bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistance of Blueberry Cultivars to Botryosphaeria Stem Blight and Phomopsis Twig Blight
Authors: Polashock James J. , Kramer Matthew
Published: February 2019

Stem diseases of blueberry (Vaccinium spp.) can cause significant crop loss as well as loss of entire bushes. Stem diseases are also more difficult to control with fungicides than foliar or fruit diseases. A screening program was initiated to test blueberry cultivars for resistance to two pathogenic fungi: botryosphaeria stem blight and phomopsis twig blight. An attached stem assay was developed to compare the host response with both fungi. The relative resistance of 50 blueberry cultivars was assessed using stem lesion lengths, analyzed on a log scale, taken at 4 weeks postinoculation. For Botryosphaeria stem blight, mean lesion length ranged from about 10 mm in resistant cultivars to about 140 mm in susceptible cultivars. The half-high cultivars Northsky, Northblue, and Chippewa, and the lowbush cultivar Putte were among the most resistant. Phomopsis twig blight lesions ranged in mean length from about 18 to 98 mm. Similar to results for Botryosphaeria stem blight, resistance was limited to half-high (`Northsky' and `Chippewa') and lowbush (`Blomidon', `Chignecto', and `Cumberland') cultivars. Individual cultivars resistant to one pathogen were not necessarily resistant to the other; although, overall, the resistances were correlated. Approximate 95% confidence intervals were established for all cultivars to predict mean performance across years. The cultivars tested varied in resistance, but the largest single factor affecting lesion length was the fungal isolate used for inoculations. These data enable us to identify cultivars resistant to both diseases that can be used for planting in problem areas, as well as selection of parental material for breeding cultivars with improved resistance.
Nitric Oxide and Nitrite Treatments Reduce Ethylene Evolution from Apple Fruit Disks
Authors: Rudell David R. , Mattheis James P.
Published: February 2019

`Golden Delicious' apple [Malus sylvestris var. domestica (Borkh.)] cortex disks suspended in solutions containing a nitric oxide (•NO) donor [S-nitrosoglutathione (GSNO) or sodium nitroprusside (SNP)], •NO gas, or nitrite (KNO2) were used to identify impacts of •NO on ethylene production and NO2– on •NO and ethylene production. Treatment with GSNO or SNP reduced ethylene biosynthesis compared with control treatments containing equimolar concentrations of oxidized glutathione (GSSG) or Na4(CN)6 respectively. Apple disk exposure to •NO gas did not impact ethylene production. Treatment with NO2– resulted in increased •NO production and decreased ethylene biosynthesis. Generation of •NO increased linearly whereas ethylene generation decreased exponentially with increasing NO2– treatment concentration. •NO was enhanced in autoclaved tissue disks treated with NO2–, suggesting that its production is produced at least in part by nonenzymatic means. Although this evidence shows •NO is readily generated in apple fruit disks by NO2– treatment, and ethylene synthesis is reduced by •NO/NO2– generated in solution, the exact nature of •NO generation from NO2– and ethylene synthesis modulation in apple fruit disks remains to be elucidated.
Genomic Variation in Micropropagated Robinia ambigua `idahoensis' Revealed by RAPD Markers
Authors: Ngezahayo Frederic , Guo Wanli , Gong Lei , Li Fangxia , Liu Bao , Dong Yingshan
Published: February 2019

The authors have previously reported an efficient in vitro system for mass micropropagation of Robinia ambigua `idahoensis' (Idaho locust). Their method used enhanced branching of axillary buds from a single donor plant along with detection of somaclonal variation by the intersimple sequence repeat (ISSR) markers. Because ISSRs tend to be clustered to specific chromosomal regions in plant genomes, the extent and scope of the genomic variations and the sequences underlying the variation warranted further investigations. In this study, the authors analyzed the same set of 40 randomly selected micropropagated R. ambigua plants by a more general molecular marker—random amplified polymorphic DNA (RAPD) using 34 selected primers. In addition, they sequenced some of the variable bands. Of the 260 reproducible RAPD bands scored, 70 were polymorphic among the 41 plants (40 micropropagated and one donor), corresponding to a polymorphism level of 26%. Cluster analysis revealed a genetic similarity ranging from 0.61 to 0.97. Of the 20 sequenced bands underlying the variations, eight showed significant homology to known or predicted functional cellular genes or retroelements. These results clearly indicated that micropropagation of R. ambigua, even by enhanced branching of axillary buds, can be accompanied by extensive genomic variations, which should be taken into account for commercial propagation of this plant by in vitro means.
Physical and Chemical Properties of Substrates Containing Earthworm Castings and Effects on Marigold Growth
Authors: Hidalgo Pablo R. , Matta Frank B. , Harkess Richard L.
Published: February 2019

The effects of various substrates with or without earthworm [Eisenia fetida (Savigny, 1826] castings on growth of marigolds were evaluated. In addition, the physical and chemical properties of such substrates were determined. Castings had a greater nutrient content than the remaining substrates. The 4 pine bark: 1 sand treatment (v/v) (PBS) had higher P, K, and Zn than 7 peat moss: 3 perlite (v/v) (PP). PP had the lowest nutrient content of all substrates. Castings (C) had the highest pH followed by 1 PBS: 1 C (v/v), 2 PBS: 1C (v/v) and 3 PBS: 1C (v/v). Sunshine Mix 1 and PP had the lowest pH. EC (ER) was increased by castings, which had high ER. Castings and PP had the greatest percentage pore space. Water-holding capacity was greatest for 2 PBS: 1C (v/v) compared with Sunshine Mix 1 followed by castings. Earthworm castings increased plant growth index, stem diameter, root growth, dry weight, and flower number of marigolds compared with PP, Sunshine Mix 1, and PBS. All mixtures of castings (C) with PP, PBS, except 3 PBS: 1C (v/v), increase the growth index of plants. 1 PP: 1 C (v/v), increased flower number compared with all substrates without castings. Castings alone increased number of open flowers, but did not differ from 1 PP: 1 C or 3 PP:1 C.
Response of Grafted Juglans nigra to Increasing Nutrient Availability: Growth, Nutrition, and Nutrient Retention in Root Plugs
Authors: Salifu K. Francis , Jacobs Douglass F. , Pardillo Guillermo , Schott Mary
Published: February 2019

We examined growth and nitrogen (N), phosphorus (P), potassium (K), and microelement nutrition of grafted black walnut (Juglans nigra L.) seedlings exposed to increasing nutrient supply and grown in the greenhouse for 18 week. Plants were potted and grafted within the first 4 week, then fertigated once each week for a 7-week period with a varying nutrient solution of 20N–4.4P–16.6K that delivered 0, 1160, 2320, and 4620 mg N/plant. Plants were harvested at week 18. There was a positive mean growth response to increased fertilization, although trends were statistically similar across treatments. Leaf nutrient concentration ranged from 22 to 31 g · kg–1 N, 5 to 14 g · kg–1 P, and 19 to 25 g · kg–1 K. The 2320 mg N/plant treatment increased leaf nutrient content 18% to 86% for N, 33% to 303% for P, and 23% to 58% for K compared with the control. Nitrogen efficiency decreased with increased N supply. Increased nutrient retention in the growing medium at higher fertility suggests root plugs could serve as immediate critical nutrient sources for grafted black walnut seedlings after outplanting. Study results suggests nursery fertilization can be used to improve the nutritional quality of grafted black walnut as well as store nutrients in root plugs for later utilization to benefit early establishment success.
Relative Salt Tolerance of Five Herbaceous Perennials
Authors: Niu Genhua , Rodriguez Denise S.
Published: February 2019

Use of recycled water to irrigate urban landscapes may be inevitable, because the freshwater supply has been diminishing and the population continues to grow in the arid and semiarid southwestern United States. However, little information exists on the performance of landscape plants irrigated with nonpotable water. Two greenhouse studies were conducted during the summer and the fall to characterize the relative salt tolerance of five herbaceous perennials by irrigating the plants with a saline solution at an electrical conductivity (EC) of 0.8 dS·m–1 (tap water), 2.0 dS·m–1, or 4.0 dS·m–1. In the summer study, after 10 weeks of treatment, Achillea millefolium L., Gaillardia aristata Foug., and Salvia coccinea Juss ex J. had an aesthetically acceptable appearance for landscape performance (visual quality scores of 4 points or more), whereas Agastache cana (Hook.) Woot. & Standl. and Echinacea purpurea (L.) Moench had relatively low tolerance to salinity. Dry weight of shoots of A. millefolium, A. cana, and G. arstata was lower at elevated salinity levels. In the fall study, A. millefolium, E. purpurea, G. arstata, and S. coccinea had acceptable growth and visual quality at elevated salinity levels, whereas A. cana had lower quality and reduced growth. Dry weight of shoots was lower in G. arstata and A. millefolium at an EC of 2.0 dS·m–1 or 4.0 dS·m–1. Leaf osmotic potential of all species in the summer experiment was significantly lower at higher salinity compared with the control. In the fall experiment, leaf osmotic potential in A. millefolium, E. purpurea, and G. aristata at 4 dS·m–1 was lower compared with lower salinity treatment and the control. Leaf osmotic potential in the fall was higher than that of the same species at the same salinity level in the summer experiment, indicating that plants in the fall were less stressed than in the summer. Combined the results from both experiments, the authors concluded that A. millefolium, G. arstata, and S. coccinea had a relatively high salt tolerance (as much as 4 dS·m–1 of irrigation water under greenhouse conditions) among the tested species, whereas A. cana and E. purpurea were not tolerant to salt and should not be irrigated with low-quality water.
Potential of Citrus junos Fruit Waste From the Food Processing Industry for Weed Management
Authors: Kato-Noguchi Hisashi , Tanaka Yukitoshi
Published: February 2019

The allelopathic potential of Citrus junos Tanaka waste from food processing industry after juice extraction was investigated under laboratory conditions. C. junos waste powder inhibited the growth of roots and shoots of alfalfa (Medicago sativa L.), cress (Lepidium sativum L.), lettuce (Lactuca sativa L.), crabgrass (Digitaria sanguinalis L.), timothy (Phleum pratense L.) and ryegrass (Lolium multiflorum Lam.). Significant reductions in the growth of roots and shoots were observed as the powder concentration increased. The concentration of abscisic acid-β-d-glucopyranosyl ester (ABA-GE) in C. junos waste was determined to be 17.9 mg · kg–1 dry weight. Its concentration in C. junos waste appears to account mostly for the observed inhibition of tested plant seedlings. These results indicate that C. junos waste is allelopathic with potential for use in agriculture to suppress weed emergence, which should be investigated further in the field.
Critical Period for Weed Control in Leek (Allium porrum L.)
Authors: Tursun Nihat , Bükün Bekir , Karacan Sinan Can , Ngouajio Mathieu , Mennan Hüsrev
Published: February 2019

Field studies were conducted in Mersin, Turkey, in 2002 and 2003 to determine the critical period for weed control in leek and to investigate the effects of weed interference on weed biomass. The critical period for weed control in leek based on a 5% acceptable yield loss level was calculated by fitting logistic and Gompertz equations to relative yield data. Total fresh biomass of weeds increased as the duration of weed infestation increased. The beginning of the critical period for weed control was 7 days after transplanting in 2002 and 13 days after transplanting in 2003. The end of the critical period for weed control was 85 days after transplanting in 2002 and 60 days after transplanting in 2003. Results of this study suggest that leek should be kept weed free between 7 days after transplanting and 85 days after transplanting to avoid yield losses in excess of 5%.
Development of Molecular Markers Linked to Cladosporium fulvum Resistant Gene Cf-6 in Tomato by RAPD and SSR Methods
Authors: Wang Aoxue , Meng Fanjuan , Xu Xiangyang , Wang Yong , Li Jingfu
Published: February 2019

Leaf mold, caused by the fungus Cladosporium fulvum, is a serious disease of tomato. In the current study, the main physiological races of C. fulvum collected from three northeastern provinces of China were identified using a set of identification hosts. The results showed that the prevalent pathogenic physiological races were 1.2.3, 1.3, 3, 1.2.3.4, and 1.2.4. F1, F2, and BC1 tomato plants were obtained by crossing C. fulvum-resistant cultivar 03748 carrying the Cf-6 gene and susceptible cultivar 03036. Three 10-mer oligonucleotide random amplified polymorphic DNA (RAPD) primers and two simple sequence repeat (SSR) primers were selected for the further molecular marking analysis after 210 RAPD primers and 50 SSR primers were screened using the bulked segregate analysis method. The polymorphic DNA bands were amplified among parents, 10 F1 plants, 184 F2 plants including 145 resistant plants and 39 sensitive plants using three RAPD primers and two SSR primers so that three RAPD molecular markers and two SSR molecular markers linked to the Cf-6 loci were identified. Three RAPD markers were linked to the Cf-6 resistant locus separated with 8.7 cM, 20.3 cM, and 33.4 cM. Also, one RAPD codominant marker S374619/559 was found. The locations of the two SSR markers were 12.6 cM and 9.7 cM away from the Cf-6 locus. After cloning and sequencing two specific DNA fragments closely connected to the Cf-6 resistant and susceptible alleles respectively, in the RAPD codominant marker S374619/559 and one codominant sequence characterized amplified region marker S674619/559 was converted from RAPD marker S374619/559. In the RAPD marker S374619/559, the length difference of two specific fragments, 619-bp fragment and 559-bp fragment, is the result of one insertion (60 bp) in the 619-bp fragment. These markers will facilitate the selection of resistant tomato germplasm containing the Cf-6 gene and cloning of Cf-6 to breed new C. fulvum resistant tomato cultivars.
Response of Eight Sweet Corn (Zea mays L.) Hybrids to Topramezone
Authors: Soltani Nader , Sikkema Peter H. , Zandstra John , O'Sullivan John , Robinson Darren E.
Published: February 2019

Topramezone is a newly introduced herbicide for use in field corn (Zea mays L.) that may have potential for weed management in sweet corn. Tolerance of eight sweet corn hybrids to topramezone applied postemergence (POST) at 0, 50, 75, 100, 150, and 300 g a.i. ha−
1 were studied at one Ontario location in 2000 and two locations in 2001 and 2002. Topramezone applied POST at 50, 75, 100, and 150 g·ha−
1 did not cause any visual injury in Calico Belle, CNS 710, Delmonte 2038, FTF 222, FTF 246, GH 2684, Reveille, and Rival sweet corn hybrids at 7 days after treatment (DAT) and caused minimal injury (less than 5%) at 300 g·ha−
1 in all hybrids. The initial sensitivity observed in these hybrids was minimal and transient with no effect on visual injury at 14 and 28 DAT. Topramezone applied POST did not reduce plant height, cob size, or marketable yield of the sweet corn hybrids included in this study. Based on these results, topramezone applied POST at the rates evaluated can be safely applied to Calico Belle, CNS 710, Delmonte 2038, FTF 222, FTF 246, GH 2684, Reveille, and Rival sweet corn.
Beneficial Role of 1-Methylcyclopropene for Cut Lupinus havardii Racemes Exposed to Ethephon
Authors: Valenzuela-Vázquez Mario , Picchioni Geno A. , Murray Leigh W. , Mackay Wayne A.
Published: February 2019

The raceme of Lupinus havardii Wats. (Big Bend bluebonnet) is a new greenhouse specialty cut flower, but postharvest life is limited by ethylene sensitivity. The authors studied the effects of 160 nL·L−1 1-methylcyclopropene (1-MCP) with 0 to 6 days exposure to a 50-μm vase solution of ethephon [(2-chloroethyl) phosphonic acid, CEPA] on raceme postharvest quality indices and mature flower cell membrane permeability. With no CEPA, 1-MCP delayed postharvest losses in fresh weight and mature flower retention, and extended vase life longevity (VLL) by 1 to 4 days relative to a non-1-MCP control. With 2 days or more of CEPA, 1-MCP deferred raceme fresh weight loss and the abscission of both mature and newly opened flowers from 3 days to 5 days. There was a relatively strong protective effect of 1-MCP on raceme fresh weight, flower retention, and newly opening flowers in the presence of CEPA compared with the absence of CEPA. The greatest raceme VLL (7.2 days) was obtained for 1-MCP-treated racemes that did not receive CEPA in the vase. Although VLL was reduced by CEPA, VLL was consistently greater (by ≈2 days) after 1-MCP treatment relative to no 1-MCP treatment and irrespective of CEPA's duration. As expected, electrolyte leakage increased with individual flower development and between 1 day and 6 days in the vase. Unexpectedly, however, the 5-day postharvest increase in leakage was intensified by 1-MCP treatment if the racemes were exposed to 1 hour of CEPA in the vase solution. Electrical conductivity measurements suggested that, in the latter treatment (+1-MCP, +CEPA), increased levels of diffusible electrolytes that had yet to be exported to the expanding apical meristem (delayed raceme development) contributed to the higher leakage. Results also demonstrate good potential for quality maintenance of L. havardii racemes by using 1-MCP, and that in addition to flower retention, raceme fresh weight and flower opening should be considered in developing VLL criteria for this new specialty crop.
Agrobacterium-Mediated Transformation of Chokecherry (Prunus virginiana L.)
Authors: Dai Wenhao , Magnusson Victoria , Johnson Chris
Published: February 2019

Chokecherry (Prunus virginiana L.) was transformed using Agrobacterium tumefaciens strain EHA105 harboring binary vector pBI121 carrying the neomycin phosphotransferase gene (nptII) and β-glucuronidase (GUS) gene (uidA). Plants were regenerated from the Agrobacterium-infected leaf tissues through organogenesis on woody plant medium (WPM) supplemented with MS (Murashige and Skoog) vitamins, 10 μm 6-benzyladenine (BA), and 250 mg·L−1 cefotaxime plus 500 mg·L−1 carbenicillin plus 15 mg·L−1kanamycin (CCK15). Transformation was verified with polymerase chain reaction (PCR) and Southern blot analysis. Four of 150 (2.67%) initial explants produced GUS- and PCR-positive shoots. Southern blot analysis confirmed that the transgenes were integrated into the chokecherry genome. Transgenic in vitro shoots were rooted in half-strength MS medium containing 10 μm naphthalene acetic acid. Rooted plants were transferred to potting mix and grown in the greenhouse. This research shows a potential for future improvement of chokecherry and other Prunus species. Chemical names used: 6-benzyladenine (BA), naphthalene acetic acid (NAA), acetosyringone (AS), 5-Bromo-4-chloro-3-indoxyl-beta-D-glucuronide cyclohexylammonium (X-Glu), cefotaxime, carbenicillin, kanamycin.
Analysis of Powdery Mildew-resistant Dogwood Accessions Using AFLP
Authors: Mmbaga, Margaret T. , Sauvé, Roger J.
Published: February 2019

Twenty-five dogwood accessions (one Cornus kousa, three C. kousa × C. florida hybrids, and 21 C. florida) were characterized using amplified fragment length polymorphism. Among the C. florida accessions, four were named cultivars and 17 were selections from Tennessee State University's dogwood breeding program. Amplified fragment length polymorphism band profiles obtained from 13 EcoRI/MseI (+3/+3) primer pairs showed the presence of high genetic diversity between species and within the C. florida accessions. Each accession was distinctly different from each other, and the resistant clones clustered into distinct groups.
Reproductive Behavior of Diploid and Allotetraploid Rhododendron L. ‘Fragrant Affinity’
Authors: Contreras Ryan N. , Ranney Thomas G. , Tallury Shyamalrau P.
Published: February 2019

Wide hybridization can lead to recombination of diverse traits and creation of unique phenotypes, but the resultant hybrids are often sterile as is the case with the intersubgeneric hybrid Rhododendron L. ‘Fragrant Affinity’. Sterility in wide hybrids can either be genic or chromosomal; the latter may be overcome by induction of polyploidy, which can restore chromosome homology and fertility. Cytologic studies of ‘Fragrant Affinity’ appear to support the presence of bridges between bivalents in metaphase I and laggard chromosomes in anaphase I. In the current study, an allotetraploid form of R. ‘Fragrant Affinity’ was developed using oryzalin (4-(dipropylamino)-3, 5-dinitro-benzenesulfonamide) as a mitotic inhibitor and chromosomal doubling agent. Genome sizes (2C) were determined using flow cytometry and found to be ≈1.6 and 3.2 pg for the diploid and allotetraploid, respectively. Pollen viability, determined by staining and germination tests, was 4% and 0%, respectively, for the diploid and 68% and 45%, respectively, for the allotetraploid. No seeds were produced when the diploid R. ‘Fragrant Affinity’ was used as a pistillate parent when pollinated with pollen from viable diploid and tetraploid parents. The allotetraploid produced viable seeds and seedlings when pollinated with pollen from either diploid or tetraploid parents, including self-pollination, demonstrating restored male and female fertility.
Introgression of Novel Alleles for Partial Resistance to Big Vein Disease from Lactuca virosa into Cultivated Lettuce
Authors: Hayes Ryan J. , Ryder Edward J.
Published: February 2019

Big vein is an economically damaging disease of lettuce (Lactuca sativa L.) incited by Mirafiori lettuce big vein virus, which is vectored by the soil-borne fungus Olpidium brassicae (Woronin) P.A. Dang. Resistance to this disease is needed because no feasible cultural control methods have been identified. Partial resistance is available within cultivated lettuce and is expressed as delayed appearance of symptoms in combination with a reduced percentage of symptomatic plants. Complete resistance has been identified only in accessions of L. virosa L., an incongruent wild relative of lettuce. Resistance from L. virosa has not been introgressed into lettuce. The objective of this research was to determine whether big vein resistance from L. virosa can be introgressed into lettuce. Progenies of backcross (BC) hybrids between L. virosa and L. sativa cultivars were greenhouse tested for big vein resistance over four generations of self-pollination. Selected plants from resistant BC families were used as parents to create BC2 progeny from crosses with high partial-resistant cultivars, intermediate partial-resistant cultivars, and susceptible cultivars to test for the presence of transgressive segregants. Experiments were conducted in the greenhouse by infecting seedlings with O. brassicae zoospores collected from big vein symptomatic plants. Plots were evaluated for area under the disease progress curve and the percentage of symptomatic plants; asymptomatic plants from resistant families were retained in every generation. Complete resistance to big vein was not recovered, and may be the result of insufficient sampling of BCF2 progeny or linkage between resistance alleles and alleles causing incongruity. Variation for partial resistance was observed in all BC generations, and transgressive segregants were identified among BC2 families from crosses using partially resistant and susceptible parents. This research suggests that L. virosa contains alleles that confer partial resistance to big vein when introgressed into an L. sativa background, and these alleles are distinct from those present in partially resistant lettuce cultivars. Alternative breeding strategies should be pursued to introgress complete resistance from L. virosa into cultivated lettuce.
DNA-based S-genotyping of Japanese Plum and Pluot Cultivars to Clarify Incompatibility Relationships
Authors: Halász Júlia , Hegedűs Attila , Szabó Zoltán , Nyéki József , Pedryc Andrzej
Published: February 2019

Diploid japanese plum (Prunus salicina Lindl.) cultivars are commonly self-incompatible. To date, 14 incompatibility alleles (S-alleles) have been identified and labeled with alphabetical (S
a-S
n) and 5 with numeric codes (S
1, S
3-S
6). We applied polymerase chain reaction amplification of the S-RNase alleles with degenerate and allele-specific primers in 10 japanese plum cultivars and two pluots of unknown incompatibility alleles. Besides DNA sequencing, an additional method for the exact length determination of the first intron region was used for the first time for S-genotype japanese plums. The S
3-allele was shown to correspond to S
k in the alphabetic nomenclature, S
4 to S
c, S
5 to S
e, and S
6 to S
f. The S
5-allele-specific primer can be used as a reliable marker for self-compatibility in japanese plum. ‘Black Amber’, ‘October Sun’, ‘TC Sun’, and ‘Super Giant’ share the S
b
S
c genotype, which was confirmed by test crosses. These cultivars belong to the widest incompatibility group currently known in japanese plum. An additional incompatibility group (S
c
S
h) was established, including ‘Green Sun’ and ‘Queen Rosa’, a cultivar formerly known as a universal donor. By incorporating all previous and recent results, a table was assembled including 49 cultivars assigned to I–VII incompatibility groups, to the self-compatible group and to the group O of unique genotypes. These data may considerably contribute to further growing and breeding activities.
Development of pGreen-derived GFP Binary Vectors for Citrus Transformation
Authors: Chen Chunxian , Zheng Qifa , Xiang Xu , Soneji Jaya R. , Huang Shu , Choi Young A , Nageswara Rao Madhugiri , Gmitter Fred G.
Published: February 2019

Eight new green fluorescent protein (GFP) binary vectors were developed by inserting gfp reporter gene cassettes into pGreen vectors. We chose one of them, pG52KF, with the nptII selection and gfp reporter gene and one recombinant construct, pG52KFp, for a preliminary evaluation in citrus using Agrobacterium-mediated transformation. High-transformation efficiency was observed, whereas green fluorescence greatly facilitated the early in vivo screening and categorizing of the transformants. These pGreen-derived GFP binary vectors, freely available on request, provide more and flexible options for genetic transformation in citrus and other woody plants.
Dry Matter Partitioning, Carbohydrate Composition, Protein Reserves, and Fruiting in ‘Autumn Bliss’ Red Raspberry Vary in Response to Pruning Date and Cane Density
Authors: de Oliveira Pedro Brás , Silva Maria José , Ferreira Ricardo B. , Oliveira Cristina M. , Monteiro António A.
Published: February 2019

In a 2-year experiment (1994 and 1995), plants of primocane-fruiting red raspberry cultivar ‘Autumn Bliss’ grown in a plastic greenhouse were destructively harvested at different growth stages to determine the effect of pruning date and cane density on dry matter distribution, carbohydrate concentration, and soluble protein concentration in different plant parts. Three summer-pruning dates (early, mid, and late July) and four cane densities (8, 16, 24, and 32 canes/m row) were imposed. Relative root biomass decreased from pruning to first flower stage and remained constant thereafter for all pruning dates. Earlier pruning dates corresponded to earlier fruit production, but yield was significantly reduced on later pruning dates and higher cane densities. Sucrose concentration was higher in fine roots than in suberized roots and had a slight decrease during flowering and the beginning of harvest. Soluble protein concentrations did not differ significantly between pruning dates. Reserve carbohydrates in the root system were unaffected by pruning and cane density, and were rapidly used during active vegetative growth, began to recover just after bloom, and were fully recovered at the end of the season. Our experiment suggested that in red raspberry plants grown under poor environmental conditions, current yield is reduced but there is enough carbohydrate accumulation to support next year's growth.
Characteristics of Grapevine (Vitis vinifera L.) ‘Albariño’ Clones Resulting from Two Clonal Selections
Authors: Alonso Susana Boso , Pilar Gago Virginia Alonso-Villaverde , Santiago José L. , Martínez Mariá C. , Rodriguez Emilio
Published: February 2019

The grapevine cultivar Albariño (Vitis vinifera L.) is one of the most economically important of northwestern Spain. It is also grown in northern Portugal. The present work examines the results obtained by two clonal selection processes involving this cultivar. The first of these was begun in 1987 by the Viticulture Research Group of the Spanish Research Council (CSIC). This involved centuries-old mother plants showing small ampelographic or agronomic differences. The second process was begun in 1989 by the wine-making company Bodegas Terras Gauda S.A. This involved the use of centuries-old ‘Albariño’ plants too, but also of other plants no older than 20 years of age. The number of mother plants originally examined in the CISC procedure was 40, but only eight were finally selected and planted (at the Misión Biológica de Galicia Research Station). In the procedure followed by Bodegas Terras Gauda S.A., 115 mother plants were originally planted. The characteristics of the eight CSIC clones and the 22 surviving Bodegas Terras Gauda S.A. clones were determined. The variability of the eight CSIC clones was found to be greater. It is recommended that candidate materials for use in clonal selection programs be examined for differences in situ before being admitted to collections.
Past, Present, and Future of Fruit Germplasm Exploration
Authors: Hummer Kim E.
Published: February 2019

The fruits of the earth have healed, nurtured, and intrigued humanity throughout history. Cultivated fruit species have complex genome that will continue to require the input of novel genetic resources. Prospecting for wild fruit species will continue. The global nature of science and commerce will drive the demand to expand available genetic resources for fruit improvement. New technologies will enable future explorers to reach remote sites and species. Recent advances, such as geopositioning and remote-communication devices, will be used to a greater degree for targeting specific collection sites and documenting records of origin. The sovereignty of countries over their plant genetic resources, as specified by the Convention on Biological Diversity and the International Treaty on Plant Genetic Resources for Food and Agriculture, will continue to be a cornerstone for negotiating bilateral agreements and plant exchange. Although this could be considered a limitation to plant exploration in some situations, global strategies now in conceptual infancy will be developed to encourage and support ex situ preservation and continued plant exchange for long-term conservation and humanitarian benefit.
DNA Markers from Different Linkage Regions of Watermelon Genome Useful in Differentiating among Closely Related Watermelon Genotypes
Authors: Levi Amnon , Thomas Claude E.
Published: February 2019

A genetic linkage map was previously constructed for watermelon using a wide testcross population [{Plant Accession Griffin 14113; Citrullus lanatus var. citroides (L.H. Baiely) Mansf.} × the watermelon cultivar New Hampshire Midget; NHM {(Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus)} × United States Plant Introduction (PI) 386015 {Citrullus colocynthis (L.) Schrad.}]. One-hundred forty-six markers [randomly amplified polymorphic DNA (RAPD), intersimple sequence repeat (ISSR), amplified fragment length polymorphism (AFLP), and sequence-related amplified polymorphism (SRAP) markers] unique to NHM and representing different linkage groups on the map were tested for polymorphism among 24 watermelon cultivars limited in genetic diversity. Five (9.4%) of 53 RAPD, six (40.0%) of 15 ISSR, 30 (81.0%) of 37 AFLP, and 33 (80.5%) of 41 SRAP markers tested produced polymorphism among the 24 cultivars. The polymorphic markers used in this study are scattered throughout the watermelon genome. However, a large number (19 of the 30) of AFLP markers clustered on one linkage group on the map. The SRAP markers proved to be most effective in producing polymorphism and in representing different linkage regions of watermelon genome. The polymorphic markers represent all 10 large linkage groups and five of the nine small linkage groups (altogether 15 of 19 linkage groups) of the genetic linkage map constructed so far for watermelon. These polymorphic markers can be useful in DNA fingerprinting of cultivars, in testing seed purity of breeding lines, and in identifying triploid (seedless) hybrid watermelons derived from crosses between closely related tetraploid and diploid lines.
‘Bhut Jolokia’—The World's Hottest Known Chile Pepper is a Putative Naturally Occurring Interspecific Hybrid
Authors: Bosland Paul W. , Baral Jit B.
Published: February 2019

In replicated trials at Las Cruces, N.M., the Scoville heat units (SHUs) of ‘Bhut Jolokia’, a chile pepper from Assam, India, reached one million SHUs. Morphologic characters revealed that ‘Bhut Jolokia’ is a Capsicum chinense Jacq. cultivar. Molecular analysis with randomly amplified polymorphic DNA markers confirmed the species identification and, interestingly, revealed that there may have been genetic introgression from Capsicum frutescens L. into ‘Bhut Jolokia’.
A Graft-transmissible RNA from Tomato Rootstock Changes Leaf Morphology of Potato Scion
Authors: Kudo Hisayuki , Harada Takeo
Published: February 2019

Heterografting experiments were conducted using potato (Solanum tuberosum) as scion and tomato (Lycopersicon esculentum) as stock to test whether an RNA molecule responsible for changing leaf shape can be transported and function across the grafting junction. Results showed that a graft-transmissible RNA from the tomato rootstock without any leaves can indeed change leaf morphology of the potato scion. Therefore, if a transgenic stock plant with acquired RNA transport competence could be constructed, it would provide an effective system for transformation of scion plants. This combination of grafting and RNA transport could provide a novel technique for cultivar improvement in horticultural crops.
Improving the Efficacy of Cytokinin Applications for Stimulation of Lateral Branch Development in Young Sweet Cherry Trees in the Orchard
Authors: Elfving Don C. , Visser Dwayne B.
Published: February 2019

Improving lateral branch development in young sweet cherry trees without reliance on pruning is a desirable component of tree training programs, especially for high-density systems. Applications of two proprietary formulations of 6-benzyladenine and gibberellins A4 and A7 (Promalin, Valent Biosciences, Walnut Creek, Calif.; and Perlan, Fine Americas, Walnut Creek, Calif.) to individual buds or intact bark of unpruned sweet cherry central leader shoots at green-tip had little effect on lateral shoot growth from buds or on distribution of new shoot growth along the treated leader shoots. Scoring, nicking, or notching cuts alone also had inconsistent effects on shoot development and distribution. In some trials, bud removal (or disbudding, removing every fourth bud on 1-year-old shoots) produced limited improvement of lateral shoot development and vertical distribution. Combining nicking, notching, scoring, or bark scraping with the application of cytokinin–gibberellic acid solution to the cut area greatly improved both number of shoots developed and the numbers originating from the lower portions of treated leader shoots. Removing the physical barrier to bioregulator product contact with active tissues was a primary factor in improving treatment efficacy.
Foliar-applied GA3 Advances Fruit Maturity and Allows Off-season Harvest of ‘Hass’ Avocado
Authors: Salazar-García Samuel , Cossio-Vargas Luis E. , González-Durán Isidro J.L. , Lovatt Carol J.
Published: February 2019

Michoacán and Nayarit are, respectively, the largest and second largest avocado-producing states in Mexico. The main harvest of the ‘Hass’ avocado in both states is concentrated during November to December, which saturates the market and reduces the price of fruit and grower income. The goal of this research was to manipulate vegetative and reproductive growth of the ‘Hass’ avocado with properly timed foliar-applied plant bioregulators (PBRs) to shift the date of flowering and harvest to the period before or after the main harvest. Effects of canopy sprays of gibberellic acid (GA3) or prohexadione calcium (a gibberellic acid biosynthesis inhibitor) applied at different stages of tree phenology on inflorescence development, time of anthesis, date of legal maturity for harvest of ‘Hass’ avocado fruit, yield, and fruit size were quantified. No PBR treatment influenced the time of anthesis. A single or double foliar application of GA3 (50 mg·L−1) ≈4 months (July) before the expected date of main harvest (November) resulted in ‘Hass’ avocado fruit reaching legal maturity (mesocarp dry matter 21.5% or greater) 24.8 to 28.2 d earlier than those of untreated control trees with no negative effect on yield or fruit size.
Management and Yield Impact of the Greenhouse Whitefly (Trialeurodes vaporariorum) on California Strawberries
Authors: McKee Gregory J. , Zalom Frank G. , Goodhue Rachael E.
Published: February 2019

Reductions in strawberry yields were observed in association with infestations of the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). The magnitude of yield impact is estimated using data from a field experiment evaluating nine management approaches for the greenhouse whitefly on strawberries, var. Camarosa. A range of effectiveness and yields was found. Imidacloprid (Admire) applied at transplanting was found to provide the greatest effect on adult whitefly densities. Pyriproxyfen (Esteem) had no immediate effect on adult density but reduced nymphal densities over time. Pairing the use of these products at transplant (Admire) and early spring (Esteem) provided the greatest reduction in whitefly density observed relative to an untreated control. Reductions in strawberry yields were found to increase as whitefly densities grow or as populations persist over time. For example, the estimates from our analysis suggest that at 20 weeks after planting, an average whitefly population may reduce average weekly yields in an untreated field by ≈80 g/plant.
In vitro Sugar and Water Use in Diploid and Tetraploid Genotypes of Daylily (Hemerocallis spp.) in Liquid Medium as Affected by Density and Plant Growth Regulators
Authors: Adelberg Jeffrey , Delgado Maria , Tomkins Jeffrey
Published: February 2019

Two tetraploid and two diploid genotypes of Hemerocallis spp. were micropropagated on an orbital shaker in Murashige and Skoog liquid medium in a factorial combination of two sucrose concentrations (90 mm and 180 mm), two 6-benzylaminopurine (benzyladenine) concentrations (0.32 μm and 3.2 μm), at two densities (57 explants/L and 171 explants/L), in the presence (0.32 μm) and absence of α-cyclopyl-α-[4-mehtoxyphenyl]-5-pyrimididinmethanol (ancymidol). There were linear relationships between fresh weight and water use (R
2 = 0.800, P < 0.0001), dry weight and sucrose use (R
2 = 0.636, P < 0.0001), and relative dry weight (dry weight/fresh weight = relative dry weight) to concentration of sucrose residual in medium after culture (R
2 = 0.553, P < 0.0001). Eighty-five percent of the water used and 74% of the sucrose used were incorporated as plant fresh weight and dry weight, respectively. A 1% increase in percent sucrose residual (mass/volume in spent medium) was correlated to an increase of 1.8% relative dry weight over the range 7% to 22% relative dry weight. In vessels with 90 mm initial sucrose, where the most growth had occurred (>15 g fresh weight), sucrose was depleted (<0.2% sucrose) and plantlets had the lowest relative dry weight (≈6.9%). In vessels from 180 mm initial sucrose, with similarly high fresh weight, plantlets had 12.0% relative dry weight with 2.1% sucrose residual in medium. Fresh weight, dry weight, or relative dry weight of plantlets in the laboratory did not correlate with subsequent survival or growth in the greenhouse. Plantlets grown without ancymidol at the lower benzyladenine concentration acclimatized to the greenhouse with 93% survival. However, greenhouse survival of plants grown with ancymidol and a higher level of benzyladenine was only 4%. ‘Barbara Mitchell’ was the largest plant in the laboratory, but often had poorest growth in the greenhouse. When optimizing a liquid micropropagation protocol for larger vessels, sucrose and water requirements may be directly related to targeted biomass yield, but each genotype needs to be handled independently with ex vitro validation of plant vigor.
Irrigation Affects Landscape Establishment of Burford Holly, Pittosporum, and Sweet Viburnum
Authors: Scheiber S.M. , Gilman E.F. , Paz M. , Moore K.A.
Published: February 2019

Ilex cornuta Lindl. & Paxt. ‘Burfordii Nana’ (dwarf burford holly), Pittosporum tobira [Dryand]. ‘Variegata’ (pittosporum), and Viburnum odorotissimum Ker Gawl. (sweet viburnum) were transplanted into field plots in an open-sided, clear polyethylene-covered shelter to evaluate growth, aesthetic quality, and establishment rates in response to 2-, 4-, or 7-d irrigation frequencies. Establishment was delayed 1 to 2 months for I. cornuta ‘Burrford Nana’ irrigated every 7 d compared with 2- and 4-d frequencies; however, growth and aesthetic quality were similar among treatments. Plants irrigated every 7 d also had higher cumulative water stress levels. Leaf area, shoot dry weight, and total biomass increased among P. tobira ‘Variegata’ and V. odorotissimum irrigated every 2 d. Pittosporum tobira ‘Variegata’ and V. odorotissimum irrigated every 2 d also had greater canopy size and root dry weight, respectively. Neither cumulative water stress nor establishment was affected by irrigation frequency for either species.
Growth and Carbon Metabolism of Tall Fescue and Zoysiagrass as Affected by Deficit Irrigation
Authors: Fu Jinmin , Fry Jack , Huang Bingru
Published: February 2019

Understanding turfgrass physiological responses to deficit irrigation will help explain potential effects of this practice on turf quality and subsequent stresses. The objective of this study was to investigate the influence of deficit irrigation growth and physiology of ‘Falcon II’ tall fescue (Festuca arundinacea Schreb) and ‘Meyer’ zoysiagrass (Zoysia japonica Steud). Turf was subjected to deficit irrigation levels of 20%, 40%, 60%, 80%, and 100% of actual evapotranspiration (ET) from June to Sept. 2001 and 2002 in Manhattan, Kans. In an earlier study, minimum deficit irrigation levels required to maintain acceptable quality (MDIL) were determined. We compared growth and physiological parameters at these MDIL with turf irrigated at 100% ET. Tall fescue had a lower canopy vertical growth rate (30% lower), canopy net photosynthesis (Pn, 14% lower), and whole-plant respiration (Rw, 11% lower) in 1 of 2 years when irrigated at the MDIL compared with 100% ET; tiller number was not reduced at the MDIL. Water use efficiency (μmol CO2 per mmol H2O) in tall fescue increased by 15% at the MDIL relative to turf receiving 100% ET in 1 of 2 years. In zoysiagrass, the MDIL had no effect on any of the growth or physiological parameters measured. Reductions in canopy vertical growth rate at the MDIL in tall fescue during deficit irrigation would likely reduce mowing requirements. Across all deficit irrigation levels, Pn was more sensitive to deficit irrigation in both grasses than was Rw, which could potentially contribute to declines in canopy vertical growth rate, tiller number, and turf quality. Zoysiagrass exhibited higher water use efficiency than tall fescue, particularly at irrigation levels 60% or more ET.
‘Hanhong’ Pear
Authors: Zhang Maojun , Ding Lihua , Wang Qiang , Feng Meiqi , Khanizadeh Shahrokh
Published: February 2019

‘Hanhong’ (Pyrus ussuriensis Maxim × P. bretschneideri Rehd.) is a new high-quality Asian pear with excellent firmness and crispness and a long shelf life. Fruit of ‘Hanhong’ are very attractive and the tree is very winter-hardy. The fruit and leaves are resistant to pear scab (Venturia pirina Aderh) and black spot (Alternaria kikuchiana Tannka) disease.
Variation in Morphological Traits among Loropetalum chinense var. rubrum Accessions
Authors: Bao Zhiyi , Chen Bo , Zhang Hua
Published: February 2019

Loropetalum chinense var. rubrum accessions in China have not been adequately characterized for their morphological traits. Such characterization would be helpful in the development of improved cultivars and in cultivar classification. In this study, the morphological traits of 23 accessions were evaluated in spring, summer, and autumn to determine their phenotypic diversity. Cluster analysis with average distance was performed for the main traits of leaf and flower using data processing system software. The morphological investigation indicated that the number of flowering accessions and the flower number of L. chinense var. rubrum in spring were more than those in autumn. Only one accession (no. 13) yielded several flowers in summer. Some accessions had the same or similar color of leaf or flower in spring and autumn. Two accessions had the same flower color in spring and autumn, whereas others showed slightly different colors in spring and autumn. The 23 entries were grouped into four clusters in spring and five clusters in autumn based on multivariate analysis of nine classification variables. Each cluster had some specific characteristics of its own. Generally, the cluster formed first because of the similarity in leaf color. The accessions with similar flower color formed subclusters within a cluster. These accessions are an important resource for the establishment of a core collection of L. chinense var. rubrum in the world. Several accessions with good qualities were selected and should be further tested for horticultural merit.
Effects of Altered Fructose 2,6-Bisphosphate Levels on Carbohydrate Metabolism in Carnation
Authors: Szőke Antal , Kiss Erzsébet , Heszky László , Kerepesi Ildikó , Toldi Ottó
Published: February 2019

The aim of this work was to examine the role of fructose 2,6-bisphosphate (fru 2,6P2) in the carbohydrate metabolism in carnation (Dianthus caryophyllus L.). For this purpose, transgenic plants harboring two modified bifunctional enzyme complementary DNAs of rat liver origin (6-phosphofructo-2-kinase/fructose 2,6-biphosphatase) were generated. Transformation with the kinase construct resulted in a 45% to 85% increase in fru 2,6P2 concentrations compared with the wild type. Transformation with the phosphatase construct reduced the fru 2,6P2 contents by 45% and 70%. These alterations in fru 2,6P2 amounts affected the key enzyme activities of sucrose and starch metabolism. Accordingly, plants with elevated fru 2,6P2 concentrations had high levels of starch, fructose, and triose phosphates, and low levels of sucrose, glucose, and hexose phosphates. In plants with reduced amounts of fru 2,6P2 different results could be observed in major carbohydrate compounds.