bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of Resistance to Southern Root-knot Nematode in `Carolina Cayenne' Pepper in Greenhouse, Microplot, and Field Tests
Authors: Thies J.A. , Mueller J.D. , Fery R.L.
Published: January 2019

The southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] is a serious pest of pepper (Capsicum annuum L.). Currently, methyl bromide is used for nematode control, but the pending withdrawal of this fumigant from the United States market has resulted in a need for effective alternative root-knot nematode management measures. We evaluated the effectiveness of resistance of `Carolina Cayenne' relative to the susceptible genotypes `Early Calwonder' and PA-136 in greenhouse, microplot, and field studies. In all tests, `Carolina Cayenne' exhibited exceptionally high resistance (minimal galling, minimal nematode reproduction, and no yield reduction) to M. incognita; `Early Calwonder' and PA-136 were highly susceptible. In a test conducted in a heavily infested field, `Carolina Cayenne' outyielded PA-136 by 339%. The exceptionally high resistance exhibited by `Carolina Cayenne' provides an alternative to methyl bromide and other fumigant nematicides for managing root-knot nematodes in pepper.
Effects of Elevated Carbon Dioxide on Key Mitochondrial Respiratory Enzymes in `Hass' Avocado Fruit and Fruit Disks
Authors: Lange Diana L. , Kader Adel A.
Published: January 2019

Preclimacteric avocado [Persea americana (Mill.) cv. Hass] fruit or fruit disks as well as fruit harvested in either June (midseason) or August (late season) and partially ripened were kept in air (21% O2 + 78% N2), 20% CO2 + 17% O2 (63% N2), or 40% CO2 + 13% O2 (47% N2) at either 10 or 20 °C. Ethylene production by preclimacteric fruit was completely inhibited during CO2 exposure, whereas there was only partial inhibition of ethylene production when partially ripened fruit were exposed. Compared to the fruit stored in air, O2 uptake of fruit stored in 20% CO2 was decreased by 20%, whereas the fruit stored in 40% CO2 showed 25% more O2 uptake than air-stored fruit. Fruit subjected to a storage regime of 40% CO2 at 10 °C followed by 2 d in air had the best visual quality. In general, climacteric fruit treated with 20% CO2 at 10 °C showed increased pyruvate dehydrogenase (PDH) activity and decreased cytochrome oxidase (CytOx) activity. Fruit stored in 40% CO2 had reduced CytOx activity compared to air-stored fruit, and PDH activity was variable depending on the harvest season of the fruit. Our results show that the effect of elevated CO2 on a given enzyme depends on concentration of CO2, duration of exposure, physiological state of the fruit, and type of tissue exposed.
Influence of Fall Nitrogen and Spring Nitrogen—Potassium Applications on Yield and Fruit Quality of `Chandler' Strawberry
Authors: Miner G.S. , Poling E.B. , Carroll D.E. , Nelson L.A. , Campbell C.R.
Published: January 2019

Annual-hill strawberry (Fragaria ×ananassa Duch.) production with black plastic mulch and drip irrigation is gaining popularity in North Carolina. Two experiments (E1 and E2) were conducted on a Wagram loamy sand (Arenic Kandiudult) in 1992 and on a Norfolk sandy loam (Typic Kandiudult) in 1993 to investigate the effects of fall-applied N and spring-applied N and K on `Chandler' strawberry yield and fruit quality. E1 treatments included factorial combinations of banded fall-applied N (0, 34, and 67 kg·ha-1) and drip spring-applied N (0, 0.19, 0.37, 0.56, and 0.75 kg·ha-1·d-1 and 0, 0.37, 0.75, and 1.12 kg·ha-1·d-1 in 1992 and 1993, respectively). E2 treatments included combinations of drip spring-applied N (0.56, 1.12, 1.68, and 2.24 kg·ha-1·d-1) and K (0.46, 1.39, and 2.32 kg·ha-1·d-1 and 0, 0.75, 1.49, and 2.24 kg·ha-1·d-1 in 1992 and 1993, respectively). There were no significant interactions among main effects for any of the measured variables. Market yield maximized with total N at ≈120 kg·ha-1 with one-half banded in the fall and the remainder drip-applied in the spring. Fruit firmness decreased with increasing N rate. Fruit pH and concentrations of total acids and soluble solids were not affected by N treatments, but soluble solids increased as the harvest season progressed. Plant crown number was not affected by N treatment but crown yield increased with N rate similar to market yield. There was no response to drip-applied K for any variable in either year. Based on soil test, fall-applied K (broadcast-soil incorporated) met the K requirements both years.
Heterotic Patterns among Open-pollinated Sweet Corn Cultivars
Authors: Revilla Pedro , Tracy W.F.
Published: January 2019

Heterotic patterns in sweet corn are weakly defined. Most sweet corn inbreds are descended from three open-pollinated cultivars: `Golden Bantam', Stowell's Evergreen', and `Country Gentleman'. Heterotic and phylogenetic relationships among these three cultivars and others are not clearly known. This investigation was designed to investigate the heterotic patterns among some historically important open-pollinated sweet corn cultivars: `Country Gentleman', `Golden Bantam', `Lindsey Meyer Blue', `Stowell's Evergreen', `Howling Mob', and `Pease Crosby'. The 15 possible hybrids from the diallel cross plus the 6 parents were grown in midspring and late summer plantings. Heterosis and combining ability effects were estimated for 13 traits. Hybrid × planting date interactions were significant for most of the main traits, hence, planting dates were analyzed separately. Average midparent heterosis for grain yield was 29.17% in the first planting date and 57.04% in the second planting. Midparent heterosis for yield and plant height were highest for hybrids with `Country Gentleman' as a parent. `Stowell's Evergreen' when crossed to `Pease Crosby', `Lindsey Meyer, and `Golden Bantam' exhibited high heterosis. The two late-maturity cultivars `Country Gentleman' and `Stowell's Evergreen' had higher general combining ability than the four early-maturity cultivars for most traits. Specific combining ability was seldom significant. Yield of `Country Gentleman' hybrids averaged over all crosses and planting dates was the highest. These data indicate a strong heterotic pattern—`Country Gentleman' × `Pease Crosby', `Golden Bantam', and `Lindsey Meyer Blue'—and a weaker one—`Stowell's Evergreen' × `Pease Crosby', `Golden Bantam', and `Lindsey Meyer Blue'.
Pea Cultivar Susceptibility and Inheritance of Resistance to the Lentil Strain (Pathotype P2) of Pea Seedborne Mosaic Virus
Authors: Kasimor K. , Baggett J.R. , Hampton R.O.
Published: January 2019

Commercial pea (Pisum sativum L.) cultivars, plant introduction (PI) lines, and Oregon State Univ. (OSU) breeding lines were tested for resistance to pathotype P2 (lentil strain) and pathotype P1 (type strain) of pea seedborne mosaic virus (PSbMV) and to bean yellow mosaic virus (BYMV) to assess the relative proportion of resistant and susceptible pea genotypes. Of the 161 commercial cultivars tested, 117 (73%) were resistant and 44 were susceptible to PSbMV-P2. Of these PSbMV-P2-resistant cultivars, 115 were tested for resistance to BYMV and all were resistant. Of the 44 PSbMV-P2-susceptible cultivars, 43 were tested for BYMV susceptibility and all were infected except two, `Quincy' and `Avon', both of which were susceptible to a BYMV isolate in another laboratory. Of 138 commercial cultivars inoculated with PSbMV-P1, all were susceptible. All PI lines and OSU breeding lines that were resistant to PSbMV-P1 were resistant also to PSbMV-P2. The high percentage of commercial cultivars resistant to PSbMV-P2 was probably attributable to the close linkage of genes sbm-2 and mo and the widespread use by breeders of BYMV-resistant `Perfection' and `Dark Skin Perfection' in developing new pea cultivars. Segregation ratios in progenies of three separate crosses between PSbMV-P2-resistant and PSbMV-P2-susceptible cultivars closely fit the expected 3 susceptible: 1 resistant ratio expected for resistance conferred by a single recessive gene.
A DNA Marker for Columnar Growth Habit in Apple Contains a Simple Sequence Repeat
Authors: Hemmat Minou , Weeden Norman F. , Conner Patrick J. , Brown Susan K.
Published: January 2019

The columnar mutation `Wijcik McIntosh' has attracted much attention because of its compact growth habit, which is compatible with high-density plantings. Using bulked segregant analysis, we identified several randomly amplified polymorphic DNA (RAPD) markers that displayed a close linkage with the columnar locus (Co). The RAPD marker that displayed the closest linkage was end sequenced to develop a sequence tagged site for rapidly screening segregating populations. A simple sequence repeat (SSR) of (GA)17 was identified within the DNA fragment. Four allelic forms, including an apparent null allele, could be distinguished among the cultivars tested. The null allele displayed close linkage with Co in two progenies, and we used this marker to identify the location of the gene on the apple linkage map.
Inheritance of Procumbent Habit from `Cipo' Sweet Orange in Crosses with `Clementine' Mandarin
Authors: Bowman Kim D.
Published: January 2019

`Cipo' sweet orange [Citrus sinensis (L.) Osbeck] combines typical midseason fruit characteristics with a unique procumbent growth habit. This distinctive habit may be of value in breeding smaller and more procumbent scion cultivars if the growth habit is transmitted to hybrid seedlings. Two hybrid populations were created using `Clementine' mandarin (Citrus reticulata Blanco) as the female parent and either `Cipo' sweet orange or `Pineapple' (another midseason sweet orange with a more typical upright growth habit) as the male parent. The `Clementine' × `Cipo' cross yielded many hybrids with the procumbent habit, many with the upright habit, and some that appeared intermediate. Both hybrid populations were compared with nucellar seedling populations from `Cipo' and `Pineapple' using two morphological characteristics that differentiate between the procumbent habit of `Cipo' and the upright habit of `Pineapple'. All the `Clementine' × `Pineapple' hybrids were of upright growth habit, while the `Clementine' × `Cipo' progeny segregated into two groups based on growth habit (upright and procumbent). The two measured characteristics were tightly correlated in the segregating population and are probably pleiotropic effects of the same genetic mutation. The observed population distributions were as expected if the procumbent habit in `Cipo' is controlled by a single dominant allele in the heterozygous condition.
Influence of Bulb Stock Origin, Inflorescence Harvest Stage and Postharvest Evaluation Conditions on Cut Flower Longevity of Asiatic Hybrid Lilies
Authors: van der Meulen-Muisers José J.M. , van Oeveren Joop C.
Published: January 2019

To improve the ability to discriminate between Asiatic hybrid lilies (Lilium L.) with regard to cut flower longevity in breeding trials, sources creating nongenetic variation during the preharvest, harvest, or postharvest phases were identified. The bulb stock origin (grower) and evaluation temperature caused only small nongenetic variation in individual flower longevity. In contrast, the developmental stage of floral buds, when cut, produced significant nongenetic variation in flower longevity. This variation could be reduced by delaying harvest. An evaluation temperature of 17 °C was optimal to discriminate between longevity levels compared to 14 and 20 °C. Flower deformation due to withering of the petals was an improved criterion for the termination of flower longevity and was preferred instead of loss of turgor of the petals. Standard conditions for screening and selecting Asiatic hybrid lilies for individual flower longevity after cutting are proposed.
Effects of Some Polyamine Biosynthesis Inhibitors and Calcium Chloride on In Vitro Growth and Decay Development in Apples Caused by Botrytis cinerea and Penicillium expansum
Authors: Saftner Robert A. , Conway William S. , Sams Carl E.
Published: January 2019

Three polyamine biosynthesis inhibitors, α-difluoromethylornithine (DFMO), α-difluoromethylarginine (DFMA), and α-methylornithine (MeOrn), alone and in combination with CaCl2, were tested for their ability to reduce in vitro growth and soft rot development in apple (Malus domestica Borkh.) fruit caused by Botrytis cinerea Pers.:Fr. and Penicillium expansum Link. All three inhibitors reduced the in vitro growth of the pathogens. Calcium had no effect on fungal growth in vitro. Pressure infiltration of millimolar concentrations of DFMO or DFMA or 25 g·L-1 CaCl2 solutions into apples reduced subsequent soft rot development by B. cinerea and P. expansum >40%. A combination treatment of Ca and DFMO or DFMA reduced decay >67%. Treatment of apples with MeOrn was less effective at inhibiting decay development. None of the inhibitors affected polyamine levels in apple cortical tissues. Some injury to the fruit surface was observed with Ca treatments. Fruit treated with Ca and any of the inhibitors were less firm than those treated with Ca alone. Specific polyamine biosynthesis inhibitors in combination with Ca may prove useful in reducing postharvest decay in apples.
Early Wound- and Ethylene-induced Changes in Phenylpropanoid Metabolism in Harvested Lettuce
Authors: Tomás-Barberán Francisco A. , Loaiza-Velarde Julio , Bonfanti Antonio , Saltveit Mikal E.
Published: January 2019

The phenolic composition of whole heads and excised midrib sections of iceberg, butter leaf, and romaine lettuce (Lactuca sativa L.) was followed at 5 and 10 °C during the first 3 days after wounding or during continuous exposure to 10 μL·L-1 ethylene in air. After 3 days of storage at 5 and 10 °C, only 5-caffeoylquinic acid (chlorogenic acid), 3,5-dicaffeoylquinic acid (isochlorogenic acid), caffeoyltartaric acid, and dicaffeoyltartaric acid were detected in wounded lettuce midribs. Of these four compounds, chlorogenic acid accumulated to the highest level in all three lettuce types. The content of caffeic acid derivatives increased 3- and 6-fold after 72 hours of storage at 5 and 10 °C, respectively. The synthesis of caffeoyltartaric acid was not induced by wounding in iceberg lettuce, while chlorogenic acid increased 5-fold at 5 °C and 10-fold at 10 °C. Similar relative phenolic compositions were detected in the three lettuce types studied, although at different concentrations. Changes observed in the content of individual phenolic compounds during the first 3 days of ethylene exposure seemed to follow the same pattern observed during wound induction of the synthesis of phenolic compounds. Chlorogenic acid increased 5-fold and isochlorogenic acid increased 10-fold, while the content of caffeoyltartaric derivatives were not significantly altered by ethylene treatment. Isochlorogenic acid, which was only present in low amounts in the control, was synthesized in the later steps of wound and ethylene induction. Similar kinetics for the induction of phenolic compounds were observed in the three lettuce types studied, suggesting that the mechanisms by which wounding induces phenylpropanoid synthesis are common for the different lettuce types.
Effect of Application Date on Absorption of 15Nitrogen by Highbush Blueberry
Authors: Throop Philip A. , Hanson Eric J.
Published: January 2019

Rates of absorption of 15N-enriched ammonium sulfate by young `Bluecrop' highbush blueberries (Vaccinium corymbosum L.) were compared following applications on six dates between late April and September. Ammonium sulfate solutions containing 2.1 g N (10.2 atom % 15N) were dripped directly into the root zone of single bushes. Soil covers and irrigation were used to maintain similar soil moisture conditions during treatment periods. Treated bushes from each application date were excavated after 2 weeks of exposure and separated into roots, stems, and current season's growth (new shoots, leaves, fruit). Tissues were dried, weighed, and analyzed for 15N and 14N by mass spectrometry. Soils were also analyzed for labeled and nonlabeled N. Bushes treated in late May, June, and July absorbed a greater percentage of applied N (6% to 9%) than bushes treated in April, August, or September (1% to 3%). Absorption of N appeared to be affected more by the demand of the plants than soil N availability. Plants absorbed N most efficiently during active growth between late bloom and fruit maturity.
Evaluating Composts to Produce Wildflower Sods on Plastic
Authors: O'Brien Tara A. , Barker Allen V.
Published: January 2019

This research evaluated production of wildflower sods in soil and composts of mixed municipal solid waste, biosolids and woodchips, fall leaves, and mixed agricultural wastes. Soil or composts were laid on plastic sheeting in outdoor plots, and a mixture of wildflower seeds was sown in July and in September in separate experiments. Quality of sods was assessed in two growing seasons. Best sods with respect to seed germination, stand establishment, and intensity and diversity of bloom over two seasons occurred in mature biosolids compost and in agricultural waste compost. These composts were low in ammonium but rich in total N. Germination and growth of wildflowers were limited by high ammonium concentrations in immature biosolids composts. Nitrogen deficiency limited sod growth and quality in leaf composts. Poor N nutrition and weed competition restricted sod production in soil. Fertilization of soil promoted unacceptably large weed growth. Summer seeding or fall seeding resulted in good sods, but many annual flowers that appeared in the summer seeding were absent in the fall-seeded planting. Using plastic-lined plots was a convenient system for evaluating composts and other media in outdoor culture.
Yield and Quality of Tomato Fruit under Water-table Management
Authors: Dodds Georges T. , Trenholm Leif , Rajabipour Ali , Madramootoo Chandra A. , Norris Eric R.
Published: January 2019

In a 2-year study (1993-94), tomato (Lycopersicon esculentum Mill. `New Yorker') plants grown in a sandy loam soil in field lysimeters were subjected to four water table depth (WTD) treatments (0.3, 0.6, 0.8, and 1.0 m from the soil surface). In 1994, precipitation during the flowering stage was far above average and apparently led to waterlogging in the shallowest WTD treatment, while in the drier year (1993), the deepest WTD treatment suffered from drought stress. In general, over the 2 years, the 0.6-m WTD showed the best yields and largest fruit, while the 1.0-m WTD showed the lowest yields and smallest fruit. However, the incidence of catfacing, cracking, and sunscald was generally higher in the 0.6 m WTD treatment and lower in the 1.0-m WTD treatment. Furthermore, fruit firmness was generally greatest for the two deeper WTD than for the shallower WTD. To strike a balance between yield and quality, a WTD of between 0.6- and 0.8-m is recommended for tomato production on sandy loam soils.
Genetic Analysis and Interrelationships between Traits for Cooking Time, Water Absorption, and Protein and Tannin Content of Andean Dry Beans
Authors: Elia Frank M. , Hosfield George L. , Kelly James D. , Uebersax Mark A.
Published: January 2019

A knowledge of the relative proportion of additive and nonadditive genetic variances for complex traits in a population forms a basis for studying trait inheritance and can be used as a tool in plant breeding. A North Carolina Design II mating scheme was used to determine the inheritance of cooking time, protein and tannin content, and water absorption among 16 genotypes of dry bean (Phaseolus vulgaris L.) representative of the Andean Center of Domestication. Heritability and the degree of dominance for the traits were also calculated to provide guidelines for adopting breeding strategies for cultivar development. Thirty-two progeny resulted from the matings and these were assigned to two sets of 16 progeny each. Variances due to general combining ability (GCA) and specific combining ability (SCA) were significant for the traits. The GCA was larger in all cases. Narrow-sense heritability for protein, tannin, water absorption, and cooking time averaged 0.88, 0.91, 0.77, and 0.90, respectively. Degree of dominance estimates indicted that the traits were governed by genes with partial dominance except, in one case, tannin had a degree of dominance value of zero, indicating no dominance. The phenotypic correlation (-0.82) between water absorption and cooking time justifies using the water absorption trait as an indirect selection method for cooking time. With regard to parent selection in crosses, significant differences between GCA females and GCA males suggested cytoplasmic influences on trait expression. Hence, the way a parent is used in a cross (i.e., as female or male) will offset trait segregation. Using fast-cooking bean cultivars in conjunction with fuel-efficient cooking methods may be the best strategy to conserve fuelwood and help reduce the rate of deforestation in East and Central Africa.
Genetic Diversity among Witchhazel Cultivars Based on Randomly Amplified Polymorphic DNA Markers
Authors: Marquard Robert D. , Davis Eric P. , Stowe Emily L.
Published: January 2019

Forty selections, including 37 cultivars of Hamamelis spp., were evaluated for genetic similarities using randomly amplified polymorphic DNA (RAPD) markers. Cluster analysis identified seven groups, which included three groups of H. ×intermedia cultivars, two groups of H. vernalis, and one group each of H. mollis and H. japonica. Three H. ×intermedia cultivars, `Arnold Promise', `Westerstede', and `Carmine Red', did not group closely with the other 20 cultivars of H. ×intermedia. Selections of the North American species H. vernalis were quite distinct from the Asiatic selections. However, data are presented that suggest hybridization exist between Asiatic Hamamelis spp. and H. vernalis. Genetic similarities between known half-sib families provides evidence that the cultivar pairs `Arnold Promise'—`Winter Beauty' and `Carmine Red'—`Hiltingbury' are, themselves, not likely half-sibs.
Consequences of Cool Storage of Broccoli on Physiological and Biochemical Changes and Subsequent Senescence at 20 °C
Authors: Pogson Barry J. , Morris Stephen C.
Published: January 2019

In most broccoli (Brassica oleracea L. var. italica) cultivars studied, the loss of chlorophyll was marginal after 5 weeks cool storage (1 °C) + 2 days at 20 °C, but there was significant loss of chlorophyll from some poor-storing cultivars, particularly after 10 weeks cool storage (+2 days at 20 °C). Soluble sugars were depleted rapidly during cool storage (especially sucrose) and were essentially exhausted after 10 weeks at 1 °C. Losses of total proteins were only 20% after 10 weeks cool storage. There is preferential catabolism of carbohydrates (sucrose, glucose, and fructose) at low temperatures, whereas, at 20 °C, protein and carbohydrate levels decline concomitantly. The patterns of sugar and protein depletion suggest that all soluble sugar is potentially accessible for metabolism, but protein catabolism is targeted to specific tissues or organs. After 5 weeks at 1 °C and placing at 20 °C, ethylene production and respiration increased to steady-state levels. Peak production of wound ethylene usually occurs 4 to 6 hours after harvest at 20 °C. After 5 or 10 weeks cool storage, this peak of production was not detected at 20 °C. After 10 weeks at 1 °C, recovery of ethylene production was delayed and the respiration rate only partially recovered to the steady level. However, chlorophyll loss is the major determinant of marketable life without cool storage, and, after 5 weeks at 1 °C, postharvest decay is the major determinant of marketable life after cool storage, particularly after 10 weeks at 1 °C.
The Effect of Altering Nitrogen and Sulfur Supply on the Growth of Cut Chrysanthemums
Authors: Huang Li-Chun , Paparozzi Ellen T. , Gotway Carol
Published: January 2019

`Dark Yellow Fuji Mefo' chrysanthemums (Dendranthema grandiflora Tzvelev.) were grown hydroponically with either 64, 127, or 254 mg·L-1 N and either 0, 1, 2, 4, 8, 16, 32, or 64 mg·L-1 S in a randomized complete block. Time to flower was measured and symptoms of S deficiency were observed on root, stem, and leaf systems. New leaves and inflorescences were analyzed for S, and lower leaves were analyzed for N concentration. There were four sampling dates and two experiments. Flower diameter was measured when flowers were present, while stem length was measured every sampling date. Nitrogen application could be reduced by half to 127 mg·L-1 as long as some S, 4 mg·L-1 in the fall and 8 mg·L-1 in the spring, was applied. Sulfur deficiency symptoms observed included branchless roots, which aged earlier, overall yellowing of new leaves, and reddening on the leaf abaxial starting from older leaves and moving acropetally. Plants receiving no S had smaller leaves, shorter stems, delayed inflorescence initiation, and restricted inflorescence development. Without S, plants did not produce flowers suitable for commercial sale.
Weed Control Increases Yield and Economic Returns from Young `Desirable' Pecan Trees
Authors: Foshee Wheeler G. , Goodman Robert W. , Patterson Michael G. , Goff William D. , Dozier W. Alfred
Published: January 2019

Yields and economic returns above treatment variable costs were determined for young `Desirable' pecan [Carya illinoinensis (Wangenh.) C. Koch] trees grown for nine seasons under ten combinations of orchard floor management practice and irrigation. Orchard floor management practices were 1) no weed control, 2) mowed, 3) total weed control with herbicides, 4) grass control only with herbicides, or 5) disking, and trees were either irrigated or nonirrigated. Total weed control with herbicides increased cumulative yield through the ninth growing season by 358% compared to no weed control. In the humid environment where this experiment was conducted, irrigation did not increase crop value obtained from the young trees, except for 1 year. At the end of the ninth season, total weed control with herbicides was the only treatment to have a positive net present value. These data indicate that establishment costs for young `Desirable' pecan trees can be recovered as early as the eighth growing season if competition from weeds is totally eliminated.
Effect of Floricane Number in `Marion' Trailing Blackberry. II. Yield Components and Dry Mass Partitioning
Authors: Cortell Jessica M. , Strik Bernadine C.
Published: January 2019

In Spring 1993 and 1994, mature trailing `Marion' blackberry (Rubus L. subgenus Rubus Watson) plants were pruned to 0, 4, 8, and 12 floricanes. In 1994, yield per cane was higher for plants with 4 floricanes compared to plants with 8 or 12 floricanes. In Summer 1993, there was a trend for lower primocane dry mass with a higher floricane number and a significant reduction in primocane branch dry mass with an increase in floricane number. Total plant, fruit, floricane, and lateral dry mass increased linearly with floricane number. Results were similar for floricane components in Summer 1994; however, there were no treatment effects on primocane or branch dry mass and there was a significant linear increase in crown dry mass with floricane number. By Winter 1994-95, there were no treatment effects on primocane or crown dry mass. Plants without floricanes produced more primocanes per plant than plants with floricanes in 1993 but not in 1994. Plants without floricanes produced primocanes that had a significantly lower percent budbreak the following year (1994) than plants with floricanes. Primocanes produced by plants without floricanes had more nodes per branch and a greater average branch cane length than those from plants with floricanes the previous season. The number of nodes per primocane tended to decrease with an increase in floricane number per plant in 1994 and 1995. There was no significant effect of floricane number per plant the previous season on fruit per lateral, fruit mass, or yield per plant the following season in either treatment year (1993 + 1994). However, in 1994, plants without floricanes the previous year had the lowest yield per cane. Topping primocanes at 30 cm in 1993 and 1994 had few significant effects on yield components the following season. Thus, `Marion' blackberry can compensate for reduced fruiting cane number through an increased percent budbreak on remaining canes. While there were differences in primocane dry mass among treatments after harvest in 1993, there were no differences by mid-winter in either 1993 or 1994. Although plants grown without floricanes in 1993 had more primocanes, these canes had a lower percent budbreak the following season. Consequently, in this study we did not see increased yield in plants grown without floricanes the previous season. This was perhaps because primocanes were not trained as they grew, a practice that improves light exposure to the canes and may increase flower bud initiation.
Changes in Carbohydrate and Nitrogen Relationships during Episodic Growth of Ligustrum japonicum Thunb.
Authors: Kuehny Jeff S. , Miller William B. , Decoteau Dennis R.
Published: January 2019

Rooted cuttings of Ligustrum japonicum Thunb., an episodically growing species, were grown hydroponically in a controlled-environment growth chamber to determine allocation of glucose, mannitol, total soluble sugars, and total protein in mature leaves, flush leaves, stems, and roots. During the 65 days of episodic growth, 43% of the total soluble sugars was glucose and 33% mannitol. Glucose concentrations of mature leaves decreased during the first root growth episode, increased in almost all plant tissue during a shoot growth episode and decreased in all plant tissue at initiation of a second root growth episode. Mannitol concentrations in the roots and stems decreased during episodes of root growth and increased during a shoot growth episode when leaf flush mannitol concentrations increased. Radiolabeled C applied to leaves before the initiation of the first period of shoot elongation was translocated to the roots. After shoot elongation, just before a root growth episode, most labeled C was translocated to new shoots and roots. Autoradiographs indicated that subsequent episodes of shoot growth were supported by photosynthate from the previous shoot flush. Protein concentrations decreased in all plant tissues during shoot growth but increased in roots and mature leaves during root growth. Concentrations of 15N in leaf and stem tissue indicated retranslocated N supported each episode of shoot growth. Changes in endogenous C and N concentrations and allocation patterns in ligustrum were linked to the control of episodic shoot and root growth.
Natural Pest Resistance of Prunus Taxa to Feeding by Adult Japanese Beetles: Role of Endogenous Allelochemicals in Host Plant Resistance
Authors: Patton Cynthia A. , Ranney Thomas G. , Burton James D. , Walgenbach James F.
Published: January 2019

Feeding intensity of adult Japanese beetle (Popillia japonica Newm.) was compared among 27 taxa of Prunus host plants during 24-hour no-choice feeding trials conducted on individual leaves. Fecal dry mass per beetle, a measure of feeding intensity, varied from 0 mg·d-1 for Prunus padus L. to 20.4 mg·d-1 for P. sargentii Rehd. and P. tomentosa Thunb. Prunus padus, P. laurocerasus L., P. mahaleb L., P. serotina Ehrh., P. virginiana L., P. americana Marsh., P. ×yedoensis Matsum., and P. besseyi Bailey were resistant based on feeding intensities of <4.3 mg·d-1 (levels not significantly different from zero). Feeding intensity decreased exponentially as endogenous foliar cyanide potential increased. Evaluation of the cyanogenic glucoside prunasin in artificial diets showed a similar relationship with feeding being reduced by 50% (ED50) at 4.9 mmol·kg-1 in the diet. Prunus mahaleb was highly resistant to Japanese beetles despite having low cyanide potential. Two coumarin compounds known to exist in P. mahaleb, herniarin and coumarin, were tested in artificial diets and were effective feeding deterrents with ED50 values of 5.9 and 2.5 mmol·kg-1 in the diet, respectively. This research demonstrated a wide range of host plant resistance to feeding by adult Japanese beetles and further indicates that prunasin, herniarin, and coumarin are important factors in host plant resistance to this pest.
Predictors of Shelf Life in Long English Cucumber
Authors: Jolliffe P.A. , Lin W.C.
Published: January 2019

Variation in shelf life of greenhouse-grown `Mustang' cucumber (Cucumis sativus L.) fruit was enhanced by preharvest experimental treatments of fruit thinning and fruit shading. Treatments also affected the dynamics of fruit elongation, fruit color at harvest, and chlorophyll fluorescence of the pericarp. Fruit color (grey level) at harvest, as measured by image analysis, had the highest simple (positive) correlation with shelf life. Rapid elongation and high photochemical quenching of fluorescence also characterized fruit having longer shelf life. The ability to predict cucumber yellowing is improved using a multiple regression approach, but prediction achieved by the best subset model is still too low to segregate commercially fruit having a short shelf life.
Interference from Broccoli Residue on Brassica Germination and Seedling Growth
Authors: Santos J.R.A. , Leskovar D.I.
Published: January 2019

Germination bioassays were conducted to assess if water-soluble extracts of broccoli (Brassica oleracea L. var. italica L.) affect germination of broccoli, cabbage (Brassica oleracea L. var. capitata L.), and cauliflower (Brassica oleracea L. var. botrytis L.). Greenhouse experiments also examined the phytotoxic potential of soil previously cropped with broccoli and broccoli plant parts on seedling growth of those species. The first bioassay used nonsterile extracts (NSEs) and filter-sterilized extracts (FSEs) of broccoli leaves. The second bioassay used nonsterile and filter-sterilized leaf extracts (LEs), stem and root extracts (SREs), and whole broccoli plant (leaves, stems, and roots) extracts (WPEs). Broccoli and cabbage germination were not affected by NSEs or FSEs, but the latter reduced cauliflower germination by 22%. LEs and SREs decreased germination speed for broccoli, cabbage and cauliflower. Greenhouse seedlings were grown in soil previously cropped with broccoli or fallow soil at three fertilizer levels. Broccoli soil was phytotoxic to cauliflower but enhanced broccoli and cabbage seedling growth. The differential sensitivity to broccoli plant residue was in the order of cauliflower > broccoli = cabbage, with SR residue having the highest phytotoxic potential.
Water Use and Crop Coefficients of Woody Ornamentals in Containers
Authors: Schuch Ursula K. , Burger David W.
Published: January 2019

Twelve species of woody ornamentals were grown in containers in Riverside and Davis, Calif., to determine plant water use and compare crop coefficients (Kc) calculated with reference evapotranspiration (ET) from local weather stations (ETcim) or atmometers (ETatm). Water use, Kcatm, and Kccim differed by species, location, and month of the year. Raphiolepis indica (L.) Lindl., Pittosporum tobira (Thunb.) Ait., Juniperus sabina L., and Photinia ×fraseri Dress. were the highest water users in Riverside and Arctostaphylos densiflora M.S. Bak., Juniperus, Cercis occidentalis Torr., and Pittosporum used the highest amount of water in Davis, when averaged over the 20-month study period. Rhamnus californica Eschsch., Prunus ilicifolia (Nutt.) Walp., and Cercocarpus minutiflorus Abrams. were among the lowest water users in both locations. Although plant water use fluctuated considerably between individual sampling dates, the relative ranking of species water use in each location changed very little over the study period. During periods of high winds, ETcim may not provide an accurate reference for container crops. Kc values fluctuated seasonally from as much as 1 to 4.7 for high water users, while values were stable for low water users and also for Buxus microphylla japonica Rehd. & E.H. Wils., an intermediate water user. During periods of low ET, especially in fall and winter, Kc values were artificially high and failed to correspond to the plants' low water use. Kc values for low water users seem to be useful to estimate water requirements over an extended period of time, whereas general Kc values seem to have limited value for plants with high water demand and need to be modified for different growth stages and growing locations.
Environmental and Physiological Effects on Cuticle Cracking in Tomato
Authors: Emmons Cheryld L. Whaley , Scott John W.
Published: January 2019

Tomato (Lycopersicon esculentum Mill.) cultivars and breeding lines were evaluated in the field for incidence and severity of cuticle cracking (CC) over four spring seasons at Bradenton, Fla. Resistant and susceptible genotypes were identified and easily distinguished by incidence of CC. When studied over 2 years, the amount of rain during the entire 14 days before harvest was more highly correlated with CC incidence than the amount of rain during the entire growing season or during 1 to 7 or 8 to 14 days before harvest. Attempts to induce CC by pruning leaves or fruit from plants were not successful. The incidence of CC was significantly higher for fruit from unstaked plants (39%) compared to fruit on staked plants (10%). Fruit exposed to direct sunlight, from plants that were staked and not pruned, had significantly greater incidence of CC (49%) than fruit protected by leaf cover (20%). Of 218 fruit monitored for affect of developmental stage on occurrence of CC, 62 developed CC. Of these 2%, 61%, 27%, and 10% first exhibited CC at immature-green, mature-green, breaker, and red stages, respectively. For 58% of fruit with CC, no increase in CC severity was observed as the fruit ripened. Increases in CC severity were observed more often between mature-green and breaker than between breaker and table-ripe stages of ripening.
Leaf Gas Exchange, Dry Matter Partitioning, and Mineral Element Concentrations in Mango as Influenced by Elevated Atmospheric Carbon Dioxide and Root Restriction
Authors: Schaffer Bruce , Whiley Anthony W. , Searle Christopher , Nissen Robert J.
Published: January 2019

The effects of atmospheric CO2 enrichment and root restriction on net CO2 assimilation (A), dry mass partitioning, and leaf mineral element concentrations in `Kensington' and `Tommy Atkins' mango (Mangifera indica L.) were investigated. Trees were grown in controlled-environment glasshouse rooms at ambient CO2 concentrations of 350 or 700 μmol·mol-1. At each CO2 concentration, trees were grown in 8-L containers, which restricted root growth, or grown aeroponically in 200-L root mist chambers, which did not restrict root growth. Trees grown in 350 μmol·mol-1 CO2 were more efficient at assimilating CO2 than trees grown in 700 μmol·mol-1 CO2. However, total plant and organ dry mass was generally higher for plants grown at 700 μmol·mol-1 CO2 due to increased A as a result of a greater internal partial pressure of CO2 (Ci) in leaves of plants in the CO2 enriched environment. Root restriction reduced A resulting in decreased organ and plant dry mass. In root-restricted plants, reduced A and dry matter accumulation offset the increases in these variables resulting from atmospheric CO2 enrichment. Atmospheric CO2 enrichment and root restriction did not affect dry mass partitioning. Leaf mineral element concentrations were generally lower for trees grown at the higher ambient CO2 concentration, presumably due to a dilution effect from an increased growth rate.
Preventing Postproduction Leaf Yellowing in Easter Lily
Authors: Han Susan S.
Published: January 2019

Postproduction leaf yellowing of Easter lily (Lilium longiflorum Thunb.) can be prevented by using growth regulators. Solutions containing benzyladenine (BA) reduced the percentage of yellow leaves in cold-stored plants, but solutions containing gibberellic acid (GA3) were not effective. Treatment with commercial products containing GA4+7 (Provide) or GA4+7 and BA (Promalin) nearly completely prevented the development of leaf yellowing. Concentrations as low as 25 mg·L-1 were effective. Leaf yellowing was prevented by growth regulators only on leaves that had been treated, indicating that the growth regulators were not mobilized in the plants. Growth regulator solutions halted further development of leaf yellowing when applied to plants that already had some chlorotic basal leaves. This result suggests that growth regulators need not be applied preventively. Treatment can be delayed until chlorotic lower leaves are first seen on plants. The striking effects of growth regulators in preventing leaf yellowing did not affect the development and opening of flower buds.
Alterations in nptII and gus Expression following Micropropagation of Transgenic M.7 Apple Rootstock Lines
Authors: Ko Kisung , Brown Susan K. , Norelli John L. , Aldwinckle Herb S.
Published: January 2019

Seven nptII and gus transgenic lines of the apple (Malus ×domestica Borkh.) rootstock Malling 7 (M.7) were examined by glucuronidase (GUS) histochemical testing and a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA). These lines had different amounts of neomycin phosphotransferase II (NPTII). The amounts of NPTII among lines was positively correlated with the ability of the transgenic lines to regenerate in the presence of kanamycin, paromomycin, or geneticin. Regenerants derived from transgenic lines also varied greatly in GUS expression. The apical portion of regenerant stem tissues had stronger GUS staining than the basal portion of stem. All regenerated tissue of T1, a transgenic line originally classified as a uniform GUS staining line, showed non-GUS staining, while the regenerated tissues of chimeric transgenic lines showed nonstaining, chimeric staining, or uniform GUS staining, indicating the potential to select uniform GUS staining lines from chimeras. Polymerase chain reaction (PCR) indicated the gus gene was present in GUS negative (nonstaining) lines. Negative PCR results with primers derived from vir G of Agrobacterium tumefaciens, and failure to isolate A. tumefaciens from M.7 transgenics indicated that PCR and GUS staining results were not due to A. tumefaciens. A modified PCR methylation assay (MPMA) indicated that methylation of cytosines of the CCGG site in the gus gene, and in the border between the CaMV35S promoter and the gus gene, was positively correlated with complete gus gene silencing (nonstaining lines). However, the MPMA indicated that methylation was not always associated with variable GUS expression, suggesting that chimeric staining could be due to a mixture of transformed and nontransformed cells in some transgenic lines.
Characterizing Salinity Limits of New Guinea Impatiens in Recirculating Subirrigation
Authors: Todd Nancy Morgan , Reed David Wm.
Published: January 2019

New Guinea impatiens (Impatiens hawkeri Bull.) were grown in a recirculating ebb-and-flow subirrigation system under increasing levels of salinity stress from a mixture of NaCl and CaCl2 (1:1 equivalent ratio, 2:1 molar ratio) and recommended production levels of other nutrients. Growth and quality decreased as salinity level increased, with a 75% to 80% growth reduction at 18 mol·m-3 NaCl-CaCl2 compared to controls. Among controls, root mass distribution was 10%, 50%, and 40% in the top, middle, and bottom layers of the root zone, respectively. In the highest salinity treatment (18 mol·m-3 NaCl-CaCl2), most of the root mass was in the middle layer (80%), while the root mass in the top and bottom layers was reduced to 5% and 15%, respectively. The electrical conductivity (EC) of the growing medium was high in the top layer in all treatments, but only exceeded maximum recommended levels in the middle and bottom layers in the 4·mol·m-3 or higher treatments. Initial postproduction leaching caused the salts in the top layer to migrate to the middle and bottom layers, which in some experiments induced a rapid and transient wilting. Up to six leaching and drying cycles of a 0.20 leaching fraction were required to reduce EC in all layers to recommended levels. Overall, salable plants of good quality and size were produced with up to 2 mol·m-3 (total 152 mg·L-1) NaCl-CaCl2 in the recirculated nutrient solution.
Transformation of Eggplant with Synthetic cryIIIA Gene Produces a High Level of Resistance to the Colorado Potato Beetle
Authors: Jelenkovic Gojko , Billings Sharon , Chen Qi , Lashomb James , Hamilton George , Ghidiu Gerald
Published: January 2019

A population of 300 putative transgenic eggplants (Solanum melongena L.) carrying the syn cryIIIA gene was produced and tested for resistance to the Colorado potato beetle [CPB; Leptinotarsa decemlineata (Say)]. Toxicity tests in planta and in vitro demonstrated that 69% of the transformed plants were resistant to neonate larvae and adult CPB. Transgenicity of the plants was confirmed by studies of GUS expression and Southern and northern analysis. Primary transformants, having a single insert of the construct, upon selfing, produced progenies cosegregating for the uidA and syn cryIIIA genes at the expected 3:1 ratios with a few exceptions in which only one of the genes was expressed. The latter was attributed to the gene silencing phenomenon. The segregating resistant R1 seedlings showed the same level of resistance as the parental genotypes in growth chamber tests and under field conditions. One genotype carrying two copies of the construct, upon selfing, segregated at a 15:1 ratio for GUS expression and resistance to CPB, while Southern analysis revealed a 9:3:3:1 genotypic segregation ratio for individual copies of the construct.
The Expression of Acrotony in Deciduous Fruit Trees: A Study of the Apple Rootstock M.9
Authors: Cook Nigel C. , Rabe Etienne , Keulemans Johan , Jacobs Gerard
Published: January 2019

One-year-old shoots of apple (Malus ×domestica Borkh.) rootstock Malling 9 (M.9 clone Nic 29), ≈60 cm long without sylleptic side shoots, were selected randomly from a commercial stoolbed in Belgium, prepared, and forced at 25 °C and 16 hours daylength to follow bud developmental rate in different positions along a 1-year-old shoot. The number of buds that reached green tip was recorded daily until 50% of shoots exhibited budburst. The evolution of dormancy of the terminal, an upper lateral, and a lower lateral bud was followed throughout the dormant period. The influence of a distal disbudded shoot piece and Promalin [3000 mg·L-1 N-(phenylmethyl)-1H-purine 6-amine and 3000 mg·L-1 gibberellins A4+A7 without a wetting agent] application on the developmental rate of these buds was evaluated. Bud developmental rate decreased during winter and increased to a maximum before budburst in spring. The distal shoot-forming ability or acrotonic branching habit in apple appears to be mediated via a greatly increased developmental rate of the terminal bud relative to the upper and lower lateral buds, respectively. The proximal budbursting tendency or basitony exhibited in early winter was weak compared to the acrotony that developed in the last month before budburst in spring. Lateral buds showed a lower developmental rate than the terminals when inhibited by a distal disbudded shoot piece, so that resultant overall growth habit within the shoot remained acrotonic throughout the dormant period. Promalin application in winter did not restore the bud developmental rate associated with spring budburst. These results are discussed with reference to observations of trees growing under conditions of insufficient winter chilling.