1 of 100% NO3-N or 60% NO3-N : 40% NH4-N; P at 7.8 and 23 mg·L-1; and leaching fractions (LFs) of 0, 0.2, or 0.4. The P at 23 mg·L-1 used in this study was about half the P concentration typically provided from a 20N-4.4P-16.6K fertilizer at 200 mg·L-1 N fertigation. The total P applied via fertigation ranged from 51 mg at the 0 LF to 360 mg at the 0.4 LF. The leachate P concentration ranged from 0.2 to 46 mg·L-1. With P at 7.8 mg·L-1, the percentage of total P recovered in the leachate was 6% to 7%. At 23 mg·L-1 P fertigation, however, the total P recovered in the leachate with 60% NO3-N treatment was 2-times greater than with 100% NO3-N treatment. This result is attributed to a lower substrate pH, which resulted from NH4-N uptake and nitrification processes with 60% NO3-N fertigation. The P concentration in the recently matured leaves with 7.8 mg·L-1 P fertigation was in the normal range of 0.3% to 0.6%. Fertigation P can be reduced by up to 80% and still be sufficient for producing quality poinsettias. Reducing the fertigation P concentration is beneficial because it reduces P leaching, reduces fertilizer costs, and reduces luxury consumption.
A New Allele (Vwf) at the V Locus for Flower and Seedcoat Color in Common Bean
Authors: Bassett Mark J.
Published: January 2019

The inheritance of flower and seedcoat color was studied using Lamprecht line M0137 (PI 527845) of common bean (Phaseolus vulgaris L.) as the source of a new allele, Vwf, at the V locus. The cross M0137 cres Vwf × C v BC2 5-593 (a genetic tester stock) was studied in progeny of the F1, F2, F3, and F4 generations. The observed segregation for flower and seed colors was consistent with the hypothesis that M0137 carried a new allele, Vwf, that produced (in the presence of P C J G B) white flowers and black seeds rather than the white flowers and mineral-brown seeds produced (in the presence of P C J G B) by v. The V/Vwf genotype produced cobalt-violet flowers, the same as V/v. A test cross of F3 Vwf × t BC1 5-593 bipunctata demonstrated that Vwf is not allelic with t, a gene that can produce white or colored flowers and self-colored or partly colored seeds, depending on background genotype.