bluuebunny/crossref_metadata_2025 huggingface dataset:
Involvement of Gibberellins in Phytochrome-regulated Stem and Petiole Elongation in Watermelon Plants
Authors: Ranwala N.K.Damayanthi , Decoteau Dennis R.
Published: February 2019

Phytochrome-regulated stem and petiole elongation is of great horticultural importance due to their effects on height and compactness of plants. Although it is believed that phytochrome action during cell elongation is controlled via gibberellin (GA) biosynthesis, conclusive evidence has not been presented. In this study, watermelon plants pre-treated with GAs or GA biosynthesis inhibitors were briefly exposed to red (R) or far-red (FR) at the end of photoperiod to investigate the involvement of GAs in phytochrome-regulated stem and petiole elongation. Two-week-old watermelon plants were applied with either GAs, GA3 (25 ppm) or GA4+7 (25 ppm), or GA biosynthesis inhibitors, paclobutrazol (early stage inhibitor, 2 ppm) or prohexadione-Ca (late stage inhibitor, 200 ppm). Following chemical application, plants were treated with low-intensity R or FR light for 15 min at the end of photoperiod for 8 days. The increased petiole length and increased dry mass partitioned to petioles caused by FR were further increased when plants were pre-treated with GA3 and GA4+7, but reduced when plants were pre-treated with paclobutrazol or prohexadione-Ca. Pre-treatment with paclobutrazol or prohexadione-Ca further reduced the petiole length and dry mass partitioned to petioles caused by R alone, but effects of R were reversed when plants were pre-treated with GA3 and GA4+7. Petiole growth changes were significant after 2 to 3 days of treatments and there was no light or growth regulator effects on stem growth. Low leaf chlorophyll content and higher photosynthesis resulted in FR-treated plants were not observed when plants were pre-treated with paclobutrazol or prohexadione-Ca. Prohexadione-Ca was more effective in reversing FR induced petiole elongation than paclobutrazol, while GA4+7 was more effective than GA3 in promoting the effects of FR and reversing the effects of R. These results provide further evidence that phytochrome regulated growth changes in watermelon are due to the changes in GA biosynthesis. It is also suggestive that phytochrome has differential regulation of GA biosynthesis.
Genetic Analysis of Chinese Cucumber Collections in the U.S. National Germplasm Collection
Authors: Staub J. , Sequen Felix , Horejsi Tom , Chen Jin Feng
Published: February 2019

Genetic variation in cucumber accessions from China was assessed by examining variation at 21 polymorphic isozyme loci. Principal component analysis of allelic variation allowed for the depiction of two distinct groupings of Chinese accessions collected in 1994 and 1996 (67 accessions). Six isozyme loci (Gpi, Gr, Mdh-2, Mpi-2, Pep-gl, and Pep-la) were important in elucidating these major groups. These groupings were different from a single grouping of Chinese 146 accessions acquired before 1994. Allelic variation in Chinese accessions allowed for comparisons with other accessions in the U.S. National Plant Germplasm System (U.S. NPGS) collection grouped by continent and sub-continent. When Chinese accessions taken collectively were compared with an array of 853 C. sativus U.S. NPGS accessions examined previously, relationships differed between accessions grouped by country or subcontinent. Data indicate that acquisition of additional Chinese and Indian cucumber accessions would be strategically important for increasing genetic diversity in the U.S. NPGS cucumber collection.
Endo-β-mannanase Activity and Seed Germination of Thermosensitive Lettuce Genotype in Response to Temperature and Seed Priming
Authors: Nascimento Warley M. , Cantliffe Daniel J. , Huber Donald J.
Published: February 2019

Under high temperatures (above 30 °C) in the greenhouse (transplant industry) or field, lettuce germination can be erratic or completely inhibited. Seed priming circumvents thermodormancy of lettuce seeds and allows germination at higher temperatures. Weakening of the endosperm layer of lettuce seeds is a prerequisite to radicle protrusion at high temperatures. Enzyme-mediated degradation of endosperm cell walls may be a crucial factor for lettuce seed germination at high temperatures. Softening of the endosperm could occur during seed priming and result in improved germination. A single-seed assay for endo-β-mannanase was used to follow the activity of this enzyme during priming in lettuce seeds. We also investigated the effects of seed priming on seed germination and mannanase activity at both inhibitory and non-inhibitory temperatures for seed germination in a thermosensitive lettuce cultivar Dark Green Boston. Seeds were primed for 3 days at 15 °C with constant light in aerated solutions of polyethylene glycol (PEG) at an osmotic potential of –1.2 MPa. Afterward, seeds were rinsed and redried at 10 °C and 45% RH for 3 days. Primed and nonprimed seeds germinated 100% at 20 °C. At 35 °C, primed seeds germinated 100%, whereas nonprimed seeds did not germinate. During priming, endo-β-mannanase activity increased between 24 and 72 h after the beginning of osmotic imbibition. Mannanase activity persisted in primed seeds, even following seed drying. Radicle protrusion did not occur under the priming conditions used in this study. Higher enzyme activity was observed in primed seeds compared with nonprimed seeds. The results suggest that priming overcomes the inhibitory effect of high temperature in thermosensitive lettuce seeds by weakening of endosperm due to increased endo-β-mannanase activity.
Hydrophobic Particle Films Improve Tree Fruit Productivity
Authors: Glenn D.M. , Puterka G. , Baugher T. , Unruh T. , Drake S.
Published: February 2019

Hydrophobic particle film technology (HPF) is a developing pest control system for tree fruit production systems. Studies were established in Chile, and Washington, Pennsylvania, and West Virginia in the United States, to evaluate the effect of HPF technology on tree fruit yield and quality. Studies in Chile, Washington, and West Virginia demonstrated increased photosynthetic rate at the leaf level. Yield was increased in peaches (Chile) and apples (West Virginia), and fruit size was increased in apples (Washington and Pennsylvania). Increased red color in apple was demonstrated at all sites with reduced russetting and `Stayman' cracking in Pennsylvania. HPF technology appears to be an effective tool in reducing water and heat stress in tree fruit resulting in increased fruit quality.
Effects of Ammonium, Nitrate, and Zero Leachate on Poinsettia
Authors: Kuehny Jeff S. , Branch Patricia C. , Landry Felix J.
Published: February 2019

Nitrate nitrogen has been recommended as the best form of nitrogen for the production of poinsettia while ammonium and urea have been reported to be deleterious to poinsettia growth. Recent studies have indicated that lower nitrogen and leaching levels will produce quality poinsettias. Poinsettias were grown with 21–7–7 Acid Special (9.15% NH4, 11.85% urea), 20–10–20 Peat-lite Special (7.77% NH4, 12.23% NO3), 15-220 plus Ca and Mg (1.5% NH4, 12.7% NO3, 0.8% urea), and 15–5–15 Excel CalMag (1.2% NH4, 11.75% NO3, 2.05% urea) applied at 200 mg·L-1. Plants were fertigated by drip irrigation with zero leachate. There were no significant differences between fertilizer treatments for plant height, width, bloom diameter, and dry weight. Electrical conductivity and pH did vary significantly between treatments; however, this did not effect plant growth. Thus, by using lower nitrogen levels and zero leachate, quality poinsettias can be grown with commercial fertilizers high in ammonium/urea or high in nitrate nitrogen, or ammonium and nitrate in combination.
Sweet Corn Performance under Different Tillage Systems
Authors: Makus D.J.
Published: February 2019

The performance of two sweet corn (Zea mays var. saccharata) cultivars grown in the Rio Grande Valley in Spring 1997 were evaluated under three tillage practices. On 25 Apr. 1997, `Champ' and `Sensor' seeds were sown on 0.76-m row centers of 4.6 x 91-m (12 x 300-ft) plots which had been in continuous conventional (CT), minimum tillage (MT), and/or no tillage (NT) since Aug. 1994. All production inputs were similar except tillage practice. Ears were harvested beginning 16 Jun 1997. Cultivars differed in leaf greenness, plant stand (P < 0.11), ear diameter, length, and dry matter, percentage of total yield at first harvest, season yield, and ears/ha. `Sensor' ears had higher concentrations (dry-mass basis) of total N, K, S, NO3, and B, but lower concentrations of Mg (P < 0.06), Ca, Fe, and Mn than did `Champ'. Amaranthus spp. weed populations were higher in `Champ' then in `Sensor' tillage treatments. MT and CT resulted in greater ear attributes, yield, ears/ha, and less corn earworm damage, lower ear S concentrations, and fewer total weeds/ha than corn grown with NT. Plant stand was highest in CT plots. Weed populations of Panicum and Amaranthus spp., but not Texas tridens [Tridens texanus (S. Wats.) Nash] or common purslane (Portulaca oleracea L.), were higher in NT-grown corn than MT- or CT-grown corn.
Application Timing of Daminizide and Flurprimidol after Shearing Affects Growth and Flowering of Coreopsis verticillata `Moonbeam'
Authors: Kessler J. Raymond , Keever Gary J.
Published: February 2019

Vegetative cuttings of Coreopsis verticillata `Moonbeam' were rooted under intermittent mist, pinched, and potted into 10-cm pots in a greenhouse. Plants were sheared to 6.5 cm above the pot rim 2 weeks after potting and given foliar sprays of daminozide at 0, 2550, 5100, or 7650 mg·L-1 or flurprimidol at 0, 50, 100, or 150 mg·L-1. Night-break lighting to provide long photoperiods was started the day of shearing. Growth retardants were applied at 0, 3, 6, 9, 12, or 15 days after shearing. Daminozide reduced shoot height, growth index, and lateral shoot length compared to the control by 69.3%, 69.2%, and 70.0%, respectively, while increasing quality rating by 67.3% and time to flower by 8 days at 5100 and 7650 mg·L-1. Response surface regression predicted that minimum plant size and maximum quality rating occurred when growth retardants were applied 5.7 to 8.3 days after shearing. Application timing had no effect on responses to flurprimidol. Shoot height, growth index, and lateral shoot length decreased quadratically with increasing rate while quality rating only improved compared to control. Flurprimidol did not cause a flowering delay.
Shelf Life of Minimally Processed Watermelon
Authors: Perkins-Veazie P. , Collins J.K. , Baldwin E.
Published: February 2019

In the United States, as much as 10% of the watermelon sold is as a minimally processed product. These products are prepared at the retail level as cubed flesh in plastic food containers or as halved slices wrapped in plastic film. The shelf life of these products at different temperatures is not known. In this study, `Allsweet' and `Jubilee' ripe watermelons were washed, wiped with a 5% bleach solution, and cut into transverse slices using surface-sterilized knives. Halves of these slices were sprayed with distilled water (pH 7.0) or with Natureseal plus 5% ascorbic acid (pH 4.5), wrapped with plastic film (0.05-mm thickness), and stored at 2 and 5 °C for 4 to 6 days. Weight loss of wrapped slices was 0.1 % at 2 and 5 °C after 4 days of storage and 0.5% of slices sprayed with Natureseal. Watermelon flesh became slimy after 3 and 5 days of storage at 5 and 2 °C, respectively, especially in slices treated with Natureseal. Fruit rinds developed brown stains and became very soft. In a separate study, watermelon slices (flesh and rind) placed in jars at 10 °C lost the characteristic watermelon odor after 2 days and a more pumpkin-like odor developed. Respiration after 1 day at 10 °C was 6 to 8 mL CO2/kg-h and increased after 5 days of storage to 13 and 25 mL CO2/kg-h for `Allsweet' and `Jubilee', respectively. Ethylene production was 0.04 to 0.06 μL/kg-h after 1 day of storage, increasing to 0.55 μL/kg-h after 5 days of storage. Results indicate that cut watermelon should be held at temperatures of 2 °C or less for no more than 3 days.
Effects of Irrigation on Sweetpotato Yields
Authors: Simonne Eric , Bannon James , Ruf Marvin
Published: February 2019

Sweetpotato (Ipomea batatas L.) is a drought-tolerant crop mostly produced without irrigation. Consequently, sweetpotato may be exposed to temporary water stress. In 1997, an irrigation scheduling model using a water balance and class A pan evaporation (Ep) was evaluated with `Beauregard' on a loam sandy soil. The model was (12.7 DAT + 76) 0.5 ASW = DDAT-1 + [Ep (0.12 + 0.023 DAT – 0.00019 DAT2) – RDAT – IDAT], where DAT is days after transplanting (DAT = 0 on 20 June), ASW is available soil water (15%), D is soil water deficit (mm), R is rainfall (mm), and I is irrigation (mm). Root depth expanded at a rate of 13 mm/day to a maximum depth of 305 mm. Irrigation rates ranging between 0 and 145% of the model rate were created with sprinklers. The model scheduled 10 irrigations between DAT = 26 and 116 (harvest). Irrigation did not alter storage root quality, but did influence all the marketable grades (P < 0.01; R2 > 0.87). However, between 0 and 129% yield increases were linear and small, suggesting that the model overestimated sweetpotato water use. Thus, deficit irrigation between 50% to 70% of the model would have a limited effect on sweetpotato yields.
Morphological Development of the North American Pawpaw during Germination and Seedling Emergence
Authors: Finneseth Cynthia H. , Layne Desmond R. , Geneve Robert L.
Published: February 2019

The North American pawpaw [Asimina triloba (L.) Dunal], a temperate member of the Annonaceae, is a deciduous woody tree with ornamental value and has merit as a fruit crop. Anatomical studies of pawpaw seed revealed a small, linear embryo that does not change in length during cold or warm stratification. Radicle and cotyledon growth from planting until radicle protrusion was concurrent and at about the same rate. Cotyledons grew through a specialized channel of cells extending above the cotyledon tips, but never emerged from the seed. The extended period of time required for the development of the cotyledons delayed seedling emergence more than 50 days. The cotyledons appear to be haustorial and translocate storage material from the endosperm to the growing embryo. At the time of epicotyl elongation, the radicle and developing root system were well developed and comprised 81 % of the seedling biomass. Seedling development could be divided into four distinct stages, including radicle protrusion, hypocotyl emergence, epicotyl elongation, and seedcoat abscission.
The Use of Ground Covers during the Establishment of Heart-of-Palm Plantations in Hawaii
Authors: Clement Charles R. , DeFrank Joseph
Published: February 2019

Pejibaye (Bactris gasipaes Kunth) is being evaluated in Hawaii for production of fresh heart-of-palm. Yields and offshoot (sucker) production were evaluated in response to woven black polypropylene mat (control), three legumes [Arachis pintoi Krap. & Greg., Cassia rotundifolia Pers., and Desmodium heterocarpon (L.) DC], and a grass (Chloris gayana Kunth) used as ground covers. D. heterocarpon and C. gayana formed closed canopies quickly and controlled weeds well, but required more frequent mowing. A. pintoi formed a closed canopy slowly and only controlled weeds after forming a thick canopy, but required less mowing. Cassia rotundifolia died out after flowering and setting seed. All vegetative ground covers delayed heart-of-palm harvest and had reduced yields 1.5 years after planting. A combination of polypropylene (adjacent to plants) and vegetative ground covers (in service rows) may provide the best solution to minimizing labor for vegetative management in this orchard crop.
Responses of “Little Leaf” vs. Normal Cucumber to Planting Density and Chlorflurenol
Authors: Nerson Haim
Published: February 2019

Two field experiments were conducted in Bet Hashita (1992) and Newe Ya'ar (1993), Israel, in order to examine the possibility of using plant growth habit, chlorflurenol, and plant population density to concentrate yield of pickling cucumber (Cucumis sativus L.) under a simulated once-over mechanical harvest system. Two near-isogenic cucumber lines, WI 1983G normal and WI 1983G little leaf, were grown under three plant densities, 5, 10, and 20 plants/m2, and at flowering half of the plants were treated with 50 mg·L-1 chlorflurenol solution. The little leaf line produced a smaller canopy than the normal line under five plants/m2 but a larger canopy under 20 plants/m2. The average commercial yield of the little leaf line was higher than that of the normal leaf line by 28% and 55% in Bet Hashita and in Newe Ya'ar, respectively. The highest yield of each line was achieved under the highest plant density. The average commercial yields under 20 plants/m2 were 1.13 and 0.91 kg·m-2 in Bet Hashita and 1.86 and 0.92 kg·m-2 in Newe Ya'ar for little leaf and normal leaf, respectively. Chlorflurenol increased fruit number per unit area but did not increase yield. Nevertheless, it increased the proportion of small fruits, which are more valuable. The present study shows that the little leaf growth habit can increase the yield concentration in pickling cucumber and make this crop more suitable for a once-over mechanical harvest. Chemical name used: methyl-2-chloro-9-hydroxyfluorene-9-carboxylate (chlorflurenol).
Priming and Seed Orientation Affect Seedcoat Adherence and Seedling Development of Muskmelon Transplants
Authors: Nascimento Warley M. , West Sherlie H.
Published: February 2019

The effects of seed priming and seed orientation on seedcoat adherence and seedling development of containerized muskmelon transplants were investigated. Seeds of muskmelon `Top Net SR' were primed for 6 days in darkness at 25 °C in an aerated solution of KNO3 (0.35 M). Primed and nonprimed seeds were individually planted in Styrofoam trays in the greenhouse. Seeds were carefully oriented with the radicle down, up, or in the horizontal position, and covered with 0.5 cm of the growing mix. Seed priming and seed orientation affected both seedcoat adherence and seedling development, and interaction between priming and orientation was significant for seedcoat adherence. Our data indicate that seed priming can minimize seedcoat adherence during emergence of muskmelon seeds.
Susceptibility of Five Landscape Pines to Pitch Canker Disease, Caused by Fusarium subglutinans f. sp. pini
Authors: Gordon Thomas R. , Okamoto Dorothy , Storer Andrew J. , Wood David L.
Published: February 2019

Pitch canker, caused by Fusarium subglutinans f. sp. pini, causes branch dieback and stem cankers in many species of pine. Monterey pine (Pinus radiata D. Don), one of the most widely planted pines in the world, is extremely susceptible to pitch canker. Four other pine species, which might serve as alternatives to Monterey pine in landscape settings, were found to be relatively resistant, based on the size of lesions resulting from branch inoculations under greenhouse conditions. Of these species, Japanese black pine (P. thunbergiana Franco) was the most resistant, followed by Canary Island pine (P. canariensis Sweet ex K. Spreng), Italian stone pine (P. pinea L.), and Aleppo pine (P. halepensis Mill.). Consistent with these findings, a field survey conducted in Alameda County, Calif., revealed Monterey pine to have the highest incidence of infection, with significantly lower levels in Aleppo, Canary Island, and Italian stone pines. Japanese black pine was not observed in the survey area.
Plant Growth Regulators Reduce Postproduction Leaf Yellowing of Potted Asiflorum Lilies
Authors: Funnell Keith A. , Heins Royal D.
Published: February 2019

The postharvest quality of potted Asiflorum lily `Donau' (Lilium hybrid) was evaluated after plants were sprayed with 0, 50, 250, or 500 mg·L-1 (BA equivalent) of Promalin (GA4+7 to BA ratio was 1:1) or Accel (GA4+7 to BA ratio 1:10) and stored at 2 to 3 °C for 0, 10, or 20 days. As storage was prolonged, more leaves senesced once plants were removed for evaluation. Leaf senescence declined with increasing concentrations of either Promalin or Accel, but Promalin was more effective. Application of 250 mg·L-1 Promalin completely eliminated leaf senescence over the 20-day shelf-life evaluation period, irrespective of duration of cold storage. The treatments did not affect flower bud opening or plant height. Chemical names used: gibberellin (GA4+7); benzyladenine (BA).
Evaluation of the Natural Variability in Irone Content and Selection of Iris sp. for Perfume Production
Authors: Firmin Laurence , Courtois Didier , Pétiard Vincent , Ehret Charles , Lerch Konrad
Published: February 2019

Rhizomes of Iris species used for perfume production do not contain scented irones immediately after harvest, precluding early selection of potentially high-producing genotypes. A recently developed technique involving a bacterial treatment (Rahnella aquatilis Izard, Gavini, Trinel, and Leclerc) of fresh rhizomes shortened the maturation time from 3 years to a few days. Variability in irone content among freshly harvested Iris species (76 clones) was evaluated, and three high-producing clones of Iris pallida Lam. were selected. Significant variability among clones was observed for irone content, growth, and yield.
Mycorrhizal Infection and Plant Growth of Highbush Blueberry in Fumigated Soil Following Soil Amendment and Inoculation with Mycorrhizal Fungi
Authors: Yang Wei Qiang , Goulart Barbara L. , Demchak K.
Published: February 2019

A field trial was conducted to investigate the effectiveness of soil fumigation on maintaining nonmycorrhizal status and the effect of mycorrhizal inoculation and preplant soil amendment on the growth of tissue-cultured highbush blueberry plants. Soil fumigation using a methyl bromide/chloropicrin (67/33) mixture at the rate of 560 kg·ha-1 was effective in maintaining nonmycorrhizal status for one growing season. Noninoculated control plants became infected during the second growing season. Field inoculation using a native Oidiodendron maius was successful, but plant growth was not significantly affected by mycorrhizal inoculation in either year. Rotted sawdust amendment, however, reduced plant growth in the first year but effects were no longer measurable in the second year. Soil fumigation and field inoculation could be used to establish mycorrhizal plants and nonmycorrhizal controls for future short-term field experiments.
Establishment and Early Growth and Yield of `Gulfcoast' Southern Highbush Blueberry
Authors: Spiers James M.
Published: February 2019

In a field study, `Gulfcoast' southern highbush blueberry plants were subjected to irrigation [7.5 L (low) or 30 L per week (high)], mulching (none or 15 cm depth), row height (level or raised 15 cm), and soil-incorporated peatmoss (none or 15 L in each planting hole) treatments, in a factorial arrangement, at establishment. Plants were grown on a well-drained fine sandy loam soil that contained <1.0% organic matter. Plant volume and fruit yield were greater with mulching, high irrigation, incorporated peatmoss, and level beds. Plants grown with the combination of mulching, level beds, incorporated peatmoss, and high irrigation levels yielded 2.4 kg per plant or approximately eight times as much as plants grown without mulch, with raised beds, without peatmoss, and with the low rate of irrigation. Of the four establishment practices evaluated, mulching had the greatest influence on plant growth and fruiting.
Adjusting Growth Stage Values to Develop a Linear Scale for Apricot Flower Bud Phenology
Authors: Austin Paul T. , Hewett Errol W. , Noiton Dominique , Plummer Julie A.
Published: February 2019

Integer values used to represent apricot (Prunus armeniaca L.) flower bud growth stages in a phenological scale were adjusted by a simple technique based on cumulative counts of bud observations. Adjusted stage values on a new continuous scale were calculated so that differences between consecutive values were proportional to the frequency with which buds were observed in each growth stage class during the entire assessment period. This meant that adjusted scale values were linearly related to bud development rate at 20 °C. The method was applied to a scale describing flower development from budbreak to petal fall for three cultivars of apricot growing under orchard conditions.
Soluble Solids Concentrations in Pecan Liquid Endosperm of Several Pecan Clones
Authors: Thompson Tommy E.
Published: February 2019

Variability in soluble solids concentration (SSC, °Brix) in liquid endosperm (LE) among individual pecan [Carya illinoinensis (Wangenh.) K. Koch] fruits and among fruits from different trees and cultivars using a sugar refractometer was determined at College Station, Texas, in 1997. Repeatability of readings from LE from the same fruit was excellent. Fruits from the same tree did not vary for SSC, but significant differences among clones were common. Soluble solids concentration appears to decrease as the fruit matures. The SSC values for two full-sib clones (one susceptible to water split and one resistant to water split) were similar. This information discounts the possibility that high osmotic water potential gradients alone induce the water split phenomenon. A wide range of SSC percents was recorded. A low of 0.5% was recorded for LE from a `Houma' fruit, while 6.1% was recorded for LE from a fruit from a drought-stressed `Burkett' tree.
Spunbonded Rowcover and Calcium Fertilization Improve Quality and Yield in Bell Pepper
Authors: Alexander Shara E. , Clough George H.
Published: February 2019

A 2-year study was conducted in eastern Oregon to evaluate the effects of hooped spunbonded polypropylene rowcovers and Ca fertilization on yield and quality of drip-irrigated bell pepper (Capsicum annuum L. Grossum group) grown on black plastic mulch. The experiment was a complete factorial with four replications of two cultivars, covered and uncovered plots, and three levels of supplemental Ca fertilization at 0, 34, and 68 kg·ha-1 applied through the drip irrigation system as Ca(NO3)2. Rowcovers increased marketable yields both at the first harvest and over the season. Blossom-end rot and sunscald were reduced substantially by rowcovers; the effect was greatest during the earlier harvests. First-harvest and season total yield of fancy grade peppers increased linearly as rate of supplemental Ca increased, as did total marketable yield at the first harvest. Both yield of fruit with blossom-end rot and the percentage of fruit with blossom-end rot at the first harvest decreased as Ca rate increased. Yield of fruit affected by sunscald decreased linearly as supplemental Ca rate increased at the first harvest; overall, yield of sunscalded fruit was reduced by application of Ca at either rate.
Flowering of Phlox paniculata Is Influenced by Photoperiod and Cold Treatment
Authors: Runkle Erik S. , Heins Royal D. , Cameron Arthur C. , Carlson William H.
Published: February 2019

Phlox paniculata Lyon ex Pursh `Eva Cullum' plants were grown under seven photoperiods following 0 or 15 weeks of 5 °C to determine the effects of photoperiod and cold treatment on flowering. Photoperiods were a 9-hour day extended with incandescent lamps to 10, 12, 13, 14, 16, or 24 hours; an additional treatment was a 9-hour day with a 4-hour night interruption (NI). Noncooled plants remained vegetative under photoperiods ≤13 hours; as the photoperiod increased from 14 to 24 hours, flowering percentage increased from 20 to 89. Flowering of noncooled plants took 73 to 93 days. Flowering percentage was 19, 50, or 100 when cooled plants were held under photoperiods of 10, 12, or ≥13 hours or NI, respectively. Time to flower in cooled plants progressively decreased from 114 to 64 days as the photoperiod increased from 10 to 24 hours. Reproductive cooled plants had at least three times more flowers, were at least 50% taller, were more vigorous, and developed seven or eight more nodes than did noncooled plants. Photoperiod had no effect on height of flowering plants.
Growth Responses of Lolium perenne L. to Trinexapac-ethyl
Authors: Ervin E.H. , Koski A.J.
Published: February 2019

A growth chamber and a greenhouse study were conducted to determine if successive applications of trinexapac-ethyl (TE) to developing perennial ryegrass (Lolium perenne L.) plants would reduce leaf elongation rate (LER) while increasing tiller number and root mass. Growth parameters measured were LER, tiller number, and root mass. In the growth chamber, developing perennial ryegrass plants were sprayed twice with TE at 0.24 kg·ha-1 a.i. at 20 and 40 days after emergence. Leaf elongation rate was reduced by ≈35% following two applications of TE in both growth chamber experiments. This treatment increased the number of tillers per plant in the growth chamber at 60 days after emergence and in the greenhouse at 150 days after emergence, but had no effect on root or shoot mass in either location. Multiple applications of TE to developing perennial ryegrass turfs may favor quicker establishment in terms of tillering, while substantially reducing mowing requirement. Chemical names used: 4-cyclopropyl-α-hydroxy-methylene-3,5-dioxo-cyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl).
Comparison of Mean Scores and R-indices for Consumer Preferences of Apple Cultivars
Authors: Cliff M.A. , King M.C. , Hampson C.
Published: February 2019

Conventional (analysis of variance, mean preference scores) and novel (R-index) methodologies for hedonic assessments of `Silken' and `Creston' apple (Malus ×domestica Borkh.) cultivars from the breeding program at Summerland, B.C., were compared with the standard cultivars Royal Gala, Jonagold, and Golden Delicious. Visual and flavor preferences were evaluated for either three or five cultivars by panels of 50 to 200 consumers. Consumers were successfully able to evaluate five apple samples at a given session. Significant differences in mean preference scores and R-indices were found among cultivars. Both `Silken' and `Creston' had higher flavor and lower visual preference ratings than did `Royal Gala'. Results were consistent for both methodologies when panels consisted of 100 or more consumers. R-index, however, expressed the results as a probability rather than a mean score, and was a more understandable and interpretable measure of consumer preference than were preference ratings.
Responses of Broccoli Seedlings to Light Quality during Low-temperature Storage in Vitro: I. Morphology and Survival
Authors: Wilson Sandra B. , Iwabuchi Keiko , Rajapakse Nihal C. , Young Roy E.
Published: February 2019

Broccoli (Brassica oleracea L. Botrytis group `Green Duke') seeds were cultured in vitro photoautotrophically (without sugar in the medium) or photomixotrophically (with sugar in the medium) for 3 weeks at 23 °C and 150 μmol·m-2·s-1 photosynthetic photon flux (PPF). Vessels were then stored at 5 °C under 1.6, 4.1, or 8.6 μmol·m-2·s-1 of white (400-800 nm), red (600-700 nm), or blue (400-500 nm) light. Concentrations of CO2 inside the vessels were monitored until equilibrium was reached. Light compensation point was reached at 3.5 μmol·m-2·s-1 for photoautotrophic seedlings and at 6.5 μmol·m-2·s-1 for photomixotrophic seedlings. Therefore, in the long-term storage experiment, seedlings were stored for 4, 8, or 12 weeks at 5 °C in darkness or under 5 μmol·m-2·s-1 (average light compensation point) of white, red, or blue light. Illumination during storage was necessary to maintain dry mass, leaf area, and regrowth potentials of in vitro seedlings. All seedlings stored in darkness were of poor quality and died when transferred to the greenhouse. Red light during storage increased seedling dry mass and chlorophyll content and improved overall appearance, whereas blue light decreased chlorophyll content and increased stem elongation. The addition of 2% sucrose to media increased dry mass and leaf area and maintained overall seedling quality during illuminated storage. However, plantlets stored for more than 4 weeks did not survive poststorage greenhouse conditions, regardless of light treatment.
007 Yellow Nutsedge is Poor Competitor with Summer Squash
Authors: Porter W.C.
Published: February 2019

Yellow nutsedge (YNS) can be a serious problem where vegetables are grown on polyethylene mulch. YNS will rapidly cover the row and become a nuisance. This study was conducted to determine the effect of various population densities of YNS on the yield response of yellow squash grown on black polyethylene. Presprouted YNS tubers were planted at densities of 0, 10, 20, 40, and 50/m2 the day after `Superpik' yellow squash was planted. In 1996 the YNS did not produce tubers. Top growth increased up to 40/m2, but root growth increased to 50/m2. In 1997 top and root growth increased up to 20/m2. Tuber production increased up to 40/m2. In 1998 top, root, and tubers dry weight increased as the YNS density increased to 50 tubers/m2. There were no differences in weight of the squash plants or fruit yields any year. In experiments over three growing seasons, YNS at the densities tested did not interfere with the yield of yellow summer squash grown on black polyethylene mulch. The rapid growth of the squash and its dense canopy provide too much shade for the YNS to grow competitively. The yield of the YNS was greater in wet years than in dry years. The increased supply of YNS tubers could cause squash yield reductions in future plantings because of potential densities greater than those use in this study. YNS competition could also be a problem in rotational crops that are less competitive.
009 Annual Weed Chemical Control in Asparagus
Authors: López-Carvajal Arturo , Grijalva-Contreras R. Leonel , Navarro-Ainza Cristóbal , Martínez-Díaz Gerardo
Published: February 2019

Approximately 50% of the asparagus plantations (3000 ha) in the Caborca, Sonora, area is furrow-irrigated. Under these conditions it is common to observe growing weeds in the furrow section, which impede water flow and compete for resources with the asparagus plant, finally reducing spear production and quality. Hence, the objective of this study was to validate herbicides to achieve an efficient annual weed control in the asparagus plantations. The validation plot was established in May 1998 on a commercial asparagus plantation that was highly infested mostly with annual grasses (Echinochloa colonum and E. crusgalli), and Amaranthus spp. and Portulaca oleracea as a secondary weeds. The herbicides and rates tested were: Prometrine (2 L·ha-1), Norflurazon (4 kg), Metribuzin (0.5 kg), Linuron (2 kg), and the control plot (no herbicide application). All the tested products showed significant weed control percentages compared with the control plot. Norflurazon, however, was clearly superior to the other herbicides, exhibiting a 100% control for a period of almost 18 weeks. Metribuzin had a 85% control for 12 weeks. Linuron and Prometrine exhibited a 68% and 47% control, respectively, for up to 12 weeks. Plant toxicity symptoms on the asparagus plant were not observed with any of the tested herbicides.
012 Inhibition of Phytophthora megasperma in Coconut Coir-based Root Substrates
Authors: Evans Michael R. , Gaul Stephen B.
Published: February 2019

Glycine max (soybean) seed were sown in root substrates composed of 80:0:20 or 0:80:20 coconut coir dust (coir):Sphagnum peat (peat):perlite (v/v) amended with dolomitic limestone to a pH of 5.5. Substrates were inoculated with Phytophthora megasperma races 5 and 25 isolated from soybean and grown in dilute liquid V-8 cultures. Uninoculated controls were included. Containers were watered daily to maintain moisture levels at or near container capacity. The experiment was repeated twice. Plants grown in peat-based root substrates inoculated with P. megasperma suffered 50% to 100% mortality. No plants in coir-based root substrates displayed visually apparent infection symptoms. Soybean seed were also sown in root substrates that contained 0:80:20, 20:60:20, 40:40:20, 60:20:20 or 80:0:20 coir:peat:perlite (v/v). Inoculum of P. megasperma races 1, 5, and 25 was grown on water agar and diluted in deionized water. Solution containing 20,000 colony-forming units (oospores) was mixed into the root substrate of each container. Uninoculated controls were included. As the proportion of coir in the substrate increased, the mortality, the number of plants displaying disease symptoms and the severity of disease symptoms decreased. Plants grown in substrates containing at least 60% coir displayed no visually evident disease symptoms.
029 Performance of Short-vined Tropical Pumpkins Derived from Temperate × Tropical Crosses
Authors: Flores Luisa , Wessel-Beaver Linda , Carle R. Bruce , Maynard Donald N.
Published: February 2019

A joint breeding effort of the Universities of Puerto Rico and Florida involves the development of short-vined tropical pumpkin (Cucurbita moschata) genotypes that are able to reach maturity earlier than traditional long-vined types. Sixteen promising hybrids and inbreds were planted in Lajas, Puerto Rico, in June 1998. Pedigrees of this material included traditional tropical genotypes crossed with bush or compact temperate genotypes. Anthesis in both pistillate and staminate flowers occurred on average 49 days after planting. However, the variability of flowering dates among genotypes was far greater for pistillate (40 to 60 days) than staminate (46 to 54 days) flowers. Hybrids flowered earlier than inbred lines. Female flowers opened before male flowers in many genotypes. It seems likely that an inadequate source of pollen contributed to the low yields of some of the earliest genotypes. The five highest-yielding genotypes had pistillate flowers that opened after their male counterparts. All plots were once-over harvested 86 days after planting. Average yield per plant varied from 1.4 to 6.0 kg. Average fruit weight varied from 0.8 to 3.1 kg. High-yielding genotypes tended to have the highest fruit weight, a factor that should be considered when breeding for the next generation of short-vined genotypes. Yields were less than what could be expected from a long-vined tropical pumpkin. However, this yield could be obtained with a once-over harvest at about 90 days, compared to multiple harvests beginning at 120 days, saving costs of additional field practices, and allowing the land to be used for other purposes.
030 Yield Evaluation of the Cucumber Germplasm Collection
Authors: Shetty Nischit V. , Wehner Todd C.
Published: February 2019

Yield was evaluated in 817 plant introduction accessions of cucumber (Cucumis sativus L.) along with 19 check cultivars. The study was conducted in spring and summer seasons of 1997 and 1998 with three replications using recommended horticultural practices and optimized field plot trials. In order to get fruit from each cultigen regardless of sex expression, plants were sprayed with ethrel (2-chloroethyl phosphonic acid) to make them gynoecious. Plots were harvested once-over when 10% of the fruit in a plot were oversize. Data were collected on fruit weight (total, marketable, early and cull), fruit number (total, marketable, early and cull), fruit type, fruit quality, and days to harvest. Total fruit weight for all cultigens ranged from 4 to 214 Mg/ha, with 1 to 40 fruit per plot. Based on statistical analysis, fruit number was the most useful trait for yield evaluation. Stand corrections for yield were not found to be useful. The cultigens with the highest fruit numbers for pickling type were PI 215589, PI 179678, PI 249561, PI 356809, and PI 370643. Highest fruit number for slicing type were PI 344440, PI 422199, and PI 342951. Highest fruit number for middle-eastern type were PI 525150, PI 525153, PI 181910, and PI 534540. Highest fruit number for Oriental trellis type were PI 432849, PI 432866, PI 508455, PI 372893, and PI 532520. Several cultigens produced more than the check cultivars. High-yielding cultigens could be used in breeding programs to improve the yield of cucumber.
038 Characterization of an Architectural Mutant of Bean (Phaseolus vulgaris L.)
Authors: Guner N. , Myers J.R.
Published: February 2019

Genetic and morphological characteristics of an architectural mutant in common beans were studied. The mutant had shiny, dark green leaves, overlapping leaflets, short petioles and a terminal reproductive bud even though the line did not carry the fin gene. Branching was nearly absent, resulting in a single stem vine. This is a new form of determinancy in common bean. Inheritance studies demonstrated that the mutant trait was controlled by a single recessive gene. Allelism tests were performed between the mutant and a previously reported similar mutants, which were overlapping leaflets mutant (ol), and dark green savoy leaf mutant (dgs). Results showed that the mutant trait was not allelic to ol and dgs. As a temporary designation, the name “”opiary” describing its compact and neat appearance is being used. Linkage was tested for growth habit (fin), shiny leaf, cross-sectional shape of pods, striped pod (prpst) and pod suture strings (st) with the topiary mutant. No linkages were detected between either the mutant and marker genes or among the marker genes. The topiary mutant has potential for improving common beans. Its single stem growth habit may allow closer row spacing leading to higher planting populations and may enhance the efficiency of mechanical harvest. Pod formation at higher nodes may escape disease. Currently, the thin stems cause lodging. Development of thick and upright forms will be the subject of future studies.
039 The Blotchy Gene, bl, is Linked to the R and Y Loci in Table Beet
Authors: Goldman I.L. , Austin Diane
Published: February 2019

The primary pigments in red beet are the betalains, which are comprised of the red-violet betacyanins and the yellow betaxanthins. Modification of betalain content and distribution in table beet has been practiced by breeders for many years, although little is known about the genetic control of these traits. The presence of dominant alleles at two linked loci (R and Y) condition production of betalain pigment in the beet plant. Red-pigmented roots are observed only in the presence of dominant alleles at the R and Y loci, while white roots are conditioned by recessive alleles at both loci and yellow roots by the genotype rrY-. A newly described gene, `blotchy' (bl), conditions a blotchy or irregular pigment patterning in either red or yellow roots. The objective of this investigation was to characterize the linkage relationships between the R and Y loci and the bl gene by evaluating segregating progenies developed from a series of matings of colored and white table beets. Segregation data indicate the bl gene is independent from R and Y and that this locus is linked to R and Y. The two-point linkage estimate between the R and Y loci pooled over eight crosses was 7.4 (1.7 cM) Linkage between R and Bl was estimated from a pooled sample of four crosses at 16.7 (10.8 cM). The most likely gene order was R-Y-Bl. These data suggest the RYBl genomic region plays a critical role in the genetic control of betalain biosynthesis in table beet.
042 Identification of High-yielding Grain Amaranth (Amaranthus spp.) Cultivars
Authors: Makinde Margaret J. , Olufolaji Adenike O.
Published: February 2019

Having established that the white-seeded amaranth (grain amaranth) can supply both green leaves and seeds (grains) for the Nigerian consumers, there was a need to find cultivars that could yield enough grains to be profitable for an amaranth farmer. Several lines (>100) were screened, with the opaque and creamy-colored seed as the ultimate target. These cultivars, NHAm 261-1 and NHAm258, were selected for yield trials. It was possible to have a high seed rate of 100 plants/m2, and thinning to 22 plants/m2 at the end of 6 weeks. These 22 plants were left to mature, and a maximum of 20 plants/m 2 were evaluated for grain yield. These two cultivars were found to give good fresh shoot yields as well as capacity for up to 3000/m2.
046 Intra-specific Variability of Feverfew: Correlation Between Parthenolide, Morphological Traits, and Seed Origin
Authors: Cutlan Alison R. , Erwin John E. , Simon James E.
Published: February 2019

Parthenolide, a biologically active sesquiterpene lactone found in feverfew [Tanacetum parthenium (L.) Schultz. Bip.], has been indirectly linked to the antimigraine action of feverfew preparations. Commercial products of feverfew leaves vary widely in parthenolide content (0-1.0%/g dwt). No comprehensive studies have quantified parthenolide variation among feverfew populations or cultivars, and whether morphological traits are correlated with this natural product. In this study, 30 feverfew accessions were examined for parthenolide content, morphological traits, and seed origin. Statistically significant differences in parthenolide levels were found among the populations studied. Parthenolide content ranged from (0.012% ± 0.017 to 2.0% ± 0.97 /g dwt) as determined by HPLC-UV-MS. Higher parthenolide levels tended to be in wild material (0.41% ± 0.27) as opposed to cultivated material (0.19% ± 0.09). Parthenolide levels correlated with flower morphology: disc flower (0.49% = B1 0.36), semi-double (0.38% ± 0.13), double (0.29% ± 0.16), and pompon-like flower (0.22 ± 0.14). Leaf color also appeared to be indicative of parthenolide levels, with the light-green/golden leafed accessions showing significantly higher parthenolide content than darker-leafed varieties, but whether this was due to inadvertent original selection of a high parthenolide-containing golden leaf selection is not yet known. This study does show that further selection for improved horticultural attributes and natural product content is promising to improve feverfew lines for the botanical/ medicinal plant industry.
059 Performance of `Guardian' Peach Rootstock Selections in Alabama
Authors: Ebel Robert C. , Wilkins Bryan , Himelrick David , Beckman Tom , Nyczepir Andy , Pitts Jim
Published: February 2019

Twelve peach rootstocks including `Lovell', `Nemaguard', `Flordaguard', `14DR51', five `Guardian' (BY520-9) selections, and three BY520-8 selections, were evaluated under field conditions to determine their effect on performance of `Cresthaven' peach. The trees were planted in 1994. Trunk cross-sectional area of BY520-8 selections SL1923 and SL4028 was 28% larger than the rest of the rootstocks, which were similar. There was no crop in 1996 due to late spring frost. Yield in 1997 and 1998 was higher for SL1923 because of higher cropload than the rest of the rootstocks, which were similar. Yield efficiency varied across years and rootstocks. Fruit weight varied among rootstocks but all were commercially acceptable. Harvest date was advanced by two days for some rootstocks compared to Lovell and none were delayed. Percent red blush, soluble solids and firmness varied among rootstocks, but none demonstrated superior quality in all of these parameters as compared to Lovell. Ring nematode population densities were above the threshhold considered to be critical for onset of PTSL for all rootstocks in 1997 and 1998. Tree survival was at or above 86% for all rootstocks and death was not correlated with ring nematode density No trees developed symptoms characteristic of Peach Tree Short Life disease complex. Guardian selections performed adequately compared to the commonly used commercial rootstocks in this study, however, the yield date are from 2 years only.