bluuebunny/crossref_metadata_2025 huggingface dataset:
Sugar Changes, Respiration, and Decay Control of Sweet-potatoes in Consumer Packages
Authors: Kilili Anthony W. , Picha David H. , Huang Yuehe
Published: January 2019

Cured `Beauregard' sweetpotatoes [Ipomoea batatas (L.) Lam] were either treated with a fungicide (300 ppm, 2,6-dichloro-4-nitroaniline), hot water (55 °C for 5 min), a combination of the two treatments, or untreated. The roots were shrink-wrapped in 2.3-kg consumer packs using a Clysar D 955 heat-shrinkable film. The packs were kept at room temperature, which ranged from 18 to 22C, for 4 weeks. The average CO2 concentration in the packages was 18% after the 4-week period. Roots in the wrapped packages lost 0.7% fresh weight, whereas nonwrapped roots lost 4.2% fresh weight. Shrink-wrapped roots maintained a lower rate of respiration for several days after removal from the packages. Hot water and fungicide treatments reduced Rhizopus spp. decay and enhanced root appearance. An additional benefit of hot water treatment was an inhibition of sprouting. Wrapped sweetpotatoes had lower alcohol insoluble solids and dry weight. The concentration of fructose and glucose was higher in wrapped roots, while sucrose concentration was lower. There was also a 20% increase in both acid and neutral invertase activity in the wrapped roots compared to nonwrapped roots. Hot water treatment is a viable alternative to fungicides in extending shelf-life of consumer packaged sweetpotatoes.
Making Sense of Cooling Data
Authors: Boyette M.D.
Published: January 2019

Prompt cooling to remove field heat is an essential part of proper postharvest handling for many types of fresh fruits and vegetables. Growers, consultants, and horticultural agents are often encouraged to collect cooling data (time vs. temperature) in order to compare cooling rates for different systems, containers, etc. These data can be misleading and confusing and seldom yield much useful information. With proper analysis, cooling data can yield a large amount of information. The problem is not the fault of the data, as much as the lack of simple methods to analyze these data. This presentation will demonstrate several simple methods to extract useful information from cooling data.
Damage Control: Handling CDC and the Media When Your Product is Attacked
Authors: Riggs David
Published: January 2019

The California strawberry industry has unfairly suffered through two food safety events in the past 2 years. In June 1996, an outbreak of a parasitic disease, Cyclospora, involved consumers in several cities in the United States and Canada. Initial reports linked the disease to consumption of strawberries from California; however, it was later determined that the likely source of the outbreak was raspberries imported from Guatemala. The impact of the initial reports implicating California strawberries was severe and resulted in industry losses of $20 to $40 million. In Mar. 1997, children in Michigan became ill from the consumption of frozen strawberries grown in Mexico and processed by a California firm. The incident clearly did not involve fresh strawberries nor California fields. Again, initial reports were not specific and the industry suffered losses estimated at $15 million. Comments will focus on the California Strawberry Commission's crisis preparedness plan, how the industry responded to these food scares, what the strawberry industry has learned, and the resulting and continuing government response to these events.
Experience with Thinning: What Factors Contribute to Contradicting Results?
Authors: Marini Richard
Published: January 2019

Results from chemical thinning trials often vary with location/researcher and from year to year within a location. Factors influencing both sources of variation will be discussed. For help explain seasonal variation, the effects of fruit size and temperature will be discussed. A multiple regression model was developed indicating that the degree of fruit thinning is influenced by the interaction of temperature two days after treatment and fruit diameter at the time of treatment. Factors contributing to contradicting results between experiments/researcher include application techniques, types of data collected, differences in experimental designs and sampling techniques, statistical analyses, and potential differences in the tree condition at the time of thinning applications.
Increased Yield and Quality of Herbs Using Plasticulture Systems
Authors: Bowen P.A.
Published: January 2019

In plasticulture, raised beds, plastic mulch, rowcovers, and fertigation are used to accelerate crop growth and improve crop quality by providing heat, nutrients, and water at near-optimum levels. Because plasticulture is intensive and input costs are high, profits are maximized when high-value crops are grown. For herb crops, plasticulture can also be used to control weeds without herbicides, to prevent soil contamination by rain splashing, and to prevent rooting of side branches. In a studies of Echinacea species, root yields in the first year were improved by 35% to 77%. Other crops found to be suitable for plasticulture include feverfew, lemon balm, pineapple sage, valerian, and Chinese licorice. Implementation methods will be described.
Properly Timed Foliar Nutrient Applications Provide an Efficient Means to Meet Nutrient Demand to Increase Flowering, Fruit Set, and Size of Citrus and Avocado
Authors: Lovatt Carol J.
Published: January 2019

The goal of our research is to identify the role that specific essential nutrient elements play in the physiology of horticultural crops and then to apply the nutrient as a fertilizer to the foliage at key times in the phenology of the tree, i.e., a time when the demand for the nutrient is likely to be high, in order to stimulate a specific physiological process. This approach proved successful in the following completed studies. A single winter prebloom application of nitrogen as low-biuret urea made to the foliage of 30-year-old `Washington' navel orange (Citrus sinensis L. Osbeck) trees at the time of irreversible commitment to flowering significantly increased yield and fruit number per tree for each of three consecutive years. In addition, the number of commercially valuable fruit with diameters of 6.1 to 8.0 cm significantly increased as yield increased (r2=0.88). Applications of boron as sodium tetraborate to the foliage of a commercial orchard of `Hass' avocado (Persea americana Mill.) trees at the cauliflower stage of inflorescence development (gametogenesis) increased the number of pollen tubes reaching the ovule, ovule viability and cumulative yield (P ≤ 0.05). Additional examples from ongoing research also will be presented.
Respiratory and Glycolytic Response of Suspension-cultured `Passe Crassane' Pear Fruit Cells to Elevated CO2 Concentrations
Authors: Kerbel Eduardo L. , Kader Adel A. , Romani Roger J.
Published: January 2019

Suspension-cultured `Passe Crassane' pear fruit (Pyrus communis L.) cells in aging media were ventilated with air or air + 20% CO2 for 4 days at 26C. Cells exposed to elevated CO2 exhibited reduced respiration (02 consumption). Ethylene production of both air and CO2-treated cells also declined to barely discernible levels by day 3. Fructose 6-phosphate (F6P) accumulated, while levels of fructose l,6-bisphosphate (F1, 6-P2), and activities of ATP and PPi phosphofructokinases (PFK and PFP) declined in response to elevated CO2. These results indicate an inhibitory effect of CO2 at the site of action of both phosphofructokinases in the glycolytic pathway, which could account, at least in part, for the observed reduction in respiration. The responses to elevated CO2 levels of the cell suspension system and intact pear fruit ventilated with air + 10% CO2 are compared, revealing a close similarity.
Modes of Inheritance of Photoperiodism in Fragaria
Authors: Ahmadi Hamid , Bringhurst Royce S. , Voth Victor
Published: January 2019

Genetic analysis of day-neutral (photo-insensitive) cultivars and their derivatives hybridized to standard short-day clones of octoploid strawberries [Fragaria × ananassa Duchn., F. chiloensis (L.) Duchn., and F. virginiana glauca Staudt., x = 7, 2n = 56] revealed that photo-insensitivity is controlled by a single dominant allele of a Mendelian gene. The dominant genetic trait is expressed in hybrids with other Fragaria spp. Intergeneric hybrids of day-neutral Fragaria and short-day Potentilla glandulosa L. and P. fruticosa L. also express photo-insensitivity. The day-neutral genes in European perpetual flowering (photo-insensitive) diploid `Alpine' F. vesca (2N = 14) apparently have evolved independently, since photo-insensitivity is recessive to photo-sensitivity. Native California diploid F. vesca have diverged considerably from European F. vesca. No photo-insensitive diploids have been found among them. Photo-sensitivity in native California F. vesca is controlled by three dominant genes. The origins of day-neutral cultivars of F. × ananassa and the classification of day-neutrality are discussed.
Inheritance of Abaxial Leaf Pubescence in Beans
Authors: Zaiter Haytham Z. , Coyne Dermot P. , Steadman James R. , Beaver James S.
Published: January 2019

Genetic variation for abaxial leaf pubescence was detected among dry bean (Phaseolus vulgaris L.) cultivars/lines. Inheritance of pubescence (long, straight hairs) was studied in the dry bean crosses of pubescent `Pompadour Checa-50' (Dominican Republic) × eight glabrous cultivars/lines. Segregation for pubescence vs. glabrousness indicated that pubescence was determined by a single major gene or by duplicate recessive epistatic genes, depending on the cross involved. Trichome density (number trichomes per mm) was a quantitative trait. Thus, pubescence was a discrete trait, but trichome density ranged from low to high.
Selection for Betalain Pigment Concentrations and Total Dissolved Solids in Red Table Beets
Authors: Wolyn D.J. , Gabelman W.H.
Published: January 2019

Three cycles of half-sib family selection were practiced in a previously unselected table beet (Beta vulgaris L.) population to produce high pigment-high solids (HPHS) and high pigment-low solids (HPLS) populations. A selection index (total pigment concentration/percent dissolved solids) was used to improve the HPLS population and another selection index (total pigment concentration × percent dissolved solids) was used to improve the HPHS population. Rates of gain for total pigment were 22.2% per cycle in the HPHS population and 18.4% per cycle in the HPLS population. The HPHS and HPLS populations showed directional but nonsignificant changes for dissolved solids: 3.0% and - 2.6% per cycle, respectively. The rate of gain per cycle for selection index value (29.1%) was greater in the HPHS population than in the HPLS population (21.2%). Realized heritabilities were high for total pigment (0.81 and 0.82) and selection index (0.74 and 0.74) and low for dissolved solids (0.25 and 0.27) in both populations. Variation among families was greater for total pigment than for dissolved solids.
Yield Component Analysis of `Harrow Delight', `Kieffer', and `Harvest Queen' Pear
Authors: Kappel Frank
Published: January 2019

Yield components of 8- to 10-year-old trees were compared among `Kieffer' [Pyrus communis (L.) x Pyrus pyrifolia (Burro.)] and `Harrow Delight' and `Harvest Queen' [Pyrus communis (L.)]. `Kieffer' set more fruit than the other cultivars, even though flower density was similar. `Kieffer' also had similar size or larger fruit than `Harrow Delight' or `Harvest Queen'. Path analysis showed that the direct and indirect effect of fruit number on yield was important for all cultivars. Flower density only had a small direct effect on yield and this was at times negative. Fruit size had a small effect on yield when compared to fruit number.
Microsprinkler Irrigation and Growth of Young `Hamlin' Orange Trees
Authors: Marler Thomas E. , Davies Frederick S.
Published: January 2019

Growth responses of young `Hamlin' orange [Citrus sinensis (L.) Osbeck] on sour orange (C. aurantium L.) trees to microsprinkler irrigation were studied under field conditions from 1985 to 1987 to determine the most-efficient irrigation rates and duration. Trees were irrigated when available soil water depletion (SWD) reached 20% (high frequency), 45% (moderate frequency), and 65% (low frequency). Trees at the moderate and low levels received 49% and 13%, respectively, as much irrigation water as the high treatment. Canopy volume, trunk cross-sectional area, dry weight, shoot length, leaf area, total root dry weight and volume, and new root dry weight were similar for the high and moderate levels in 2 of 3 years, but were significantly reduced at the low level. Summer and fall growth flushes were delayed or did not occur at the moderate and low levels. More than 90% of root dry weight was within 80 cm of the trunk at the end of the first growing season.
Leaf Edge Burn and Axillary Shoot Growth of Vegetative Poinsettia Plants: Influence of Calcium, Nitrogen Form, and Molybdenum
Authors: Bierman Peter M. , Rosen Carl J. , Wilkins Harold F.
Published: January 2019

Poinsettia (Euphorbia pulcherrima Wind. ex. Klotzsch cv. Gutbier V-14 Glory) plants were grown under conditions simulating commercial stock plant production to investigate the effects of NH4-N: NO3-N fertilizer ratios, foliar Ca sprays, medium-applied Ca, and medium-applied Mo on leaf edge burn (LEB) and cutting production. Leaf edge burn expression was nearly 100% greater with NH4-N: NO3-N fertilizer ratios of 1:2 or 2:1 than with NO3-N only. However, cutting production was 28% lower with NO3-N as the sole N source. There was little difference in either LEB or cutting production between the two NH4-N levels. Weekly Ca sprays at 500 mg·liter-1 were effective in reducing LEB, while medium-applied Ca as gypsum was ineffective. Foliar Ca sprays reduced both the number of LEB leaves (90%) and symptom severity of individual leaves. Spraying plants with tap water (Ca at 25 to 30 mg·liter-1) plus wetting agent had an intermediate effect. Medium-applied Mo was ineffective in reducing LEB, despite greatly increasing leaf Mo levels. The Ca concentration in chlorotic, marginal leaf tissue was significantly lower than the Ca concentration in green leaf margins. There was also a strong, negative correlation between the Ca concentration in young leaves at the susceptible growth stage and the incidence of LEB in various treatment groups. Supplemental applications of Ca and Mo did not consistently affect cutting production. Leaf edge burn appears to be a localized Ca deficiency due to inadequate Ca uptake and/or translocation to the numerous axillary shoots simultaneously developing on poinsettia stock plants.
Nitrogen Form and Solution pH Influence Growth and Nutrition of Two Vaccinium Clones
Authors: Rosen Carl J. , Allan Deborah L. , Luby James J.
Published: January 2019

The effects of pH and N form on growth and nutrition of blueberry (Vaccinium corymbosum L. × V. angustifolium Ait. cv. Northblue) and cranberry (V. macrocarpon Ait. cv. Searles) were tested in separate greenhouse hydroponic experiments. A factorial treatment arrangement of two pH levels (4.5 and 6.5) and three N forms (NO3-N, NH4-N, and NH4-N/NO3-N) was used for each clone. Blueberry shoot growth and final dry weight were greatest at pH 4.5, regardless of N form. In contrast, cranberry fresh weight accumulation and final dry weight were higher with NH4-N/NO3-N or NH4-N than with NO3-N alone. Cranberry plants receiving NO3-N alone accumulated low levels of tissue N and grew relatively poorly at both pH levels. Differences in N response by these two species may be due partially to the environments in which they were selected. Soil from the site where `Northblue' blueberry was selected contained relatively high NO3-N and low NH4-N levels; soil from commercial `Searles' cranberry bogs had relatively low NO3-N and high NH4-N levels. Both species accumulated relatively high levels of root Fe, regardless of pH or N form. Levels of Fe in the root were as much as 100 times higher than in the shoot. Based on X-ray microanalysis of cranberry roots, most of the Fe appeared to be precipitated on the root surface as iron phosphate. Concentrations of Mn in shoots and roots depended on N form and pH. In general, root Mn was highest at pH 6.5 and apparently was precipitated with Fe.
Nitrogen Fertilization Influences the Physiology of Apple Leaves Subjected to European Red Mite Feeding
Authors: Campbell Richard J. , Marini Richard P.
Published: January 2019

The interaction of N fertilization and European red mite (ERM) [Panonychus ulmi (Koch)] feeding on the physiology of greenhouse-grown `Imperial Delicious' apple (Malus domestica Borkh.) leaves was evaluated. Visual damage was noticeable with 75 mite days (MD) and was consistently greatest on the low-N leaves. Net photosynthesis (Pn) was decreased by mite feeding in all N treatments. However, with equal MD, the high-N treatment retained higher Pn than the low- or medium-N treatments. Transpiration, dark respiration, leaf N, and total chlorophyll increased with N and were reduced by mite feeding. Mite feeding increased dark transpiration at all N levels. Relative water content was unaffected by N and was reduced by mite feeding. Specific leaf weight increased with N and MD.
Mobility Limitations of Bound Polygalacturonase in Isolated Cell Wall from Tomato Pericarp Tissue
Authors: Rushing James W. , Huber Donald J.
Published: January 2019

Enzymically active cell wall isolated from mature-green and ripening tomato (Lycopersicon esculentum Mill cv. `Rutgers') fruit was employed to investigate the mobility of the enzyme polygalacturonase (PG, EC 3.2.1.15). Cell walls from mature-green `Rutgers' fruit or from the ripening mutant rin, which alone exhibits little or no release of pectin, were unaffected by the addition of enzymically active cell wall from ripening `Rutgers' fruit, indicating that PG is either not transferred at all or is not transferred to sites of pectin hydrolysis. The quantity of pectin released by the addition of soluble PG to enzymically active wall depended on the quantity of enzyme added. Similar data were obtained using purified PG2. Pectin solubilization from all wall isolates exhibiting enzymically mediated pectin release diminished with time; however, transfer to fresh buffer initiated a resumption of autolytic activity, indicating that an inhibitor is released during the course of pectin hydrolysis.
Differential Growth Responses of Apple Species to Chilling and Root Pruning
Authors: Arnold Michael A. , Young Eric
Published: January 2019

Malus dometica Borkh., M. anis, M. prunifolia Borkh., M. × robusta Rehd., M. antonovka, M. borwinkw, and M. ranetka bare-root seedlings were chilled at 5C for 0, 400, 800, 1200, or 1600 hours. After chilling treatments, one-half of the seedlings were root-pruned and all seedlings were placed in a greenhouse for 15 days. Quantitative differences between species in the timing and magnitude of new root and shoot growth responses to chilling were observed. Root pruning decreased and delayed the production of roots <0.6 mm in diameter in response to chilling, while the production of larger roots was less affected. Regeneration of both root types differed among species. For new large (≥ 0.6 mm in diameter) root growth criteria, interactions between chilling hours and species were apparent. Chilling requirements and growing degree hour requirements for vegetative budbreak of each species were estimated.
Ripening and Fruit Weight of Eight Strawberry Cultivars Respond to Row Cover Removal Date
Authors: Gent Martin P.N.
Published: January 2019

Strawberry (Fragaria × ananassa Duchesn.) cultivars differ in response to removal date of row covers when they are used for winter protection and to accelerate fruit development and production. In 1986-87 and 1987-88, eight cultivars were overwintered under either spun-bonded polypropylene row cover or under straw. The straw was removed from control plots in late March. Row covers were removed on four dates beginning in late March and separated by about 2-week intervals. The time of flowering, fruit set, and fruit ripening was advanced in direct relation to the time that row covers remained over plants in spring. The differences in time of fruit ripening were less than those of time of flowering, however. The mid-harvest date was advanced as much as 8 days for `Earlidawn' and `Midway', but only 4 days for `Redchief' and `Scott'. Weight per fruit and percentage of marketable fruit were reduced when plants remained under row cover until mid-May. This effect was most noticeable for `Earlidawn', `Guardian', and `Redchief'. The fruit quality of `Midway' and `Jerseybelle' was not significantly affected by date of row cover removal. These cultivar-specific responses were probably not related to the stage of fruit development when row covers were removed, as both early and late-flowering cultivars were sensitive (and insensitive) to the date of row cover removal.
Planting Method and Irrigation Rate Influence Vegetative and Reproductive Growth of Peach Planted at High Density
Authors: Williamson J.G. , Coston D.C.
Published: January 2019

Several planting treatments modified vegetative and reproductive growth of young, own-rooted peach (Prums persica) trees evaluated at two levels of irrigation in a high-density orchard (5000 trees/ha). Trees planted in auger holes, narrow herbicide strips, and in fabric-lined trenches, but not those from raised beds, were smaller than control trees set in holes dug with a shovel. After two growing seasons, trees planted in the fabric-lined trenches were smaller and had more flowers per node and greater flower bud densities than trees in other planting treatments. Yield efficiency was greatest for this treatment, although fruit size was small throughout the orchard. Irrigation rates did not affect fruit yield or size. The effects of irrigation rate on vegetative growth were small compared to differences among planting treatments.
Nitrogen Fertilizer Management Practices to Enhance Seed Production by `Anaheim Chili' Peppers
Authors: Payero J.O. , Bhangoo M.S. , Steiner J.J.
Published: January 2019

The effects of six applied N treatments differing by rates and frequencies of application on the yield and quality of pepper (Capsicum annuum var. annuum L. `Anaheim Chili') grown for seed was studied. The timing of N applications was based on crop phenology, leaf petiole nitrate-nitrogen concentrations (NO3-N) minimum thresholds, and scheduled calendar applications of fixed amounts of N. Solubilized NH4NO3 was applied through a trickle-irrigation system to ensure uniform and timely applications of N. Rate of mature (green and red) fruit production was unaffected by any treatment except weekly applications of 28 kg·ha-1 of N, which stopped production of mature fruit before all other treatments. Early season floral bud and flower production increased with increasing amounts of N. The two highest total N treatments produced more floral buds and flowers late in the season than the other treatments. Total fruit production was maximized at 240 kg N/ha. Differences in total fruit production due to frequency of N application resulted at the highest total N level. Red fruit production tended to be maximized with total seasonal applied N levels of 240 kg·ha-1 and below, although weekly applications of N reduced production. Total seed yield was a function of red fruit production. Pure-1ive seed (PLS) production was a function of total seed production. Nitrogen use efficiency (NUE) for red fruit production also decreased with N rates >240 kg·ha-1, but PLS yield and NUE decreased in a near-linear fashion as the amount of total seasonal applied N increased, regardless of application frequency. Season average NO3-N (AVE NO3-N) values >4500 mg·kg-1 had total seed and PLS yields less than those treatments <4000 mg·kg-1. Six-day germination percentage was reduced with weekly N applications of 14 kg·ha-1. Seed mass was reduced with weekly N applications of 28 kg·ha-1. Final germination percent, seedling root length and weight, and field emergence were unaffected by any of the N treatments. These findings indicate that different N management strategies are needed to maximize seed yield compared to fruit yield and, therefore, there may be an advantage to growing `Anaheim Chili' pepper specifically for seed.
Seasonal Fluctuations of Some Enzymes Relating to Sucrose and Sorbitol Metabolism in Peach Fruit
Authors: Moriguchi Takaya , Sanada Tetsuro , Yamaki Shohei
Published: January 2019

Sugar levels and composition were determined in developing `Hakuto' peach (Prunus persica Batsch var. vulgaris Maxim.) fruit. Glucose and fructose in nearly equal amounts were the predominant sugars detected during the early stage of development. Sucrose subsequently began to accumulate and was the predominant sugar in mature fruit. Sorbitol remained at a low level throughout development. The large increase in the amount of sucrose was accompanied by a rapid increase in sucrose synthase (EC 2.4.1.13) activity. Sucrose phosphate synthase (EC 2.4.1.14) was also detected in flesh extracts, but the activities were low throughout development. Acid invertase (EC 3.2.1.26) activity was highest in young fruit and declined with development. Activity, however, increased again at a later stage of development. Peach fruit contained appreciable sorbitol oxidase activity, while other sorbitol-related enzymes were barely detectable, suggesting that transported sorbitol was predominantly converted to glucose. These results suggest that the supply of glucose and fructose depends on acid invertase and sorbitol oxidase, and that accumulation of sucrose depends on-sucrose synthase.
Relationship of Porphobilinogen Deaminase Activity to Chlorophyll Content and Fruit Development in `Heinz 1350' Tomato
Authors: McMahon Robert W. , Stewart Cecil R. , Gladon Richard J.
Published: January 2019

Chlorophyll a and b contents were determined in developing tomato fruit (Lycopersicon esculentum Mill. `Heinz 1350') at 5-day increments from 10 or 15 days past anthesis to fulIy ripe (55 to 60 days). When presented on a whole-fruit basis, chlorophyll a and b contents increased from 15 days past anthesis to 35 days and then decreased to zero at 55 days. Porphobilinogen (EC 4.2.1.24; PBG) deaminase activity was measured in extracts from the fruit, and changes in PBG deaminase activity correlated with changes in chlorophyll and protein contents with respect to fruit age. Partial characterization of tomato PBG deaminase enzyme showed similarities to PBG deaminase enzymes isolated from other sources.
Bud Dormancy Status, Frost Hardiness. Shoot Moisture Content, and Readiness of Black Spruce Container Seedlings for Frozen Storage
Authors: Colombo Stephen J.
Published: January 2019

Black spruce [Picea mariana (Mill) B. S. P.] first-year seedlings were exposed to 8-hr photoperiods and warm temperatures (26C maximum, 15C minimum) and tested weekly to determine bud dormancy status, frost hardiness, shoot moisture content, and the amount of damage caused. by a period of frozen storage (- 3C). Bud dormancy status, frost hardiness, and shoot moisture content were all strongly correlated to the time of bud initiation. Frost hardiness was low (- 5 to - 7.5C) during the period of needle primordia initiation until week 3 (3 weeks after 100% bud initiation), but bud dormancy decreased linearly over this period, from 37 days to budbreak for seedlings sampled at week - 1 (1 week before 100% of the seedlings had initiated terminal buds) and placed under conditions favoring shoot elongation, to 14 days to budbreak for seedlings sampled on week 3. From week 5 to week 8, there was a strong (r2 > 0.999) linear correlation between frost hardiness and bud dormancy status. Shoot moisture content declined linearly from 84% on week - 1 to 74% on week 8 (r2 = 0.97), and shoot moisture content was correlated with both frost hardiness (r2 = 0.87) and the percentage of seedlings that suffered needle damage in frozen storage (r2 = 0.85). Bud dormancy status, measured as number of days to 50% budbreak, was curvilinearly correlated with seedling damage following frozen storage, whereas linear relationships with damage in storage were found for dormancy release index (r2 = 0.92) and frost hardiness (r2 = 0.85).
Inheritance of Isocitrate Dehydrogenase, Malate Dehydrogenase, and Shikimate Dehydrogenase in Peach and Peach × Almond Hybrids
Authors: Mowrey Bruce D. , Werner Dennis J. , Byrne David H.
Published: January 2019

Eighteen isozyme systems were surveyed in the peach [Prunus persica (L.) Batsch.] plant introduction collection. Seven systems were polymorphic. Three previously unreported isocitrate dehydrogenase (IDH; EC 1.1.1.41), three malate dehydrogenase (MDH; EC 1.1.1.37) and two shikimate dehydrogenase (SDH; EC 1.1.1.25) banding patterns were detected in the clones. Isocitrate dehydrogenase was dimeric in structure, with two alleles present at a single locus. Malate dehydrogenase was dimeric in structure, with three alleles present at the fast locus, while a second locus was monomorphic. Shikimate dehydrogenase was monomeric, with one allele present in most clones, while PI 113452, PI 113650, and PI 117679 were heterozygous for a slow SDH allele. Electrophoretic evidence suggests PI 113452, PI 113650, and PI 117679 are peach × almond (P. dulcis Webb) hybrids, since they were heterozygous for alleles previously reported only in almond.
Rapid Generation Cycling of Chrysanthemum Using Laboratory Seed Development and Embryo Rescue Techniques
Authors: Anderson Neil O. , Ascher Peter D. , Widmer Richard E. , Luby James J.
Published: January 2019

The generation time (0.75 to 1.5 years) in perennial, hexaploid chrysanthemums [Dendranthema grandiflora Tzvelv. (Chrysanthemum morifolium Ramat.)] impedes the rate of progress for sexual breeding programs in creating new clonal cultivars, inbred lines for hybrid seed production, and genetic studies. Modifications to the crossing environment and embryo rescue were evaluated to minimize the chrysanthemum generation cycle. One greenhouse chrysanthemum clone was outcross-pollinated using a bulk pollen source. Following emasculation, inflorescences were either left in situ or the peduncle bases were placed in styrofoam boards floating on a solution of 1% sucrose and 200 ppm 8-HQC under laboratory conditions. Embryogenesis occurred at a faster rate under laboratory conditions as tested with histological techniques; the heart stage appeared as early as the second day after pollination, compared with 11 days using in situ methods. Total embryogenic development time ranged from 25 (laboratory seed development) to 52+ days (in situ ripening). In a second test, embryo rescue (ER) significantly improved percent seed set, percent germination, and percent of progeny reaching anthesis relative to normal development. ER progeny from both garden parents were significantly earlier in total generation time than corresponding non-ER siblings. Laboratory seed development and ER were then used sequentially to obtain an average progeny generation time of =100 days, thus allowing for three generations per year. The potential impact of these two techniques on breeding chrysanthemums and other perennial crops with long generation times is discussed.
Summer Pruning Affects Yield and Improves Fruit Quality of `McIntosh' Apples
Authors: Autio Wesley R. , Greene Duane W.
Published: January 2019

The effects of summer pruning on the yield and quality of apples (Malus domestica Borkh.) from mature `Rogers McIntosh'/M.7 trees were assessed in 1986-88. Summer pruning from 1 July through 1 Sept. enhanced red coloring and increased the percentage of the crop graded U.S. Extra Fancy. Fruit weight was not altered by summer pruning. Total yield was reduced by summer pruning only in 1 year, however, in no year was the harvested yield reduced. The portion of the crop that was picked in the first harvest was increased by summer pruning. Dormant-pruning time was decreased by summer pruning, and the total time required for pruning was increased only 1 of the 2 years where it was measured. Summer pruning and daminozide treatment significantly increased the estimated net returns.
Three-year-old Pecan Pollen Retains Fertility
Authors: Yates I.E. , Sparks Darrell
Published: January 2019

Stored pollen from pecan [Carya illinoensis (Wangenh.) C. Koch] was analyzed for in vitro germination, fertilization efficiency, final fruit set, and characteristics of mature fruits. We demonstrate pecan pollen can be stored for several years and set fruit. Pollen stored for 1, 2, and 3 years at -80C and 1 year at -196C retained the capacity for fertilization. Pollen stored at -196C was more viable than pollen stored at -80C, with no significant correlation between length of storage at -80C, as judged by fruit abortions during the second drop. Final fruit set was not affected by pollen storage conditions, except for pollen collected in a season of drought. Fruit set is a more reliable indicator of pollen viability than in vitro germination. With two minor exceptions, fruits produced with stored pollen were similar to those developing after pollination with fresh pollen.
Mechanical Harvestability of Y-shaped and Pyramid-shaped `Empire' and `Delicious' Apple Trees
Authors: Robinson Terence L. , Millier William F. , Throop James A. , Carpenter Stephen G. , Lakso Alan N.
Published: January 2019

Mature `Empire' and `Redchief Delicious' apple trees (Malus domestica Borkh.) trained to a Y-shaped trellis (Y/M.26) or trained as pyramid-shaped central leaders (CL/M.7) were mechanically harvested with the Cornell trunk recoil-impact shaker during 4 years. With `Empire', fruit removal from the Y/M.26 trees (85% to 90%) was significantly less than from the CL/M.7 trees (95% to 97%). With `Delicious' there were no differences in fruit removal (90% to 95%) between the two tree forms in any year. When the catching pad was on the ground, fruit grade based on damage was only slightly better for the Y/M.26 trees than for the CL/M.7 trees. When the catching pad was raised up near the Y/M.26 canopy, fruit grade was significantly improved for the Y/M.26 trees and was better than the CL/M.7 trees. Fruit grade for both cultivars ranged from 83% to 94% Extra Fancy with 5% to 16% culls for the Y/M.26 trees and from 74% to 88% Extra Fancy and 11% to 21% culls for the CL/M.7 trees. Skin punctures, skin breaks, and number of large and small bruises were lower and the percentage of nondamaged fruit was higher with the Y/M.26 trees when the pads were close to the canopy than when the pads were on the ground. The CL/M.7 trees had higher levels of all types of fruit damage than did the Y/M.26 trees. Damaged fruit from the CL/M.7 trees was mainly from the top half of the tree, while fruit from lower-tier scaffold branches had low levels of damage. Mechanically harvested fruit from the Y/M.26 trees had lower incidences of fruit rot and flesh breakdown after a 6-month storage period than did fruit from the CL/M.7 trees. Stem pulling was high with both systems and averaged 60% for `Delicious' and 30% for `Empire'. The advantage of the single plane Y-trellis system for mechanical harvesting appears to be that the catching pads can be placed close to the fruit, thereby reducing fruit damage.
Physical Properties of and Plant Responses to Rockwool-amended Media
Authors: Fonteno William C. , Nelson Paul V.
Published: January 2019

Loose rockwool had a total porosity similar to peatmoss (92%, by volume) but with water retention capabilities similar to sand. Root media formulations containing loose rockwool were tested with seven plant species for plant response and nutrient uptake. The volume percent formulation, 20 rockwool : 10 peatmoss : 20 vermiculite : 45 pine bark : 5 perlite, was superior to formulations containing 10% or 30% rockwool. Plant response in this rockwool medium in bedding plant flats was superior to that in two high-performing commercial media for impatiens (Impatiens sultanii Hook), marigold (Tagetes patula L.), and petunia (Petunia hybrida Vilm) and equal to one commercial medium for tomato (Lycopersicon esculentum Mill.). However, response of chrysanthemum (Chrysanthemum × morifolium Ramat.), geranium (Pelargonium × hortorum Bailey), and poinsettia (Euphorbia pulcherrima Willd. ex Kl.) in 1.58-liter pots was inferior to both commercial media in one-half of the trials. Differential plant responses in the root media treatments did not relate directly to differences found to occur in plant nutrient composition. The high initial pH level of rockwool necessitated reduced application of limestone and increased application of calcium sulfate to offset Ca deficiency.
Fruit Abscission and Fruit Quality of Apples Following Use of Dicamba to Control Preharvest Drop
Authors: Marini Richard P. , Byers Ross E. , Sowers Donald L. , Young Rodney W.
Published: January 2019

Five apple (Malus domestica Borkh.) cultivars were treated with dicamba at concentrations of 0 to 200 mg·liter-1 during 3 years. Although the response varied with cultivar, dose, and year, dicamba always delayed fruit abscission. At similar concentrations, dicamba usually reduced fruit drop more than NAA, but less than fenoprop. Dicamba at 10 mg·liter-1 effectively delayed drop of `Delicious', whereas 20 to 30 mg·liter-1 was required for `Red Yorking', `Rome', `Winesap', and `Stayman'. Dicamba did not influence flesh firmness, soluble solids content, water core, or starch content at harvest or after storage. Chemical names used: naphthaleneacetic acid (NAA); 2-(2,4,5-trichlorophenoxy)propionic acid (fenoprop); 3,6dichloro-2-methoxybenzoic acid (dicamba).
Vegetative Responses of Apple Trees Following Benzyladenine and Growth Regulator Sprays
Authors: Greene Duane W. , Autio Wesley R.
Published: January 2019

Benzyladenine (BA) stimulated lateral branching on young apple (Malus domestica Borkh.) trees at concentrations as low as 100 mg·liter-1. BA reduced lateral shoot length indirectly through increased intersboot competition, whereas daminozide reduced lateral shoot growth as a direct effect of the chemical inhibition. Daminozide reduced the number of spurs that were induced by BA to grow into lateral shoots. BA reduced the size of terminal buds on spurs that were stimulated to grow into lateral shoots. When daminozide was included with BA, spur quality was increased, as determined by Increased bud size. The positive effect of daminozide on BA-treated spurs was indirect, and other growth retardants used in combination with BA may be equally effective at improving spur quality. It may not be possible to stimulate lateral branching with BA on young trees just coming into production without causing an unacceptable amount of thinning. However, on bearing `Empire' trees, lateral shoot growth was increased with BA while still achieving an appropriate level of thinning. In general, there was no advantage to applying BA in a split application. Chemical names used: N-(phenylmethyl)-1H-purine-6-amine [benzyladenine (BA)]; butanedioic acid mono(2,2-dimethylhydrazide) (daminozide).
Foliar-applied Iron Enhances Bermudagrass Tolerance to Herbicides
Authors: Johnson Billy J. , Carrow Robert N. , Murphy Tim R.
Published: January 2019

Field experiments were conducted to determine the effects of foliar iron (Fe) applied with postemergence herbicides on injury, color, and quality of `Tifway' bermudagrass [Cynodon transvaalensis Burtt-Davy × Cynodon dactylon (L.) Pers.]. Iron significantly decreased injury and improved quality and color of `Tifway' bermudagrass in conjunction with herbicide treatment. Turf injury was less for 4 to 18 days after the initial MSMA application when Fe was added. Injury was also less from sequential Fe treatment with MSMA + metribuzin (up to 4 days) and MSMA + imazaquin (from 4 to 10 days) compared to the respective herbicides applied alone. There was no difference in turf injury from Fe when imazaquin at 1.3 kg·ha-1 was applied as a single treatment. However, turf treated with Fe and two applications of imazaquin (9- to 10-day interval) recovered from herbicide injury faster than when treated only with the herbicide. Iron did not prevent immediate 2,4-D + mecoprop + dicamba injury to the bermudagrass, but did hasten turf recovery from injury at 26 days after treatment. With a few exceptions, `Tifway' bermudagrass quality was higher and color improved when Fe was added. However, injury expressed as loss of shoot density was not affected by Fe and only injury expressed as color loss was improved by Fe. Chemical names used: 3,6-dichloro-2-methoxybenzoic acid (dicamba), 2-[4,5-dihydro-4-methyl)-4-(1-methylethyl)-5-oxo-1H-imidazol-2yl]-3-quinolinecarboxylic acid (imazaquin), (±)-2-(4-chloro-2-methylphenoxy)propanoic acid (mecoprop), 4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one (metribuzin), monosodium salt of MAA (MSMA), and (2,4-dichlorophenoxy)acetic acid (2,4-D).
Floral Lipoxygenase: Activity during Senescence and Inhibition by Phenidone
Authors: Peary James S. , Prince Timothy A.
Published: January 2019

Analysis of petal extracts from various species revealed a wide range of lipoxygenase (LOX) activity among sources. A large increase in LOX activity was observed during senescence in both gladiolus (Gladiolus × hortulanus Bailey) and carnation (Dianthus caryophyllus L.) petal tissue. The increase began before the first visible signs of senescence were evident and activity peaked at early to mid-senescence stages. LOX activity of petal extracts from gladiolus was inhibited in vitro by phenidone, a known LOX inhibitor.
Comparison of Extraction Methods for the Rapid Determination of Essential Oil Content and Composition of Basil
Authors: Charles Denys J. , Simon James E.
Published: January 2019

Essential oils were extracted from leaves, flowers, and stems of Ocimum basilicurn, O. kilimandscharicum, and O. micranthum by solvent extraction, hydrodistillation, and steam distillation for essential oil content and the oil analyzed by GC and GC/MS for composition. While the yield of essential oil was consistently higher from steam distillation than hydrodistillation, a similar number of compounds was recovered from both hydrodistillation and steam distillation. Though the relative concentration of the major constituents was similar by both methods, the absolute amounts were higher with steam distillation. Essential oil content and composition varied by plant species and plant part. Essential oil content was highest in flowers for O. basilicum and in leaves for O. micranthum. No significant differences were observed in essential oil yield and relative concentration of major constituents using fresh or dry samples and using samples from 75 g to 10 g of dry plant tissue. While minor differences between hydrodistillation and steam distillation were observed, both methods resulted in high yields and good recovery of essential oil constituents. Hydrodistillation is a more-rapid and simpler technique than steam and permits the extraction of essential oil where steam is not accessible.
Enhancement of Growth and Flowering of Triteleia laxa by Ethylene
Authors: Han Susan S. , Halevy Abraham H. , Sachs Roy M. , Reid Michael S.
Published: January 2019

Exposure of dormant corms of Triteleia laxa `Queen Fabiola' to 20 ppm C2H4 for 7 days promoted flowering of small corms and resulted in increased apical meristem size, early sprouting, early flowering, more flowers per Inflorescence, and increased fresh weight of daughter corms and cormels. The respiration rate of the C&treated corms increased to four to five times that of the controls during the 7-day treatment, declined markedly after termination of the C2H4 treatment, but remained higher than that of the controls. The C2H4 effects were associated with increased growth rate and consequently a greater final size of the apical meristem (determined by scanning electron microscopy). Leaves produced by C2H4-treated corms were wider, longer, and weighed more than those of the controls.
Unreduced Pollen in a Wild Tetraploid Relative of Sweetpotato
Authors: Jones Alfred
Published: January 2019

Nonreduction of pollen mother ceils was observed in a wild tetraploid morning-g&y related to the sweetpotato (Ipomoea batatas L. Lam.). Techniques for identifying and determining the frequency of expression of the trait are straightforward. Previous strategies for transfer of germplasm from tetraploid (2n = 4x = 60) species to the hexaploid (2n = 6x = 90) sweetpotato involved crosses with diploids (2n = 2x = 30) to obtain triploids that then were doubled to 6x. Nonreduction of pollen mother cells probably represents the natural mechanism for raising 4x to 6x since pollination of 2x ovules with unreduced pollen (4x) should give rise to 6x progeny without need for somatic doubling. Plants carrying this trait should be useful as bridging types for introgressing genes from wild 4x species into sweetpotato. A wide range in nonreduction (up to, 74%) was recovered In progeny of controlled crosses among selected plants, but data were not sufficient to estimate gene action.
Fruiting as a Factor in Accumulation of Carbohydrates and Nitrogen and in Fall Cold Hardening of Day-neutral Strawberry Roots
Authors: Gagnon Bernard , Desjardin Yves , Bédard Roger
Published: January 2019

Nitrogen and carbohydrate content of roots and the onset of crown cold hardiness were compared in `Tristar' day-neutral (DN) strawberries (Fragaria × ananassa Duch.) that were given various fruit removal treatments. Nontreated `Hecker' DN and `Redcoat' Junebearer were also used to determine genotypic variation. The removal of fruit after 15 or 30 Sept. promoted the accumulation of starch and increased cold tolerance of crowns as compared to fruiting plants. Nitrogen was increased only when fruit was removed after 15 Sept. DN cultivars were less hardy than Junebearing cultivars, but `Tristar' was almost as hardy as `Redcoat'. When compared to `Redcoat', DN cultivars had a less abrupt temperature-kill profile, perhaps because they were multicrowned.
Influence of Clonal Variation, Pruning Severity, and Cane Structure on Yield Component Development in `Cabernet Sauvignon' Grapevines
Authors: Bowed P.A. , Kliewer W.M.
Published: January 2019

Yield components responsible for yield variation within and among three `Cabernet Sauvignon' grape (Vitis vinifera L.) clones in a cane-pruned vineyard were determined over 2 years using a multivariate analysis procedure, two-dimensional partitioning (TDP). TDP analysis indicated that canes were producing at their capacity and yield per vine was limited by the number of canes retained. Yield per cane was limited by the portion of nodes at which shoots developed, and yield per shoot was limited by cluster number and fruit-set. The highest-yielding clone bore more fruit on non-cane shoots and fewer and larger clusters on cane shoots than the moderate-yielding clone. Poor fruit-set exhibited by the lowest-yielding clone resulted from inadequate or inviable pollen. In one year, thicker canes were more productive than thinner canes due to better bud burst and fruit set.