bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Strawberry F. chilocnsis and F. ×ananassa in Response to Water Stress: I. Leaf Water Potential, Relative Water Content, and Gas Exchange Characteristics
Authors: Chen Chuhe , Cameron J. Scott , Klauer Stephen F.
Published: February 2019

Leaf water potential (LWP), relative water content (RWC), gas exchange characteristics, and specific leaf weight (SLW) were measured six hours before, during, and after water stress treatment in F. chiloensis and F. ×ananassa grown in growth chambers. The leaves of both species showed significantly lower LWP and RWC as water stress developed. F. ×ananassa had consistency lower LWP under stressed and nonstressed conditions than F. chiloensis. F. ×ananassa had higher RWC under nonstressed conditions, and its RWC decreased more rapidly under water stress than F. chiloensis. In comparison to F. ×ananassa, F. chiloensis had significantly higher CO2 assimilation rate (A), leaf conductance (LC), and SLW, but not transpiration rate (Tr), under stressed and nonstressed conditions. LC was the most sensitive gas exchange characteristic to water stress and decreased first. Later, A and stomatal conductance were reduced under more severe water stress. A very high level of Tr was detected in F. ×ananassa under the most severe water stress and did not regain after stress recovery, suggesting a permanent damage to leaf. The Tr of F. chiloensis was affected less by water stress. Severe water stress resulted in higher SLW of both species.
Seedling Selection in Pomegranate (Punica granaturn)
Authors: Shi Peng
Published: February 2019

Seedling selections in pomegranates began in 1986. `Giant Green Sweet' (GGS) was used as the female parent. GGS was characterized by fruit size from 340 to 500 g, a green color with slight blush, thin fruit coat, hexalobate calyx, and semi-open ovary with 8 to 12 loculi. The seeds are red, abundant, juicy, and sweet. The seeds contain 15% to 16% soluble solids. The male, pollinating cultivars in the same garden were `Giant Red Sweet', `Giant Horse Teeth', `White Sweet', `Red Sour', `Bing Tang Zi', and `Qing Gang Liu'. Seeds were harvested from fruit that were open-pollinated and weighed 500 g. Seeds were germinated and planted at the end of March. One-year-old seedlings grew to 30 to 50 cm. Two-year-old seedlings grew to 1 to 1.5 m tall with many branches. Seedlings passed the juvenile period after 3 years of growth. Some seedlings blossomed, and a few blossoms developed into fruit. Seedlings were adult by the fourth year, and all of them blossomed and developed fruit. This is a shorter interval to maturation than the parent cultivars. Fruits were located from the lower middle of the tree crown to the top. Adult seedlings produced fruit of ≈400 g with a few seedlings producing fruits of 500 to 600 g. There were 400 to 500 seeds per fruit averaging 40 g per 100 seeds. Seeds from the offspring were bright red and larger than those of the female parent. Fruit flavor was similar to the female parent. Offspring were more cold hardy than the parent cultivars. There were no signs of cold injury in hybrid seedlings to –19°C. This study indicates that seedling selection in pomegranates has a high potential to create higher yield and quality pomegranates. Continuing experiments will reselect the best offspring to develop higher quality cultivars.
Fertilizer, Irrigation, and Root Ball Slicing Affects Shrub Growth after Planting
Authors: Gilman Edward F. , Yeager Thomas H. , Weigle Diane
Published: February 2019

Dwarf burford holly (Ilex cornuta `Burfordii Nana') fertilized with N at 22.1 g per container yearly during production in the nursery generated more new shoot weight but less root weight after transplanting to a landscape than those receiving N at 14.8 g per container yearly. Slicing the root ball at planting, compared to not slicing, resulted in comparable regenerated root weight but reduced new shoot number, new shoot dry weight, and new shoot:regenerated root dry-weight ratio when irrigation was not applied daily after transplanting. Although irrigation frequency did not impact total weight of regenerated roots into landscape soil, more roots grew from the bottom half of the root ball when plants were irrigated periodically after planting than when plants received daily irrigation. Plants irrigated other than daily produced fewer shoots and less shoot weight than those receiving irrigation daily after transplanting. When plants were without irrigation for 4 or 6 days in the first week after transplanting, those planted without the nursery container on the root ball were more stressed (more negative xylem potential) than those planted with the container still on the root ball. However, 2 weeks later, plants without the nursery container were less stressed due to root growth into landscape soil.
Effect of Hole Size, Organic Amendments, and Surface Mulches on Tree Establishment in Southwestern Soils
Authors: Tipton Jimmy L. , Davison Elizabeth , Barba Juan
Published: February 2019

Southern live oak (Quercus virginiana), and South American mesquite (Prosopis alba) were planted in a shallow soil (≈15 cm deep) underlain by indurated calcium carbonate in Tucson, Ariz. Oaks were planted in three hole sizes, with backfill amended or unamended with undigested wood material and with or without 9 cm of an organic surface mulch. The surface mulch was a blend of undigested wood material and yard waste compost. Initial oak trunk diameters were ≈2 cm. Mesquites were planted according to these treatments: 1) a hole 150 cm square with amended backfill, 2) a hole twice as wide and 30 cm deeper than the root ball with amended backfill, and 3) a hole five times as wide and no deeper than the root ball with unamended backfill. Initial mesquite trunk diameters were ≈4 cm. Sixteen (oaks) and 28 (mesquites) months after planting soil was removed from the planting holes by a sewage vacuum truck. We will report the effect of treatments on trunk and canopy growth, and root growth from the side and beneath the original root ball.
NH4+:NO3− Optimization for Hydroponic Rice Culture in a Controlled Ecological Life-support System
Authors: Goldman K.R. , Mitchell C.A.
Published: February 2019

Mineral resources will be recycled in a controlled ecological life-support system (CELSS) deployed in space. N typically is supplied to crops as or mixtures. In a CELSS, will be abundant, but nitrification will require energetically costly chemical or biological oxidization. Rice is tolerant of and preferentially absorbs if provided a 1 : 1 ratio in hydroponics. Hybrid rice absorbs more N as than does inbred rice. To determine how much and in what proportion to rice will tolerate and how varying N sources will affect grain yield, semi-dwarf hybrid rice cultivar `Ai-Nan-Tsao' was grown hydroponically in a growth chamber. Nutrient solutions supplied 5 mm N as 40%, 60%, or 80% , the remainder as . Periodic analysis of solutions tracked mineral uptake, and solutions were modified to maintain proper concentrations. Treatment stands were harvested 84 to 86 DAP. Across all treatments, yield characteristics were similar but were highest for the border plants, presumably due to greater light absorption. Yield-efficiency rate (YER: grams of grain·per cubed meter per day·[grams inedible shoot biomass]) was 0.09 for all treatments (border) and ranged from 0.03 to 0.05 (interior), Harvest index ranged from 0.28 to 0.30 (border) and 0.26 to 0.39 (interior). Edible yield rate (EYR: grams of grain per cubed meter per day) ranged from 20.97 to 26.45 (border) and 8.52 to 14.96 (interior). The sector provided with 80% had the highest YER, HI (interior), and EYR (interior), indicating that rice productivity was not limited by high percentages of N supplied as . Supported by NASA grant NAGW-2329.
The Effect of School Gardens on Self-Esteem, Interpersonal Relationships, Attitude toward School, and Environmental Attitude in Populations of Children
Authors: Waliczek Tina M. , Zajicek J.M.
Published: February 2019

Children develop their personalities and attitudes at an early age. With children spending 25% of each day in the classroom, schools are a major influence on self-esteem, interpersonal relationships, and environmental attitudes. Studies in human issues in horticulture have focused on how gardens affect self-esteem in nontraditional populations but have yet to research children in mainstream school districts. Our main goal was to initiate and integrate an environmental education garden program into the curriculum of several schools in the midwest and Texas. Our objectives included evaluating whether the students participating in the garden program were receiving various emotional, physical, and psychological benefits and whether they were developing positive environmental attitudes as a result of participation in the garden program. The garden program, titled “The Green Classroom,” was designed to provide third-through eighth-grade teachers some basic garden activities that could be infused into their classroom lessons and would serve to reinforce curriculum in various disciplines with hands-on activities. Eight schools, ≈1000 students, took part in the study. Students participating in this study were administered a pretest before participation in the garden program and an identical posttest after its completion. The questionnaire included a psychological inventory, an environmental attitude survey, and a short biographical information section. Comparisons were made between children based on age, ethnic background, gender, and length of garden season. Results examine the relationship between the garden program and self-esteem, interpersonal relationships, attitude toward school, and environmental attitudes of children.
Effects of the Master Gardener Program on the Self-development of Female Inmates of a Federal Prison Camp
Authors: Migura Melanie M. , Zajicek J.M. , Whittlesey L.A.
Published: February 2019

More than one million people were incarcerated in U.S. prisons at the end of June 1995. Increasing emphasis has been placed on inmate rehabilitation with society's realization that 95% of those incarcerated will be released from prison and returned to society. The responsibility of undertaking the rehabilitation process lies in part with vocational programs, one of which is horticulture. In addition to developing job skills, horticulture may provide another viable means of rehabilitation in the form of horticultural therapy. The women's Federal Prison Camp in Bryan, Texas, implemented the Master Gardener program as part of its vocational training program in March 1991. The prison's Master Gardener program is sponsored by the Texas Agricultural Extension Service and constitutes a horticultural therapy program. More than 225 inmates have completed the program; however, the effectiveness in inmate rehabilitation brought about by such programs has not been extensively documented. Consequently, our objectives were to determine the effects of participation in the Master Gardener program on the locus of control, self-esteem, and life satisfaction of female inmates. About 80 inmates were administered a pretest before the Master Gardener program and an identical posttest at its conclusion. The 55-item questionnaire included a biographical section, a locus of control inventory, a self-esteem inventory, and a life satisfaction inventory. Data were analyzed using the Statistical Package for the Social Sciences. Results examine the relationship between the Master Gardener program and the psychological well-being of the female inmates at the Federal Prison Camp in Bryan, Texas.
Effects of Cover Crops and Tillage on Production and Nitrogen Nutrition of Watermelon
Authors: Silvernail Anthony F. , Cline Gary R.
Published: February 2019

Effects of tillage, winter cover crops, and inorganic N fertilization on watermelon production were examined in a split-plot factorial experiment. Main plots received tillage or no tillage, whereas cover crops consisted of hairy vetch, winter rye, or a mix. Nitrogen treatments consisted of plus or minus addition of ammonium nitrate. Following melons not receiving inorganic N, vetch produced cover crop total N yields of ≈130 kg·ha–1, which were four times greater than those obtained with rye. Melon yields and foliar N concentrations obtained without inorganic N fertilization following vetch were similar to those obtained with N fertilization following rye. Available soil N in vetch treatments remained significantly (P < 0.05) higher than in rye treatments for ≈70 days after melon planting and was greater in tilled treatments. Tillage significantly (P < 0.05) reduced melon yields by 20% and also reduced soil temperatures compared with no-till treatments. We conclude that N fixed by vetch could sustain watermelon production and no tillage may be useful when soil erosion is a problem.
Screening Malus Germplasm for Field Resistance to Apple Replant Disease and Root-lesion Nematodes
Authors: Isutsa D.K. , Merwin I.A. , Brodie B.B.
Published: February 2019

Apple replant disease (ARD) is a serious problem in fruit production, and none of the major clonal rootstocks are resistant to ARD. We have screened Malus domestica clones and species accessions from the USDA Malus Germplasm Repository at Geneva, N.Y., including M. angustifolia-2375.03 (MA), M. coronaria-2966.01 (MC), M. fusca-3031.01 (MF), M. ioensis-3059.01 (MI), M. sieversii-3530.01 (MS), and M. kirghisorum-3578.01 (MK), for resistance to ARD and root-lesion nematodes (RLN, Pratylenchus spp.), in a composite soil collected from 11 New York orchards with known ARD. Plant dry mass and height, root necrosis, and nematode populations in different apple species and clones were compared after 60 days growth in steam-pasteurized (PS), RLN-inoculated (IS), and naturally infested field (FS) soils with 1200 RLN per 100 cm3. More severe stunting, reduced plant dry mass, and root necrosis occurred in FS seedlings compared with those in PS, but M. angustifolia seedlings were substantially more resistant or tolerant to RLN and ARD than the other species tested. Plant dry mass ranked MK>MS>MA>MI>MF>MC, and these differences were significant at the 5% level. RLN root populations were negatively correlated with plant dry mass, and accounted for about 10% of its variation, with nematode populations in roots ranking MC>MF>MK>MI>MS>MA. Useful resistance to ARD and parasitic nematodes apparently exists within Malus germplasm collections, and can be identified by testing more genotypes, developing rapid resistance screening methods, and comparing RLN host preferences among Malus genotypes and various orchard cover crops.
Taxonomic Relationships in Rubus based on RAPD and Hybridization Analysis
Authors: Pamfil Doru , Zimmerman R.H. , Naess S.K. , Swartz H.J.
Published: February 2019

RAPD analysis was performed on 44 species of Rubus. These species included representatives from seven of the 12 subgenera within the genus and several series within the Idaeobatus (raspberries) and Eubatus (blackberries) subgenera. For all species, up to five plants were initially analyzed by two 10-mer primers. The most heterozygous of these individuals was then analyzed using 13 additional primers. Wide band diversity exists among Rubus species; these differences were analyzed using the PHYLIP software program. These differences are repeatable, for example color sports of `Heritage' red raspberry produced identical banding patterns. The genetic similarity between eastern United States blackberries (Eubatus) and numerous species was compared to the ability of these same species to act as a suitable pollen parent for eastern blackberries. These data were used to construct a dendrogram of the subgenera studied here.
Identification of Raspberry–Blackberry Hybrid Seedlings by Isozyme Staining and Soluble Protein Banding Patterns
Authors: Lopez-Medina Jose , Murphy B.J. , Moore J.N.
Published: February 2019

Isozyme staining and SDS-PAGE of soluble proteins were performed using leaf homogenates from 6- to 8-month-old field-grown seedlings resulting from the cross of either `Heritage' or `Nova' raspberry with ARK-577 diploid blackberry, the latter used as the pollen-donor parent. Four enzyme systems were tested: ADH, PGM, MDH, and PGI. Of these, ADH and PGM did not show any activity; MDH was monomorphic in both raspberry and blackberry parents, with activity at the same migration distance. PGI was polymorphic in the two raspberry cultivars, showing three dimeric bands, but monomorphic in blackberry; the allele for PGI in blackberry being common to that allele coding for the most cathodal band in raspberry. This phenomenon, in addition to poor resolution of bands (due, perhaps to low enzyme activity) and evidence of accidental self-pollination in our populations, prevented us from positively identifying the hybrid offspring using isozymes. By SDS-PAGE of soluble proteins, two bands were detected that seemed to be unique to ARK-577 blackberry and were also expressed in some of the offspring, suggesting a hybrid origin of these seedlings. Morphological comparisons indicated that those seedlings possessing the two unique bands highly resemble the blackberry male parent, greatly supporting their hybrid origin. Unless additional analysis shows otherwise, SDS-PAGE can be used to identify Raspberry–Blackberry hybrids during their vegetative stage of development, and might prove applicable to other interspecific hybrids of Rubus.
Yield, Viral Reaction, and Plant Characteristics of Summer Squash Lines and Hybrids
Authors: Ramirez-Reyes Francisco , Garza-Ortega Sergio
Published: February 2019

Culture of the Gray Zucchini (GZ) variety of summer squash in northwestern Mexico during the fall is severely affected by a viral disease, which is apparently caused by squash leaf curl virus (SLQV). Resistance to this disease was introduced from local Cucurbita moschata landraces and uniform GZ-type lines and hybrids (GZLH) were developed. Crosses between lines were performed during Spring 1995. In the Fall, 21 GZLH plus the commercial materials PSR-59792, Raven, and GZ (usually included as a control) were studied. The commercial materials showed a higher degree of virus infection than GZLH. Four of the materials that showed symptoms of virus infection and one free of symptoms were tested for SLCV and all were positive for this virus. Eight GZLH had higher overall and 1× yields than GZ and nine and four GZLH were better than GZ for 2× and 3× yields, respectively. Number of stems varied from one to seven and stem and internode length had values from 42 to 145 cm and from 1.2 to 4.8 cm, respectively. These results were consistent with other similar studies previously reported.
Breeding for Root-knot Nematode Resistance in Cucumber
Authors: Walters S. Alan , Wehner Todd C.
Published: February 2019

Root-knot caused by Meloidogyne spp. is the primary disease of cucumber (Cucumis sativus L.) in North Carolina, causing an annual yield loss of approximately 12 %. All cucumber cultivars we have tested are resistant to M. hapla, but none are resistant to any of the four important nematodes found on cucumber in North Carolina: M. incognita, M. arenaria races 1 and 2, and M. javanica. However, we are preparing to release three cucumber inbreds with resistance to four out of five of those nematodes. `Marion' (NC-44), `Shelby' (NC-45), and `Lucia' (NC-46) are high yielding, monoecious pickling cucumber inbreds that have resistance to M. arenaria races 1 and 2, M. javanica, and M. hapla. Length: diameter ratio was 3.4, 3.0, 3.9 for `Marion', `Shelby', `Lucia' (`Calypso' was 2.9 in the same trial), respectively. Thus, different length requirements for the pickling industry can be met with the three cultivars. Based on the 1995 North Carolina stage 1 pickle trial, performance (as % of `Calypso') for `Marion', `Shelby', and `Lucia' respectively was 79%, 94%, and 115% for total fruit number/ha; 71%, 96%, and 113% for marketable fruit number/ha; and 102%, 84%, and 97% for fruit quality rating. Therefore, nematode resistant cultivars are available that match the performance of the gynoecious hybrid check cultivar for the region.
Rhododendron Root Rot Resistance
Authors: Krebs S.L.
Published: February 2019

Root rot caused by the soil-borne pathogen Phytophthora cinnamomi is one of the deadliest and most costly diseases in rhododendron culture. Unfortunately, the majority of cultivars appear to be susceptible to this fungus. Host resistance does occur, but it represents a tolerance of rather than immunity from the disease. A breeding program has been initiated to develop a broader array of root rot resistant cultivars and to determine the genetic basis for resistance. Greenhouse inoculations and screenings of 48 contemporary cultivars yielded seven clones with moderate to high levels of resistance to P. cinnamomi. Protocols for evaluation at the seedling stage were developed in order to screen large breeding populations of about 200 seedlings per cross. Root rot tolerance appears to have low-moderate heritability in these rhododendron populations. Groups of progeny with one resistant parent had a slower mortality rate and higher survivorship (avg. 10%) after 2 months of disease pressure than crosses in which both parents were susceptible (0 survivorship). A recurrent selection strategy is planned to increase the frequency of alleles for resistance in breeding populations of rhododendrons.
Performance of Virus-free and Virus-infected Plants of Mashua (Tropaeolum tuberosum, Ruiz & Pavon)
Authors: Soria S. , Taboada C. , Rojas R. , Evans T. , Damsteegt V. D. , Kitto S.
Published: February 2019

Mashua, closely related to the garden nasturtium, has been cultivated by people of the Andean highlands since Incan time; however, it is disappearing from Ecuadorean markets due to decreasing yields. The main objectives of this research were to compare 1) in vitro proliferation and rooting, and reestablishment, and 2) field plant qualities such as vigor and yield between virus-infected and virus-free plant material. Virus-free material was obtained from shoot apices about 0.2 mm in size isolated from virus-infected, in vitro maintained, microcuttings of a number of mashua lines. Mashua line had an effect on proliferation, reestablishment and tuber yield. Virus infection appeared to have a detrimental effect on the general in vitro performance of all lines. There were no differences in reestablishment between the virus-infected and virus-free plants. Although there were no overall yield differences between the virus-infected and virus-free lines, virus-infected lines produced significantly more large tubers.
Control of Bacteria and Alteration of Plant Growth in Tissue Cultures of Tansy (Tanacetum vulgare L.) Treated with Antibiotics
Authors: Keskitalo M. , Pohto A. , Savela M.L. , Valkonen J.P.T. , Pehu E. , Simon J.
Published: February 2019

Ten bacteria were isolated from the in vitro shoot cultures of different tansy (Tanacetum vulgare) genotypes. All isolates were Gram-negative. Five isolates belonged to Enterobacteriaceae, three isolates were strains of fluorescent Pseudomonas, and two isolates were strains of other aerobic bacteria. The combined treatment with gentamicin (50 mg·L–1) and rifampicin (25 mg·L–1) prevented the growth of all bacteria, whereas none of the antibiotics (ampicillin, cefotaxime, rifampicin, gentamicin, or streptomycin) controlled all bacteria when used alone. The antibiotics ranged based on their increasing adverse effects on shoot cultures as follows: rifampicin, cefotaxime, and gentamicin. Increased antibiotic concentration reduced the initiation and growth rates of shoots, roots and calli with some exceptions. Low concentrations of gentamicin and cefotaxime both increased the growth rate and shoot number per plant. Rifampicin stimulated the root growth of some of the biotypes tested. The growth rate of calli increased significantly in the presence of both gentamicin (25 mg·L–1) and rifampicin (25 mg·L–1) in the growth media, whereas the use of either antibiotic alone reduced the calli growth relative to the control. Viability of tansy protoplasts was enhanced by rifampicin and to a lesser extend by gentamicin and cefotaxime. The growth of bacteria isolated from tansy tissue culture can be prevented with a combined gentamicin and rifampicin treatment. The growth rate of plants decreased slightly when grown in the media supplemented with the same antibiotic combination. However, the growth retardation was not permanent, and the plants recovered and grew vigorously when transferred to antibiotic free medium.
Bio-osmopriming Tomato and Cucumber Seeds for Better Stand Establishment
Authors: Warren J.E. , Bennett M.A.
Published: February 2019

Improved germination under unfavorable soil conditions is an important safeguard against yield losses in direct-seeded crops. Osmoprimed seed has been shown to provide earlier and more uniform germination as well as improve low temperature germination. These attributes combined with the reduced rates of damping-off associated with Pseudomonas aureofaciens AB254 creates a bioosmopriming seed treatment that provides rapid germination under a wider range of soil temperatures while exhibiting the disease resistance and improved growth associated with bacterial coatings. The objective of this work is to combine biopriming and osmopriming into one procedure, thus creating an environment for adequate seed hydration and rapid multiplication of beneficial bacteria which will thoroughly colonize the seed surface. Processing tomato seeds (Lycopersicon esculentum Mill. `OH8245') were bio-osmoprimed in aerated –0.8 MPa NaNO3 at 20°C for 4 days. On the fourth day, a mixture of nutrient broth, a defoaming agent, and bacteria that have been adjusted to the same osmotic potential is added. This is done so that the removal of seeds from the tank at the end of the 7-day treatment coincides with peak populations of bacteria. Pseudomonas aureofaciens AB254 multiplies very rapidly in this environment, with colony forming units for tomato averaging 4 × 105/seed. Results will also be reported for cucumber seed (Cucumis sativus L. `Score'), which were treated using a similar procedure. Bacterial populations per seed, germination characteristics and pathogen control will be discussed.
Anatomy of Adventitious Root Formation in Stem Cuttings of Mussaenda erythrophylla L. `Rosea'
Authors: St. Hilaire Rolston , Berwart Carlos A. Fierro
Published: February 2019

Mussaendas (Mussaenda spp.) are ornamental shrubs, and some cultivars are difficult to root. This study was conducted to explore how adventitious roots initiate and develop in the cultivar Rosea, and to determine if anatomical events are associated with difficulty in rooting stem cuttings. Stem cuttings were treated with 5, 10, 15 mm 1H-indole-3-butyric acid (IBA), or distilled water, and sampled every 2 days over 26 days to observe adventitious root formation and development. For analysis by light microscopy, the basal 1 cm of cuttings was embedded in wax and stained with safranin-fast green. Adventitious roots initiated from phloem parenchyma cells and from basal callus in nontreated cuttings. Cuttings treated with 15 mm IBA had a mean of 18 root primordia per basal 1 cm of cutting after 10 days. Root primordia were not observed in non-treated cuttings at 10 days. Root primordia that developed in non-treated cuttings lacked clear vascular connections. These results suggest that non-treated cuttings are difficult to root because few primordia are produced.
The Effects of Combinations of Three Scions and Three Rootstocks on Yield and Quality of Iranian Pistachio Nuts
Authors: Panahi B. , Sheibani A. , Peat W. E.
Published: February 2019

Rootstocks in various species have been shown to significantly influence vigor of scion growth, yield, fruit size, maturity, quality, and other phenomena. This research studied the effects of combinations of three scions and three rootstocks of Iranian pistachio on characteristics of fruit. A split-plot design was laid out at Rafsanjan/Iran in 1993 and results for a period of 2 years from 1994 to 1995 are presented. Diameter of trunk 5 cm above and below the graft area, weight of nuts with hull, weight of nuts without hull, weight of in-shell nuts, weight of blank, percent of shell splitting and total yield weight were measured. Almost all the treatment differences in the experiment were associated with rootstock effects and not scions. Statistical analysis indicated that different scions had no effect on any of the measured characteristics except the diameter of trunk 5 cm below the graft area. Rootstocks, however, had large and significant effects on all the characters except percent shell splitting. Interactions between scion and rootstock were important such that the combination of the scion `Kalehghochi' with the rootstock `Ahli' gave substantially higher yields than any other combination.
Postharvest Handling of Cut Inflorescences of Ebenus cretica L.
Authors: Vlahos J.C. , Papadimitriou M.
Published: February 2019

Ebenus cretica, Leguminosae, is a perennial bush endemic to the island of Crete, and produces attractive pinky red or purple flowers on 15-cm long racemes. To study the possibility of its use as a cut flower, cut inflorescences on 40-cm-long spikes were taken from plants grown outdoors in the farm of the Technological Educati Institute and used to determine the postharvest characteristics of Ebenus flowers. Without any postharvest treatments, the inflorescences held in water had an average life of about 7 days. A solution of 100 ppm 8-hydroxyquinone sulfate (HQS) in DI water, supplemented with 5% Ca(NO)3 increased vase life for 2 days and improved the water potential without affecting transpiration, whereas the addition of 2% or 5% sucrose decreased vase life by 1 or 2 days respectively. Pulsing with 0.2 mm STS for 2 h improved flower quality and vase life. Addition of 6-BAP (2 ppm) or GA3 (3 ppm) in the preservative solution did not affect flower quality or vase life compared to control. These results indicate that inflorescences of Ebenus cretica may be used as cut flowers; however, further research is required to determine their sensitivity to ethylene as well as its storage capabilities.
Alleviation of Grapefruit Peel Injury after Exposure to Irradiation and Storage
Authors: Miller W.R. , McDonald R.E.
Published: February 2019

Low-dose irradiation (0.15 kGy) of grapefruit is reportedly a viable quarantine treatment for pests such as Caribbean fruit fly larvae, and is expected to be approved soon for use by the U.S. citrus industry. For the application of ionizing gamma irradiation to be efficacious for all fruit treated on commercial pallet units, fruit will likely require doses 3 to 4 times the required minimum dosage. Grapefruit peel is known to be slightly injured at 0.3 kGy, and can be seriously injured at 0.6 kGy but no peel injury is allowed for U.S. #1 grade fruit. A forced-air vaporheat treatment at 38°C for 2 hours reduced the severity and incidence of grapefruit peel injury by irradiation at doses to 1.0 kGy. The heat treatment reduced the incidence of peel injury at 0.5 and 1.0 kGy by about 50% and 21%, respectively. No other quality or condition attribute was affected by the combination treatment of heat and irradiation. Peel injury was not reduced however by pretreatment with thiabendazole (TBZ) at 1000 ppm or 4000 ppm, or a combination of 1000 ppm each of TBZ and imazalil. A combination treatment of heat before irradiation may allow for doses higher than attainable without heat during the application of irradiation as a quarantine treatment of grapefruit.
Tolerance of Grapefruit and Mexican Fruit Fly Larvae to High-temperature Controlled Atmospheres
Authors: Shellie Krista C. , Mangan Robert L. , Ingle Sam J.
Published: February 2019

The objective of this research was to investigate whether a controlled atmosphere established inside a high temperature forced air chamber could enhance the mortality of the most heat-resistant life stage of Mexican fruit fly larvae (Anastrepha ludens Loew) and thereby reduce the amount of time grapefruit (Citrus paradisi Macf.) harvested from Mexican fruit fly-infested regions must be exposed to high-temperature forced air to achieve quarantine security. The mortality of third instar larvae treated on diet was significantly higher after exposure to 1% oxygen or 1% oxygen enriched with 20% carbon dioxide than it was in either air or air enriched with 20% oxygen. Reducing the amount of oxygen in air from 21% to 1% during forced air heating at 46°C, reduced the exposure time required for 100% kill of larvae inside artificially infested grapefruit from 5 hours to 3.5 hours. Inconsistent fruit quality results warrant further study to optimize controlled atmosphere conditions during heating. Based upon relative levels of carbon dioxide inside the grapefruit during heating, fruit respiration during heating in 1% oxygen was lower than during heating in air. Results from this research suggest that reducing the amount of oxygen in a high temperature forced air chamber during heating can reduce the amount of time fruit must be exposed to heat for quarantine security against Mexican fruit fly.
Applanation Tonometry for Fruit Firmness Measurements
Authors: Marler Thomas E. , Marler Philip W.
Published: February 2019

The eyecare industry has used various instruments and methods for determining intraocular pressure. Some of the methods may be applicable for measurement of fruit firmness in the horticultural industry. We determined fruit firmness with an applanation tonometer, currently one of the most popular instruments in the eyecare industry. We then measured firmness of the same sample using a penetrometer with an 8-mm probe. Kiwi, mango, peach, strawberry, tomatillo, and tomato fruit were included in the study. With the exception of mango, tonometer and penetrometer measurements within a species were significantly correlated. The contact area of the tonometer probe was 1.5 mm2, which was less than 3% of the contact area of the penetrometer probe. The heterogeneous nature of mango mesocarp due to fibers and this large difference in contact area between the two instruments may have caused the lack of correlation for that species. The data indicate that tonometry may be useful for determining firmness of fruit, and further development may lead to a nondestructive method of obtaining these data.
Quality Parameters in Four Melon Hybrids Stored at Different Temperatures
Authors: Manzano Juan , Pérez Yolanda , Delgado Douglas
Published: February 2019

Melon fruit (Cucumis melo L.) from Chando, Concorde, Explorer, and Durango hybrids, collected from a Sante Ines farmer from Rio Tocuyo, were stored at 5, 10, and 18°C and room temperature for 7, 14, and 21 days with the objective of getting the response of melon hybrids in relation to quality characteristics. The soluble solids content and dry matter were not significant in the studied hybrids, titratable acidity was higher at 5°C, Chando had the highest values. Explorer had the highest pH values and soluble solids: titratable acid ratio at room temperature. Reducing and total sugars had the lowest values at 18°C and room temperature, Chando had the highest values. Concorde had the highest values for fresh weight loss at room temperature during 21 days of storage.
Effect of Thermal Blanch Treatment on the Quality of Frozen Chinese Chestnuts
Authors: Smith Durward , Norton Joseph D.
Published: February 2019

Chinese chestnuts (Castanea molissima Blume) are very susceptible to spoilage, and require artificial storage means to maintain fresh nuts. Frozen shelled nuts would offer the consumer a convenient product with no waste or spoilage, however chestnuts have traditionally been cured and held in storage to develop a desirable texture and conversion of starch to sugars. This research was initiated to determine the effect of thermal blanch treatment (water vs. syrups) on the texture, color and acceptability cured and uncured frozen, shelled Chinese chestnuts. After frozen storage nuts blanched in syrup had better color and firmer textures than water-blanched nuts. Uncured nuts were firmer than cured nuts, and were ranked above cured nuts by sensory panelists.
Lowest Survival Temperature Estimation in 45 Magnolia Varieties by Controlled Freezing
Authors: Wachter John F. , Cappiello Paul E.
Published: February 2019

Lowest survival temperature (LST) estimations for 45 varieties of Magnolia from Delaware were obtained over 4 testing dates with some varieties tested on fewer dates due to a shortage of material. Terminal stem cuttings were subjected to a controlled freezing regime, incubated at 100% humidity for 10–14 days and evaluated for injury by visual observation. LSTs were estimated as the lowest temperature at which 100% survival was observed. LSTs were difficult to estimate due to a lack of consistency caused by fungal pathogens. Incubation in moist towels and aluminum foil, post-freeze addition of moist towels following prefreeze sodium hypochloride dip, and dry incubation were employed to eliminate fungal pathogenicity as a source of post-freeze damage. Results show varieties with M. ×loebneri heritage to be the most consistently cold tolerant. Varieties such as M. `Raspberry Ice' and M. `Merril' rated as inconsistent with no definite LST estimated. Direct comparisons of incubation method, date of test, fungal pathogenicity and varietal consistencies will be discussed.
Effects of Short-term Water Stress, Hydrophilic Polymer Amendment, and Antitranspirant on Stomatal Status, Transpiration, Water Loss, and Growth in `Better Boy' Tomato Plants
Authors: Gu Sanliang , Guak Sunghee , Fuchigami Leslie H. , Shin Charles H.
Published: February 2019

Seedling plugs of `Better Boy' tomato plants (Lycopersicon esculentum Mill.) were potted in processed fiber:perlite (60:40% by volume) media amended or nonamended with either crystalline or powdered hydrophilic polymer (2.4 kg·m–3), and treated with one of the several concentrations (0, 2.5, 5, 7.5, and 10%) of antitranspirant GLK-8924, at the four true-leaf stage. Plants were either well-irrigated or subjected to short-term water stress, water withholding for 3 days, after antitranspirant GLK-8924 application. Leaf stomatal conductance, transpiration rate, whole plant transpirational water loss, and growth were depressed by short-term water stress and antitranspirant GLK-8924. In contrast, hydrophilic polymer amendment increased plant growth, resulting in higher transpirational water loss. The depression of stomatal conductance and transpiration rate by short-term water stress was reversed completely in 2 days after rewatering while the reduction of plant growth rate diminished immediately. The effects of antitranspirant GLK-8924 were nearly proportional to its concentration and lasted 8 days on stomatal conductance and transpiration rate, 4 days on plant growth rate, and throughout the experimental period on plant height and transpirational water loss. Plant growth was reduced by antitranspirant GLK-8924 possibly by closing leaf stomata. In contrast, hydrophilic polymer amendment resulted in larger plants by factors other than influences attributed to stomatal status. Hydrophilic polymer amendment did not interact with antitranspirant GLK-8924 on all variables measured. The application of antitranspirant GLK-8924 was demonstrated to be useful for regulating plant water status, plant growth and protecting plants from short-term water stress.
Gas Exchange, Stem Water Potential, and Leaf Orientation of Rubus idaeus L. Are Influenced by Drought Stress
Authors: Percival David C. , Proctor John T.A. , Privé J.P.
Published: February 2019

Rubus idaeus L. cv. Heritage raspberries were placed in controlled environment chambers (25°C, 14-hour photoperiod, 2.0 kPa vapor pressure deficit, CO2 concentration of 380 mol·m-2·s-1) to study the effects of drought stress on leaf gas exchange and stem water potential. Whole-plant photosynthesis (Pn) and transpiration were sensitive to drought stress and gradually decreased from the second day of the study until rehydration. Stomatal aperture feed-back regulation was present during the initial 48 hours of the study with transpiration rates dropping in response to a decrease in stem water potential. Spatial differences were also present with leaf Pn, and stomatal and CO2 conductance values of the younger, distal (i.e., closer to the apex) leaves decreasing at a faster rate than the older, proximal leaves (i.e., close to crown). Evidence of increased mesophyll resistance to drought stress was apparent with ci either remaining constant or increasing, while Pn and carboxylation efficiency simultaneously decreased. Protection of the underlying photochemistry was evident with parahelionastic leaf movements which resulted in a reduction in the effective leaf area and subsequent heat load. Therefore, an optimum balance between water loss and ci existed, and an alteration in these rates represented a stomatal conductance adjustment to match the intrinsic photosynthetic capacity rather than just a causal relationship.
Demand for Herbaceous Ornamental Germplasm from the North Central Regional Plant Introduction Station
Authors: Widrlechner Mark P.
Published: February 2019

In 1991, the USDA–ARS North Central Regional Plant Introduction Station made available for distribution 129 accessions of germplasm representing 31 genera of herbaceous ornamentals. This number increased to 329 accessions of 42 genera by 1995. During 1991–95, more than 500 seed packets were distributed to fulfill requests for these plants received from a diverse array of public and private researchers. An analysis of this demand together with expert advice from Crop Germplasm Committees and technical considerations, such as ease of culture and seed production, can help set priorities to plan germplasm regeneration to meet future demand. A recent analysis of demand at U.S. National Plant Germplasm System active sites indicated that demand ranging between 0.23 and 0.97 distributions per available accession per year was typical. Of the 42 ornamental genera analyzed in this study, 9 were demanded more frequently than was typical, 10 were demanded less frequently, with the remainder in the typical range. In order of increasing frequency, the nine genera with the highest distribution rates were Verbena, Gypsophila, Echinacea, Lapeirousia, Delphinium, Cerastium, Baptisia, Lilium, and Tanacetum. Six of these genera are represented only by a single available accession. Notably, Echinacea and Tanacetum are of research interest both as ornamentals and as medicinal/industrial crops. This poster gives a brief overview of the economic value of these genera, display the results of the demand analysis, discuss the results relative to recommendations from Crop Germplasm Committees and requestors, and consider how demand can shape management plans for the acquisition and regeneration of ornamental germplasm.
Adapting a Nursery Production Budget to Containerized Specialty Vegetables
Authors: Lamberts Mary , Gordon Slyvia , Fitzpatrick George
Published: February 2019

Production budgets for both field grown vegetables and ornamental crops, field and container grown, are fairly common. Container grown vegetables, other than transplants, are much less common and do not have specific budgets which would allow growers to set realistic prices for individual plants. A specialized budget was adapted from one developed for container nurseries. Specific production costs were taken from a budget for field grown vegetables. This process could be adapted for use with other specialty crops. It could be used for county or state fairs and other situations where individual vegetable plants need to be raised in containers.
Farmer's Bookshelf: Hypermedia Information System to Recommend Trees for Landscaping
Authors: Kobayashi Kent D. , Young Mary A. , Hensley David L. , Bittenbender H.C. , Yogi Julie Ann T.
Published: February 2019

A hypermedia information system was developed to recommend trees for landscaping and to obtain information on these individual trees. Using the software HyperCard on the Macintosh computer, we developed a system that uses the idea of index cards with information being stored on separate screens called “cards.” Using a mouse, the user navigates from one card to another by click on a “button” on the card. The user may select from several criteria including tree type, tree height, soil type, drought tolerance, wind tolerance, shade tolerance, salt tolerance, and growth rate. The program then finds which trees meet the desired criteria and provides information on these trees. This easy-to-use system requires no typing except to enter a word to search for. The user can quickly browse for the desired information and save it as a text file or print it. The Farmer's Bookshelf provides a tool for extension agents, growers, and homeowners to easily obtain vitally needed information. The program has further application for landscape companies, Master Gardener programs, and in horticultural courses.
Effect of Cutting Characteristics on Cut-stem Quality of Single-stem Roses
Authors: Anderson Robert G. , Jia Wenwei
Published: February 2019

Commercial quality cut-roses were produced in a single-stem production system from single-node cuttings. Single-node cuttings from cut stems of `Lady Diana' rose were characterized by the location of the node of origin in numerical sequence from the flower and initial stem size, large (thick stems, long length, many nodes), moderate (moderate thickness, moderate length, and node number), and small (generally not commercial quality). Cuttings were treated with a 5-second dip in 500 ppm IBA/250 ppm NAA solution, placed in growing media in 8-cm pots and placed under intermittent mist (5 second every 5 minutes) with growing medium temperature of 35°C. Seven sequential crops of rose cuttings were grown from Feb. through May 1995. The initial node of origin was significantly correlated to the final stem length of the single-stem rose and to the number of days for axillary budbreak on the cutting. The number of days to rooting was not effected by the initial node of origin of the cutting. The correlation with initial stem size had variable results.
Calibration Coefficients Added to ROSESIM Improve Predictions of Growth in Greenhouse Conditions
Authors: Hopper Douglas A. , Cifelli Kevin T.
Published: February 2019

Growth predictions derived from data collected in controlled-environment chambers would be expected to differ from growth responses observed in variable greenhouse conditions. ROSESIM was developed as a dynamic plant growth model based on `Royalty' rose (Rosa hybrida L.) response to 15 unique treatment combinations of photosynthetic photon flux (PPF), day temperature (DT), and night temperature (NT) under constant growth chamber conditions. Regression coefficients for growth equations are read from an external ASCII file, thus permitting coefficients up to a full quadratic model form. Calibration coefficients (CC) were added to ROSESIM to enable predictions to be altered proportionally to permit improved prediction of specific growth characteristics. Numerator and denominator values for CC are adjustable for the first 10 days (initial) growth equations, subsequent growth until anthesis equations, and for the prediction of anthesis. Validation studies were used to set CC values; this enables the model based on growth in controlled environment chambers to be systematically calibrated on site to fit actual growth measured at a specific greenhouse location.