bluuebunny/crossref_metadata_2025 huggingface dataset:
055 An Apple Linkage Map with SSRs and Other Sequence Tagged Sites Suitable for Comparative Mapping
Authors: Hemmat Minou , Weeden Norman F. , Cheng Frank S. , Brown S.K.
Published: February 2019

The positions of over 50 SSR loci and other sequence tagged sites (STSs) have been located on the linkage maps of five apple cultivars (Rome Beauty, White Angel, Golden Delicious, Liberty, McIntosh) and two New York accessions. In most cases, the primers used produced single amplification products, permitting identification of homologous loci in the different cultivars and the precise alignment of the linkage maps generated for each. Based on this information, we present a general linkage map for apple with STS markers on each linkage group. The map consists of 17 linkage groups (equal to the haploid chromosome number for the species) with over 500 markers. The positions of several resistant gene analogues have been located on this linkage map. None of these sequences map near genes conferring resistance to scab or powdery mildew. SSR loci exhibited a tendency to cluster in certain regions of the linkage map. This clustering slightly reduces their effectiveness as genome markers for comparative mapping or germplasm diversity. However, the SSR markers definitely displayed a high level of polymorphism, making them particularly useful for genetic studies.
060 `Blake's Pride' Fire Blight-resistant Pear Cultivar
Authors: Bell Richard L. , van der Zwet T. , Blake R.C.
Published: February 2019

`Blake's Pride' has been released jointly by USDA and The Ohio State Univ. as a new fire blight-resistant cultivar. The original seedling tree was selected in 1977 at the Ohio Agricultural Research and Development Center in Wooster by R.C. Blake and T. van der Zwet from a cross of US 446 × US 505, performed in 1965 by H.J. Brooks, and was tested under the original seedling number, OHUS 66131-021. The fruit of `Blake's Pride' is pyriform to round-pyriform in shape, and is moderate in size, averaging ≈2.75″ to 3″ in diameter, and 3.25″ in height. The stem is short, medium in thickness, and upright. Skin undercolor is yellow, the finish is glossy, and 20% to 30% of the fruit surface is covered with a smooth, light tan russet. Harvest maturity occurs about 3 weeks after `Bartlett', and the fruit will store in air storage for at least 3 months without core breakdown or superficial scald. The flesh texture is moderately fine, juicy, and buttery. Grit cells are moderately small and occur primarily around the core and in a thin layer under the skin, similar to `Bartlett'. The flavor is subacid and aromatic. The tree is moderate in vigor on `Bartlett' seedling rootstock, and upright-spreading in habit. Yield has been moderate to moderately high. Fire blight infections are rare, and extend no further than 1-year-old growth. Artificial blossom inoculations indicate a moderate degree of resistance of blossoms to fire blight infection. Resistance of `Blake's Pride' to both shoot and blossom infection is much greater than that of `Bartlett'.
064 The History of Macadamia Nut Introduction and Development in Kenya
Authors: Wasilwa L.A. , Ondabu N. , Watani G.W.
Published: February 2019

The macadamia nut was introduced to the Kenyan highlands from Australia in the early 1960s. Seedlings were propagated at a nursery near Kiambu in central Kenya by Bob Harris and were subsequently distributed in the central and eastern highlands and later the western highlands. The majority of seedlings planted were one two species, Macadamia integrifolia Maiden and Betche or M. tetraphylla L. S. A less common species, Macadamia ternifolia, was also planted. Several hybrids of M. integrifolia and M. tetraphylla have been identified in the central and eastern highlands. A macadamia improvement research program was launched in the early part of 1980 by the Ministry of Agriculture. Since then, 30 trees of the seedlings planted in the later part of 1960s have been selected and evaluated in trial orchards located in the Kenyan highlands. Most of the recently planted orchards constitute of 10 clones that yield between 40 to 90 kg of nuts annually. Five high-yielding macadamia varieties from Hawaii were introduced to Kenya in the early 1980s. To date >90% of the cultivated macadamia trees in Kenya are either M. integrifolia or hybrids of M. integrifolia and M. tetraphylla. Until the late 1970s, there was no market for macadamia nuts in Kenya. Since then, several companies market this crop, which is mainly exported to Japan and Europe.
069 Molecular-facilitated Selection of Maintainer Lines in Edible Onion (Allium cepa L.)
Authors: Gokce Ali Fuat , Havey Michael J.
Published: February 2019

Cytoplasmic-genic male sterility (CMS) is used to produce hybrid onion seed. For the most widely used source of CMS in onion, male sterility is conditioned by the interaction of sterile (S) cytoplasm and the homozygous recessive genotype at a single nuclear male-fertility restoration locus (Ms). Maintainer lines used to seed-propagate male-sterile lines possess normal fertile (N) cytoplasm and the homozyous recessive genotype at the Ms locus. Presently, it takes 4 to 8 years to establish if maintainer lines can be extracted from an uncharacterized population or family. We previously developed a PCR marker useful to distinguish N and S cytoplasms of onion. To tag the nuclear male-fertility restoration locus (Ms), we evaluated segregation at Ms over at least three environments. Segregations of AFLPs, RAPDs, and RFLPs revealed molecular markers flanking the Ms locus. We are working to convert these linked molecular markers to nonradioactive PCR-based detection. The organellar and nuclear markers were used to select plants from open-pollinated onion populations and determine if the number of test-crosses required to identify maintaining genotypes.
072 Backcross Breeding with RAPD Molecular Markers to Enhance Resistance to Common Bacterial Blight in Pinto Beans
Authors: Mutlu N. , Coyne D.P. , Park S.O. , Steadman J.R.
Published: February 2019

Common bacterial blight (CBB) in common bean (Phaseolus vulgaris L.), caused by Xanthomonas campestris pv. phaseoli (Xcp), reduces bean yields and quality throughout the world. Pinto `Chase' is a high-yielding variety with moderate resistance to Xcp derived from great northern Nebraska #1 selection 27, whose resistance is derived from an unknown tepary (P. acutifolius) bean source. XAN-159 is a black mottled small seeded breeding line with different genes for high resistance to Xcp derived from a different tepary source (PI 319443). Our objective was to pyramid different genes for Xcp resistance from the donor parent XAN-159 into the rust-resistant recurrent parent Pinto `Chase' using the classical back-cross breeding method with confirmation of resistance using RAPD molecular markers. Resistance was confirmed in some BC2F2 generation plants. Seven RAPD markers and the V locus (flower color) previously identified were confirmed in the BC1 and BC2 populations. Smaller seed size, purple flower color, and black mottled seed coat color were coinherited with resistance to Xcp. However, a recombinant plant with enhanced CBB resistance and moderate-sized pinto seed was identified. Backcross breeding is being continued.
073 Determining Genomic Regions Associated with Common Bean Reaction to Agrobacterium tumefaciens Infection
Authors: Figueira Antonio , Kodama Kelson , Sathler Isabela , Mamani Eva , Tsai Siu Mui
Published: February 2019

Resistance genes (QTLs and major genes) to various pathogens tend to occur in clusters at specific locations in plant genomes. In common bean (Phaseolus vulgaris), common genomic regions associated with host response to the bacterial pathogen Xanthomonas campestris pv. phaseoli and to the symbiont Rhizobium have been identified. Agrobacterium tumefaciens causes crown gall disease in common bean, and shares similar gene activation mechanisms and host recognition signals with Rhizobium. Genotypic differences in tumorigenesis have been observed and could restrict Agrobacterium-mediated bean genetic transformation. The objectives of this research were: 1) to identify wild Agrobacterium strains inducing contrasting response in bean genotypes; and 2) to identify genomic regions in a core linkage map associated with host response to Agrobacterium infection, in comparison with the position of other symbiont or pathogen resistance genes. Among 10 wild A. tumefaciens strains tested under controlled inoculations of 1-week-old seedlings, Ach5, R10, and mainly Chry5 were virulent to the genotypes tested. The genotype BAT93 was susceptible to Chry5, even at low inoculum concentration, in contrast with JaloEEP558. Increasing levels of N enhanced susceptibility to Chry5, R10 and Ach5. Fifty recombinat inbred lines of BAT93 × JaloEEP558 were inoculated with Chry5 and segregated for tumor formation, with 21 lines not forming tumors. Analysis of variance identified 25 markers in five linkage groups of the core linkage map, significantly associated with Agrobacterium resistance, sharing the same location with QTLs identified for other host-bacteria interactions. (Financed by FAPESP 97/12066-1).
075 Confirmation of Molecular Markers and Flower Color Associated with QTL for Resistance to Common Bacterial Blight in Common Beans
Authors: Park Soon O. , Coyne Dermot P. , Mutlu Nedim , Steadman James R. , Jung Geunhwa
Published: February 2019

Common bacterial blight, incited by Xanthomonas campestris pv. phaseoli (Xcp), is a serious disease of common bean (Phaseolus vulgaris). RAPD markers and flower color (V gene) previously had been reported to be associated with six QTL affecting leaf and pod resistance to Xcp. However, the markers for the QTL were not confirmed in different populations and environments to indicate their merit in breeding. Our objective was to determine if the associations of RAPD markers and the V gene with QTL for leaf and pod resistance to Xcp in a RI backcross population from the cross BC2F6 `PC-50' × XAN-159 and for leaf resistance to Xcp in a F2 population from a different cross Pinto `Chase' × XAN-159 could be confirmed. Among six QTL previously detected, five in the RI backcross population and three in the F2 population were confirmed to be associated with resistance to Xcp. The V gene and RAPD marker BC437.1050 on linkage group 5 were most consistently associated with leaf and pod resistance to two to five XCP strains in the RI backcross population and with leaf resistance to two Xcp strains in the F2 population. The confirmed marker BC437.1050 and V gene on linkage group 5, along with other resistance genes from other germplasm, could be used to pyramid the different genes into a bean cultivar to enhance the resistance to Xcp.
077 Identification of Molecular Markers Linked to Crown Rot Resistance (Frl) in Tomato
Authors: Robbins Matthew D. , Stevens Mikel R. , Fazio Gennaro , Fazio Gennaro
Published: February 2019

Fusarium crown and root rot (crown rot) develops on tomato from the fungus Fusarium oxysporum f.sp. radicis-lycopersici (FORL). Genetic resistance to crown rot was previously introduced into the cultivated tomato from the wild species Lycopersicon peruvianum and found to be a single dominant gene, Frl, on the long arm near the centromere of chromosome 9 of the tomato genome. In an effort to identify molecular markers tightly linked to the gene, Ohio 89-1 Fla 7226, Fla 7464, `Mocis', and `Mopèrou', lines homozygous for Frl (resistant), were screened with restriction fragment length polymorphism (RFLP) markers in comparison to Fla 7482B and `Monalbo', lines homozygous for Frl+ (susceptible). Frl was determined to be between the RFLP markers CT208 and CD8. These two markers are separated by a genetic map distance of 0.9 cM according to Pillen et al. (1996). In addition, we screened a pool of eight resistant plants against a pool of nine susceptibles from a BC1 population segregating for Frl for amplified fragment length polymorphism (AFLP) markers. Fazio et al. (1998) previously determined that crossover events occurred in these 17 plants between Frl and a rapid amplified polymorphic DNA (RAPD) marker, UBC194. Our research has indicated that UBC194 is also between CT208 and CD8 on the centromeric side of Frl. Of the 62 AFLP primer combinations tested, 34 showed more than 63 strong polymorphisms in linkage to resistant phenotypes.
078 Mapping of the Citrullus Genome using Populations Segregating for Fusarium Wilt Resistance
Authors: Hawkins Leigh K. , Dane Fenny , Kubisiak Thomas L. , Rhodes Billy
Published: February 2019

Fusarium wilt, caused by the soilborne fungus Fusarium oxysporum f.sp. niveum (FON), is a serious disease of the watermelon (Citrullus lanatus). Three races of this pathogen (races 0, 1, and 2) have been identified based on differential pathogenicity assays. Most commercially available cultivars are resistant to races 0 and 1. Inheritance for resistance to these races is thought to be controlled by a single dominant gene. No cultivars are resistant to race 2 and resistance is thought to be a quantitative trait. F2 lines derived from a cross between the Fusarium-resistant Citrullus lanatus PI296341, and the Fusarium-susceptible watermelon cultivar `New Hampshire Midget' were used to generate a RAPD-based map of the Citrullus genome. F2:3 families were assayed in the greenhouse for resistance to races 1 and 2. Those families that were either highly resistant or highly susceptible were used in identifying markers linked to Fusarium wilt resistance. A preliminary map of the Citrullus genome based on random amplified polymorphic DNA (RAPD) markers has been expanded with the inclusion of simple sequence repeats (SSRs), amplified fragment length polymorphisms (AFLPs), and isozymes.
081 Genetic Analysis of Direct Shoot Organogenesis on Hypocotyls of Antirrhinum majus L.
Authors: Figueroa-Cabanas Monica E. , Stimart Dennis P.
Published: February 2019

Direct shoot organogenesis (DSO) on Antirrhinum majus L. (snapdragon) was evaluated in vitro to determine the inheritance of genes conditioning this response. One-centimeter-long hypocotyls excised from 2-week-old seedlings started in vitro in the dark on Murashige and Skoog medium served as explants. Optimal conditions for DSO on explants included hypocotyl excision from 10-day-old seedlings, 2.22 μmol BA in the culture medium, and a 21-day culture duration. An adventitious shoot was counted once it developed a stem terminated by at least one leaf appearing to have originated from an apical meristem. Seven populations were evaluated for DSO: parent 1 (P1) with lowest DSO (0.3 shoots); parent 2 (P2) with highest DSO (13.9 shoots); F1 (P1 × P2); F1 (P2 × P1); F2 (self-pollination of F1); P1 × [P1 × P2]; and P2 × [P1 × P2]. P1 and P2 were chosen as parents based on DSO counts being lowest and highest, respectively, of inbreds evaluated. DSO appears to be a trait under nuclear genetic control. High DSO appears to be dominant over low DSO. The trait appears to be simply inherited through one or two genes.
085 Horticultural (Cultivated Plant) Taxonomic Research within ASHS
Authors: Fantz Paul R. , Zhang Donglin
Published: February 2019

Horticultural Science in the past quarter of a century has been shifting to increased emphasis on ornamental plants due to the growth of the modern green industry. Numerous species are being introduced into the exterior and interior landscapes. For popular species, the cultivar, as defined by the International Code of Nomenclature for Cultivated Plants (ICNCP), has become the basic taxon of cultivated plants. Named ornamental plant cultivars are rising at a rapid rate creating identification and segregation problems in the landscape industry, nurseries, botanic gardens, arboreta, and breeding programs. Government regulations and legal issues are beginning to infringe as solutions to the problems. There is a critical need existing for taxonomic research on ornamental cultivars utilizing classical morphological analysis supplemented with modern biotechnological techniques (e.g., anatomical, chemical, cytological, DNA, Sem analysis). Taxonomic research on existing and newer cultivars can provide quantitative botanical descriptions, keys of segregation, correct identification, determination of correct names and synonymy, improved cultivar documentation, and grouping of similar cultivars in large complexes. The taxonomic research is basic science that has immediate applied application within the horticultural society, and results should be published in the journals of ASHS.
087 Localization of ENOD2 Transcript Accumulation in Indeterminant Nodules of Maackia amurensis Rupr. & Maxim. (Amur Maackia)
Authors: Horner Harry T. , Hannapel David J. , Graves William R. , Foster Carol M. , Hannapel David J. , Graves William R. , Foster Carol M. , Horner Harry T. , Foster Carol M.
Published: February 2019

Early nodulin genes, such as ENOD2, play a role in the first stages of nodulation. Although ENOD2 is conserved among nodulating legumes studied to date, its occurrence and activity have not been studied among woody legumes such as Maackia amurensis Rupr. & Maxim. Our objective was to localize MaENOD2 transcripts during nodule development and describe the anatomy of nodules formed on the roots of M. amurensis in relation to ENOD2 mRNA accumulation. Nodules (<1 mm, 1-2 mm, >2 mm in diameter, and mature) were prepared for light microscopy, sectioned, and stained with safranin and fast green for structural contrast or with the periodic acid Schiff's reaction for starch. The location of ENOD2 transcripts was determined by using in situ hybridization with DIG-labeled sense and antisense RNAs transcribed from a 602-bp fragment of the coding region of MaENOD2. Mature nodules from M. amurensis possessed peripheral tissues, a distal meristem, and a central infected region characteristic of indeterminant development. In situ hybridization showed that MaENOD2 transcripts accumulated in the distribution layer and uninfected cells of the central symbiotic region. Amyloplasts that contained starch grains were identified in these tissues and in the inner parenchyma of the nodule. Throughout nodule development, transcripts were restricted to areas with high levels of stored starch that surrounded cells actively fixing N2. Our results suggest that ENOD2 in M. amurensis may be a cell wall component of tissues that regulate nutrient flow to and from sinks, such as symbiotic regions of a nodule. These data may lead to a better understanding of the role of the ENOD2 gene family during nodulation.
089 Biolistic Transformation of Zoysiagrass for Gluphosinate Resistance
Authors: Ahn B.J. , Choi J.S. , Kamo K. , King J.W.
Published: February 2019

Biolistic transformation methods for zoysiagrasses (Korean lawngrass) were developed and used to introduce a herbicide-resistant trait. Embryogenic calli were induced from mature caryopses on MS medium supplemented with 2 mg/L of 2,4-D, and used to establish liquid agitation cultures. The cultures have been maintained over a year without loss of the embryogenic competence. A particle bombardment method was optimized for zoysiagrass based on transient gusA gene expression. The most transient GUS expression upon bombardment treatments occurred at 1100 psi of helium pressure with 10 cm of particle flying distance and 0.125 M sorbitol preculture treatment. Promoters suitable for zoysiagrass were compared, and actin and ubiquitin promoters were found effective in expressing gusA gene. Vector DNAs containing a herbicide resistant gene (bar), pBY505, were introduced into embryogenic cells of zoysiagrass using the optimized method. Total 194 putatively transformed plants were regenerated from 60 biolistic plates for over 6 months through selection culture containing 4-10 mg/L of phosphinothricin. Regenerants were grown in potting soil in greenhouse and sprayed with 1.7 g/L of Ignite herbicide. The transgenic plants showed various levels of resistance to the herbicide, while untransformed control plants were all dead. Recombination of the bar gene into the genomes of the transformants were confirmed through PCR and Southern blot analysis.
094 Cloning Blueberry Dehydrins and Their Expression under Stress Conditions
Authors: Panta Ganesh R. , Rowland Lisa J. , Panta Ganesh R.
Published: February 2019

Dehydrins are major plant proteins that increase with cold or drought. Using a previously identified 2.0-Kb blueberry dehydrin cDNA, additional dehydrin clones were isolated and characterized. Experiments were conducted to determine effect of drought and cold treatment on dehydrin gene expression in several blueberry cultivars. Besides previously characterized 65, 60, and 14 kDa dehydrins in floral buds additional less abundant dehydrins were observed in stem and root tissues. The same major dehydrins were induced by both drought and cold stress but at different levels. Dehydrin expression was positively correlated with cold and drought tolerance. In addition, photoperiod was observed to affect dehydrin expression. Dehydrins were induced to higher level in cold treated plants kept in total dark than in plants kept at a short photoperiod of 10 hours of light/14 hours dark.
097 Aspects of Self- and Cross-fertility in Recently Released Highbush Blueberry Cultivars
Authors: Ehlenfeldt Mark K.
Published: February 2019

Self- and cross-fertility was evaluated in the highbush blueberry cultivars Bluegold, Duke, Legacy, Nelson, Sierra, Sunrise, and Toro, all released since 1987, by comparing them to standards of `Bluecrop' and `Rubel'. Percent fruit set increased with cross-pollination in all cultivars except `Bluecrop', which decreased by 13%. The average increase in the recently released cultivars was 43%. Fruit weight also increased in cross-pollinations for all cultivars except `Rubel', which showed a decrease of 2%. Average increase in fruit weight on cross-pollination in the recently released cultivars was 27%. Fruit set and fruit weight measurements suggest that `Duke', `Legacy', and `Nelson' could perform well in solid stands, but `Sierra' and `Toro' are more likely to need cross-pollination for best yields. Investigations were also made on a group of 10 cultivars, to evaluate whether ripening time of the pollen source cultivar had any effect on the ripening time of the fruiting parent. No single pollen source had consistent general effects on ripening, although specific combinations of females and males appeared to either hasten or delay ripening. The largest deviations were seen in delays of ripening, suggesting that poor pollination may have been the greatest factor contributing to the observed variation in ripening times.
098 High Regeneration Ability of Benzyladenine and Naphthalene Acetic Acid Induced Callus of Eastern Hibiscus
Authors: Jenderek M.M. , Olney A.J.
Published: February 2019

The ability of Hibiscus syriacus explants to produce regenerable callus was investigated. Fragments of cotyledons, hypocotyl, and roots were cultured on MS media supplemented with two different auxins (2,4-D and NAA, both 0.3 mg/L) and three different cytokinin (BA, 2iP and kinetin, all 0.1 mg/L). Plants were regenerated on McCown media with three different cytokinins at two different concentrations (0.1 and 1.0 mg/L). The biggest volume of callus was produced on medium containing 2,4-D/2iP (2,821 mm3/explant). The smallest mass of callus was induced on medium with NAA/kinetin (120 mm3/explant). On BA-supplemented media, the auxin type had no significant influence on the amount of callus produced. The highest number of shoots and leaves was produced on callus induced on NAA/BA supplemented media and regenerated on medium with 0.1 mg/L BA (4.2 shoots and 20 leaves/explant). Callus cultured on medium with 1.0 mg/L of BA produced significantly less shoots (2.4 shoots/explant). The lowest number of shoots was observed on callus originating from NAA/kinetin and NAA/2iP callus media and grown on medium with kinetin or 2ip (both 1.0 mg/L). The highest number of roots was produced by cultures originating from NAA/BA callus medium grown on the BA regeneration medium, irrespective of the cytokinin level. The longest shoots were observed on medium supplemented with 1.0 mg/L BA (18 mm). In this study, the best plant regeneration results were obtained for callus initiated on NAA/BA supplemented medium and regenerated on medium with 0.1 mg/L BA, however, the highest production of callus was observed on medium with 2,4-D/2iP.
101 Propagation of Juglans cinerea L. (Butternut)
Authors: Pijut Paula M. , Barker Melanie J.
Published: February 2019

Butternut trees are becoming endangered as a result of butternut canker disease; thus, it is desirable to propagate disease-resistant trees for screening and provenance tests. The objective of this study was to determine the conditions necessary for successful cutting propagation. In 1998, 10 trees were selected from a 4-year-old butternut plantation located in Rosemount, Minn. Hardwood cuttings were collected 30 Mar., 21 Apr., and 6 May. The auxins, indole-3-butyric acid-potassium salt (KIBA) in water at 0, 29, or 74 mmol·L-1 were tested for root induction. The basal end of cuttings were dipped in treatment solutions for 10 to 15 s and placed in a 1 peat: 1 perlite mixture in Deepots™ (D40) in a mist bed. Mist was applied for 5 s every 15 min. Greenhouse conditions were: 12-h photoperiod provided by high-pressure sodium lamps (60 μmol·m-2·s-1), 22 °C, and bottom heat of 27 °C (heating pads). Softwood cuttings were collected 20 May, 18 June, 30 June, and 23 July. Rooting treatment solutions and greenhouse conditions were the same as for the hardwood cuttings, except no heating pads were used. Rooted cuttings were planted in Treepots™ (10 × 10 × 36 cm) and gradually hardened off from the mist bed. Hardwood cuttings from the first two collection dates did not initiate roots. Best rooting (12.5%) was achieved on hardwood cuttings collected 6 May using 29 mmol·L-1 KIBA. Softwood cuttings rooted to some degree at all concentrations of rooting solution and at every collection date. The greatest rooting (70%) was achieved using 74 mmol·L-1 IBA. In general, best rooting percentages were achieved with softwood cuttings collected 18 June and 23 July and treated with 62 mmol·L-1 KIBA or 74 mmol·L-1 IBA. Both rooted hardwood and softwood cuttings were successfully acclimatized from the mist bed and many have initiated new growth.
109 Enhancing Rooting of In Vitro-propagated Chestnut Shoots
Authors: Yang Guochen , Kamp-Glass Marihelen , Read Paul E.
Published: February 2019

American chestnut (Castanea dentata) is one of the United States' most valuable resources for its nuts and timber. Many scientists are exploring genetic transformation techniques to improve chestnut blight resistance in addition to conventional breeding. In vitro shoot production must be first obtained and optimized in order to establish an efficient transformation system. Although shoot proliferation has been achieved, chestnut is still considered difficult for tissue culture with poor rooting. Therefore, this research has focused on improving rooting ability of micropropagated chestnut shoots. In vitro shoot production was established and maintained in WPM supplemented with 0.1 mg/l BA, 3% sucrose, and 0.7% agar with the pH adjusted to 5.8. The shoots were then transferred to rooting medium containing the same components as for shoot proliferation plus an auxin at various concentrations. Right after placing shoots onto rooting medium, a very thin layer (5 ml) of the same auxin (diluted) was added to provide a quick stimulation of rooting. Detailed discussion will be presented.
111 Successful in Vitro Micropropagation of Purported Blight-resistant Chestnuts (Castanea spp.)
Authors: Miller-Roether Virginia , Read Paul E. , Szendrak Erika
Published: February 2019

The American Chestnut Foundation (ACF) has conducted a breeding program aimed at developing blight-resistant chestnut trees exhibiting the phenotype of American Chestnut (Castanea dentata). We developed a protocol for in vitro micropropagation and multiplication of candidate blight-resistant plants from the ACF breeding program. The protocol included forcing dormant shoots to budbreak, culture establishment, shoot multiplication, inducing a functional root system on the microcuttings produced by this system and establishment of autotrophic plants. Because Castanea spp. is recalcitrant to rooting, a unique bilayer method of rooting was developed. The unique bilayer consisted of a clear basal medium of 50% DKW and 50% WPM (Long and Preece), with a continuous level of 0.01 mg IBA/L and 0.2 mg BA/L. The clear basal medium was over-laid with an opaque layer. Rooting response occurred for 27 of the 31 genotypes at various frequencies. Rooted plantlets were planted in 50% peat: 50% perlite in order to become autotrophic and acclimated. Acclimated trees were planted in 10″ × 2″ Deepots® and placed in the greenhouse. These trees exhibited a very vigorous functional root system. Acclimated trees were hardened off, placed in cold storage (≈4-5 °C) for 5 months. All trees placed in cold storage broke dormancy for spring growth and ≈100 trees were sent to ACF for planting into field trials.
118 The Effect of Hydroponics on the Yield and Quality of Sweet Basil
Authors: Kreder Susan , Markhart Albert H.
Published: February 2019

Environmental conditions are known to affect the growth and quality of culinary and medicinal herbs. Hydroponic growing conditions often produces greater yields for many leafy crops compared to growth in more-traditional media. The objective of this investigation was to compare the yield and quality of sweet basil grown in continuous flow solution culture or well-irrigated Universal Mix. Sweet basil plants were germinated under mist and then transplanted to a continous-flow hydroponics system or to 6-inch pots containing Universal Mix. Rows of pots alternated with a row of hydroponic plants in a temperature-controlled greenhouse. Temperatures were maintained between 20 and 25 °C, the relative humidity was not controlled, pot-grown plants were irrigated as needed. HID lights added sublimentry irradiation and maintained a photoperiod of 18 h. Cohorts of plants were harvested at five time points between transplanting and maturity. Plants were divided into leaves, stems, and roots, dried, and the data subjected to mathmatical growth analysis. Several leaves from each plant were harvested and analyzed by gas chromotograpth for essential oils. Plants grown in hyroponics grew faster and produced more harvestable leaf material than the media-grown plants. Details of the plant growth analysis and the essential oil composition will be presented.
121 Fertilizer Formulation, Placement, and Tex-R Geodiscs Influence the Growth of `Compacta' Holly
Authors: Ruter John M.
Published: February 2019

A study was conducted to compare four different controlled-release fertilizers when used in conjunction with Tex-R Geodiscs on the growth of Ilex crenata Thunb. ex J.A. Murray `Compacta' in 3.8 L (#1) containers. The fertilizers used were Osmocote Plus Southern Formula (18N-3.9P-10K), Osmocote Plus Northern Formula (18N-3.9P-10K), Wilbro (15N-1.7P-7.5K), and Nutricote T-360 (17N-2.6P-6.6K) all applied at the rate of 1.8 kg N/m3. Geodisc treatments were: 1) no disc, 2) fertilizer placed on top of the disc, and 3) fertilizer placed beneath the disc. At 2 and 4 months after the initiation of the study, the growth indices for plants grown with both Osmocote Plus fertilizers were larger than for either of the other two fertilizers. After 7 months, final growth indices were greater for the Osmocote Plus and Wilbro treatments compared to Nutricote. Final leaf, stem, and root dry masses were all greater for the Osmocote Plus fertilizers compared to the other two, as was final plant quality. Plants with fertilizer placed on top of the disc were smaller compared to the no disc or beneath the disc treatments. Geodisc treatment had no influence on shoot dry mass or final plant quality. Data for leachate nutrient analysis and evapotranspiration will also be presented.
141 Effects of Two AM Fungi on the Yield and the Quality of Carrot (Daucus carota L.) Grown in Field Conditions
Authors: Gotoèchan Henriette , Coulombe Jean , Yelle Serge , Desilets Hèlène
Published: February 2019

Two cultivars of carrot were sown in a sandy loam soil over two seasons with and without introduction of commercial inoculum of Glomus intraradices or Glomus etunicatum, which was spread with an experimental sowing machine. VAM fungi effects on the yield and the quality of carrot varied from season to season. In 1997, both of the VAM fungi enhanced the average saleable yield of the two cultivars from 66.21 t/ha to 69.85 t/ha and 80.81 t/ha, respectively, for the treatment without the introduction of VAM fungi, G. etunicatum, and G. intraradices. The slight difference (5.03%) that occured between G. intraradices and the non-inoculated treatment, although not significant, represented 20.38% of the total percentage of rejected carrots. For the last season, the amount of rejected carrots was in the same range for all the treatments (13% to 14%). Nevertheless, both of the cultivars responded differently to mycorrhization. In both of the seasons, mycorrhizal colonization was high in all plots, with an average of 70% in the treatment without inoculation and 75% in those that received G. intraradices or G. etunicatum. In our experimental conditions, reduction of phosphate fertilization to 50% of the recommanded quantity had no influence either on the mycorrhizal colonization or on the yields.
142 Missouri Master Gardener Demographics
Authors: Schrock Denny , Meyer Mary , Ascher Peter , Snyder Mark
Published: February 2019

A survey was conducted of current and former Missouri Master Gardeners to identify the demographics of volunteers and to determine if Master Gardeners fit the demographic pattern of volunteers in general. Sixty-eight percent of survey respondents were active in the program, while 32% were inactive. Females accounted for 65% of respondents and males 35%. Nearly 60% of Missouri Master Gardeners were 50 years old or older; however, those in their 40s comprised the largest demographic group. The majority of Missouri Master Gardeners were married with children. Over 50% had at least a college degree, while 22% had post-graduate work. One-third had household incomes of $60,000 or greater; in addition, just under one-quarter had household incomes between $40,000 and $60,000. The largest occupational group was retired persons, at 26.9%; the second largest category was homemakers at 14.6%. Missouri Master Gardeners are more likely to be from small towns or rural areas than from medium or large cities. They tend to be long-term residents of their communities; 57.2% had lived at their current residence for more than 10 years. Missouri Master Gardener volunteer demographics fit the pattern of volunteers in general, but demographic data proved to be a poor predictor of intent to continue volunteering in the Master Gardener program.
143 Benefits and Values of the Master Gardener Program
Authors: Schrock Denny , Meyer Mary , Ascher Peter , Snyder Mark
Published: February 2019

Current and former Missouri Master Gardeners were asked to respond how strongly they agreed or disagreed with a list of benefits provided by the Master Gardener program. The survey instrument was an adaptation of Rohs and Westerfield's (1996) Master Gardener Societal and Personal Benefits survey. Questions were assigned to one of the six principal components of volunteer motivation developed by Clary et al. (1998): Understanding, Values, Enhancement, Social, Protective, and Career. Master Gardeners who are currently active volunteers in the program were more likely to respond favorably to many of the benefits provided by the Master Gardener program. Respondents most strongly indicated their agreement that the Master Gardener program, more than any other similar organization, provides benefits related to new learning experiences, exercising knowledge, skills, and abilities, categorized as understanding (U). The overall mean for U was 4.35 on the 5-point Likert scale, a significantly higher score than any other category according to Duncan's multiple range test. Benefits related to personal growth and self-esteem, labeled enhancement (E); those related to altruism and humanitarian concern, labeled values (V); and guilt reduction over being more fortunate than others and addressing one's own personal problems, labeled protective (P), formed the second tier of benefit importance. Benefits related to preparation for a new career or maintaining career-relevant skills, categorized as career (C) were next. Benefits concerning relationships with others, classified as social (S), concluded the list.
145 Survey of Virginia Master Gardener Volunteer Management
Authors: Dorn Sheri , Relf Diane , McDaniel Alan , James-Deramo Michele
Published: February 2019

Virginia Cooperative Extension's (VCE) Master Gardener volunteer program in available in 73 of 102 unit offices. The unit programs are managed by MG coordinators who currently include 10 locally funded agents, eight locally funded non-agents, and 26 volunteers. In 1998, the VCE Master Gardener Coordinator Manual was developed for use by coordinators in managing the local MG program. The 12-unit resource book was developed cooperatively with teams of MGs, coordinators, and agents to enhance coordinators' skills. The manual was the basis of four local MG coordinator training sessions conducted in 1998. Before MG coordinator training, local coordinators were asked to complete an eight-page survey about MG program management practices used locally. In addition to basic questions about coordinator status and length of time with VCE, the survey asked about techniques used in recruitment and training; motivation, retention, and recognition; individual and local MG program evaluation; and other topics. Two months after the last training, all coordinators were asked to evaluate the usefulness of the VCE Master Gardener Coordinator Manual, which was the base text for the training. Finally, 6 months following the final training session, MG coordinators were asked to again complete the eight-page survey about management practices used locally. The results of the survey information have indicated areas in which the management of MG programs are strong and can be strengthened in order to provide enthusiastic, qualified volunteer staff to assist VCE in implementing horticultural educational programs in local communities. The results of the survey are helpful in focusing the work of the state Master Gardener coordinator to provide adequate and appropriate training and other resources for local coordinators. The results of the evaluation survey have assisted the finalization of the VCE Master Gardener Coordinator Manual, a useful resource to any state's Master Gardener program management effort.
149 An Overview of the Clemson University/Carolina Nurseries Research Partnership
Authors: London Jason B. , Whitwell Ted , Fernandez R.T.
Published: February 2019

In 1993, Carolina Nurseries and the Dept. of Horticulture at Clemson Univ. entered into a partnership for a research and development program to solve short- and long-term production problems in the ornamental nursery industry. Carolina Nurseries, located near Charleston, S.C., is a 110-ha commercial container-grown landscape plant nursery that sells >12 million units yearly. Research is conducted on site in a specially designed area that provides nursery conditions and control of other variables, including water and pesticide applications. An on-site graduate student works cooperatively with faculty on campus and manages the research area, collects data, maintains the projects using standard nursery practices, interacts with Carolina Nurseries personnel, and initiates needed studies. Over the past 6 years, research diversity increased with cooperative efforts from faculty in the Depts. of Entomology, Pathology, and Agricultural Engineering. In addition, cooperative studies with faculty members with Univ. of Georgia, Michigan State Univ., and North Carolina State Univ. have been completed. Research results were presented to the nursery industry at research update meetings at the research area site. Approximately 200 attendees from commercial nurseries and horticulture-related companies in surrounding states attended the 1998 research update. Surveys collected at research updates are helpful in tailoring research to the specific needs of the nursery industry, and are the basis for some of the current research projects. Research results are also in published in the Southern Nursery Association Research Proceedings, Journal of Environmental Horticulture, and The South Carolina Nurseryman Newsletter.
155 Farmer's Bookshelf: Evolution of an Information System for Crops in Hawaii
Authors: Kobayashi Kent D. , Bittenbender H.C.
Published: February 2019

In 1988, the Farmer's Bookshelf started out as a computerized information system of crops grown in Hawaii. The first version was created on an Apple Macintosh computer using a hypermedia program called HyperCard. Because HyperCard came with each Macintosh computer, only the crop files needed to be sent to clientele. As the demand for an IBM-compatible version of the Farmer's Bookshelf increased, the Windows version was created using a hypermedia program called Plus. In addition to the crop files, the runtime version of Plus was also distributed to clientele. Later, other files were added to the Farmer's Bookshelf, including files to diagnose problems of macadamia in the field, select ground covers, select landscape trees, recommend fertilization, calculate nut loss for macadamia growers, and calculate turfgrass irrigation. Cost of analysis spread-sheets for several crops were also added. Recently, the Farmer's Bookshelf was moved to the World Wide Web, which has the advantages of reaching a world-wide clientele, easier updating and modifications, and linking to sites of related information. We have added links to newspaper articles on agriculture in Hawaii, to related sites on a particular crop, to on-line agricultural magazines and newsletters, to agricultural software, to upcoming agricultural events, and to Y2K sites. Because of the benefits of the Web version, the diskette versions (Macintosh and Windows) are no longer supported. Putting the Farmer's Bookshelf on the Web has allowed us to better meet the needs of our clientele for up-to-date information.
161 Using a Controlled Water Table Irrigation for Class Demonstrations of Plant Growth
Authors: Buxton J.W. , Phillips T.
Published: February 2019

In class demonstrations, it is almost impossible to maintain the same water: air ratio in growing media. If some treatments result in greater plant growth than others, treatment effects on plant growth are often confounded with the effect of water: air ratio in the growing media. In a laboratory demonstration of nutrient deficiencies symptoms in plants, a controlled water table irrigation system maintained a constant water: air ratio in the growing media regardless of the nutrient deficiency affect on plant growth. The modified capillary mat irrigation system consists of one mat edge extending over the edge of the bench into a narrow trough on the side of the bench. The nutrient solution level in the trough is controlled by a liquid level controller, so it is at a fixed distance below the bench surface. The nutrient solution is drawn upward by capillarity to the bench surface and then moves by capillarity over the bench. The system automatically maintains a constant air: water ratio in the growing media. A standard Hogland solution was modified to demonstrate deficiencies in N, P, K, Mg, Ca, Cu, Fe, and Zn on corn, squash, radish, soybeans, and marigold. Seeds were germinated and grown to maturity in either a 10- or 15-cm pot. Students set up the demonstration, were provided instruction in preparing solutions, regularly observed plant growth, and answered questions at the end of the study about differences in plant growth observed. However, possibly because low concentrations of some minor elements in the capillary mat, Zn deficiency was not observed and other elements, although resulting in poor growth compared to the control, did not show severe deficiency symptoms.
165 Learning Communities in Horticulture Enhance Student Learning
Authors: Nonnecke Gail R.
Published: February 2019

A learning community was developed for first-year students majoring in horticulture at Iowa State Univ. in 1998. Learning communities are a curriculum design that schedules courses for both students and faculty to encourage community and connections among students, between students and faculty, and among faculty. Learning communities can offer students more opportunities for interactions among each other, academic assistance through supplemental instruction and/or group study sessions, and planned horticulture-related activities, all of which are important for success and retention of first-year students. First-year students in the horticulture learning community enrolled in the same courses and sections of five courses. The first-year English composition course was linked to the second-year principles of horticulture course that requires writing-across-the-curriculum activities. Faculty mentoring was provided through local field trips to horticultural sites of keen interest to the students. Academic environment survey results showed students rated their expectations highly for developing a network of other students as a resource group and for learning cooperatively in groups. Iowa State Univ. supports learning communities by providing faculty development and facilitating course registration, peer mentoring, supplemental instruction for challenging core courses, and academic and student services, to strengthen undergraduate teaching programs within and outside of the classroom.
169 Progress in the Development of a Sustainable Production System for Fresh-market Tomatoes
Authors: Mills D.J. , Coffman C.B. , Teasdale J.R. , Anderson J.D. , Everts K.L.
Published: February 2019

In the production of fresh-market vegetables, off-farm inputs, such as, plastic, nitrogen fertilizer, fungicides, insecticides, and herbicides are routinely used. One aim of the sustainable agriculture program at the Beltsville Agricultural Research Center is to develop systems that reduce these inputs. We have completed the second year of a study designed to examine foliar disease progress, foliar disease management, and marketable fruit yield in staked fresh-market tomatoes grown in low- and high-input production systems. Specifically, four culture practices (black plastic mulch, hairy vetch mulch, dairy manure compost, and bare ground) were compared in conjunction with three foliar disease management treatments (no fungicide, weekly fungicide, and a foliar disease forecasting model, TOMCAST). Within all culture practices, use of the TOMCAST model reduced fungicide input nearly 50%, compared with the weekly fungicide treatment, without compromising productivity or disease management. With regard to disease level, a significant reduction of early blight disease severity within the hairy vetch mulch was observed in 1997 in relation to the other culture practices. Early blight disease severity within the black plastic and hairy vetch mulches was significantly less than that observed in the bare ground and compost treatments in 1998. In addition, despite a 50 % reduction in synthetic nitrogen input, the hairy vetch mulch generated yields of marketable fruit comparable to or greater than the other culture practices. It appears that low-input, sustainable, production systems can be developed that reduce the dependence on off-farm inputs of plastic, nitrogen fertilizer, and pesticides, yet generate competitive yields.