bluuebunny/crossref_metadata_2025 huggingface dataset:
Injuries from Mechanical Harvesting Have Little Effect on Tree Vigor and Productivity in Citrus
Authors: Li Kuo-Tan , Syvertsen Jim , Burns Jacqueline
Published: February 2019

The shedding of leaves, branches, flowers, and young fruit; scuffing of bark; and exposed roots that are caused by trunk or canopy shakers during harvest appears to be unavoidable, but generally does not reduce long-term yields. Nonetheless, such visible injuries have limited the widespread adoption of mechanical harvesting in Florida's citrus industry. We determined if such physical injuries caused by a properly operated trunk shaker resulted in any physiological injures or any consequent decline in vigor and productivity of well-managed, healthy citrus trees. We continuously monitored various physiological indexes in mature `Hamlin' and `Valencia' orange trees annually harvested by hand or by a linear-type trunk shaker with various shaking durations. Trunk shaking did not reduce return bloom, fruit set, young fruit growth, or canopy and root growth. There was a correlation between the seasonal timing of a simulated bark injury and recovery from the injury. Although some root exposure was frequently observed during trunk shaking, leaf water relations and fine root growth were unaffected. There was no difference in leaf dry weight per area and leaf nitrogen among treatments. Mechanical and hand harvesting in late season `Valencia' during full bloom removed similar amounts of flowers. However, immature fruit were removed by trunk shaking when `Valencia' were harvested after mid-May, and the number of young fruit removal increased with shaking duration and fruit size. The loss of young fruit for the next crop remains a major problem of mechanical harvesting in late harvest `Valencia'.
A Modified Method for Inducing Precocious Flowering in Grape Seedlings
Authors: Boyden Laurie E. , Cousins Peter S.
Published: February 2019

Breeders of woody perennials seek to shorten the time from propagation to flowering and the turnover time between generations. Grapevines usually flower and fruit no earlier than their third season. Onset of flowering occurs when anlagen, undifferentiated primordia arising from axillary and terminal bud meristems, begin to develop into inflorescences as well as tendrils. This occurs in response to hormonal stimuli; high levels of gibberellins in juvenile tissue favor vegetative growth, whereas increased cytokinin levels in physiologically mature tissue favor reproductive growth. We modified a method developed for Vitis vinifera for use on grape rootstock seedlings. Exogenous applications of chlormequat and N-benzyl-9-(2-tetrahydropyranyl) adenine (PBA, a cytokinin) were used induce precocious flowering by increasing the cytokinin:gibberellin ratio, triggering anlagen to develop into inflorescences on physiologically juvenile vines. The optimum treatment was a single application of 3000 micromolar chlormequat and 250 micromolar PBA, followed by 10 subsequent daily applications of PBA alone. Lower concentrations of treatments resulted in a loss of efficacy, and higher treatment concentrations and/or longer durations resulted in phytotoxicity. Abnormalities in flower and leaf morphology were observed with all treatments. Grape rootstock seedlings are dioecious and staminate vines were more responsive to the treatments than pistillate vines. We did not observe production of hermaphroditic flowers on staminate vines. Pollen collected from flowering staminate seedlings was successfully used in crosses that produced fruit and viable seeds. The ability to induce precocious flowering in juvenile grape seedlings has many applications in grape breeding and genetic research.
(20) Effect of Fruit Dipping into Germanium Solution Just After Harvest on Fruit Quality of `Niitaka' Asian Pear
Authors: Kim Wol-Soo , Kim Tae-Hyun , Chung Soon-Ju , Choi Hyun Suk
Published: February 2019

Germanium has been reported as a mineral element affecting plant cell metabolism. Many trials to supply germanium to fruit have been carried out since tests have confirmed germanium's role as a medical substance. Supplying germanium to orchards by soil and foliar application was not effective because of loss from rainfall. Also, tree injection with germanium solution required the insertion of a tube to the tree xylem at each injection site. In order to increase germanium absorption by fruit, this study carried out the postharvest dipping of fruit into germanium solution. `Niitaka' pear (Pyruspyrifolia) fruit was treated with two types of germanium, GeO (inorganic type) and Ge-132 (organic type), in a concentration of 50 mg·L–1 just after harvest in early Oct. 2004. Flesh browning after peeling the fruit was delayed by germanium treatment, and polyphenoloxidase (PPO) activities were lowered. Postharvest potentials were maintained at high levels for fruit firmness, physiological disorders, and decayed fruit during cold storage at 0 to 1 °C for 2 months. Antioxidant and some phenolic compounds were higher than those of control fruit.
(26) Commercial Film Coatings Reduce Weight Loss and Improve Appearance of `Keitt' Mango Fruits (Mangifera indica L.)
Authors: Baez-Sañudo Manuel , Siller-Cepeda Jorge , Contreras-Martinez Rosalba , Contreras-Angulo Laura , Velez Rosabel , Muy-Rangel Dolores
Published: February 2019

Mango `Keitt' is characterized by a poor external color development and a slightly high transpiration rate during ripening, which affect external quality. When fruit is ripening, the peel turns from a green to yellowish or dull green color, and the peel has no shine. We evaluated the effectiveness of three film coatings to reduce weight loss, improve appearance, and maintain quality during ripening of `Keitt' mango fruits. Four lots of fruits were obtained from a packinghouse in late September and transported to the laboratory. Each lot was sprayed at the commercial recommended rates with SemperFresh™, Natural Shine™, TFC 210, and FreshSeal™ coatings. Water sprayed fruits were used as a control. After applications, fruits were stored for 15 days at 22 °C and 85% RH to simulate marketing conditions. Quality parameters evaluated included weight loss (%), firmness, external and internal colors (hue, chroma, l), respiration rate (CO2 production), and chemical parameters such as pH, titratable acidity and °Brix. After 15 days, fruits coated with Natural Shine reduced 50% of the weight loss as compared to control fruits, while fruits coated with FreshSeal and SemperFresh reduced only 1.7% and 3.5%, respectively. Firmness declined from 155 N to 10 N during storage, being more evident on day 10, when fruits were table ripe. Fruits treated with SemperFresh were softer as compared with the other treatments. Titratable acidity decreased from 0.8% to 0.2% during storage and °Brix increased from 13 to 17–18 in all treatments. Fruit coated with Natural Shine had reduced weight and firmness loss. Additionally, fruits developed a better external color, with lower hue values, higher chromaticity and luminosity, which improve fruit appearance.
(28) Lenticel Development and Discoloration of Some Mango [Mangiferaindica (L.)] Cultivars
Authors: Bezuidenhout Jan-Louis , Robbertse Hannes
Published: February 2019

Discoloration of the lenticels of some mango cultivars is a serious problem, affecting the economic value of the fruit. Mango fruit lenticels develop from ruptured stomata on fruit from 20 mm in `TA' and `Keitt' and 30 to 40 mm in `Kent'. Lenticels enlarge as the fruit grow due to stretching of the fruit surface. Adult lenticels of `TA' and `Keitt' are larger in size than those of `Kent'. `Kent' lenticels are also better insulated than `TA' and `Keitt', having a thick cuticle in the lenticel cavity and, in some instances, a phellogen is also present where `TA' and `Keitt' lack both of the above mentioned. Resin present in the skin of the fruit play an important role in the discoloration of `TA' and `Keitt' lenticels. Resin of both `TA' and `Keitt' fruit contain a considerable amount of an aggressive compound termed terpenes. These terpenes are volatile and able to move out of the resin ducts via the sublenticellular cells to the outside of the fruit. The integrity of tonoplasts situated in sublenticellular cells are lost due to the presence of terpenes, causing vacuolar bound phenols to come into contact with polyphenol oxidase, present in the cell walls. The product of the resultant reaction is a quinone, accumulating as a brownish deposit in the cell walls, the black markings visible from the outside. This is the spontaneous discoloration process. Lenticel discoloration may also occur due to maltreatment, i.e., rough handling, to high temperatures, extended period on brushes on the packline, breaking of the cold chain, and spilling of resin onto the surface of the fruit.
(134) “Plant Propagation” CD-ROM
Authors: Welch-Keesey Mary , Lerner B. Rosie , Katz Sharon , Crow Joan , Goetz Becky , Griffiths Janie Nordstrom
Published: February 2019

“Plant Propagation” is a CD-based course that covers seed propagation, divisions, layering, cuttings, and grafting. It is multimedia at its best—hundreds of photos, illustrations, and videos show close-up details of each propagation method and create a fresh and enjoyable way to test the viewer's knowledge. Although designed for the amateur gardener, it is detailed enough to be used as a supplemental text in college-level plant propagation courses. Additional features include: 1) an extensive Resources section that lists additional book and internet resources, scientific names of all the plants discussed in the course, and sources for tools; 2) an extensive Glossary, including audio of the correct pronunciation of 50 terms; 3) a Basics section that reviews the different types of plant propagation, plant biology, and horticultural concepts, such as potting media, lighting, and plant growth regulators; and 4) a short discussion of the use of tissue culture for plant propagation. “Plant Propagation” is available for $40 from Purdue Extension's online education store at http://www.ces.purdue.edu/new/. It's also available by calling (888) EXT-INFO or e-mailing media.order@purdue.edu. The product code is CD-HO-3.A free preview of the course is available online at http://www.hort.purdue.edu/plantprop/webversion/Intro.html. If you have questions about the course content, please contact the authors directly: Mary Welch Keesey (marywk@purdue.edu) or (317) 630-3257 and B. Rosie Lerner (rosie@purdue.edu) or (765) 494-1311.
(135) Planttalk Colorado™: 24-hour Answers for Gardeners
Authors: Klett James
Published: February 2019

Planttalk Colorado™, established in Fall 1997, is a 24-hour toll-free automated phone service available in English and Spanish and website that provides gardening consumers with reliable and timely information on a variety of horticultural and related areas topics. Planttalk Colorado™ is unique in that it is sponsored by Colorado State University Cooperative Extension, Denver Botanic Gardens and the Green Industries of Colorado. Over 450 topics edited and approved by all entities ranging from general gardening to emerging issues, such as new disease and insect concerns. Recent efforts have included translation of a portion of the scripts into Spanish to reach a larger audience and the rising Hispanic population in the state and region. Marketing efforts have evolved to include a website with photos and illustrations along with linkages to other university research-based information. Other marketing tools have included: free incentives, mass media marketing, and tabletop and banner displays for use at educational functions. A review of phone usage vs. web hits will be discussed. Web hits averaged 92,528 monthly in 2004 vs. phone usage averaged 309 monthly in 2004. Consumers have the ability to post comments on both web and phone systems. They can rank the overall program on the web. Funding is a cooperative effort between all three partners. Planttalk Colorado™ has increased visibility to Cooperative Extension and built partnerships with the Green Industry of Colorado and Denver Botanic Gardens for delivering reliable and accurate information to all citizens of Colorado and beyond.
(137) Cultivar Comparison of Heliconias for Use in Guam
Authors: McConnell James
Published: February 2019

Cultivars of heliconias were evaluated for use in Guam as a cut flower and in the landscape. Forty-five cultivars were planted at three locations in Guam. Due to insufficient plant material, the evaluation was preliminary. Noteworthy differences were observed among the cultivars. Differences were noted in time to establish, frequency of flowering, and resistance to wind damage. Establishment required large quantities of water. Once established, some cultivars appeared to be drought-tolerant; however, feral pigs and carabao became a problem due to massive mechanical damage. Typhoons also caused severe damage to the foliage. Rhizomes did not suffer obvious damage, resulting in recovery within 1 year. Heliconias as a cut flower does not appear feasible. As a landscape plant, heliconias should be given further consideration.
(138) Guam Native Trees and Shrubs for the Landscape
Authors: McConnell James
Published: February 2019

Plants native to Guam are being evaluated for use in the Guam landscape. The selected plants are being propagated by seed and/or cutting. The genera currently being evaluated and propagated include Scaevola, Eleaocarpus, Ochrosia, Guamia, Pemphis, and Bikkia. Variation in flower color and floral fragrance were observed in Scaevola and selections have been made. There has been some difficulty establishing some of the plants in the landscape environment. There have been some significant insect problems occurring on established plants.
(61) Pot-in-pot Production of Intermountain West Native Herbaceous Perennials
Authors: Cardoso Guillermo , Kjelgren Roger , Cerny-Koenig Teresa , Koenig Rich
Published: February 2019

Low water landscapes are increasing popular and important in the urban areas of the Intermountain West (IMW). Perennial wildflowers are an essential part of low water landscapes, and are a dominant plant type in IMW native habitats. We compared pot-in-pot (PIP) vs. conventional above-ground (CAG) production of six IMW native wildflower species, Mirabilismultiflora, Aquilegia caerulea, Penstemon palmeri, Polemonium foliosissimum, Sphaeralcea grossularifolia, and Penstemonstrictus in #1 (4-L) containers. Media temperature, container-plant water loss, stomatal conductance, and growth were measured during two production cycles per year over 2 years. Growing medium temperatures in the PIP system averaged 10 °C cooler than in the CAG system. Consistent with cooler growing media, overall water loss of PIP-grown plants averaged 10% lower than plants grown in the CAG production system. Lower growing media temperatures apparently affected transpiration, as stomatal conductance was about 60% higher in the PIP system as compared to the CAG-grown plants. The integrated effect of lower growing media temperatures on plant performance resulted in about one-third greater top and root growth for plants growing in the PIP system compared to those in the CAG system. Pot-in-pot production may be an economically suitable nursery system for producing IMW native perennial wildflowers by reducing water loss and enhancing growth.
(1) Genetic Diversity of Cowpea [Vigna unguiculata (L.) Walp.] Breeding Lines from Different Countries Determined by AFLP Markers
Authors: Fang Jinggui , Devanand Panchanoor S. , Chao Chih Cheng T. , Roberts Philip A. , Ehlers Jeff D.
Published: February 2019

Cowpea (2n=2x=22) is a high protein, short-cycle, and essential legume food crop of the tropics, especially in the low input agricultural areas of sub-Saharan Africa, Asia, and South America. Lack of genetic diversity within breeding programs can limit long-term gains from selection. The cowpea gene pool is thought to be narrow and the genetic diversity within breeding programs could be even less diverse. Genetic relationships among 87 cowpea accessions, including 60 advanced breeding lines from six breeding programs in Africa and the United States, and 27 accessions from Africa, Asia, and South America were examined using amplified fragment length polymorphism (AFLP) markers with six near-infrared fluorescence labeled EcoR I + 3/Mse I + 3 primer sets. A total of 382 bands were scored among the accessions with 207 polymorphic bands (54.2%). Overall, the 87 cowpea accessions have narrow genetic basis and they shared minimum 86% genetic similarities. The data also show that the advanced breeding lines of different programs have higher genetic affinities with lines from the same program but not with lines from other programs. The results suggest that there is a need to incorporate additional germplasm of different genetic background into these breeding lines and to ensure the long-term genetic gains of the programs.
(2) A Unique Late-blight Resistance Locus from Solanum pinnatisectum
Authors: Norby Monica J. , Havey Michael J.
Published: February 2019

Phytophthorainfestans is the casual agent of late blight and is a major threat to potato production worldwide. There are no curative control agents available and resistance genes offer promise in controlling late blight. To date, the primary source of late-blight resistance has been from hexaploid (6x) [4 Endosperm Balance Number (EBN)] Solanum demissum. Mexican diploid (2x) (1EBN) Solanum species possess a wealth of late-blight resistances, but have been neglected due to crossing barriers. Manipulation of EBN and ploidies should allow integration of 2x (1EBN) germplasm into cultivated potato. Synteny between late-blight resistance loci from Solanum species of disparate ploidies and EBNs may facilitate the identification of unique resistance alleles and loci. Isolate MSU96 (US8/A2) of P. infestans revealed a late-blight resistance locus (Rpi1) from 2x(1EBN) S. pinnatisectum (PI 253214) that mapped to chromosome seven (MGG 265:977-985). MSU96 was also avirulent on the late-blight differential R9-Hodgson 2573 (LB3), revealing the presence of the avirulence gene for R9 originating from S. demissum. To test the relationship between Rpi1 and R9, we evaluated a family segregating for R9 and revealed that it does not map to chromosome seven. The independent inheritance of R9 and Rpi1 indicates that Rpi1 is a unique resistance locus. We are conducting a variety of crossing schemes to introgress Rpi1 into cultivated potato.
(4) Genotypic Variability of Iron and Zinc in Sweetpotato
Authors: La Bonte Don , Courtney Michael
Published: February 2019

Sweetpotato[Ipommabatatas (L.) Lam.] is a major subsistence crop in southern Africa, where iron and zinc deficiency in humans is an important health problem. A cultivar of sweetpotato that is suited for subsistence farming in this region and that is high in iron and zinc could be an important means of combatting these deficiencies. As part of a program of the International Potato Center (CIP) to develop such a cultivar, we are working to identify the high and low range of iron and zinc in sweetpotato cultivars grown throughout the world by testing a number of cultivars for these nutrients. Subsidiary objectives include determining the heritability of iron and zinc levels and surveying the variability in the levels of these nutrients from root to root on the same plant, from plant to plant of the same cultivar, from the proximal to the distal end of a given root, and from cambium to cortex.
(5) A Comparative Study of SRAP, AFLP, and SSR Markers for Detecting Genetic Differences among Elite Broccoli Inbreds
Authors: Hale Anna , Farnham Mark W.
Published: February 2019

Private and public vegetable breeders are interested in using current and emerging PCR-based marker systems in their respective improvement programs. However, before new systems are employed to replace existing ones, the new systems must prove to be efficient and cost-effective alternatives. Sequence related amplified polymorphisms (SRAPs), amplified fragment length polymorphisms (AFLPs), and simple sequence repeats (SSRs) were compared for their ability to differentiate individuals of a diverse group of 24 elite broccoli (Brassica oleracea L. italica) inbreds. Genomic DNA was assayed using 24 AFLP, 24 SRAP, and 44 SSR primer pairs. In this assessment, SSRs produced an average of only two bands per primer, with 25% of these bands being monomorphic, and the remaining bands detecting very few differences among the inbreds. Although the AFLP method resulted in a lower rate (63%) of polymorphism than the SSRs, it produced about 20 bands per primer. SRAPs produced an average of 14 bands per primer, with 82% of these bands being polymorphic. Since AFLP and SRAP markers had a higher multiplex ratio and SSRs were frequently monomorphic, AFLP and SRAPs were more effective in differentiating the elite broccoli inbreds examined in this study. Similarity matrices were generated from the AFLP and SRAP data, and resulting dendographs were compared.
(6) Highly Polymorphic Genesin Cultivated Tomato
Authors: Baldo Angela , Robertson Larry , Labate Joanne
Published: February 2019

Cultivated tomato varieties are genetically extremely similar. We identified 764 Unigenes with potential single nucleotide polymorphisms (SNPs) among more than 15 cultivars from public expressed tomato data. By sequencing regions from 53 of these Unigenes in two to three cultivars, we discovered an unexpected wealth of nucleotide polymorphism (62 SNPs and 12 indels in 21 Unigenes). This included a high proportion of predicted nonsynonymous nucleotide (17 of 33 SNPs in exons) and nonconservative amino acid (6 of 16 nonsynonymous SNPs) changes. We hypothesize that five of these regions are associated with introgressions from wild relatives. Identifying polymorphic, expressed genes in the tomato genome will be useful for both tomato improvement and germplasm conservation.
Adaptability of Pecan as a Species
Authors: Sparks Darrell
Published: February 2019

Pecan [Carya illinoinensis (Wangenh.) C. Koch] is indigenous to the Mississippi River drainage system of the United States. Climate in the native pecan region ranges from humid to semiarid and from mild to harsh winters. Rainfall is bimodal with peaks in March to April and in August to September. Pecan is site specific and is the climax tree species on loamy, well drained, first bottom river land with a relatively high water table. Detrimental effects from pecan's shade intolerance from its more vigorous, sympatric species are minimized as these species are specific to differ sites. Pecan's deep and phreatophytic rooting habit ensures soil moisture during drought periods and facilitates pecan's survival in semiarid regions. Root development in the humus-surface layer ensures nutrient uptake from the most nutrient rich layer of the soil and, when the lower soil profile is saturated, aeration for the roots and water and nutrient uptake. The bimodal rain pattern replenishes soil profile moisture and its timing ensures seed germination, stand establishment, well-developed seed, and minimal drought stress. Natural selection for freeze tolerance and for minimum fruit development time allows survival in areas with harsh winters and short growing seasons. Regulation of seed germination and budbreak by heating and chilling results in pecan being native in cold and warm climates, greatly increasing the native range. The northern limit for pecan is dictated by heat units; the southern limit is restricted by lack of bimodal rains and vivipary. Reproductive stress is caused by the high lipid content of seed, but is counteracted by a long juvenile growth period of the seedling, by a small nut size and low percentage kernel, and by “off” production years of the tree. Nut and percentage kernel decrease as the growing season decreases which contributes to species survival in geographical regions with a short growing season. Selection for small nuts with low percentage kernel is enhanced by predators. Tree reserves are depleted by heavy production during “on” years and are replenished during “off”years. Perpetuation of pecan forests is apparently from sib/half sib seedlings following predator satiation while dissemination into new areas may be mainly by predators. Pecan and its pests successfully co-exist. Major defense against fruit feeders is escape in time, leaf feeders by biological associations and accommodation, and leaf diseases by confrontation. Heterozygous progenies from cross-pollination provide ample genetic diversity for continuous pecan selection to endure pressures imposed throughout a wide climatic range. Ecological adaptions within native pecan forests should be used in developing and maintaining commercial pecan orchards.
Fruit Nitrogen Content of Sixteen Strawberry Genotypes Grown in an Advanced Matted Row Production System
Authors: Black Brent L. , Hokanson Stan C. , Lewers Kim S.
Published: February 2019

In the perennial strawberry production system, removal of the harvested crop represents a loss of nitrogen (N) that may be influenced by cultivar. Eight strawberry (Fragaria ×ananassa Duch.) cultivars and eight numbered selections grown in advanced matted row culture were compared over three seasons for removal of N in the harvested crop. Replicated plots were established in 1999, 2000, and 2001 and fruited the following year. `Allstar', `Cavendish', `Earliglow', `Honeoye', `Jewel', `Northeaster', `Ovation', and `Latestar' and selections B37, B51, B244-89, B683, B753, B781, B793, and B817 were compared for yield and fruit N concentration. Harvest removal of N (HRN) was calculated from total season yield and fruit N concentration at peak harvest. There were significant differences in HRN among genotypes, ranging from 1.80 to 2.96 g N per meter of row for numbered selections B781 and B37, respectively. Among cultivars, HRN ranged from 2.01 to 3.56 g·m–1 for `Ovation' and `Jewel', respectively. The amount of HRN was largely determined by yield, however, there were also significant genotype differences in fruit N concentration, ranging from 0.608 to 0.938 mg N per gram fresh weight for B244-89 and `Jewel', respectively. These differences indicate that N losses in the harvested crop are genotype dependent.
The Length of the Juvenile Period in Olive as Influenced by Vigor of the Seedlings and the Precocity of the Parents
Authors: Santos-Antunes Fernando , León Lorenzo , de la Rosa Raúl , Alvarado Juán , Mohedo Ana , Trujillo Isabel , Rallo Luis
Published: February 2019

A first attempt to determine the effect of vigor and parents on the length of the juvenile period of olive seedlings is here reported. Vigor seems to have a significant influence on the percentage of flowering seedlings, especially in the first 2 years of bearing. The different parents used have produced differences in the juvenile period of their descendants. A correspondence between the length of the unproductive period of the parents and the length of the juvenile period that they transmit to their descendants has been observed. The seedling forcing growth protocol described here has been able to produce flowering seedlings 28 months after germination, with >93% of seedlings flowering 65 months after germination.
Carotenoid and Chlorophyll Pigments in Sweet Basil Grown in the Field and Greenhouse
Authors: Kopsell Dean A. , Kopsell David E. , Curran-Celentano Joanne
Published: February 2019

Sweet basil (Ocimum basilicum L.) is a popular culinary herbal crop grown for fresh or dry leaf, essential oil, and seed markets. Recently, basil was shown to rank highest among spices and herbal crops for xanthophyll carotenoids, which are associated with decreased risks of cancer and age-related eye diseases. The research goal for the current study was to characterize the concentrations of nutritionally important carotenoid pigments in popular varieties of basil. Eight cultivars of sweet basil (`Genovese', `Italian Large Leaf', `Nufar', `Red Rubin', `Osmin Purple', `Spicy Bush', `Cinnamon', and `Sweet Thai') were grown in both field and greenhouse environments and evaluated for plant pigments using HPLC methodology. Environmental and cultivar differences were observed for all of the pigments analyzed. `Sweet Thai' accumulated the highest concentrations of lutein, zeaxanthin, and β-carotene carotenoids in the field, while `Osmin Purple' accumulated the highest carotenoid concentrations in the greenhouse. Comparing the two environments, cultivar levels for carotenoid and chlorophyll pigments were higher in the field environment when expressed on both a fresh and dry weight basis. Exceptions were found only for the purple leaf basils (`Osmin Purple' and `Red Rubin'). Positive correlations existed between carotenoid and chlorophyll pigments in both environments. This study demonstrates sweet basil accumulates high levels of nutritionally important carotenoids in both field and greenhouse environments.
Within- and Between-family Variability for Important Bulb and Plant Traits among Sexually Derived Progenies of Garlic
Authors: Jenderek Maria M. , Zewdie Yayeh
Published: February 2019

Until recently, there has been no large-scale production of true seeds in garlic (A. sativum L. and A. longicuspis L.). The recent discovery of male fertile garlic accessions stimulated research on the genetics and breeding of garlic. However, there is no information regarding the phenotypic characteristics of garlic populations generated from true seeds. We evaluated the first generation of sexually derived families of garlic for bulb and clove weight, number of cloves per bulb, flower stalk height, number of leaves, plant height, and days required to achieve bulb maturity. Significant variations were observed within and among families for these important traits.
Patterns of Variation in Alkamides and Cichoric Acid in Roots and Aboveground Parts of Echinacea purpurea (L.) Moench
Authors: Qu Luping , Chen Ying , Wang Xiping , Scalzo Richard , Davis Jeanine M.
Published: February 2019

We investigated patterns of variation in alkamides and cichoric acid accumulation in the roots and aboveground parts of Echinacea purpurea (L.) Moench. These phytochemicals were extracted from fresh plant parts with 60% ethanol and quantified by high performance liquid chromatography (HPLC) analysis. Concentrations of alkamides and cichoric acid were measured on a dry-weight basis (mg·g–1). For total alkamides, concentrations among individual plants varied from 5.02 to 27.67 (mean = 14.4%) in roots, from 0.62 to 3.42 (mean = 1.54) in nearly matured seed heads (NMSH), and 0.22 to 5.25 (mean = 0.77) in young tops (about ½ flower heads, ¼ leaves, and ¼ stems). For cichoric acid, concentrations among individual plants varied from 2.65 to 37.52 (mean = 8.95), from 2.03 to 31.58 (mean = 10.9), and from 4.79 to 38.55 (mean = 18.88) in the roots, the NMSH, and the tops, respectively. Dodeca-2E, 4E, 8Z, 10E-tetraenoic acid isobutylamide and dodeca-2E, 4E, 8Z, 10Z-tetraenoic acid isobutylamide (alkamides 8/9) accounted for only 9.5% of the total alkamides in roots, but comprised 87.9% in the NMSH, and 76.6% in the young tops. Correlations of concentrations of alkamides or cichoric acid between those of roots and those of the NMSH were not statistically significant, and either within the roots, the NMSH, and the young tops. However, a significant negative correlation was observed between the concentration of cichoric acid in the roots and in young tops, and a significant positive correlation was observed between total alkamide concentration in the roots and cichoric acid concentration in the young tops. These results may be useful in the genetic improvement of E. purpurea for medicinal use.
A Chilling Model to Estimate Rest Completion of Erect Blackberries
Authors: Warmund Michele R. , Krumme Joan
Published: February 2019

The time of rest completion of `Apache', `Arapaho', `Chickasaw', `Darrow', `Kiowa', `Navaho', and `Shawnee' blackberry (Rubus subgenus Rubus Watson) buds was compared and various models for estimating chilling were evaluated. `Kiowa' and `Arapaho' buds had the shortest rest periods, while those for `Shawnee', `Navaho', and `Chickasaw' buds were intermediate. `Apache' and `Darrow' buds had the longest rest periods. The model that accounted for the variation in percent budbreak among cultivars and temperatures during two dormant periods had the following two components: 1) a chilling inception temperature of –2.2 °C and 2) weighted chilling hours that accumulated after the chilling inception temperature. The chilling hours in this model were weighted as follows: 0 to 9.1 °C = 1; 9.2 to 12.4 °C = 0.5; 12.5 to 15.9 °C = 0; 16 to 18 °C = –0.5; >18 °C = –1. This study also elucidated that a blackberry model with a chilling inception temperature of –2.2 °C estimated chilling more accurately than one with chilling inception just after the maximum negative accumulation of chill units as used in the Utah chilling model. Also, temperatures between 0 and 2.4 °C must be weighted more heavily in a blackberry model than in the Utah peach model to accurately estimate chilling and rest completion.
Comparing Novel Sweet Cherry Crop Load Management Strategies
Authors: Whiting Matthew D. , Ophardt David
Published: February 2019

The development of novel crop load management techniques will be critical to the adoption and success of high density sweet cherry orchard systems based on new clonal rootstocks. Herein we report on a comparison of potential means of balancing crop load of `Bing' sweet cherry grown on the productive and precocious rootstocks `Gisela 5' and `Gisela 6'. In 2002, thinning treatments were applied to entire trees and consisted of an unthinned control (C), and manual removal of 50% of the blossoms (B) or 50% of 2-year-old and older fruiting spurs (S), throughout the tree. In 2003 all trees were left unthinned to characterize the carry-over effect of thinning treatment in 2002. In 2002, compared to C, thinned trees had 38% to 49% fewer fruit per tree, 22% to 42% lower yield, 8% to 26% higher fruit weight, and 2% to 10% larger fruit diameter. S and B treatments reduced yield by 42% and 22% on `Gisela 5' and by 40% and 31% on `Gisela 6', respectively. `Gisela 5'-rooted trees showed greater improvements in fruit quality than did trees on `Gisela 6'. Compared to C-, S-, and B-treated trees on `Gisela 5' yielded fruit that was 15% and 26% heavier, respectively. Yield of fruit ≥25.5 mm diameter was increased by 240% by S and 880% by B, though yield of this size fruit was still low (1.5 and 5.2 kg/tree, respectively). Neither technique had any beneficial carryover effect in the year following treatment despite S trees bearing about 25% fewer fruit than B and C trees. In both years, `Gisela 5'-rooted trees bore about 15% fewer fruit than trees on `Gisela 6'. Compared to `Gisela 5', `Gisela 6'-rooted trees were about 41%, 46%, and 24% more productive for C, S, and B, respectively. Number of fruit/tree in 2003 was within 4% and 8% of the previous year on `Gisela 6' and `Gisela 5', respectively. Crop value analyses suggest growers would be rewarded for producing high yields of medium size fruit (e.g., 21.5 to 25.4 mm) compared to low yields of high quality fruit.
A Comparison between Semi- and Fully Compatible Apple Pollinators Grown under Suboptimal Pollination Conditions
Authors: Schneider Doron , Stern Raphael A. , Goldway Martin
Published: February 2019

Apple (Malus domestica) has a gametophytic self-incompatibility (GSI) system. Consequently, fertilization is achieved by cross-pollination with a compatible pollinator. Compatibility is governed by a multiallelic S locus. Cultivars are fully compatible when both of their S-loci differ and are semi compatible when one locus is identical and the other differs. In a previous study we found that the fruit set and yield of the apple cultivar `Topred' was reduced when it was pollinated by a semi compatible cultivar. To examine if this occurrence is a general feature in apples grown under suboptimal conditions, three additional cultivars, `Golden Delicious', `Granny Smith' and `Royal Gala', were studied as pollen recipients of semi and fully compatible pollinators. Based on PCR analysis of the S-RNase allele, it was determined that the pollination rate of the semi compatible was significantly lower than that of the fully compatible pollinator in all cases. This was reflected by the lower fruit set and seed set of `Golden Delicious' and `Royal Gala', but not of `Granny Smith'. In hand pollination experiments, where pollen was in excess, no difference was found between the semi and fully compatible pollinators in all three cases. These results indicate that the low yield, conferred by semi compatible pollinators, is due to insufficient cross-pollination (and not to cultivar characteristics). Thus, low yields due to semi compatibility may be avoided by appropriate honeybee management that will increase pollination. Still, under suboptimal conditions, for growth and pollination, full compatibility is preferable.
Effects of Air Temperature Regimes on Physiological Disorders and Floral Development of Tomato Seedlings Grown under Continuous Light
Authors: Ohyama Katsumi , Omura Yoshitaka , Kozai Toyoki
Published: February 2019

Providing continuous light (24-h photoperiod) at a relatively low photosynthetic photon flux (PPF) is one possible way to reduce both initial and operational costs for lighting and cooling during transplant production with an artificial light. However, physiological disorders (i.e., chlorosis and necrosis) are often observed in several species under continuous light with a constant temperature. The objective of this study was to find an effective air-temperature regime under the continuous light to avoid such physiological disorders, and simultaneously enhance floral development, using tomato [Lycopersicon esculentum Mill.] as a model. The seedlings with fully expanded cotyledons were grown for 15 d at a PPF of 150 μmol·m–2·s–1, a relative humidity of 70%, and a CO2 concentration of about 380 μmol·mol–1 (atmospheric standard). Leaf chlorosis was observed when the air temperature was constant regardless of average air temperature (16, 22,or 28 °C). Neither leaf chlorosis nor necrosis was observed when the air temperatures were alternated [periods of high (28 °C) and low (16 °C) air temperatures of 16/8, 12/12, and 8/16 h·d–1]. Faster floral development was observed in the seedlings grown at lower average air temperatures. These results indicated that physiological disorders of tomato seedlings grown under continuous light could be avoided, and at the same time floral development could be enhanced, by lowering the average air temperature through modification of the periods of high and low air temperatures.
Root Zone Temperature, Plant Growth, and Fruit Yield of Tomatillo as Affected by Plastic Film Mulch
Authors: Díaz-Pérez Juan C. , Phatak Sharad C. , Giddings David , Bertrand Denne , Mills Harry A.
Published: February 2019

Tomatillo (Physalis ixocarpa Brot. ex Hornem) is a popular crop in Mexico and other Latin American countries. There is an increasing demand for this vegetable in the United States, particularly from the growing Latino population. However, there is limited information about tomatillo production. The objectives of this study were to determine the effects of plastic mulches on plant growth, yield, and root zone temperature in two cultivars of tomatillo. The study was conducted in Spring and Summer 2000. The design was a randomized complete block with a split plot arrangement, where plastic film mulch (black, gray, and silver mulches, and bare soil) was the main plot and cultivar (`Toma Verde' and `Verde Puebla]) the subplot. In the spring, mulch treatments had little effect on plant growth during the first 30 days after transplanting and there were no significant differences in fruit yields. In the summer planting, both early growth and fruit yields were greatest with the silver and gray mulch treatments and lowest on bare soil. Plant growth during the establishment was related with subsequent plant growth and yield. In mature plants, vegetative top fresh weight and total fruit yield were higher (P < 0.01) in the spring than in the summer. Total fruit yield (both seasons), marketable yield (spring) and cull yield (spring) were lower in `Toma Verde' than in `Verde Puebla'. Root zone temperatures (RZTs) in the spring (mean = 26.4 °C) were lower than in the summer (mean = 29.3 °C). In both seasons, mean RZT was highest under black mulch and lowest in bare soil. In the summer, plant growth and fruit yields tended to decrease with increasing RZTs. Tomatillo plants grown on mulches with a mean seasonal RZT of 30 °C had fruit yields that were 65% (`Toma Verde') or 50% (`Verde Puebla') lower respectively than those of plants on mulches with a RZT of 27 °C. There were no significant differences in foliar concentrations of N, Ca, Mg, S, B, Zn, Cu and Na among mulches. Foliar concentrations of the majority of mineral nutrients were not related with the mean RZT for the season.
Growth and Yield of Broccoli as Affected by the Nitrogen Content of Transplants and the Timing of Nitrogen Fertilization
Authors: Feller Carmen , Fink Matthias
Published: February 2019

The nitrogen requirement of broccoli (Brassica oleracea var. italica) ranges from 300 to 465 kg·ha–1. Recommendations for N fertilization are accordingly high. High fertilizer rates applied at planting result in a high soil mineral N content that remains high for weeks because the N requirement of the crop is low at early growth stages. Therefore, the risk of leaching is high for several weeks until the available N is finally taken up by the crop. Our study had two objectives: 1) to quantify yield responses to preplant fertilization, and 2) to test our hypothesis that the preplant fertilization rate could be reduced without yield losses by increasing the N content in the transplants and improving crop establishment. Field experiments were carried out on transplants with four levels of N content in dry matter (0.018 to 0.038 g·g–1 dry weight), which were tested in all combinations with four fertilization timings. All treatments received the same amount of N fertilizer (270 and 272 kg·ha–1 in 2001 and 2002, respectively), but with different rates of supply at the time of planting (0 to 90 kg·ha–1 N fertilizer plus 30 and 28 kg·ha–1 soil mineral N in 2001 and 2002, respectively). Total and marketable yields increased significantly with an increasing N supply at time of planting. In our experiments, in which topdressing was applied 25 days after planting, an N supply at planting of 80 to 118 kg·ha–1 was required to obtain maximum marketable yields. The N content in transplants had little effect on growth and yield, and there were no significant interactions between the N content in the transplant and fertilizer timing.
Changes in the Respiration, Growth, and Vitamin C Content of Soybean Sprouts in Response to Chitosan of Different Molecular Weights
Authors: Lee Young-Sang , Kim Yong-Ho , Kim Sung-Bae
Published: February 2019

To study the effects of chitosan on the productivity and nutritional quality of soybean (Glycine max L.) sprouts, soybean seeds were soaked in solutions containing 1,000 ppm chitosan of low (<10 kDa), medium (50 to 100 kDa), or high (>1,000 kDa) molecular weight, and the respiration, growth, and vitamin C content of the sprouts were subsequently evaluated. Sprouts treated with high molecular weight chitosan exhibited a significant increase in respiration, 5%, within 1 day of treatment. Chitosan effectively increased the growth of the sprouts: sprouts treated with high molecular weight chitosan showed increases of 3%, 1%, 3%, 1%, and 12% in the total length, hypocotyl length, root length, hypocotyl thickness, and fresh weight, respectively, as compared to a control. The growth-improving effects of chitosan were proportional to the molecular weight of the molecule used in the treatment. Chitosan treatment did not result in any significant reduction in vitamin C content or postharvest chlorophyll formation, traits that determine the nutritional and marketing values of soybean sprouts. All these results suggest that soaking soybean seeds in a solution of chitosan, especially of high molecular weight, may effectively enhance the productivity of soybean sprouts without adverse effects on the nutritional and postharvest characteristics.
Photosynthetic Daily Light Integral During the Seedling Stage Influences Subsequent Growth and Flowering of Celosia, Impatiens, Salvia, Tagetes, and Viola
Authors: Pramuk Lee Ann , Runkle Erik S.
Published: February 2019

The photosynthetic daily light integral (DLI) dramatically increases during the spring when the majority of bedding plants are commercially produced. However, the effects of DLI on seedling growth and development have not been well characterized for most bedding plant species. Our objectives were to quantify the effects of DLI on growth and development of Celosia, Impatiens, Salvia, Tagetes, and Viola during the seedling stage and determine whether there were any residual effects of DLI on subsequent growth and development after transplant. Seedlings were grown in growth chambers for 18 to 26 days at 21 °C with a DLI ranging from 4.1 to 14.2 mol·m–2·d–1. Average seedling shoot dry weight per internode (a measure of quality) increased linearly 64%, 47%, 64%, and 68% within this DLI range in Celosia, Impatiens, Tagetes, and Viola, respectively. Seedlings were then transplanted to 10-cm containers and grown in a common environment (average daily temperature of 22 °C and DLI of 8.5 mol·m–2·d–1) to determine subsequent effects on plant growth and development. Flowering of Celosia, Impatiens, Salvia, Tagetes, and Viola occurred 10, 12, 11, 4, and 12 days earlier, respectively, when seedlings were previously grown under the highest DLI compared with the lowest. Except for Viola, earlier flowering corresponded with the development of fewer nodes below the first flower. Flower bud number and plant shoot dry weight at first flowering (plant quality parameters) decreased as the seedling DLI increased in all species except for flower number of Tagetes. Therefore, seedlings grown under a greater DLI flowered earlier, but plant quality at first flowering was generally reduced compared with that of seedlings grown under a lower DLI.
Carryover Effects of Prohexadione-calcium on Apples
Authors: Greene Duane W.
Published: February 2019

Proheaxadione-calcium (ProCa) was applied to `Spencer' apple trees at rates between 250 to 750 mg·L–1 after harvest but before leaf fall. The following spring terminal growth was reduced linearly from early petal fall through the growing season to leaf fall. ProCa was applied after harvest and before leaf fall at 500 mg·L–1 to `Spigold' apples. The carryover effect on terminal growth persisted for about 2 weeks after bloom. A combination of 500 and 82.5 mg·L–1 ProCa on `Spigold' in the fall and spring, respectively, reduced terminal growth greater than the individual treatments for about 3 weeks after petal fall. Recent report have shown that ProCa can induce physiological resistance to fire blight and apple scab when applied near petal fall. These data support the suggestion that ProCa may be used as a fall application and the carryover effects may result in early growth control. Potential benefits of the carry-over effects of ProCa for early-season suppression of fire blight and apple scab are discussed.