bluuebunny/crossref_metadata_2025 huggingface dataset:
013 Euphorbia pulcherrima Cultivars Differ in Susceptibility to Varying Inoculum Levels of Pythium ultimum
Authors: Gaul Stephen B. , Nelson Eric D. , Evans Michael R.
Published: February 2019

Rooted cuttings of 22 different Euphorbia pulcherrima Willd. ex Klotzsch cultivars were grown in root substrate inoculated with 0, 5000,15,000, and 30,000 oospores of Pyuthium ultimum Trow per 10-cm containers. The root substrate was a mixture of 50% peat, 30% perlite, and 20% soil, adjusted to a pH 5.5. Plants were grown in a greenhouse with a temperature range of 15-32 °C, and were fertilized daily with 200 ppm N (Excel 15-5-15, Scotts Co. Marietta, Ga). After 8 weeks, roots were rated for disease incidence and root fresh and dry weights were determined. The data were analyzed using ANOVA with six blocks in a 22 × 4 factorial design, linear regression, and cluster analysis. Significant differences among the responses of the cultivars were found. The slopes of the regression equations, using the log10 of the inoculum level for the X axis, were more positive for disease incidence and more negative for fresh and dry root weights in the more susceptble cultivars. The cultivars were separated, by the cluster analysis, into three groups, less susceptible, moderately susceptible, and highly susceptible. Cultivars Marblestar and Galaxy Red were representative of less susceptible, `Pepride' and `Jolly Red' were representative of moderately susceptible, and `Snowcap' and `Success' were representative of highly susceptible cultivars.
014 Weed Control and Productivity of Field-grown Cut Flowers
Authors: Holcomb E. Jay , Harpster Tracey L. , Berghage Robert D. , Kuhns Larry J.
Published: February 2019

A set of studies was established in Summer 1998 to determine the tolerance of field-grown cut flower species to specific preemergence herbicides, the effectiveness of weed control by those materials, and to determine if productivity of cut flowers is affected either by the herbicides or by colored mulches. Pendimethalin provided excellent early season weed control, but poor late-season control. It consistently caused injury at 4 lb a.i./A and sometimes at the 2 lb a.i./A rate. Oryzalin provided good to excellent weed control, but slightly injured celosia and zinnia when applied at 4 lb a.i./A. Napropamide provided excellent early season weed control, but marginally acceptable weed control later in the season. Though napropamide caused some injury to celosia early in the season when applied at the high rate, no injury to any of the plants was observed later in the season. Prodiamine and trifluralin were the overall safest of the herbicides, but they provided the weakest weed control. OH-2 was very effective when placed on the soil surface, but was less effective when placed on an organic mulch. The organic mulch was designed to keep the OH-2 particles from splashing on to the crop plant and injuring the plants. OH-2 tended to be safer placed on a mulch than on the soil surface, but statice was slightly injured even when a mulch was used.
017 Influence of Surfactants on Manage Herbicide Control of Nutsedge and Nursery Crop Tolerance
Authors: McDaniel G.L. , Fare D.C. , Witte W.T. , Flanagan P.C.
Published: February 2019

Research was conducted to compare non-ionic, paraffin-based crop oil, soybean oil, sunflower oil, and organosilicone surfactants combined with Manage (MON 12051, holosulfuron) applied at a reduced rate for yellow nutsedge (Cyperus esculentus) control efficiency and evaluation of phytotoxicity to five container-grown ornamental species. Manage at 0.018 kg a.i./ha was combined with 0.25% or 0.5% (v/v) of the following surfactants: X-77, Scoil, Action “99”, Sun It II, or Agri-Dex. Yellow nutsedge tubers (10 per 3.8-L container) were planted into containers along with the following nursery crops: `Lynnwood Gold' forsythia, `Big Blue' liriope, `Pink Lady' weigela, `Blue Girl' Chinese holly, and `Bennett's Compacta' Japanese holly. Treatments were applied 5 weeks after potting on 13 June 1998 and phytotoxicity ratings taken 4 and 8 weeks later and growth measured after 8 weeks. Sun It II provided the most-effective nutsedge control without reducing growth and causing minimal phytotoxicity to the ornamental plants tested. X-77 (the recommended surfactant for Manage) provided only moderate nutsedge control. Efficient nutsedge control can be accomplished with Manage at one-half the recommended rate when combined with the correct surfactant. Some temporary phytotoxicity symptoms can be expected and a slight overall growth reduction is possible, depending on the surfactant selected.
018 Preemergent Weed Control in Container-grown Herbaceous Perennials
Authors: Klett James E. , Potts Laurel , Staats David
Published: February 2019

During the 1998 season, preemergent herbicides were applied to container-grown herbaceous perennials and evaluated on the basis of weed control, phytotoxicity, and effect on plant growth. The herbicides and rates were: Napropamide (Devrinol 10G), 0.72 and 1.44 kg a.i./ha; Oryzalin (Surflan 40AS), 0.36 and 0.72 kg a.i./ha; Oxadiazon (Ronstar 2G), 0.72 and 1.44 kg a.i./ha; Oxyfluorfen + Oryzalin (Rout 3G), 0.54 and 2.16 kg a.i./ha; Oxyfluorfen + Pendimethalin (Scott's OH II), 0.54 and 1.09 kg a.i./ha; and Trifluralin (Treflan 5G), 0.72 and 1.44 kg a.i./ha. Herbicides were applied to Phalaris arundinacea `Picta', Scabiosa caucasica, Sedum × `Autumn Joy', Pennisetum setaceum `Rubrum', Salvia argentea, Penstemon × mexicali `Red Rocks', Osteospermum barberiae v. compactum `Purple Mountain', and Gazania linearis `Colorado Gold'. Phytotoxicity symptoms (visual defects) were apparent with Napropamide on Phalaris (at both rates) but recovered by the end of season. All herbicides provided good weed control.
019 Hybrid Poplar Establishment in Tilled Ground or Grass Sod Using Polyethylene Films for Weed Control
Authors: Van Sambeek J.W. , Preece John E.
Published: February 2019

Hybrid poplar is traditionally established using dormant stem cuttings in tilled soils followed by chemical or mechanical weed control. In 1996, we initiated a study to evaluate the effects of site preparation and four weed control treatments on growth and morphology of three hybrid poplar clones established on a 0.2-ha tall fescue field in southern Illinois. Site preparation included application of 2000 kg/ha of 12N-12P-12K. The experiment was arranged as a split-split plot. Main plots were closely mowed tall fescue or tilled to remove the grass sod. Within each main plot, weed control treatments were applied to 1-m wide strips in rows 2.4 m apart. Weed control treatments included porous black film, solid black film, and solid white film, and a control treatment of 3.7 L/ha of glyphosate applied each spring. On 15 Apr. 1996, three 25-cm-long dormant stem cuttings from each of three clones were randomly planted 15 cm deep every 1.8 m within each row. Clonal differences existed after the first year for survival, number of stems, stem height, stem basal diameter, and stem volume, but not for number and total length of lateral branches. Nearly all tree growth measurements analyzed during the first 3 years had a highly significant interaction between type of site preparation and method of weed control. With polyethylene films, tree survival exceeded 90% on both the tilled ground and grass sod sites after 3 years; however, with the herbicide treatment survival averaged only 18% in the grass sod and 51% in tilled soil. Excluding the herbicide treatment, tree growth was better in the grass sod than in the tilled soil. Tree growth using porous black polyethylene film was usually less than that with either of the two solid polyethylene films. The best tree growth was found with a grass sod and solid white polyethylene film for weed control.
021 Assessment of Insecticide Efficacy For Root Weevil Control
Authors: Rosetta R. , Svenson S. , Bell N.
Published: February 2019

The efficacy of new formulations and application techniques were compared to existing standard pesticides for adult root weevil control. A known number of adult black vine weevils (Otiorhynchis sulcatus) were added to Rhododendron `Cunningham's Blush' growing in 1-gal containers. Spray or hand-applied treatments were assigned to three plants each within the six blocks of a randomized complete-block design. Treatments were evaluated for percentage adult mortality at 7 and 14 days after treatment (DAT). Orthene (16 oz/100 gal), Pinpoint (2.0 g and 3.0 g prod/pot), Talstar (20 oz/A; both day- and night-applied), and CGA 293 343 (8.5 oz thiamethoxam/100 gal) provided greater than 90% control of root weevil adults 2 weeks after treatment. Although providing less than 50% control at 7 DAT, the low rate of Pinpoint (0.5 g prod/pot), Cryolite bait (30 lb/A), and Kryocide (50 lb/A) treated blocks showed greater than 60% mortality by 2 weeks after treatment. Bifenthrin-treated weed barriers (1.5% ai) placed on the surface of the growing medium provided more than 50% control 14 days after treatment. Differences in speed of control may reflect differing modes of action or application methods. One possible benefit in use of the slower-acting stomach poisons and systemic insecticides is reduced risk to nontarget organisms such as predator mites.
022 Delivery of Gases to the Soil Matrix via Buried Drip Irrigation Tubing
Authors: Karlik John F. , Becker J. Ole , Schuch Ursula K.
Published: February 2019

The impending worldwide restrictions on the use of methyl bromide (MeBr) as a soil fumigant have prompted an intensive search for more-effective methods for delivering MeBr or replacement compounds. Although the majority of agrochemicals are applied in the solid phase or the liquid phase at ambient pressure and temperature, some chemicals, including certain soil fumigants such as MeBr, are gases under normal field conditions. Experiments were conducted to evaluate use of two types of commercial drip irrigation tubing to deliver gases to nontarped planting beds. Air moved through each tubing type immediately after burial; water was not necessary for inflation. Air was also able to move through 40 m of buried rigid drip tubing and through 90 m of buried flat tape that had been used for subsurface drip irrigation for more than 1 year. Mixtures of known ratios of propane and air were introduced into the buried tubing over several time intervals to evaluate gas movement from buried drip tubing into the surrounding soil matrix. Samples were collected from sets of three soil gas sampling tubes placed 15, 30, and 45 cm to the side of the buried tubing and at regular intervals along the length of the tubing, and propane concentrations were quantified by gas chromatography. Tubing lengths and run times affected the magnitudes and uniformity of propane concentrations. Results suggest gas-phase chemicals can be delivered via buried drip-irrigation tubing, but effective distances from the point of introduction will be limited by the low densities and viscosities of gases, and corresponding high rates of escape through tubing emitters.
026 Genetic Analysis and Breeding for Resistance to Bacterial Wilt in Capsicum Pepper
Authors: Cheung J.D. , Cha Y.S. , Kim B.S.
Published: February 2019

Bacterial wilt caused by Ralstonia solanacearum is sporadically causing damage to pepper in Korea. We put efforts in analyzing the genetics of resistance to bacterial wilt and in subsequent breeding for resistance by selection. Two Korean cultivars, Subi and Chilsung, were crossed with a resistant source, MC-4, which was kindly provided by Lopes in Brazil. In addition, four breeding lines bred for resistance to Phytophthora blight were crossed with another resistance source, PBC631, which we received from AVRDC. F2 and backcross populations of the crosses were developed and tested by inoculation by dipping the roots of the seedlings before transplanting 25 days after seeding. Segregation in the F2 and backcross populations did not fit any mode of simple Mendelian inheritance, but appeared inheriting in a quantitative mode with relatively low heritability. Selection was practiced in the subsequent F3, BC1F2, F4, and BC1F3 generations and a few resistant selections were obtained.
035 A New Southernpea
Authors: Morelock T.E. , Motes D.R. , Gonzalez A.R.
Published: February 2019

Southernpea (cowpea), Vigna ungiculata L. Walp, is an important processing and fresh-market vegetable in the southern United States. While many of the newer varieties are early maturing, there is still a need for late-maturing, high-yielding varieties. Arkansas 92-552 fills this niche. It is a bush plant that produces silver pods in the upper portion of large plants that are free of basal runners. The seed are medium size with a bright pink eye. Maturity is 5 to 7 days later than `Coronet' under Arkansas conditions. The variety processes well and canned peas have been rated equal to `Coronet' by consumers panels. The yield potential is high and it has produced higher yield than `Coronet' in replicated trials in Arkansas. 92-552 is also resistant to rootknot nematode.
040 Pedigree of Publicly Released Onion Germplasm in the United States, 1931-1997
Authors: Schroeck G. , Goldman I.L. , Havey M.J.
Published: February 2019

Since the 1930s, more than 130 inbred lines and 60 hybrid cultivars of onion have been released in the public sector in the United States. Other than breeder's reports from the period 1946-1965 and anecdotal information kept by onion workers, no systematic treatment of the pedigree of public onion germplasm releases has been developed. The objective of this research was to collect, characterize, and display the genetic relationships among more than 200 public onion germplasm sources used in the United States since 1931. Pedigree information revealed that most modern onion cultivars in the United States descend from a few open-pollinated populations brought to this country by immigrants. For example, selection in the open-pollinated populations Common Yellow and Silverskin by onion farmers in the eastern U.S. resulted in the formation of Yellow Globe Danvers, which was a precursor to virtually all Eastern storage onion germplasm in the U.S. Open-pollinated populations such Yellow Globe Danvers, Valencia, Sweet Spanish, Bermuda, and Grano formed the foundation germplasm for the first public U.S. onion breeding programs. Findings from this study suggest a relatively narrow germplasm base of public onion germplasm in the United States; however, this narrow pool coexists alongside significant gains through scientific breeding efforts, particularly during the past 75 years.
043 New Honeydew Melons for Commercial Production in Western Mexico
Authors: Larios J. Farias , Aguirre J. G. López , Cruz E. Rincón , Juarez F. Radillo
Published: February 2019

Since 1980, farmers from western Mexico have cultivated melon cantaloupe; however, during the past few years, they have seen the better advantages of honeydew melon. Some of them represent a good alternative to farmers because chemical products and labor costs are reduced, and because they are tolerant to several diseases. The purpose of this experiment was to evaluate 15 new hybrids of honeydew melon in western Mexico. The hybrids evaluated were: Dey Break, Hmx 4596, Hmx 4595, Hmx 4607, Sunex 7051, Rocio, creme de menthe, Silver world, Emerald sweet, Sme 5303, Sme 5302, Santa Fé, PSR 10994, and PSR 8994, Honey Brew was test. Fifteen -day-old plants were transplanted by hand. Treatments were replicated four times in a randomized complete-block design. Beds 1.2 m wide and 7.0 m long were prepared, 1.5 m between beds, distance plant-plant 0.5 m (plant density ≈13,332 plant/ha). Results show that yield of SME 5302, SME 5303, HMX 4596, Rocío, Dey Break, PSR 8994, Sunex 7051, and HMX 4607 had a yield higher of 50 t/ha, Emerad sweet had more number fruit (59 per 10 plants), whereas SME 5303, SME 5302 and Silver world had higher fruit weight (>1.719 gr). We suggest the evaluation of these hybrids in other regions to know the adaptation to different conditions and to select the best in commercial quality and production.
048 Collection and Evaluation of Four Varieties of Celosia trigna
Authors: Makinde Margaret J. , Olufolaji Adenike O.
Published: February 2019

Celosia trigyna has become an underutilized species of Celosia in Nigeria, it is known to be medicinal and very nutritive. It is therefore intended that with their collection and evaluation, they could be domesticated. So far four varieties have been identified and described. All of them have a high tendency of shattering of the seeds from the inflorescence. The plant structure for all of them is prostrate, the varieties described are: NHcta01, NHcta03, NHcta4, and NHcta7. It was dicovered that compared with C. argentea, they branch profusely and the leaves are smaller and ovate rather than lancolate.
050 Heritage Pears of the National Clonal Germplasm Repository
Authors: Hummer Kim E.
Published: February 2019

The pear, Pyrus L., originated in prehistoric times. Records of its cultivation date back 3000 years both in Europe, with the ancient Romans and Greeks, and in Asia, with the Chinese. Pear culture was significant in France and England by the 16th century. The European golden age of pear improvement occurred from the 17th through the 19th centuries. The pear genetic resource collection for the United States Department of Agriculture, Agricultural Research Service, National Plant Germplasm System is maintained at Corvallis, Ore. This collection preserves more than 2000 diverse pear accessions, represents 26 species, and includes more than 410 heirloom cultivars. At least 10 of the cultivars have obscure origins from the ancient Roman, Greek, or Chinese cultures. Another dozen are at least 400 years old, and more than 250 were introduced during the European golden age. Another 120 “antique” cultivars of the collection were introduced during the first half of the 1900s. The “big four” economically important Pyrus communis L. cultivars in the United States, `Bartlett', which originated in 1777; `Anjou', late 1700s; `Bosc', 1807; and `Comice', 1845; are also represented. Origin and background information for these heirloom clones is web accessible through the Germplasm Resource Information Network (GRIN) database. Although many ancient pear genotypes have been lost, the Repository staff continues to search for significant heirloom cultivars that are not yet represented. Besides having direct value in crop improvement, these plants are a significant part of our human heritage. Their preservation is a sacred trust.
051 The USDA-ARS/Cornell University Apple Rootstock Breeding and Evaluation Program
Authors: Johnson William C. , Forsline Phil L. , Aldwinckle Herb S. , Johnson William C. , Forsline Phil L. , Holleran H. Todd , Robinson Terence L. , Norelli John J.
Published: February 2019

In 1998, the USDA-ARS and Cornell Univ. instituted a cooperative agreement that mobilized the resources for a jointly managed apple rootstock breeding and evaluation program. The program is a successor to the Cornell rootstock breeding program, formerly managed by Emeritus Professor of Horticultural Sciences James N. Cummins. The agreement broadens the scope of the program from a focus on regional concerns to address the constraints of all the U.S. apple production areas. In the future, the breeding program will continue to develop precocious and productive disease-resistant rootstock varieties with a range of vigor from fully dwarfing to near standard size, but there will be a renewed emphasis on nursery propagability, lodging resistance, tolerance to extreme temperatures, resistance to the soil pathogens of the sub-temperate regions of the U.S., and tolerance to apple replant disorder. The program draws on the expertise available at the Geneva campus through cooperation with plant pathologists, horticulturists, geneticists, biotechnologists, and the curator of the national apple germplasm repository. More than 1000 genotypes of apple rootstocks are currently under evaluation, and four fire blight- (Erwinia amylovora) resistant cultivars have been recently released from the program. As a service to U.S. apple producers, rootstock cultivars from other breeding programs will also be evaluated for productivity, size control, and tolerance to a range of biotic and abiotic stress events. The project will serve as an information source on all commercially available apple rootstock genotypes for nurseries and growers.
052 Characterization of Somaclones and Apple Rootstocks (Malus sp.) by Using Isoenzymatic Systems
Authors: de M. Dantas Adriana C. , de L. Fortes Gerson R. , dos Anjos e Silva Sergio D. , da Silva João Baptista
Published: February 2019

This work aimed to evaluate apple rootstock somaclones by characterizing the genetic variability among them. The isoenzymatic systems were used for analyzing variability as follows: FAC (acid phosphatase), PRX (peroxidase), and 6-PGD (6-phosphogluconate dehydrogenase). The migration were performed by applying a potential difference around 10 volt/linear cm. A data matrix was built so that the genotypes were placed in the lines and the bands in the columns. The scores were attributed as follows: band present (1) and band not present (0). By the gel analyses in relation to the presence/absence and band intensity, we observed marked differences among the somaclones and within somaclones as well. In the peroxidase system a higher band polyimorphism was detected with 18 enzymatic patterns. The group analyses for the 73 apple somaclones revealed a large variability through the enzymes (18 peroxidases, 8 FAC, and 6 6-PGD), which were classified into two groups. Group I was represented by M.7 somaclones with seven subgroups with 43% similarity among the clones. Differences among M.9 and M.111 cultivars and two clones referred to as M9b and M925 were fitted within somaclones M.111. The remaining somaclones of cultivar M.9 showed a higher variability bearing 43 subgroups. Clones M929, M930 and M932 presented 100% similarity.
056 Evaluation of Low-chilling Requirements of Apricot Selections in Northwestern Mexico
Authors: Grijalva-Contreras Raúl Leonel , López-Carbajal Arturo , Fimbres-Fontes Adán , Navarro-Ainza Cristobal , Juárez-González Rogelio , Robles-Contreras Fabián
Published: February 2019

Apricot production in México is limited; actually, the area devoted to this crop is ≈880 ha, from which 230 ha are established in Sonora State. The main cultivar is `Canino'. The fruit yield ranges from 15 top 20 t·ha-1. The present study tested 20 low-chilling (300-400 chill hours) requirements of apricot selections; `Nemaguard' was the rootstock used. On the fourth production year, from the 20 apricot selections tested, 7-23, 1-81, and 15-1 yielded 31.8, 20.2, and 15.5 t·ha-1, respectively. all of these selections showed higher yields than `Canino' (14.6 t·ha-1). The fruit of these apricot selections ripened by mid-May, exhibiting a similar fruit quality (size, flavor, color, and °Brix) in all the tested selections. We have not recorded any important insect pests or diseases during this trial.
057 A New Plumcot Adapted to the Southeastern United States
Authors: Okie W.R.
Published: February 2019

Plumcots are hybrids of plums (usually Japanese-type) and apricots. In recent years, several new plumcots have been released, but most of these have been unreliable croppers and tree health of those tested in the Southeast has been poor. Some do have very high quality fruit, combining the best features of both parents. BY88Z1092 appeared as a chance hybrid in a lot of open-pollinated seedlings from the plum selection BY8111-6, which was a hybrid of BY4-601 (=`Queen Anne'*`Santa Rosa')*`Frontier'. BY8111-6 was a high-quality, midseason plum with black skin and amber flesh. BY88Z1092 blooms about with 750 chill hour peaches, and appears to be somewhat self-fertile. Cropping is heavy at Byron in absence of severe spring frosts. Tree health is good, comparable to local adapted plums such as `Black Ruby'. Trees are upright in growth habit. Fruit of BY88Z11092 ripen in late May, when quality of other adapted plums is insipid. It has firm yellow-orange flesh and a purple-black skin with light pubescence. Flavor is acidic until the fruit begins to soften, at which time it is very good. Fruit size will reach 4 to 5 cm in diameter if properly thinned. BY88Z1092 is in the final stages of testing and will likely be named within the next year.
058 Cloning of a Defensin-related Gene and Its Expression during Dormancy and Fruit Development in Peach [Prunus persica (L.) Batsch]
Authors: Wisniewski M. , Artlip T. , Webb R. , Bassett C. , Callahan A.
Published: February 2019

During the past several years we have been involved in identifying seasonally regulated proteins and genes from peach bark. In the present study, we describe the cloning of a protease inhibitor from a cDNA library made from winter bark tissues. A partial clone obtained from the library was extended to full length by 5' RACE. The full-length cDNA clone (final3b) is 613 bp in length, not including the poly A+ tail. The open reading frame of 237 bp codes for a 79 amino acid protease inhibitor related to the defensin family of proteins. This family of small, cysteine-rich, extracellular proteins play a role in the plantís defense response through their antifungal properties. Sequence comparison of the encoded protein using BLAST analysis revealed significant homology to protease inhibitors from Glycine max, Arabidopsis thaliana, and a defensin protein from bell pepper (Capsicum annuum). Similar to these other cysteine-rich proteins, the peach defensin contains a consensus cys arrangement and is predicted to have an amino terminal signal peptide, presumably targeting it for extracellular transport. RNA-blot analysis indicated that the gene is seasonally expressed in bark tissues of 1-year-old shoots. Transcript abundance of final3b increased in the fall, reached a peak in midwinter and then decreased. The gene was also expressed during early stages of fruit development. RNA-blot analysis of the gene in other tissues, and in response to environmental stress and wounding, is in progress.
062 Genetic Relationships among Corylus Species
Authors: Erdogan V. , Mehlenbacher S.A.
Published: February 2019

Interspecific hybridization, pollen-stigma incompatibility, and DNA sequence analysis were used to study the relationships among hazelnut (Corylus) species. Interspecific crosses resulted in a wide range of cluster set from 0% to 65%. Reciprocal differences were common. In general, crosses involving C. avellana and C. heterophylla were more successful when used as pollen parents, but crosses involving C. americana were more successful when it was the female parent. C. cornuta, C. californica and C. sieboldiana intercrossed freely in both directions, as did C.colurna and C.chinensis. The Asian species, C. sieboldiana, C.heteropyhlla, and C. chinensis, were not cross-compatible with each other. Fluorescence microscopy showed that pollen-stigma incompatibility exists within and among wild hazelnut species, in addition to the cultivated European hazelnut C. avellana. Pollen-stigma incompatibility and embryo abortion (blank nuts) appear to be major blocks to interspecific gene flow. In addition, the chloroplast matK gene and the Internal Transcribed Spacer (ITS) region of the nuclear ribosomal DNA (nrDNA) were amplified and sequenced. The matK sequence was highly conserved and thus was not informative. However, the ITS sequence was highly informative and parsimony analysis agreed with morphological similarities. Corylus species were placed into four groups: 1) C. avellana, C. maxima, C. americana and C. heterophylla 2) C. colurna, C.chinensis, and C. jacquemontii 3) C. cornuta, C. californica and C. sieboldiana 4)C. ferox.
066 Development of Simple Sequence Repeat DNA Markers for Use in Pecan Genetic Studies
Authors: Iqbal M.J. , Grauke L.J. , Reddy A.S. , Thompson T.E.
Published: February 2019

A microsatellite library has been developed from `Halbert', a native pecan selection from Coleman County, Texas, using methods developed at the Texas A&M Univ. Crop Biotechnology Center. A total of 6144 DNA fragment clones were archived in 384 well plates for screening. Four-hundred-thirty-nine clones were positive after Southern hybridization using di- and tri-nucleotide repeats as probes. One-hundred-twenty-five positive clones were sequenced on an ABI 377 automated DNA sequencer. Of these, 24 repeats had enough sequences at the two ends to design primers. Primers were designed using Primer Express software, and were synthesized by Genosys, USA. The simple sequence repeats (SSRs) chosen for primer analysis include di- (CA and GA) and tri-nucleotide repeats (CTT, GAA and GAT). The SSRs were amplified under high stringency conditions with temperatures based on length and GC content. Reproducibility was verified using `Halbert' DNA isolated from different inventories. Of the 24 primer pairs tested, 20 successfully amplified microsatellites from `Halbert'. DNA was isolated from 48 pecan and hickory accessions selected to strategically represent the genetic diversity of the NCGR Carya collections (a core collection). The accessions included parent-progeny combinations, individuals from geographically distant native populations, species, and interspecific hybrids. The 20 SSR primers that produced good amplification products in `Halbert' were used to evaluate the collection, with 11 revealing multiple sizes of the repeat. The number of bands amplified with different primer combinations ranged from 4 to 32 in the 48 genotypes tested. We used RFLPscan software to aid in gel scoring (sizing amplified fragments, and comparing amplification profiles), and NTSYSpc software to evaluate genetic similarities. Evaluation of the data confirms the utility of the primers in delimiting known relationships.
067 A Long-term Comparison of Six Rootstocks for `Nonpareil' and `Carmel' Almond Cultivars
Authors: Hendricks Lonnie C. , Younce Everett L. , Micke Warren C. , Yeager James
Published: February 2019

A rootstock comparison trial for almond was planted in sandy soil near Atwater, Calif., in Feb.1989. The study consisted of five replications of five trees each for six rootstocks, each with two cultivars. The rootstocks were `Nemaguard' peach, `Nemared' peach, `Hansen 536' peach × almond hybrid, `'Bright's hybrid' (peach × almond), `Halford' peach seedling, and `Lovell' peach seedling. Two cultivars, `Nonpareil' and `Carmel', were used with each rootstock. The accumulated kernel production from `Nonpareil' through the 1998 harvest was highest for trees on `Hansen 536', second highest for those on `Nemaguard', and third highest for trees on `Bright's Hybrid'. The accumulated kernel production from `Carmel' was greatest for trees on `Bright's Hybrid' and second highest for those on `Hansen 536'. The hybrids have produced the largest trees, as indicated by trunk circumference, for both `Nonpareil' and `Carmel'. The greater production of trees on the hybrid rootstocks over those on the peach seedling rootstocks was probably a result of their greater size and not that the trees on the hybrid rootstocks were inherently higher-yielding.
068 QTL Analysis of Solid Content, Pungency, and Antiplatelet Activity of Onion (Allium cepa L.)
Authors: Galmarini C.R. , Goldman I.L. , Havey M.J.
Published: February 2019

Solid content is an important characteristic related to onion flavor, texture, and storability and has practical importance for the dehydration industry. Among the salutary effects of Allium vegetables on the cardiovascular system is the inhibition of platelet activity. Platelets play a key role in thrombosis and acute coronary syndromes because they facilitate blood coagulation. Pungency is also an important commercial trait. A 138-point genetic map is being used to identify and estimate the magnitude of quantitative trait loci controlling solid content, pungency, and health-enhancing attributes of onion. QTL controlling pungency, total solids, soluble solids, and antiplatelet activity were estimated using 54 F3 families, derived from the cross between Brigham `Yellow Globe 15-23' (BYG15-23) and `Ailsa Craig' (AC43). The families, the two parents, and controls were evaluated in four environments, at Palmyra or Randolph, Wis., during 1997 and 1998, on muck soils. For the analyzed traits there is evidence of trangressive segregation, the distributions are, in general, skewed towards the BYG 15-23 parent. Our results confirmed the existence of strong phenotypic correlations among the traits under study. QTL data available also suggest the existence of significant correlations between markers and the traits under study. Most of the markers that are significant for pungency and antiplatelet activity are also significant for solids, suggesting that these characteristics may be controlled by the same chromosome regions.
071 A Saturated Linkage Map for the Garden Pea
Authors: Weeden Norman , Timmerman-Vaughan Gail
Published: February 2019

A linkage map for a set of 51 F2-derived recombinant inbred lines has been constructed from the segregation data of ≈850 morphological, isozyme, RFLP, STS, RAPD, and AFLP markers. The final map consists of seven clear linkage groups with a total length of nearly 900 cM. The wide variety of loci placed on this map permits its comparison with partial maps that have been developed in other programs. For the most part, the arrangement of loci agrees with that in previous maps, and no evidence for translocation heterozygosity in this cross is apparent. Although some clustering of markers is observed, for the most part the markers are well-distributed, and few gaps greater than 5 cM are found in the coverage. The availability of this first “complete” and highly saturated map for pea should permit more efficient comparison of the partial maps that have been generated in a number of different crosses, as well as provide a firm basis for future mapping and molecular studies in this species.
074 Molecular Markers Linked to the Ur-7 Gene Conferring Specific Resistance to Rust in Common Bean
Authors: Park Soon O. , Coyne Dermot P. , Steadman James R.
Published: February 2019

Bean rust, caused by Uromyces appendiculatus, is a major disease of common bean (Phaseolus vulgaris). The objective was to identify RAPD markers linked to the gene (Ur-7) for specific resistance to rust race 59 using bulked segregant analysis in an F2 segregating population from the common bean cross GN1140 (resistant to rust) × Nebraska #1 (susceptible to rust). A single dominant gene controlling specific resistance to race 59 was found in the F2 and was confirmed in the F3. Seven RAPD markers were detected in a coupling-phase linkage with the Ur-7 gene. Coupling-phase RAPD markers OAA11.500, OAD12.550, and OAF17.900 with no recombination to the Ur-7 gene were found. Three RAPD markers were identified in a repulsion-phase linkage with the Ur-7 gene among the three markers at a distance of 8.2 cM. This is the first report on RAPD markers linked to the Ur-7 gene in common bean. The RAPD markers linked to the gene for specific rust resistance of Middle American origin detected here, along with other independent rust resistance genes from other germplasm, could be used to pyramid multiple genes into a bean cultivar for more-durable rust resistance.
079 Molecular Tagging of ZYMV Resistance in Squash (Cucurbita moschata)
Authors: Brown Rebecca Nelson , Myers James R.
Published: February 2019

Marker-based selection for resistance to zucchini yellow mosaic virus in squash (Cucurbita spp.) would allow breeders to screen individual plants for resistance to multiple viruses. The C. moschata landrace Nigerian Local is widely used as a source of resistance in C. pepo breeding programs. We used RAPDs and bulk-segregant analysis to screen two BC1 populations for a marker linked to the dominant major gene for resistance from Nigerian Local. The initial cross was Waltham Butternut × Nigerian Local; the test populations were created from reciprocal backcrosses to Waltham Butternut. Both populations segregated 1:1 for resistance when hand-inoculated with ZYMV. RAPD primers were screened on a resistant bulk and a susceptible bulk from each population, and Waltham Butternut and Nigerian Local. Primers that gave bands linked to resistance were further screened using DNA from individual plants in each population. The potential markers will be tested on several populations derived from crosses between summer squash (C. pepo) and Nigerian Local to determine if they would be useful for selection in a C. pepo background.
084 Plant Preservative Mixture (PPM) can Reduce Shoot Regeneration from Leaf Explants of Selected Plants
Authors: George M.W. , Tripepi R.R.
Published: February 2019

Plant preservative mixture (PPM) is a new broad-spectrum biocide that may be useful for plant tissue culture. The objective of this study was to determine if PPM interfered with adventitious shoot regeneration on leaf explants from several plant species. Leaf explants from Dendranthema grandiflora `Iridon', Betula pendula, Rhododendron catawbiense var. album and R.c. `America' were made from the top two apical leaves on the microshoots. In the first experiment, 0, 0.5, 1, 2, or 4 mL·L-1 PPM were added to species-appropriate regeneration media. In the second experiment, only mum leaf explants were placed on regeneration media containing 0, 0.1, 0.2, 0.3, or 0.4 mL·L-1 PPM. The percentage of explants forming shoots and the number of shoots per regenerating explant were recorded after 4, 6, and 10 weeks, for mum, birch, and rhododendron leaves, respectively. The percentages of shoot regeneration from birch and rhododendron leaf explants were unaffected by up to 4 mL·L-1 PPM, and the number of shoots formed per R.c. album explant were also unaffected by the tested concentrations of PPM. In contrast, the numbers of shoots formed on birch and `America' explants were reduced 48% and 25%, respectively, when 4 mL·L-1 PPM was used in the media. The percentages of shoot regeneration and number of shoots per explant were drastically reduced on mum explants when only 0.5 mL·L-1 PPM was used in the medium. In fact, 0.3 mL·L-1 PPM or higher reduced shoot formation by more than 5-fold. This study demonstrates that the effects of PPM on shoot regeneration from leaf explants are species specific.
092 RNA Localization of a Strawberry MADS-Box Gene (SAG1) Involved in Fruit Development
Authors: Rosin Faye M. , Hannapel David
Published: February 2019

MADS-box genes are an important family of highly conserved regulatory genes in plants, animals, and yeast. Genetic analyses have shown that plant MADS-box genes are homeotic and control both the spatial and temporal location of specific organs. While MADS-box genes have been extensively studied and characterized in floral organ development, their involvement in other developmental processes, such as fruit development, is not well understood. From a strawberry fruit cDNA library, we have identified a strawberry AGAMOUS-like MADS-box gene (SAG1) that is expressed in developing fruit, but not in leaves. This is the first MADS-box gene to be isolated from strawberry. The hypothesis guiding this research is that SAG1 plays an important role in the development of the fruit. Nucleotide sequence analysis showed that this cDNA had the highest sequence match to genes from the AGAMOUS family. Comparison of amino acid sequence similarity between SAG1 and members of this family ranged from 70 to 75% overall, and between 98% to100% within the MADS-box. Involvement in stamen and carpel identity is one function of this family of MADS-box genes. Northern hybridizations were performed in order to analyze the expression of this gene at the RNA level. RNA was extracted from various organs of Fragaria ×ananassa, c.v. Calypso. SAG1 RNA expression was specific to stamens, carpels and all stages of fruit and seed development. No expression was detected in roots, leaves, or sepals. Thus, we conclude that SAG1 RNA is involved in reproductive organ and fruit development.
095 `Jupiter' Seedless Table Grape
Authors: Clark John R. , Moore James N.
Published: February 2019

`Jupiter' is the fifth table grape cultivar released from the Univ. of Arkansas grape breeding program. `Jupiter' originated from a cross of Ark. 1258 × Ark. 1672 made in 1981. The original seedling vine was selected in 1984, and `Jupiter' was tested as Ark. 1985. `Jupiter' was tested at two locations in Arkansas (Fayetteville and Clarksville) and at West Lafayette, Ind. Fruit of `Jupiter' are reddish-blue, and berry weight averaged 5.5 g over 12 years of evaluation at Clarksville. Fruit are seedless, have a non-slipskin texture, ripen early mid-season, and averaged 19.8% soluble solids. Flavor is a mild muscat, a noteworthy character of this new cultivar. Clusters averaged 257 g over 12 years and are well-filled. Yields of `Jupiter' have been very good, exceeding 29 t/ha at Clarksville. Hardiness of `Jupiter' was greater than `Einset Seedless', `Himrod', or `Vanessa Seedless', but less than `Mars' or `Reliance' at West Lafayette. `Jupiter' is recommended for trial where other other eastern U.S. table grape cultivars are adapted.
100 A Comparison of Two Media on Growth of Deciduous Azalea Shoots In Vitro
Authors: Robacker Carol D. , Robicheaux Betty
Published: February 2019

Micropropagation is a useful technique to propagate species such as deciduous azaleas, which are difficult to root from cuttings. To develop a micropropagation protocol that would be effective with a wide range of species and cultivars of native azalea, two culture media, Woody Plant Medium (WPM) (Lloyd and McCown, 1980) and ER medium (Economou and Read, 1994) were evaluated for ability to support growth of 11 species and four cultivars of deciduous azalea. Shoot tips were obtained from the first flush of growth in the spring on plants growing in the greenhouse or field. Following disinfection, the terminal and basal ends were removed from each explant. The explants were placed in culture tubes containing either WPM or ER medium with 12 mg/L 2iP and solidified with agar. Cultures were transferred to fresh medium every 4 to 6 weeks. Initial evaluations were made in 1996, and the experiment was repeated in 1997. In 1998, six of the taxa were evaluated for a third year. For most of the taxa evaluated, growth was superior on ER medium. On WPM, many of the cultures browned and died. R. canescens, R. viscosum, R. prunifolium, and R. austrinum are examples of species that preferred ER medium. R. alabamense, R. arborescens, and `My Mary' performed similarly on either medium.
102 Container Production of Ornamental Grasses: The Effects of Propagation Time on Winter Survival and Sale Date
Authors: Cunliffe Bruce A.
Published: February 2019

It is common practice to propagate grasses by division in the spring rather than the fall. This is particularly true of warm-season grasses. Production schedules for grasses do not often fit the general production pattern of other herbaceous perennial or woody crops. Five ornamental grass species were studied: Schizachyrium scoparium, Sporobolus heterolepsis, Calamagrostis × acutiflora `Karl Foerster', Miscanthus sinensis `Purpurascens', and Miscanthus sinensis `Variegatus'. Uniform divisions based on species were planted in 4-inch (480-ml) pots, #1 (2780-ml), and #2 (6240-ml) containers. Fall divisions were done between 28 Oct. and 10 Nov. 1997. Spring divisions occurred between 30 Apr. and 7 May 1998. The experiment is a randomized complete-block design blocking on pot size. All containers were over-wintered under the same cover of plastic, straw, and plastic. Plants were evaluated for post-winter survival and growth. Plants were given a visual rating (0-3) every 2 weeks to assess salability. Spring survival of fall divisions was 99% for S. scoparium, C. × acutiflora `Karl Foerster', and M. sinensis `Purpurascens'. M. sinensis `Variegatus', and S. heterolepsis each had ≈50% survival. Fall divisions reached a salable rating a minimum of 2 weeks ahead of spring divisions. These results indicate that some ornamental grass species may benefit from fall rather than spring handling.
103 Optimizing the Propagation of the Ornamental Grass Hakonechloa macra `Aureola'
Authors: Harvey Michael P. , Brand Mark H.
Published: February 2019

Studies initiated in Spring 1998 analyzed the influence of division size, shade, and temperature on the growth rate of the ornamental grass Hakonechloa macra `Aureola' in nursery-container production. To determine the optimum division size for production, container-grown stock plants were used to make early spring divisions of four sizes (1-2, 4-6, 8-10, and 12-15 buds). Divisions were established in 325-ml pots for 1 month before being transplanted to 3.7-L nursery containers. Plants were grown outdoors and received topdressed 17-6-10 slow-release fertilizer (containing micronutrients) and drip irrigation from June through September. Average leaf area, shoot number and bud count increased linearly as division size increased, but average height remained the same between each treatment. Plants of all division sizes exhibited healthy growth, with 50% of the plants in the 4-6 buds/division treatment growing to marketable size compared to 45%, 35% and 15% in the 8-10, 12-15, and 1-2 buds/division treatments, respectively. Four shade densities (0%, 30%, 50%, and 70%) were tested to determine which promoted optimum growth. As shading increased, average shoot number per plant decreased, average height and shoot length increased and bud count remained the same. To determine the optimum growing temperature for Hakonechloa, divisions were grown in 325-ml pots under four different day/night temperatures (15/10, 21/16, 27/22, and 33/28 °C) for 12 weeks in growth chambers. Plants were fertigated daily with a 5-25-5 liquid fertilizer. Average bud count, leaf area, plant height, plant width, shoot length, and shoot number increased as temperature increased to 27/22 °C, then decreased significantly beyond this temperature optimum.
106 Propagation of Alnus maritima from Softwood Cuttings
Authors: Schrader James A. , Graves William R.
Published: February 2019

Alnus maritima [Marsh.] Nutt. (seaside alder) is a rare, North American species with strong potential for use in managed landscapes. Information on the propagation and production of this species is not available. Our objective was to evaluate the potential for using softwood cuttings to propagate A. maritima, with emphasis on how IBA and plant provenance affect rooting success. Propagation trials were conducted with cuttings from seven trees native to the Delmarva Peninsula and seven trees from Oklahoma. Cuttings from both provenances were collected on 14 June and 23 Aug. Cuttings were wounded; treated with 0, 1, or 8 g/kg IBA; and placed under intermittent mist in a greenhouse for 9 weeks. The highest percentage of rooting (67.9) was achieved for the Oklahoma provenance by using 8 g/kg IBA in June. Across IBA treatments, rooting of cuttings from Oklahoma, 54.8% (June) and 12.4% (August), was higher than rooting of cuttings from Delmarva, 27.1% (June) and 3.1% (August). IBA at 8 g/kg caused a higher rooting percentage than the other IBA rates at both times of the season. More cuttings collected 14 June rooted (41%) than those collected 23 Aug. (7.7%) over IBA treatments. Another experiment involved cuttings from one juvenile, greenhouse-grown seedling from Oklahoma that showed 100% rooting with both 1 and 8 g/kg IBA. Shoot growth appeared more vigorous on rooted cuttings from these juvenile stems than on plants derived by rooting mature tissue collected in nature. We conclude that using softwood cuttings can be an effective way to multiply clones of A. maritima, particularly when stock plants are juvenile and cuttings are treated with IBA.