bluuebunny/crossref_metadata_2025 huggingface dataset:
Fractional Surface Coating Modifies Gas Diffusion and Ripening in Bananas
Authors: Perez Rufino , Beaudry Randolph M.
Published: January 2019

We hypothesized that the blocking of O2 influx and CO2 efflux in banana (Musa acuminata) by sealing nearly 100% of the pores over a fraction of the surface would generate a modified internal atmosphere in a manner similar to fruit coatings that cover 100% of the banana surface but only block a fraction of the pores. This hypothesis was based on the observation made by previous workers that the flesh of mature green bananas has insignificant resistance to O2 diffusion relative to the resistance imposed by the skin of the fruit. We modified the O2 diffusion pathway in bananas by covering, beginning at one end, ¼, ½, ¾, and ⅞ of the fruit surface with paraffin, which sealed essentially 100% of the surface where it was applied. Large end-to-end O2 and CO2 gradients developed within coated fruit, relative to the uncoated control, suggesting that the diffusive resistance in the pulp was not insignificant. Since the large gradients of O2 generated caused uneven ripening, using fractional coatings may help analyze gas exchange properties, but it is not suitable for commercially controlling ripening of bananas.
Tomato Irregular-ripening Symptom Development and Ripening of Silverleaf Whitefly-infested Dwarf Cherry Tomatoes
Authors: Hanif-Khan Shahab , Bullock Robert C. , Stoffella Peter J. , Powell Charles A. , Brecht Jeffrey K. , McAuslane Heather J. , Yokomi Raymond K.
Published: January 2019

Silverleaf whitefly (SLW) (Bemisia argentifolii Bellows and Perring) feeding was associated with development of tomato irregular ripening (TIR) symptoms. `Micro-Tom', `Florida Basket', `Florida Lanai', and `Florida Petite' dwarf cherry tomatoes (Lycopersicon esculentum Mill.) were infested with adult SLW to observe oviposition preference, plant tolerance, and TIR symptom development in two experiments. There was no oviposition preference among the cultivars in either of the trials. TIR fruit symptoms were expressed as longitudinal red streaks with yellow, green, pink, or red blotches externally and white tissue internally. External TIR symptoms at the pink stage of ripening ranged from 32% (`Micro-Tom') to 82% (`Florida Basket') in Expt. 1 and 44% (`Micro-Tom') to 93% (`Florida Petite') in Expt. 2. In Expt. 1, external TIR symptoms disappeared from 18% (`Florida Lanai') to 37% (`Micro-Tom') and, in Expt. 2, 16% (`Micro-Tom') to 39% (`Florida Basket') of the fruit during ripening. SLW-infested plants exhibited 82% (`Florida Lanai') to 99% (`Florida Basket') and 76% (`Micro-Tom') to 90% (`Florida Petite') of fruit with internal white tissue regardless of external symptoms in Expts. 1 and 2, respectively. Tomatoes with severe TIR symptoms rarely ripened to full red. Postharvest characteristics of ripening SLW-infested and control fruit were evaluated (Expts. 3 and 4). Generally, the SLW-infested fruit were lighter in color than the control fruit. The control fruit developed normal red color while the SLW-infested fruit developed a blotchy, streaky color that was overall more of an orange-red. SLW-infested fruit were firmer than the control fruit in both experiments. Ethylene production was higher in SLW-infested fruit. While the total soluble solids contents were not significantly different between the treatments, the SLW-infested fruit were more acidic than the control fruit. Each cultivar was susceptible to oviposition by SLW and induction of TIR symptoms. However, TIR symptom expression differed among the cultivars. Despite higher ethylene levels, the ripening process in the SLW-infested fruit appeared slower or may have been inhibited by factors induced by the SLW compared with the control fruit, which ripened normally.
Physicochemical Characterization of Hybrid Honey Dew Muskmelon Fruit (Cucumis melo L. var. inodorus Naud.) following Maturation, Abscission, and Postharvest Storage
Authors: Lester Gene
Published: January 2019

Hybrid honey dew muskmelon (Cucumis melo L. var. inodorus Naud.) fruit physiological maturity, the period of maximized or greatest compositional changes, occurs by 40 days after anthesis (DAA). Fruit maturity was determined by major changes in quality attributes: glucose, fructose, sucrose, and moisture content, firmness, mass, volume, and hypodermal-mesocarp plasma membrane specific H+-ATPase (E.C. 3.6.1.3) activity. Fruit ripening occurs by 50 DAA, as determined by additional changes in the mentioned quality attributes, and by fruit abscission at 50 DAA. Fruit senescence begins with decreases in almost all quality attributes, H+-ATPase activity, protein content, by the largest increase in the total free sterol : total phospholipid (FS:PL) ratio, and in hypodermal-mesocarp lipoxygenase (E.C. 1.13.11.12) activity. Physicochemical profiles of hybrid honey dew muskmelon fruit during growth and maturation should be useful to schedule commercial harvest of mature fruit, which is necessary for maximum honey dew fruit quality, extended shelf-life, and enhanced consumer satisfaction.
Postharvest Pitting of `Fallglo' Tangerine
Authors: Petracek Peter D. , Montalvo Lymari , Dou Huating , Davis Craig
Published: January 2019

The morphology and etiology of postharvest pitting of `Fallglo' [Bower citrus hybrid (Citrus reticulata Blanco × C. reticulata Blanco × C. paradisi Macf.) × Temple (C. reticulata Blanco × C. sinensis L.)] peel were determined. The disorder was characterized by scattered collapse of the flavedo that resulted from necrosis of cells within and enveloping the oil glands. In severe cases, damage occurred in epidermal and hypodermal cells above collapsed oil glands and surrounding vascular tissues, but cells between oil glands were often undamaged. Pitting was caused by storing waxed fruit at high temperature (≥15.5 °C), but was not affected by ethylene exposure during degreening. Fruit coated with commercially available shellac- and polyethylene-based waxes pitted more than fruit coated with carnauba-based waxes. Pitting was controlled by not coating the fruit with wax or storing the fruit at low temperature (4.5 °C) within hours after wax application.
The Effects of Carbon Dioxide Enrichment, Natural Ventilation, and Light Intensity on Growth, Photosynthesis, and Transpiration of Cauliflower Plantlets Cultured in vitro Photoautotrophically and Photomixotrophically
Authors: Kanechi Michio , Ochi Masakatsu , Abe Michiko , Inagaki Noboru , Maekawa Susumu
Published: January 2019

The effects of natural ventilation and CO2 enrichment during the rooting stage on the growth and the rates of photosynthesis and transpiration of in vitro cauliflower (Brassica oleracea L.) plantlets were investigated. In vitro plantlets were established in airtight or ventilated vessels with or without CO2 supplied (≈1200 μg·L-1) through gas permeable films attached to the vessel's cap for 15 days before transplanting ex vitro. Leaves generated in vitro in ventilated vessels had a higher photosynthetic rate than those produced in airtight vessels, which lead to greater leaf expansion and shoot and root dry matter accumulation during in vitro culture and acclimatization. Enhanced photosynthesis in leaves of ventilated plantlets was positively correlated with chlorophyll content. Increasing photosynthetically active radiation from 70 to 200 μmol·m-2·s-1 enhanced the growth of in vitro plantlets under ventilated conditions but it depressed photosynthesis of the leaves grown photomixotrophically with sugar and CO2 enrichment which might be due to the feedback inhibition caused by marked accumulations of sucrose and starch. Higher CO2 levels during in vitro culture enhanced photosynthesis under photoautotrophic conditions, but inhibited it under photomixotrophic conditions. Fifteen days after transplanting ex vitro, high photosynthetic ability and stomatal resistance to transpiratory water loss of ventilated plantlets in vitro had important contributions to rooting and acclimatization. Our findings show that the ventilated culture is effective for accelerating photoautotrophic growth of plantlets by increasing photosynthesis, suggesting that, especially for plantlets growing in vitro without sugar, CO2 enrichment may be necessary to enhance photosynthetic ability.
Composition and Variability of Epicuticular Waxes in Apple Cultivars
Authors: Belding Robert D. , Blankenship Sylvia M. , Young Eric , Leidy Ross B.
Published: January 2019

Variation in amount and composition of epicuticular wax among several apple (Malus ×domestica Borkh.) cultivars was characterized by gas chromatography, thin-layer chromatography, and gas chromatography-mass spectroscopy. Across cultivars, wax mass ranged from 366 to 1038 μg·cm-2. Wax mass decreased during the 30 days before harvest. Ursolic acid accounted for 32% to 70% of the hydrocarbons that make up the epicuticular wax. Alkanes, predominantly 29-carbon nonacosane, comprised 16.6% to 49%. Primary alcohols of the hydrocarbons ranged from 0% to 14.6% of the epicuticular wax. Secondary alcohols of the hydrocarbons were the most cultivar specific, making up 20.4% of the epicuticular wax in `Delicious' and only 1.9% `Golden Delicious' strains. Aldehydes and ketones of the hydrocarbons represented a small amount of total wax, ranging from 0% and 6.0%. Percentage of primary alcohol in the epicuticular wax increased as fruit developed. Other components showed no distinct trends with fruit development. Examination of the ultrastructure of cuticular wax using scanning electron microscopy revealed structural differences among cultivars.
Potential Maturity Indices and Developmental Aspects of Melting-flesh and Nonmelting-flesh Peach Genotypes for the Fresh Market
Authors: Brovelli Ernesto A. , Brecht Jeffrey K. , Sherman Wayne B. , Sims Charles A.
Published: January 2019

Potential maturity indices were determined for two melting-flesh (FL 90-20 and `TropicBeauty') and two nonmelting-flesh (`Oro A'and Fl 86-28C) peach [Prunus persica (L.) Batsch.] genotypes. A range of developmental stages was obtained by conducting two harvests and separating the fruit based on diameter. Fruit in each category were divided into two groups. One group was used to determine potential maturity indices: soluble solids, titratable acidity, soluble solids to titratable acidity ratio, peel and flesh color on the cheeks and blossom end, cheek and blossom-end firmness, ethylene production, and respiration rate. The other group was stored at 0 °C for 1 week and ripened at 20 °C for 2 days to simulate handling conditions and presented to a trained sensory panel, which rated the fruit for three textural aspects (hardness, rubberiness, and juiciness) and six flavor aspects (sweetness, sourness, bitterness, and green, peachy, and overripe character). Principal component (PC) analysis was used to consolidate the results of the descriptive sensory evaluation into a single variable that could be correlated with the objective measurements at harvest. The attributes that best correlated with the first sensory PC of each genotype, and thus are promising maturity indices, were as follows: for FL 90-20, peel hue, peel L, and cheek firmness; for `TropicBeauty', peel L, cheek firmness, and blossom-end firmness; for `Oro A', cheek firmness, blossom-end firmness, and cheek chroma; and for 86-28C, blossom-end firmness, cheek hue, and cheek firmness.
Heat Treatment of Mature-green Tomatoes: Differential Effects of Ethylene and Partial Ripening
Authors: McDonald R.E. , McCollum T.G. , Baldwin E.A.
Published: January 2019

Mature-green `Sunbeam' tomatoes (Lycopersicon esculentum Mill.) were treated in varying order with C2H4, 42 °C water for 1 hour, 38 °C air for 2days, held 2 days at 20 °C (partial ripening), or not treated and then stored at 2 °C (chilled) for 14 days before ripening at 20 °C. Heat-treated fruit stored at 2 °C and transferred to 20 °C ripened normally, while 63% of nonheated fruit decayed before reaching the red-ripe stage. Partially ripened fruit developed more chilling injury, were firmer, were lighter, and were less red in color than fruit not partially ripened. Lycopene content and internal quality characteristics of fruit were similar at the red-ripe stage irrespective of sequence of C2H4 exposure, heat treatment, or a partial ripening period. Of the 15 flavor volatiles analyzed, 10 were reduced by storage at 2 °C, Exposure to C2H4 before the air heat treatment reduced the levels of four volatiles, while C2H4 application either before or after the water heat treatment had no effect on flavor volatiles. Two volatiles were decreased and two were increased by partial vipening, Storage at 2 °C decreased the level of cholesterol and increased levels of campesterol and isofucosterol in the free sterol pool. Exposure to C2H4 before or following heat treatments, the method of heat treatment, and partial ripening had little effect on free sterols, steryl esters, steryl glycosides, or acylated steryl glycosides in the pericarp of red-ripe fruit. A shortor long-term heat treatment of mature-green tomatoes could permit storage at low temperatures with little loss in their ability to ripen normally, whereas partial ripening did not reduce chilling injury.
Using Ethylene as a Sprout Control Agent in Stored `Russet Burbank' Potatoes
Authors: Prange Robert K. , Kalt Willy , Daniels-Lake Barbara J. , Liew Chiam L. , Page Robyne T. , Walsh John R. , Dean Paul , Coffin Robert
Published: January 2019

The effect of ethylene on tuber sprout growth and quality in potato (Solanum tuberosum L. `Russet Burbank') was tested in laboratory and commercial studies for 6 and 3 years, respectively, in comparison with untreated (laboratory study) and CIPC-treated tubers (laboratory and commercial studies). In both studies, ethylene was applied continuously at 166 μmol·m-3 for at least 25 weeks, beginning in early December (laboratory study) or early December to early January (commercial study). In the laboratory study, ethylene delayed the appearance of sprouts for 5 to 15 weeks, compared with untreated tubers. In the ethylene-treated tubers in both studies, sprouts appeared on many eyes but most of them remained very small (<5 mm long). Longer sprouts (>5 mm) appeared after 15 weeks but did not exceed 12 and 59 mm in the laboratory and commercial studies, respectively. Sprouts on ethylene-treated tubers were more easily detached up to 6 weeks after ethylene treatment ended, compared with untreated tubers. In both studies, ethylene treatment was not associated with decay, disorder or internal sprouting problems. In both studies, the Agtron fry color [or U.S. Dept. of Agriculture (USDA) color grade] of ethylene-treated tubers was darker than CIPC-treated tubers at almost all sampling times. Continuous exposure to ethylene was an effective sprout control agent but it produced a darker fry color, compared with CIPC-treated potatoes.
Large Sunflower Seeds are Characterized by Low Embryo Vigor
Authors: Saranga Yehoshua , Levi Avishag , Horcicka Pavel , Wolf Shmuel
Published: January 2019

The cause for the differences in germination ability of large and small confection sunflower (Helianthus annuus L.) seeds was investigated over 3 years. The source-sink relationship was manipulated to better explore the differences between seeds of various sizes and to study the role of the embryo and the pericarp (hull) in controlling germination ability. Percent germination of large seeds was significantly lower than that of small seeds when tests were performed at 15 °C. Increasing the ratio of leaf area to number of developing seeds caused an increase in mean seed mass, but resulted in a lower percentage of germination. Seed vigor, as measured by mean time to germination or to emergence of hulled seeds or by rate of root elongation, was negatively correlated with embryo mass, indicating that the low vigor of large seeds is not due to the mechanical barrier imposed by the hull. Analysis of electrolyte leakage confirmed the hypothesis that the low quality of large seeds results from a disturbance during the process of seed development.
Flower Bud Thinning and Winter Survival of `Redhaven' and `Cresthaven' Peach in Response to GA3 Sprays
Authors: Taylor Bradley H. , Geisler-Taylor Dagmar
Published: January 2019

The timing and concentration of dilute foliar sprays of gibberellic acid (GA3) were tested for their flower bud thinning effect during three consecutive years on two common cultivars of peach [Prunus persica (L.) Batsch.] grown in commercial culture under midwestern conditions. There was a strong trend for June sprays to minimize the total flower bud density (buds/cm shoot) of unbranched shoots on mature `Redhaven' and `Cresthaven' trees. The GA3 treatments applied between early July and late October did not reduce the total flower bud density. Increasing the concentration from 25 or 50 mg·L-1 to 200 mg·L-1 tended to decrease total flower bud density, especially when applied May through July. During the same period the GA3 treatments reduced total flower bud density of short shoots (<10 cm), but only about two-thirds as effectively as on long shoots. The `Redhaven' live flower density on trees treated in May, June or September was up to 2 times greater then the control in March following exposure to extreme fluctuations in winter temperatures to near critical lows in 1988 and 1989. Although 50 mg·L-1 GA3 applied in June 1989 reduced total flower bud density by 70%, it resulted in a live flower density only 35% lower than the control. The treatment induced 2.3 times greater survival of the total flower buds existing after thinning when winter temperatures gradually declined to critical levels. The increased live flower density caused by the GA3 sprays translated to a cropload 1.3 to 2.25 times greater than control. The length of neither fruiting quality shoots in the bearing canopy nor 1-year-old upright branched shoots in the top of trees (watersprouts) was appreciably affected by the GA3 applications. GA3 treatments at 100 and 200 mg·L-1 in late July and early August slightly delayed time of full bloom. Defoliation was delayed slightly by treatments applied in September and late July. Moderate doses of appropriately timed GA3 sprays reduced flower bud densities without adverse effects on winter survival, yield, defoliation or bloom time. Our results support the use of GA3 as a reliable peach thinning tool.
Using the Floral Status of Strawberry Plants, as Determined by Stereomicroscopy and Scanning Electron Microscopy, to Survey the Phenology of Commercial Crops
Authors: Manakasem Y. , Goodwin P.B.
Published: January 2019

Field surveys were conducted on cultivated strawberries (Fragaria ×ananassa Duch.) to determine the time of flower initiation and its relation to maximum and minimum temperatures and daylength. Stereomicroscopy and scanning electron microscopy (SEM) were compared. Flower initiation in `Torrey' strawberry was more dependent on minimum temperature than on daylength or maximum temperature. Flower initiation in the day-neutral `Aptos' occurred regardless of daylength or temperature during sampling. For the study of flower initiation and inflorescence development, SEM gave more detail than stereomicroscopy.
Protein Changes in the Flower Buds of Japanese Pear during Breaking of Dormancy by Chilling or High-temperature Treatment
Authors: Tamura Fumio , Tanabe Kenji , Itai Akihiro , Tanaka Hiroshi
Published: January 2019

The dormancy of Japanese pear (Pyrus pyrifolia Nakai) floral buds was broken by prolonged chilling or short-term high-temperature treatment (45 °C for 4 hours). Changes in the protein profiles of the floral buds were studied using two-dimensional electrophoretic analysis (2-DE). The quantities of nine cold-induced proteins (CIPs) increased in the floral buds with increases in chill unit (CU) value, but did not change rapidly when bud dormancy was near completion. When dormancy of floral buds was broken by high-temperature treatment, nine heat-shock proteins (HSPs) accumulated. These HSPs were distinct from the CIPs. The isoelectric point of the 19-kDa CIP shifted to the basic side by high-temperature treatment as well as by chilling. These results suggest that the 19-kDa protein may be a usable marker to measure the degree of bud dormancy in Japanese pear.
Fruit Development and Ripening in Yellow Pitaya
Authors: Nerd Avinoam , Mizrahi Yosef
Published: January 2019

Changes occurring during fruit ripening and duration of fruit development were studied in Selenicereus megalanthus (Scum. ex Vaupel) Moran (yellow pitaya), a climbing cactus grown in protected structures at three sites in the Israeli Negev desert. During ripening, peel color turned from green to yellow, fruit dimensions slightly changed, and pulp content markedly increased. Total soluble solids and soluble sugars in the pulp increased, while starch content decreased. Acidity decreased at the last stage of ripening. Fruit in which most of the peel area had turned yellow (stage 4) were given the highest taste grade by a panel of tasters. Measurements of ethylene and CO2 evolution indicated that fruit was nonclimacteric. The mean number of days from anthesis to fruit of stage 4 was negatively correlated with the mean of the maximum and the minimum temperatures during the growth period. Daily accumulation of heat units (HUs) was calculated as the difference between daily mean temperature and a base temperature of 7 °C. Sum of HUs for the period from anthesis to ripening was 1558±12 HUs.
The Effects of Temperature, Photoperiod, and Photosynthetic Photon Flux on the Time to Flowering of Petunia `Express Blush Pink'
Authors: Adams S.R. , Hadley P. , Pearson S.
Published: January 2019

The effects of temperature and sowing date on the time to first flowering were investigated in Petunia ×hybrida Vilm `Express Blush Pink' sown on three separate dates (8 Feb., 1 Mar. and 22 Mar. 1993) and grown in glasshouse compartments set to provide six air temperature regimes (minimum temperatures of 4, 10, 14, 18, 22, and 26 °C). Flowering was hastened under high temperatures and sowing later in the season (22 Mar.). To determine the extent to which this seasonal effect was due to photoperiod, a second experiment was conducted where plants were grown under controlled daylengths (8, 11, 14, and 17 h·d-1) within six temperature-controlled glasshouse compartments (set to provide minimum temperatures of 6, 10, 14, 18, 22, and 26 °C). The rate of progress to first flowering increased linearly with lengthening photoperiod up to a critical photoperiod of 14.4 h·d-1, while further increases in daylength had no further affect in hastening flowering. The rate of progress to flowering increased linearly with increasing temperature, however, the optimum temperature, at which the rate of progress to flowering was maximal, was lower under short days compared to long days. Furthermore, the rate of progress to flowering increased linearly with increasing photosynthetic photon flux (PPF). Data from both experiments were analyzed to construct a model to predict the effects of temperature, photoperiod, and PPF on time of flowering in petunia. This model accurately (r2 = 0.88) predicted the flowering times of a different set of plants sown on three dates and grown under six temperature regimes (6, 10, 14, 18, 22, and 26 °C).
Effects of Rooting Volume Restriction on the Growth and Carbohydrate Concentration in Tomato Plants
Authors: Nishizawa Takashi , Saito Kenji
Published: January 2019

Tomato plants (Lycopersicon esculentum Mill `Ougata-fukuju' and `Korokoro') were grown in a soil or a hydroponic culture to study effects of rooting volume restriction on plant growth and carbohydrate concentrations. In soil culture, leaf lengths decreased linearly as container volume decreased, while plant height did not decrease linearly, irrespective of fruiting. The root to shoot ratio decreased in smaller volume containers, irrespective of fruiting, because dry mass accumulation in the stem and leaves was relatively less inhibited than that in the roots. Total plant dry mass did not differ between fruiting and deblossomed plants, irrespective of container volume. In hydroponic culture, plant height in small containers (37 cm3) was similar to that in large containers (2024 or 4818 cm3). The root to shoot ratio of the plants grown in small containers was lower than that of the plants grown in large containers, mainly due to less inhibition of the dry mass accumulation in the stem than in the leaves. When small containers were almost filled with roots (28 days after transplanting), soluble sugar and starch concentrations in leaves became ≈2-fold higher in the plants grown in small than in those grown in large containers. At the end of experiment (42 days after transplanting), sucrose and starch concentrations in the stem were higher in plants grown in small than in those grown in large containers. However, soluble sugar and starch concentrations in the leaves did not differ between treatments.
Storage Temperature and Duration Affect Flower Bud Development, Shoot Emergence, and Flowering of Leucocoryne coquimbensis F. Phil.
Authors: Ohkawa Kiyoshi , Kim Hyeon-Hye , Nitta Emiko , Fukazawa Yukinori
Published: January 2019

Leucocoryne, a native to Chile, has violet, blue, or white flowers and is increasing in popularity as a cut flower. The effects of storage temperature and duration on flower bud development, shoot emergence, and anthesis were investigated. Bulbs stored at 20 to 30 °C for 22 weeks produced 3.4 flower stems per bulb between March and April. Bulbs stored at 20 °C flowered earliest, followed by those stored at 25 °C. Bulbs stored at 30 °C flowered last. After 16 weeks of storage at 20 °C, a further 2 weeks dry storage at 15 °C before planting resulted in 1 month earlier flowering with no reduction of the number of flowering stems. As dry storage at 20 °C increased to 11 months, the time to emergence and flowering decreased. After dry storage at 20 °C for 12 months, the primary flower stems aborted and secondary stems then developed. Secondary and tertiary flower stems tend to commence flower bud development after the flower bud on the primary flower stem has reached the gynoecium or anther and ovule stage of initiation.
Genetic Signatures from Amplification Profiles Characterize DNA Mutation in Somatic and Radiation-induced Sports of Chrysanthemum
Authors: Trigiano R.N. , Scott M.C. , Caetano-Anollés G.
Published: January 2019

The chrysanthemum (Dendranthema grandiflora Tzvelev.) cultivars `Dark Charm', `Salmon Charm', `Coral Charm' and `Dark Bronze Charm' are either radiation-induced mutants or spontaneous sports of `Charm' and constitute a family or series of plants that primarily differ in flower color. These cultivars, which were difficult to differentiate genetically by DNA amplification fingerprinting (DAF), were easily identified by using arbitrary signatures from amplification profiles (ASAP). Genomic DNA was first amplified with three standard octamer arbitrary primers, all of which produced monomorphic profiles. Products from each of these DNA fingerprints were subsequently reamplified using four minihairpin decamer primers. The 12 primer combinations produced signatures containing ≈37% polymorphic character loci, which were used to estimate genetic relationships between cultivars. Forty-six (32%) unique amplification products were associated with individual cultivars. The number of ASAP polymorphisms detected provided an estimate of the mutation rate in the mutant cultivars, ranging from 0.03% to 1.6% of nucleotide changes within an average of 18 kb of arbitrary amplified DAF sequence. The ASAP technique permits the clear genetic identification of somatic mutants and radiation-induced sports that are genetically highly homogeneous and should facilitate marker assisted breeding and protection of plant breeders rights of varieties or cultivars.
The Effect of the Ph 6 Gene on the Color of Petunia hybrida Vilm. Flowers
Authors: Griesbach R.J.
Published: January 2019

An in vivo system was developed to determine the effects of pH on naturally occurring pigment complexes within cells. The in vivo system was based on a transposable element activator (Ac) inserted into the Ph6 gene. The transposable element activator (Ac) was crossed into two genetically marked Petunia hybrida lines expressing known flavonoid pigments. Plants expressing the transposable element activator (Ac) produced variegated flowers in which the background tissue was lighter in intensity than the sectors. Depending on the genetic background in which the transposable element is expressed, progeny with darker sectors that were also redder in color than the background tissue could also be obtained. The anthocyanin and copigment composition was the same for both of the differently colored sectors and background tissue, while the pH was lower by 0.4 unit in the redder sectors. It was suggested that the Ph6 gene might be a regulatory gene that controls the expression of the pH and anthocyanin concentration.
Chemical Composition and Physical Properties of Pericarp, Locule, and Placental Tissues of Tomatoes with Internal Bruising
Authors: Moretti Celso L. , Sargent Steven A. , Huber Donald J. , Calbo Adonai G. , Puschmann Rolf
Published: January 2019

`Solar Set' tomatoes (Lycopersicon esculentum Mill.) were harvested at the mature-green stage of development and treated with 50 μL·L-1 ethylene at 20 °C. Breaker-stage fruit were dropped from 40 cm onto a solid surface to induce internal bruising and held along with undropped fruit at 20 °C. At the ripe stage, pericarp, locule, and placental tissues were analyzed for soluble sugars, vitamin C, pigments, titratable acidity, soluble solids content, pericarp electrolyte leakage, extractable polygalacturonase activity, and locule tissue consistency. Bruising significantly affected chemical composition and physical properties of pericarp and locule tissues, but not placental tissue. For bruised locule tissue, carotenoids, vitamin C, and titratable acidity were 37%, 15%, and 15%, lower, respectively, than unbruised fruit. For bruised pericarp tissue, vitamin C content was 16% lower than for unbruised tissue, whereas bruising increased electrolyte leakage and extractable polygalacturonase activity by 25% and 33%, respectively. Evidence of abnormal ripening following impact bruising was confined to locule and pericarp tissues and may be related to the disruption of cell structure and altered enzyme activity.
Compositional Changes during the Fruit Development of Two Peach Cultivars Differing in Juice Acidity
Authors: Moing Annick , Svanella Laurence , Rolin Dominique , Gaudillère Monique , Gaudillère Jean-Pierre , Monet René
Published: January 2019

Changes in metabolites were studied during the fruit development of two greenhouse grown peach [Prunus persica (L.) Batsch] cultivars with low acidity (`Jalousia') or normal acidity (`Fantasia'). Both cultivars had the same sucrose concentration in fruit mesocarp at maturity. In the fruit juice, pH was higher and titratable acidity was lower for `Jalousia' than for `Fantasia' from 80 days after bloom to maturity. At four different times during fruit development, in vivo 13C NMR spectroscopy was used to measure the vacuolar pH of fruit mesocarp. At 55 days after bloom, the vacuolar pH of fruit mesocarp was not significantly different between `Jalousia' and `Fantasia', whereas the juice pH was different between cultivars. The three major organic acids in fruit mesocarp were malic, citric, and quinic acids for both cultivars. Citric acid concentrations were similar in both cultivars until ≈85 days after bloom and then became significantly higher in `Fantasia'. A significantly higher concentration in malic acid in `Fantasia' than in `Jalousia' was observed from the end of the first growth phase to maturity. At maturity, `Fantasia' fruit had two and five times more malic and citric acid, respectively, than `Jalousia' fruit. The differences observed between `Jalousia' and `Fantasia' fruit for malic and citric acid concentrations accounted for the difference in titratable acidity. The differences in acid concentration appeared during the plateau between the two rapid growth phases of the fruit, i.e., far before the onset of maturation. The three major amino acids were asparagine, glutamic acid, and proline for both cultivars. Their concentration followed similar patterns in acid and low-acid fruit.
Survival and Recovery of `Meyer' Zoysiagrass Rhizomes after Extracellular Freezing
Authors: Warmund Michele R. , Fuller Rusty , Dunn John H.
Published: January 2019

Rhizomes of `Meyer' zoysiagrass (Zoysia japonica Steud.) were subjected to temperatures below 0 °C and were subsequently placed in a growth chamber with air at 34 °C day/28 °C night to determine the rate of shoot growth from nodes. Rhizomes exposed to subzero temperatures produced shoots steadily up to 16 days after freezing (DAF), but subsequent shoot growth from rhizomes was minimal. At 32 DAF, shoots were present on 68% and 44% of the nodes of unfrozen control (2 °C) rhizomes and those frozen to -7 °C, respectively. In another study, samples were frozen to a sublethal temperature (-7 °C) to examine the distribution of extracellular ice voids near the apical meristems of rhizomes and to characterize tissue recovery. Extracellular voids were present within the leaf tissue and between the leaves in samples prepared for scanning electron microscopy (SEM) immediately after freezing to -7 °C. By 12 DAF, most of the remaining voids were observed in older leaves. Nearly all extracellular voids in the leaves were absent by 20 DAF. However, by 28 DAF, some rhizomes still had small voids between leaves. Although the structure of zoysiagrass rhizomes subjected to -7 °C was temporarily disrupted, tissues recovered from extracellular freezing and new shoot growth was produced following exposure to warm temperatures.
Comparing Callus Growth with Discoloration and Electrical Conductivity as Measures of Stem Injury after Freezing Woody Plants
Authors: Pellett Norman E. , Heleba David A.
Published: January 2019

Most of 36 crabapple and 19 other woody plant taxa demonstrated the ability, when dormant, to grow a continuous row of callus along the cambial region on split-stem pieces within 5 to 7 days of incubation at 25 °C. The ability to grow callus after freezing tests was compared with discoloration and electrical conductivity for determining laboratory freeze injury to selected taxa. Hardiness levels were determined using the procedures of callus growth, discoloration, and electrical conductivity after freezing stem pieces of Jack crabapple [Malus baccata (L.) Borkh. `Jacki'], pink bud Sargent crabapple [M. sargentii Rehd. `Rosea'], Mary Potter crabapple [Malus sp. `Mary Potter'], and snowberry mountainash [Sorbus discolor (Maxim.) Maxim.]. Sampling dates for laboratory freezing tests were chosen to represent midwinter cold hardiness and partial hardiness of either late fall or early spring. There was a high correlation between discoloration and callus ratings for most plants; however, the two methods usually did not identify the same critical temperature (T50) for injury. The critical temperatures identified by callus growth was often 3 to 6 °C lower than for discoloration. For many taxa, callus growth was easier to see than discoloration of cambium and phloem, providing a less subjective evaluation of injury. TTC (2,3,5-triphenyl tetrazolium chloride) treatment was sometimes useful to identify callus growth that died after forming. The critical temperature (Tc), the highest temperature at which relative electrical conductivity differed significantly from the control temperature, was higher in most cases, indicating less cold hardiness than the T50 for callus and discoloration. The callus procedure may have value for evaluating injury to the cambial zone from freezing and other plant stresses because it determines the ability of the plant to continue growth.
Nuclear and Cytoplasmic Interactions for Petaloid Male-sterile Accessions of Wild Carrot (Daucus carota L.)
Authors: Wolyn D.J. , Chahal A.
Published: January 2019

Male-sterile carrot plants with petaloid-stamens were discovered in wild populations in the vicinity of Guelph, Ontario, Canada and inheritance of phenotype was assessed. Genetic analyses were also conducted to identify nuclear restorer genes of petaloid cytoplasmic male sterility (CMS) from wild carrot, and determine if Guelph, Cornell and Wisconsin cytoplasmic male-sterile accessions interacted similarly with alleles of restorer genes from different sources. Petaloid male-sterility was inherited cytoplasmically for the new Guelph accessions, and nuclear genotypes which normally produce `green' or `white' petaloid-stamens in combination with the Cornell cytoplasm also produced corresponding phenotypes when backcrossed to Guelph cytoplasmic accessions. Two duplicate restorer genes were identified from wild carrot. Dominant alleles of single restorer genes from three sources, one from wild carrot and two from cultivated germplasm, restored stamen production to Guelph, Cornell and Wisconsin petaloid cytoplasmic accessions, suggesting that the cytoplasms were genetically identical.
Genetic Analysis of Resistance to the Southern Root-knot Nematode in Capsicum chinense Jacq.
Authors: Fery Richard L. , Thies Judy A.
Published: January 2019

Greenhouse tests were conducted to compare the levels of resistance to the southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] exhibited by recently released Capsicum chinense Jacq. Scotch Bonnet-type germplasm lines PA-353, PA-398, and PA-426 to the levels of resistance exhibited by C. annuum L. `Carolina Cayenne' and `Mississippi Nemaheart'; to determine the inheritance of the resistance in C. chinense germplasm line PA-426; and to determine the genetic relationship between the resistances exhibited by C. chinense germplasm line PA-426 and C. annuum `Carolina Cayenne'. The results of a replicated test indicated that the level of resistances exhibited by the resistant released C. chinense germplasm lines is equal to the level of resistances exhibited by the resistant C. annuum cultivars. Evaluation of parental, F1, F2, and backcross populations of the cross PA-426 × PA-350 (a susceptible Habanero-type C. chinense cultigen) indicated that the resistance in C. chinense is conditioned by a single dominant gene. The results of an allelism test indicated that this dominant gene is allelic to the dominant gene that conditions much of the southern root-knot nematode resistance in the C. annuum `Carolina Cayenne'. The ease and reliability of evaluating plants for resistance to root-knot nematode and the availability of a simply inherited source of outstanding resistance makes breeding for southern root-knot nematode resistance a viable objective in C. chinense breeding programs.
A Test Cross Protocol for Determining the Genotype of Dark Red Seedcoat Colors in Common Bean
Authors: Bassett Mark J.
Published: January 2019

The red common bean (Phaseolus vulgaris L.) seedcoat colors produced by the dominant gene R and the dark red kidney gene rkd are very similar, making it difficult for breeders of red bean varieties to know which genotype is in their materials. A protocol employing test crosses with genetic stocks having known genotypes for seedcoat colors was developed to identify genotypes with either of two very similar dark red seedcoat colors: garnet brown controlled by rkd and oxblood controlled by R. Twenty bean varieties and breeding lines were test crossed with genetic tester stocks cu BC3 5-593 and b v BC3 5-593, and four of the varieties were test crossed with [? R] b v BC3 5-593. Analysis of the seedcoat colors and patterns in the F1 progenies from the test crosses demonstrated that unambiguous identification of the genotypes of the two dark red colors could be achieved using the cu BC3 5-593 and b v BC3 5-593 testers. The dark red color (garnet brown) of the Small Red market class materials was demonstrated to be produced by rkd, and the dark red color (oxblood) of `Jacobs Cattle' was demonstrated to be produced by R. A Light Red Kidney market class stock was derived from `Redkloud' and used in two crosses: cu b v rk BC1 5-593 × b v BC3 5-593 and cu b v rk BC1 5-593 × cu BC3 5-593. Classification of the F2 progenies demonstrated that the cu gene does not entirely prevent rk red color from being modified by V. The interactions of rk, rkd, and R with C, cu, G, B, and V are discussed, and previous literature concerning those interactions is critically reviewed.
Training and Pruning System Effects on Vegetative Growth Potential, Light Interception, and Cropping Efficiency in Peach Trees
Authors: Grossman Y.L. , DeJong T.M.
Published: January 2019

Plant dry matter production is proportional to light interception, but fruit production does not always increase with increased light interception. Vegetative growth potential, the effect of cropping on vegetative growth, light interception and cropping efficiency of a clingstone peach [Prunus persica (L.) Batsch `Ross' on `Nemaguard' rootstock] were assessed in four production systems differing in tree density and training system. The four systems were a perpendicular V (KAC-V) system, a high-density perpendicular V (HiD KAC-V) system, a cordon system, and an open vase system. Vegetative growth potential, assessed on defruited trees, was higher in the cordon system and lower in the open vase system compared to the V systems. Cropping reduced leaf growth on the V and cordon systems and stem growth on the KAC-V and cordon systems. On a ground area basis, the HiD KAC-V system had the highest crop yields and the open vase system had the lowest. The cordon and HiD KAC-V systems intercepted more light and produced more fruit, stem, and leaf biomass than the open vase system. However, the modified harvest increment, the ratio of fruit dry mass to the sum of fruit, leaf, and stem dry mass, was lower in the cordon system than in the other systems. Thus, on this basis, the cordon system was the least efficient. On a trunk cross-sectional area basis, there were no significant differences in fruit production among any of the four training systems. For current year production, crop production per unit ground area is the best measure of economic efficiency. However, when planning the spacing, training and pruning of orchard trees, the most appropriate goal seems to be a system that increases light interception without increasing vegetative growth potential, such as the HiD KAC-V system.
Fruiting and Shading Effects on Metabolic Heat Rates of Inflorescence Buds, Current-year, and One-year-old Shoots of `Kerman' Pistachio Trees
Authors: Nzima Muntubani D.S. , Martin George C. , Breidenbach R.W.
Published: January 2019

Isothermal microcalorimetric measurements of metabolic heat rates of `Kerman' pistachio (Pistacia vera L.) individual inflorescence buds, current-year and 1-year-old shoots were used to investigate the roles of current and reserve photosynthates in the abscission of inflorescence buds. In the early stages of development metabolic heat rates of individual inflorescence buds were two and three times those of individual current-year and 1-year-old shoots respectively. Individual shoot organs (1-year-old shoots, current-year shoots, and inflorescence buds) sampled from “on” trees had higher metabolic heat rates than similar individual organs sampled from “off” trees. Artificial shading of pistachio trees for 14 days in early June depressed metabolic heat rates of individual inflorescence buds within 24 h, but there was a delay of 4 days before the decline in metabolic heat rates of individual current-year and 1-year-old shoots. This suggests that metabolic heat rates of individual inflorescence buds apparently depended on currently fixed photosynthates.
Leaf Mass Partitioning as a Determinant of Dry Matter Accumulation in Zantedeschia
Authors: Funnell Keith A. , Hewett Errol W. , Warrington Ian J. , Plummer Julie A.
Published: January 2019

Dry matter accumulation and partitioning in plants of Zantedeschia Spreng. `Best Gold' aff. Z. pentlandii (Wats.) Wittm. (syn. Richardia pentlandii Wats.) were quantified under a range of temperature and photosynthetic photon flux (PPF) regimes using plant growth analysis. The relative rate of dry matter accumulation [relative growth rate (RGRM), g·g-1·d-1] was highly correlated with the partitioning of the daily increment of dry matter into leaf tissue [leaf matter partitioning (LMP), g·d-1 per g·d-1]. In contrast, a poor correlation existed between RGRM and net assimilation rate (NAR, g·m-2·d-1). Maximum values of RGRM increased linearly with increasing temperature (from 13 to 28 °C), with a base temperature of 2.1 ± 2.7 °C. The optimum temperature for growth was PPF dependent with maximum total plant dry mass occurring under high PPF (694 μmol·m-2·s-1) at 25 °C. However, as the plant responded to PPF by altering LMP, final total plant dry mass was actually greater under the low PPF regime (348 μmol·m-2·s-1) at temperatures <22 °C. The optimum temperature for dry matter accumulation was close to the average daily air temperature during the growing season for the natural habitat of the parent species. Similarly, the greater dry matter accumulation under the combination of either low PPF and cooler temperatures or high PPF and warmer temperatures was paralleled by the diversity of PPF habitats in the natural open grassland and forest margin the parent species occupies. It is therefore suggested that Zantedeschia `Best Gold' is well adapted to optimize growth under these environmental conditions.
Derivatives of Vaccinium arboreum × Vaccinium Section Cyanococcus. II. Fertility and Fertility Parameters
Authors: Brooks Sylvia J. , Lyrene Paul M.
Published: January 2019

Fertility of F1 hybrids and their open-pollinated progeny was studied for the intersectional cross Vaccinium darrowi Camp × V. arboreum Marsh as part of a project to determine the feasibility of using V. arboreum to breed vigorous, drought-tolerant southern highbush blueberry cultivars. The 16 F1 hybrids that were studied were vigorous but very low in fertility. Second generation hybrids [MIKs (mother is known) obtained by open-pollination of the F1s] and MIK derivatives were extremely variable in vigor and fertility, but averaged far higher in fertility than the F1s as evidenced by pollen stainability and amount of pollen produced. F1s produced an average of 0.4 seedlings per 100 pollinated flowers when hand-pollinated in a greenhouse with pollen from V. darrowi, 0.2 when pollinated by V. arboreum and 3.4 when pollinated by cultivated highbush. Some MIKs that were crossed with other MIKs and with cultivated southern highbush were very high in male and female fertility. Female fertility was estimated in greenhouse crosses from fruit set, berry weight, number and weight of seeds, number of plump seeds per berry, and number of seedlings obtained. Male fertility was estimated by pollen stainability with acetocarmine and amount of pollen shed. Chromosome counts showed that three F1s were diploid and that four fertile MIKs were tetraploid. One MIK appeared to be aneuploid. Aneuploidy may explain much of the low fertility found in MIK populations. These results indicate that good progress is being made in returning the hybrid plants to cultivar quality in only a few generations of backcrossing.