bluuebunny/crossref_metadata_2025 huggingface dataset:
RFLP-based Analysis of Recombination Among Resistance Genes to Fusarium Wilt
Authors: Scott* John W. , Agrama Hesham A. , Jones John P.
Published: February 2019

Tomato (Lycopersicon esculentum) line E427 has resistance genes to three races of Fusarium oxysporum f.sp. lycopersici derived from L. pennellii (L.pen) accession LA 716 and L. pimpinellifolium (L.pimp) accession PI 126915. E427 was crossed to susc. Bonny Best and F2 and backcross seed were obtained. Progeny were inoculated separately with Fusarium wilt races 1, 2, or 3. Lines with suspected recombination of resistance were selfed and re-inoculated until disease reactions were homozygous. Four lines were obtained with resistance to both races 2 and 3, but susceptible to race 1. These lines had the L.pen alleles at RFLP markers linked to I-3 on chromosome 7 and lacked L.pimp alleles linked to I and I-2 on chromosome 11. Complementation (F2) data indicated race 2 resistance on chromosome 7 was controlled by a single dominant gene. Three lines were resistant to race 2, but susceptible to races 1 and 3. These lines had L.pimp alleles at TG105 indicating the presence of I-2, and no L.pen alleles at markers linked to I-3. Three lines were resistant to race 1, but susceptible to races 2 and 3. All three had L.pimp alleles at TG523 confirming linkage to I on chromosome 11 and no L.pen alleles at markers tightly linked to I-3. However, one of the lines had L.pen alleles at CT113 on chromosome 7. This and F2 complementation data suggests the possible location of a race 1 resistant locus, I1. Two lines that were Fusarium wilt race 3 resistant and susceptible to race 1 had intermediate resistance to race 2. These two lines did not have the L. pennellii alleles at TG183, TG174, and CT43 near the I-3 locus indicating crossovers in this region reduced race 2 resistance.
Variety and Planting Date Effects on Anthocyanin Concentrations in Field-grown Lettuce (Lactuca sativa)
Authors: Gazula* Aparna , Kleinhenz Matthew D. , Scheerens Joseph C. , Ling Peter P. , Streeter John G.
Published: February 2019

Anthocyanins (Antho) are the source of red color in plants and the intensity of redness is an important quality parameter in red leaf lettuce. Despite the importance of Antho in leaf lettuce, little information is available regarding the effects of major production-related factors, such as planting date, on their levels. To address this issue, field studies were conducted in 2002 and 2003 in which Antho levels were measured in nine lettuce varieties planted in early and late summer (ES and LS, respectively) using a RCB design. Leaf tissue was sampled 30 d after transplanting. Data for three strongly related Lolla Rossa-type varieties (`Lotto', `Valeria', `Impuls') are reported here. The planting date × variety interaction was significant; however, Antho concentrations were higher following planting in LS than ES, regardless of variety. Planting date effects were more pronounced in 2002, when differences in average daily temperature between ES and LS plantings tended to be larger. Regardless of planting date and year, Antho levels followed the pattern `Impuls' (three genes) > `Valeria' (two genes) > `Lotto' (one gene). Correlations between human visual and two types of instrumented assessments of color are being tested in samples from the same study.
Supplemental Calcium Application to Potatoes Reduces the Incidence of Black Spot Bruise Induced by Mechanical Harvest
Authors: Karlsson Bjorn H. , Palta* Jiwan P.
Published: February 2019

Supplemental calcium application has been shown in our previous work to improve tuber quality and reduce internal defects. We evaluated the response under field conditions of five commerically significant cultivars to a combination of calcium nitrate, calcium chloride and urea (168 kg·ha-1 per season) over three seasons. We were able to determine that the cultivar with the greatest response to supplemental calcium for reduced bruising, `Atlantic' had the lowest levels of tuber tissue calcium. Conversely, cultivars with least response to supplemental calcium, `Dark Red Norland' and `Superior', had the highest levels of tuber tissue calcium. `Snowden' was both intermediate in response to calcium and tuber tissue concentration. Based on data for 3 years, we determined that across cultivars the calcium concentration at which tubers no longer respond is ≈250 ppm and ranges for individual years from 195 to 242 ppm. These results suggest that seasonal variation for individual cultivars may affect the tuber need for calcium for reduced bruising. Although the exact mechanism is not known, we believe that calcium supplemented to bulking tubers may lead to improved cell membrane stability, increased wall structure or enhanced ability of tubers to repair following injury. The results of our study show that supplemental calcium fertilization has the ability to significantly reduce the incidence of tuber bruising for several cultivars.
Differing Vernalization Responses of Laurentia axillaris and Veronica spicata `Red Fox': Evidence for Two Thermometers?
Authors: Fausey Beth A. , Cameron* Arthur C.
Published: February 2019

Many herbaceous perennials require vernalization although effective temperatures (ET) and durations for specific species are largely unknown. To investigate vernalization of Laurentia axillaris (Lindl.) E. Wimm. and Veronica spicata L. `Red Fox', vegetative plugs were stored at -2.5, 0.0, 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0 °C for 0 to 15 weeks (Laurentia) or 0 to 8 weeks (Veronica). Following storage, plugs were grown in a 20 °C glass greenhouse with a 16-h photoperiod. Laurentia plugs did not survive storage at -2.5 or 0 °C. Survival varied for plants stored at 2.5 °C, and some plants flowered. ET and the minimum duration for 100% flowering of Laurentia were: 5 weeks at 5 to 10 °C and 10 weeks at 12.5 °C. Time to first visible bud and node number below first visible bud decreased with increasing duration at ET. Veronica plugs survived storage at all temperatures. 100% flowering occurred when plants were vernalized at -2.5 and 0 °C for 4 or more weeks, at 2.5 and 5.0 °C for 6 or more weeks, and at 7.5 °C for 8 weeks. Incomplete vernalization (19 to 93%) occurred at temperatures of 2.5 °C for 4 weeks, 5 °C for 4 or 6 weeks, 7.5 °C for 6 weeks and at 10 °C for 6 or 8 weeks. Vernalization did not occur above 10 °C or following 2 weeks storage at any temperature. The percentage of reproductive lateral shoots increased while node number below the inflorescence remained constant or decreased with increasing storage at ET. The results indicate distinct vernalization optima for the two species; Laurentia 5 to 10 °C, and Veronica -2.5 to 0 °C. These differences provide evidence that separate “thermometers” may be involved in vernalization perception.
Translocation of the Mango Florigenic Promoter
Authors: Davenport* Thomas L. , Ying Zhentu
Published: February 2019

Floral induction of mango is determined by interaction of a short-lived, florigenic promoter that is up-regulated in leaves during exposure to cool temperatures and an age-dependent vegetative promoter at the time that initiation of shoot growth occurs. Research conducted during the past flowering season demonstrated that 1/4 of a leaf per stem was sufficient to stimulate flowering in 100% of the tested stems. Three or more leaves on a donor stem of an isolated branch also bearing five defoliated stems induced flowering on all six stems. One leaf on the donor stem was sufficient to induce flowering in all of the donor stems and most of the five defoliated stems, and 1/2 leaf on the donor stem stimulated flowering in that stem and in less than 1/2 of the defoliated stems. Stems that did not flower initiated vegetative shoots instead. Flowering occurred on those stems that were inserted into main branches in the same phylotaxic position as the leaf. Evidence suggests that leaves are capable of producing far greater amounts of florigenic promoter during floral inductive conditions than needed for induction of buds and that the promoter can move great distances in phloem aligned in the same phylotaxic position as the source leaf.
The Effect of Leaf Wax Extracts from the Leaves of Eight Azalea Genotypes (Rhododendron spp.) on Feeding and Oviposition by Azalea Lace Bug [Stephanitis pyrioides (Scott)]
Authors: Chappell* Matthew R. , Robacker Carol , Baden Sherrod , Byous Allen
Published: February 2019

Azalea Lace Bug (ALB) is a significant pest on azalea species. ALB feeding injury causes a stippled appearance on the leaves of susceptible genotypes from late spring until leaf drop. To determine whether leaf surface lipids are a factor in determining resistance or susceptibility to ALB, epicuticular leaf wax was extracted from the leaves of eight azalea genotypes, half with resistance and half susceptible to ALB. Leaf wax from each genotype was extracted and re-suspended in an 2 ethanol: 1 water solution for application to all entries in a full diallel manner, including a control of solution only. Each treatment included three replications. The leaf wax solution was applied to each replication (single leaf) by painting the solution on one side of the midrib, on both abaxial and adaxial surfaces. By applying solution to one side of the leaf, the untreated leaf surface served as a control. Each leaf and two female ALB were placed in separate 50-mL sealed tubes at 24 °C and 12-hour daylength for 48 hours, at which time the number of live adults, frass spots, and eggs were counted. Frass and egg data were recorded separately for treated and untreated sides of each leaf. The application of leaf wax solution had an impact on the level of frass and egg deposition by ALB in all genotypes. The effect was most pronounced when solution of resistant genotypes was placed on susceptible genotypes, resulting in lower numbers of frass spots and eggs. The solution alone had little effect on frass or egg numbers. This research acknowledges that a major constituent of an azalea's resistance or susceptibility to ALB is via epicuticular wax components.
Plant Growth in Plastic, Peat, and Processed Poultry Feather Fiber Growing Containers
Authors: Evans Michael R. , Hensley David L.
Published: February 2019

A biodegradable container made from processed waste poultry feathers was developed, and plant growth was evaluated in plastic, peat, and feather containers. Under uniform irrigation and fertilization, dry shoot weights of `Janie Bright Yellow' marigold (Tagetes patula L.), `Cooler Blush' vinca [Catharanthus roseus (L.) G. Don.] and `Orbit Cardinal' geranium (Pelargonium ×hortorum L.H. Bailey) plants grown in feather containers were higher than for those grown in peat containers, but lower than those grown in plastic containers. Container type did not significantly affect dry shoot weights of `Dazzler Rose Star' impatiens (Impatiens walleriana Hook.f.). `Better Boy' tomato (Lycopersicum esculentum L.) dry shoot weights were similar when grown in peat and feather containers. Feather containers were initially hydrophobic, and several irrigation cycles were required before the feather container walls absorbed water. If allowed to dry, feather containers again became hydrophobic and required several irrigations to reabsorb water from the substrate. Peat containers readily absorbed water from the substrate. Substrate in peat containers dried more rapidly than the substrate in feather containers. Plants grown in peat containers often reached the point of incipient wilting between irrigations, whereas plants grown in feather containers did not. This may have been a factor that resulted in higher dry shoot weights of plants grown in feather containers than in peat containers. Tomato plants grown in feather containers had higher tissue N content than those grown in plastic or peat containers. The availability of additional N from the feather container may also have been a factor that resulted in higher dry shoot weights of plants grown in feather containers than in peat ones. Under non-uniform irrigation and fertilization, dry shoot weights of impatiens and vinca grown in feather containers were significantly higher than those of plants grown in plastic or peat containers. When grown under simulated field conditions, geranium dry shoot weights were significantly higher for plants initially grown in feather containers than for those initially grown in peat containers. Container type did not significantly affect dry shoot weights of vinca when grown under simulated field conditions. As roots readily penetrated the walls of both feather and peat containers, dry root weights of vinca and geranium were not significantly affected by container type when grown under simulated field conditions.
The Influence of 1-Methylcyclopropene on `Cortland' and `McIntosh' Apple Quality Following Long-term Storage
Authors: DeLong John M. , Prange Robert K. , Harrison Peter A.
Published: February 2019

`Redcort Cortland' and `Redmax' and `Summerland McIntosh' apples (Malus ×domestica Borkh.) were treated with 900 nL·L-1 of 1-methylcyclopropene (1-MCP) for 24 hours at 20 °C before storage and were kept at 3 °C in either a controlled atmosphere (CA) of 2 kPa O2 and <2.5 kPa CO2 or in an air (RA) environment for up to 9 months. After 4.5 months, half of the fruit were treated with a second 900 nL·L-1 1-MCP application in air at 3 °C for 24 hours and then returned to RA or CA storage. At harvest and following removal at 3, 6, and 9 months and a 7-day shelf life at 20 °C, fruit firmness, titratable acidity (TA) and soluble solids content (SSC) were measured, while internal ethylene concentrations (IEC) in the apple core were quantified after 1 day at 20 °C. Upon storage removal and following a 21-day shelf life at 20 °C, disorder incidence was evaluated. 1-MCP-treated apples, particularly those held in CA-storage, were more firm and had lower IEC than untreated fruit. Higher TA levels were maintained with 1-MCP in all three strains from both storages, while SSC was not affected. Following the 6- and/or 9-month removals, 1-MCP suppressed superficial scald development in all strains and reduced core browning and senescent breakdown in RA-stored `Redmax' and `Summerland' and senescent breakdown in RA-stored `Redcort'. 1-MCP generally maintained the quality of `Cortland' and `McIntosh' fruit held in CA and RA environments (particularly the former) to a higher degree than untreated apples over the 9-month storage period. A second midstorage application of 1-MCP at 3 °C did not improve poststorage fruit quality above a single, prestorage treatment.
Chlorophyll Fluorescence and Needle Chlorophyll Concentration of Fir (Abies sp.) Seedlings in Response to pH
Authors: Cregg B.M. , Duck M.W. , Rios C.M. , Rowe D.B. , Koelling M.R.
Published: February 2019

We assessed variable chlorophyll fluorescence (Fv/Fm) and needle chlorophyll concentration of seedlings of Maccedonia fir (Abies borisii regis Mattfeld), subalpine fir [A. lasiocarpa (Hooker) Nuttall], Sakhalin fir [A. sachalinensis (Schmidt) Mast.], Siberian fir [A. sibirica (Lebed.)], and Veitch fir (A. veitchii Lindl.) grown under varying soil media pH. Soil media pH was modified using liquid flowable dolomitic limestone, resulting in five pH levels (3.4, 4.0, 5.4, 6.0, and 6.8). Increasing media pH significantly reduced Fv/Fm and needle chlorophyll concentration in all of the species tested. The effect of pH on photochemistry was due to depressed nutrient uptake of P, Mn, B, and Cu. Because photosynthetic quantum yield may be related to deficiencies of several elements affected by pH, Fv/Fm may serve as a criterion to select for improved pH tolerance. Among the species examined, A. veitchii and A. lasiocarpa were most tolerant of increased pH based on Fv/Fm and needle chlorophyll concentration.
Salinity Tolerance of Selected Seashore Paspalums and Bermudagrasses: Root and Verdure Responses and Criteria
Authors: Lee Geungjoo , Carrow Robert N. , Duncan Ronny R.
Published: February 2019

Seashore paspalum (Paspalum vaginatum Swartz) is a warm season turfgrass that survives in sand dunes along coastal sites and around brackish ponds or estuaries. The first exposure to salt stress normally occurs in the rhizosphere for persistent turfgrass. Information on diversity in salinity tolerance of seashore paspalums is limited. From Apr. to Oct. 1997, eight seashore paspalum ecotypes (SI 94-1, SI 92, SI 94-2, `Sea Isle 1', `Excalibur', `Sea Isle 2000', `Salam', `Adalayd') and four bermudagrass (Cynodon dactylon × C. transvaalensis Butt-Davy) cultivars (`Tifgreen', `Tifway', `TifSport', `TifEagle') were investigated for levels of salinity tolerance based on root and verdure responses in nutrient/sand culture under greenhouse conditions. Different salt levels (1.1 to 41.1 dS·m-1) were created with sea salt. Measurements were taken for absolute growth at 1.1 (ECw0; electrical conductivity of water), 24.8 (ECw24), 33.1 (ECw 32), and 41.1 dS·m-1 (ECw40), threshold ECw, and ECw for 25% growth reduction from ECw0 growth (ECw25%). Varying levels of salinity tolerance among the 12 entries were observed based on root, verdure, and total plant yield. Ranges of root characteristics were inherent growth (ECw0) = 0.20 to 0.61 g dry weight (DW); growth at ECw24 = 0.11 to 0.47 g; growth at ECw32 = 0.13 to 0.50 g; growth at ECw40 = 0.13 to 0.50 g; threshold ECw = 3.1 to 9.9 dS·m-1; and ECw25% = 23 to 39 dS·m-1. For verdure, ranges were inherent growth at ECw0 = 0.40 to 1.07 g DW; growth at ECw40 = 0.31 to 0.84 g; and ratio of yields at ECw40 to ECw0 = 0.54 to 1.03. Ranges for total growth were inherent growth at ECw0 = 0.72 to 2.66 g DW; growth at ECw24 = 0.55 to 2.23 g; growth at ECw32 = 0.54 to 2.08 g; growth at ECw40 = 0.52 to 1.66 g; threshold ECw = 2.3 to 12.8 dS·m-1; and ECw25% = 16 to 38 dS·m-1. Significant salinity tolerance differences existed among seashore paspalums and bermudagrasses as demonstrated by root, verdure, and total growth measurements. When grasses were ranked across all criteria exhibiting a significant F test based on root, verdure, and total growth, the most tolerant ecotypes were SI 94-1 and SI 92. Salinity tolerance of bermudagrass cultivars was relatively lower than SI 94-1 and SI 92. For assessing salinity tolerance, minimum evaluation criteria must include absolute growth at ECw0 and ECw 40 dS·m-1 for halophytes, but using all significant parameters of root and total yield is recommended for comprehensive evaluation.
Update on and Review of the Incompatibility (S-) Genotypes of Apple Cultivars
Authors: Broothaerts Wim , Van Nerum Ilse , Keulemans Johan
Published: February 2019

Apple cultivars display a self-incompatibility system that restricts self-fertilization and fertilization between cultivars bearing identical S-alleles. There has been considerable progress in identification of S-alleles in apple in recent years and methods are now available for the accurate S-genotyping of cultivars. Following a recently revised numerical identification system for apple S-alleles, we present the first extensive compilation of apple cultivars with their S-genotypes. This list contains data from our own investigations using S-allele-specific PCR methodology, including a number of new data, as well as published data from various other sources. Eighteen different S-alleles are discriminated, which allowed the determination of the S-genotypes for 150 diploid or triploid European, American, and Japanese cultivars. Many of these cultivars are cultivated worldwide for their fruit. Also included are a number of old, obsolete cultivars and a few nondomestic genotypes. We observed a wide variation in the frequency of S-alleles in the apple germplasm. Three S-alleles (S2, S3, and S9) are very common in the cultivars evaluated, presumably as a result of the widespread use of the same breeding parents, and seven alleles are very rare (S4, S6, S8, S16, S22, S23, S26).
Growth and Yield of Snap Beans as Affected by Wind Protection and Microclimate Changes due to Shelterbelts and Planting Dates
Authors: Hodges Laurie , Suratman Mohd Nazip , Brandle James R. , Hubbard Kenneth G.
Published: February 2019

The effects of wind protection on growth and total and marketable yields of snap bean (Phaseolus vulgaris L.) planted at 2-week intervals through the 1994 and 1995 growing seasons were examined. Research was conducted under nonirrigated conditions at the Shelterbelt Research Area, Univ. of Nebraska Agricultural Research and Development Center (ARDC) near Mead. `Strike' (white-seeded) and `Rushmore' (dark-seeded) were planted in locations sheltered from wind stress by tree windbreaks (shelterbelts) and in locations exposed to normal winds using a randomized complete-block design with a split-split plot arrangement of treatments. Air temperature, soil temperature, humidity, wind speed, and wind direction were monitored. Detailed microclimate conditions at bean canopy level in sheltered and exposed plots are provided in the text. Wind speed in sheltered areas averaged 36% of open field wind speed in 1994 and 43% of open wind speed in 1995. Soil temperatures were higher in sheltered areas than in exposed areas. Microclimate changes due to shelter had no effect on the percent seedling emergence or number of days to emergence. Plants in shelter had significantly higher total dry weight and leaf area index and greater total internode length than exposed plants. Both total and marketable yields were increased significantly by production under sheltered conditions each year. Planting date and cultivar also had a significant impact on average pod yields. No interactions between shelter and planting date, or shelter and cultivar, were found in either year. The results suggest that wind protection provided by shelterbelts (tree windbreaks) can increase pod yields of snap bean both early and late in the season. This may result in greater profit for the grower due to a tendency for higher prices at these times.
Ethylene Production throughout Growth and Development of Plants
Authors: Wheeler Raymond M. , Peterson Barbara V. , Stutte Gary W.
Published: February 2019

Ethylene production by 10 or 20 m2 stands of wheat, soybean, lettuce, potato, and tomato was monitored throughout growth and development in an atmospherically closed plant chamber. Chamber ethylene levels varied among species and rose during periods of canopy expansion and rapid growth for all species. Following this, ethylene levels either declined during seed fill and maturation for wheat and soybean, or remained relatively constant for potato and tomato (during flowering and early fruit development). Lettuce plants were harvested during rapid growth and peak ethylene production. Chamber ethylene levels increased rapidly during tomato ripening, reaching concentrations about 10 times that measured during vegetative growth. The highest ethylene production rates during vegetative growth ranged from 1.6 to 2.5 nmol·m-2·d-1 during rapid growth of lettuce and wheat stands, or about 0.3 to 0.5 nmol·g-1 fresh weight per hour. Estimates of stand ethylene production during tomato ripening showed that rates reached 43 nmol·m-2·d-1 in one study and 93 nmol·m-2·d-1 in a second study with higher lighting, or about 50× that of the rate during vegetative growth of tomato. In a related test with potato, the photoperiod was extended from 12 to 24 hours (continuous light) at 58 days after planting (to increase tuber yield), but this change in the environment caused a sharp increase in ethylene production from the basal rate of 0.4 to 6.2 nmol·m-2·d-1. Following this, the photoperiod was changed back to 12 h at 61 days and ethylene levels decreased. The results suggest three separate categories of ethylene production were observed with whole stands of plants: 1) production during rapid vegetative growth, 2) production during climacteric fruit ripening, and 3) production from environmental stress.
Using RAPD and AFLP Markers to Distinguish Individuals Obtained by Clonal Selection of `Arbequina' and `Manzanilla de Sevilla' Olive
Authors: Belaj A. , Rallo L. , Trujillo I. , Baldoni L.
Published: February 2019

Eight and seven clones, respectively selected within the olive cultivars `Arbequina' and `Manzanilla de Sevilla', were studied by means of randomly amplified polymorphic DNA (RAPD) and amplified fragment-length polymorphism (AFLP) markers. Two clones of `Arbequina', C3 and C12, showed polymorphism with respect to the standard cultivar by means of both markers. In fact, about 33.6% RAPD bands and 9.2% AFLP bands were polymorphic for these clones. This high level of polymorphism and the presence of a high percentage of bands absent in `Arbequina' suggest their possible origin as `Arbequina' seedlings. The dendrogram obtained by both molecular markers also supports the hypothesis of a seedling origin of these clones as they clustered separately from the original cultivar and the rest of monomorphic clones at low values of similarity. Also within the `Manzanilla de Sevilla' group, two clones (31 and 44) showed diversity with respect to the standard cultivar; 4.5% RAPD and 6.3% AFLP markers were polymorphic for these genotypes while all the other clones didn't show any difference with the standard `Manzanilla de Sevilla'. RAPD and AFLP markers effectively revealed intracultivar variability due to gametic or multiple mutational events, while the detection of other kind of differences such as eventual single mutations remains uncertain and requires further investigation.
Application of Pseudomonas aureofaciens Tx-1 through Irrigation for Control of Dollar Spot and Brown Patch on Fairway-height Turf
Authors: Hardebeck Glenn A. , Turco Ronald F. , Latin Richard , Reicher Zachary J.
Published: February 2019

Pseudomonas aureofaciens strain Tx-1 is suggested as a biological control for Sclerotinia homoeocarpa (F.T. Bennett) and brown patch (Rhizoctonia solani Kuhn) on golf courses. To overcome application difficulties, a field bioreactor is used to grow Tx-1 daily and then inject into nightly irrigation on the golf course. Though Tx-1 shows some promise for disease control in vitro, it is relatively untested under field conditions. We conducted three field experiments to 1) evaluate the efficacy Tx-1 when applied through an irrigation system for the control of dollar spot and brown patch; 2) determine if there is an interaction between nitrogen fertility or fungicides on efficacy of Tx-1; and 3) determine if Tx-1 can extend the duration of dollar spot control by a single application of fungicide. Nightly applications of Tx-1 through irrigation did not affect brown patch on `Astoria' colonial bentgrass (Agrostis capillaris Sibth.) during the 2 years of our study. Tx-1 reduced dollar spot in `Crenshaw' creeping bentgrass (Agrostis palustris Huds.) by 37% in 1998 compared to non-Tx-1 treatments, but Tx-1 had no effect on dollar spot in 1999. Under low disease pressure, Tx-1 increased the dollar spot control of fungicides by 32% and increased the duration of control by 2.6 days. However, Tx-1 had no effect on fungicide efficacy or duration of control later in the summer when dollar spot pressure was high. Fungicides did not negatively affect Tx-1's control of brown patch or dollar spot, nor did fertilizer regime affect brown patch or dollar spot control by Tx-1. Although delivery of Tx-1 in our studies was optimized, disease control was marginal and occurred only under low disease pressure. Therefore, we conclude Tx-1 has limited practical value for turfgrass disease control on golf courses.
(234) Self-incompatibility in Pink Tickseed, Coreopsis rosea Nutt.
Authors: Loehrlein Marietta , Siqueira Sandy
Published: February 2019

Coreopsis rosea is important as a landscape plant and is of some impor-tance for restoration of native species. In both situations it is important to understand the breeding system so that the pollination process may be controlled for optimal seed production. The study of the incompatibility system is important to seed production. In commercial crops, seeds may be products of open pollination or F1 hybrids. In the former, genetic variability exists. In conservation and recovery programs of local flora, seeds with genetic variability are desirable. In development of commercial crops, uniform seeds and plants are desirable. Regardless of whether seeds will ultimately be used for commercial crops or for species restoration, an understanding of self-incompatibility will allow the pollination process to be manipulated for optimal seed production. The purpose of this research was to investigate the sexual reproduction mode in Coreopsis rosea. The objectives were to determine whether Coreopsis rosea operates with a self-incompatibility system, and, if so, to discover whether it is a sporophytic or gametophytic mode. The sporophytic form of self-incompatibility has been found in other plants in the Asteraceae family, but no one has studied self-incompatibility in Coreopsis rosea. The purpose of this research was to identify the self-incompatibility system in Coreopsis rosea. A series of self- and cross-pollinations were made in situ, and in vivo pollinations were made and the pistils studied under the microscope. Results indicate that Coreopsis rosea is self-incompatible and operates under the sporophytic mode.
(239) Genetics, Anatomy and Biochemistry of Flower Color in Anagallis monelli (L.) `Pimpernel'
Authors: Quintana Andrea , Albrechtova Jana , Davis Tom , Griesbach Robert J. , Freyre Rosanna
Published: February 2019

Wild Anagallis monelli has blue or orange flowers. Hybrids with red flowers were developed at the Univ. of New Hampshire. Orange is due to pelargonidin, but delphinidin and malvidin can also be present; red is due to delphinidin and malvidin; and blue is due to malvidin only. In this study, blue and orange wild diploid accessions were used to develop four F2 populations (n = 46 to 81). In three populations, segregation ratios supported a previously proposed three-gene model for flower color in this species (P> 0.01). In the fourth population, white flower color was obtained in addition to blue, orange, and red. Molecular studies of genes in the anthocyanin pathway using a candidate gene approach are in progress. In a separate F2 population, blue, violet, lilac, and red flower colors were obtained. One hybrid per color was studied on three replicate plants. Cells with vacuoles containing anthocyanins in upper and lower petal epidermis peels were counted in five flowers per clone using light microscopy (M = 200×). Blue and red hybrids had mostly blue and red cells, respectively, on both surfaces. Lilac and violet hybrids included cells that were blue and intermediate (containing both red and blue) on both surfaces, and also had red cells on the lower epidermis only. Violet hybrids had more blue cells on the upper epidermis than the lilac hybrids. Anthocyanins were determined by HPLC for each petal epidermis in the four flower colors. The blue hybrid had only malvidin in both upper and lower epidermis, and the red hybrid had mainly delphinidin in both surfaces. Lilac and violet hybrids had small amounts (2% and 2.5%, respectively) of delphinidin on upper surfaces, while lower surfaces had 25% to 33% delphinidin.
(160) Are All Vermicomposts Created Equal?
Authors: Bachman Gray R.
Published: February 2019

The horticulture industry continues to show interest in using stabilized organic wastes as a component of container media. Vermicompost, also known as worm-worked waste or worm castings, is one of these materials of interest and can be produced from a number of organic wastes, including manure wastes. One issue that has not been addressed is the uniformity of vermicomposts produced from wastes of different sources. Are all vermicomposts created equal? The uniformity of vermicompost is important for growers to consider when using as a medium amendment. This research project investigated the physical properties of vermicompost 1) from different sources of wastes and 2) from a single waste source sequentially sampled over time. The first stage determined the physical properties of vermicompost from beef manure, hog manure, and peat-based media used by two earthworm growers. There were significant differences between the four vermicomposts in bulk density, air volume, percent air volume, percent volumetric moisture, total porosity, and water holding capacity. The second stage involved determining the physical characteristics of vermicompost produced from beef manure collected at the Illinois State University Research Farm from cattle receiving a consistent diet through the year. Manure was collected bimonthly. There was no difference in vermicompost bulk density among the samples. There were significant differences in air volume, percent air volume, percent volumetric moisture, total porosity, and water holding capacity. These changes in vermicompost physical characteristics must be quantified for growers to accurately predict performance as a growth medium amendment.
(165) Use of Chicken Manure as Source of Nutrients for Sweet Corn Production
Authors: Rangappa Muddappa , Bhardwaj Harbans , Dalton Harry
Published: February 2019

An on-farm animal manure, such as chicken manure, can be a source of nutrients for the growth and production of agricultural crops. However, use of manures at rates that are considered adequate for crop production may cause excessive accumulation of phosphorus (P) and also result in leaching of nitrogen (N), thus leading to potential pollution of ground and surface water. Composting of manures with a carbon (C) source can reduce P and N to manageable levels to support production of crops. In order to determine the potential of composted manure for crop production, we studied growth and production of sweet corn by using poultry manure composted with a carbon source of crimson clover hay or wheat straw. These experiments, conducted during 2002 and 2003, compared six treatments: 1) uncomposted chicken manure alone; 2) composted with wheat straw turned weekly; 3) composted with wheat straw turned bi-weekly; 4) composted with crimson clover hay turned weekly; 5) composted with crimson clover hay turned bi-weekly; and 6) a control with a commercial recommendation rate of N fertilizer. These treatments resulted in 9244; 13,866; 15,688; 16,734; and 11,977 marketable ears/acre, respectively, indicating significant superiority of treatments 4 and 5 over all others. Similar results were obtained for ear length, ear fresh weight, and plant height. Results indicated that composting of poultry litter with wheat straw or crimson clover hay is a viable way to utilize poultry manure for production of sweet corn and other agricultural crops. This study implies that composting of on-farm animal manure with organic material, such as hay and straw, could play an important role in development of an environmentally friendly, economically feasible, and sustainable organic production of agricultural crops.
(233) Relationship of European Persimmon Cultivars to Asian Cultivars Is Characterized using AFLPs
Authors: Yonemori Keizo , Honshu Chitose , Aradhya Malli , Giordani Edgardo , Bellini Elvio , Parfitt Dan E.
Published: February 2019

Sixty-two persimmon selections, including 16 Italian, 9 Spanish, 16 Japanese, 6 Korean, and 5 Chinese cultivars, were evaluated for genetic differences by AFLP analysis. Four-hundred-seventy characters were scored. Similarities were calculated by the method of Nei and Li. Relationships among cultivars were evaluated by UPGMA clustering and neighbor joining. Most cultivars were quite diverse (0.60 to 0.80 similarity between cultivars), while similarities among groups were generally less than 0.60. Both UPGMA and neighbor joining produced clusters for the European and Asian cultivars. Spanish and Italian cultivars did not cluster, while Chinese and Korean cultivars formed distinct groups. The diversity within groups was greater than the diversity between groups. In addition, the presence of several Japanese cultivars in the European group and Spanish cultivars in the Asian group suggest that similar, but diverse progenitors were used in the development of the current cultivars. Duplicate accessions of `Kaki Tipo' from different sources were clearly different by AFLP pattern (similarity less than 0.85).
(295) Measuring and Reporting Growing Conditions in Controlled Environments
Authors: van Iersel Marc W.
Published: February 2019

Do you accurately measure and report the growing conditions of your controlled environment experiments? Conditions in controlled environment plant growth rooms and chambers should be reported in detail. This is important to allow replication of experiments on plants, to compare results among facilities, and to avoid artefacts due to uncontrolled variables. The International Committee for Controlled Environment Guidelines, with representatives from the U.K. Controlled Environment Users' Group, the North American Committee on Controlled Environment Technology and Use (NCR-101), and Australasian Controlled Environment Working Group (ACEWG), has developed guidlines to report environmental conditions in controlled environment experiments. These guidelines include measurements of light, temperature, humidity, CO2, air speed, and fertility. A brochure with these guidelines and a sample paragraph on how to include this information in a manuscript will be available.
(305) Influence of Hypobaria on Gas Exchange and Growth of Lettuce for Advanced Life Support Systems (ALS)
Authors: He Chuanjiu , Davies Fred T. , Lacey Ronald
Published: February 2019

There are advantages in growing plants under hypobaric (reduced atmospheric pressure) conditions in biomass production for extraterrestrial base or space-flight environments. Elevated levels of the plant hormone ethylene occur in enclosed crop production systems and in space-flight environments—leading to adverse plant growth and sterility. Objectives of this research were to characterize the influence of hypobaria on growth and ethylene evolution of lettuce (Lactuca sativa L. cv. Buttercrunch). Growth was comparable in lettuce grown under low (25 kPa) and ambient (101 kPa) total gas pressures. However, tip burn occurred under ambient, but not low pressure—in part because of adverse ethylene levels. Under ambient pressure, there were higher CO2 assimilation rates and dark respiration rates (higher night consumption of metabolites) compared to low pressure. This could lead to greater growth (biomass production) of low pressure plants during longer crop production cycles.
(71) Day Length Controls Flowering and Height of Sunflower
Authors: Karlsson Meriam , Werner Jeffrey
Published: February 2019

Flowering in response to day length was identified for sunflower (Helianthus annuus L. `Pacino Gold'). Germination and seedling development occurred at 20 °C and long days (ld, 16 hours) following direct seeding into 10-cm pots. Sixteen days after seeding, plants were placed at ld or short days (sd, 8 hours), 20 °C and 8 mol·d-1·m-2. Flowering was recorded at the stage of reflexed petals after 48 sd. At the time of flowering in sd, flower buds were of minute size under ld. Plants started at ld, and moved to sd after 1, 2, or 3 weeks, flowered at similar times as those grown under uninterrupted sd conditions. Four initial weeks of ld delayed flower development with 7 days, compared to a continuous sd environment. On the other hand, 2 to 3 weeks of initial sd followed by ld hastened flowering with 5 to 10 days. With increasing number of early ld from 1 to 4 weeks, plant height at flowering doubled from 20 to 40 cm. Average plant height in continuous sd was 18 cm. Plants grown exclusively or moved to ld after 1 to 4 weeks of sd were similar in height to plants finished at sd with 4 initial weeks of ld. Combinations of sd and ld may be used to manage height and rate of development in the sunflower `Pacino Gold'.
(262) Transgenic Tomato Lines Expressing Plant Defense Genes Show Resistance to Early Blight Disease
Authors: Schaefer Scott C. , Gasic Ksenija , Korban Schuyler S.
Published: February 2019

Several plant defense genes, including an iris ribosomal-inactivating protein (I-RIP) and a maize β-glucanase (M-GLU) as well as a small antimicrobial peptide (5 kd) from Mirabilisjalapa(Mj-AMP) were separately introduced into tomato (Lycopersiconesculentum) cv. Sweet Chelsea using Agrobacteriumtumefaciens-mediated transformation. Transgenic lines carrying each of the transgenes were confirmed for integration into the tomato genome using Southern blot hybridization. Transcription of I-RIP, M-GLU, and Mj-AMP genes in various transgenic lines was determined using Northern blot analysis. Plants of some transgenic lines were inoculated with a 2 × 104 to 3 × 104 conidial spores/mL suspension of the fungal pathogen Alternariasolani, the causal agent of tomato early blight disease. Several transgenic lines carrying either a M-GLU or Mj-AMP transgene showed a higher level of resistance to early blight than control (nontransgenic) plants. The implications of this approach on developing disease resistance in tomato will be discussed.
(264) In Vitro Pollen Germination of Wild Type and Transgenic `Galia' Male Parental Line Melon [Cucumis melo (L.) var. reticulatus Ser.]
Authors: Nunez-Palenius Hector G. , Cantliffe Daniel J. , Klee Harry J. , Huber Don J.
Published: February 2019

Pollen germination timing has a paramount role in fertilization of a flower. Rapid germination and outgrowth of a pollen tube that penetrates the stigma is required. Physical and biological factors can affect pollen germination timing. The objective of this study was to determine if ACC oxidase antisense gene expression could influence in vitro pollen germination and in vitro pollen tube length growth. A transgenic (ACC oxidase antisense) `Galia' male parental line had a reduced fruit set compared to its wild type. Likewise, embryo abortion and empty seeds after self-pollination in a `Galia' male parental line were observed. Wild type and transgenic `Galia' male parental line melon plants were grown in a greenhouse according to the practices of Rodriguez (2003). Male flowers were collected from these plants between 10 to 12 am; pollen was obtained by dipping the anther in germination medium (10.25% sucrose, 0.031% calcium nitrate, 0.015% boric acid, 0.0075% KNO3, and 0.016% MgSO4) at 25 °C and analyzed immediately, either for total percentage of germination after 5 minutes of incubation or to measure pollen tube growth rate every 5 minutes during 1 hour. Each flower provided an average of 250 pollen grains. Assays were conducted by using the “Hanging Drop Method” (Okay and Ayfer, 1994). Percentage of pollen germination in WT `Galia' male parental line was greater than the transgenic line. Likewise, in vitro pollen tube growth in wild type `Galia' melon was greater than pollen from the transgenic line. Possibly the ACC oxidase antisense gene expression in `Galia' male parental line may have had an influence on the reduced fruit set observed.
(266) Gene Discovery in Octoploid Strawberry
Authors: Stewart Philip J. , Bies Dawn H. , Folta Kevin M.
Published: February 2019

Fragaria ×ananassa, the cultivated octoploid strawberry, is an intensively cultivated fruit crop in which relatively small variations in disease susceptibility and flowering habit can have significant economic impacts. In order to facilitate future studies of the molecular mechansisms governing these characters, we have initiated studies to identify and sequence the strawberry homologs of a number of important genes known to be critical to pathogenesis response and photoperiodism in model systems such as arabidopsis, rice, and tomato. Using the primary Florida cultivar Strawberry Festival, we have employed a variety of techniques to identify such genes, including EST sequencing of a salicylate-induced cDNA library, PCR with degenerate primers, and colony hybridization. Possible homologs of the targeted genes and their relationships to similar genes in other species are presented. These results will form the basis of future studies of gene expression and evolutionary relationships among the Rosaceae and other species.
(267) A Rapid Transformation System for Octoploid Strawberry
Authors: Howard Leighan , Stewart Philip , Dhingra Amit , Chandler Craig , Folta Kevin
Published: February 2019

Cultivated strawberry (Fragari×ananassa) is a valuable crop, yet has benefitted little from recent advances in biotechnology and genomics. A high-throughput system for transformation and regeneration would hasten elucidation of gene function for strawberry and possibly the Rosaceae in general. In this report, a protocol for high-frequency octoploid strawberry transformation and regeneration is presented. The protocol uses leaf, petiole, and stolon as explants from a newly selected genotype, `Laboratory Festival #9'. This genotype was selected from progeny of a `Strawberry Festival' self-cross exclusively for its rapid regeneration and robust growth in culture. Direct organogenesis has been achieved from the leaf or from prolific callus with multiple shoots being visible in as few as 14 days. Over 100 viable regenerants may be obtained from a single leaf explant of about 3-cm2 size. This laboratory-friendly genotype allows high-throughput, statistically relevant, studies of gene function in the octoploid strawberry genetic background as well as generation of large transgenic populations.
(250)`Elegance' and Ark 98-348: Two New Southernpea Varieties for the Mid-South
Authors: Morelock Teddy E. , Motes D. R. , Martin L. W. , Eaton S. E.
Published: February 2019

Southernpeas, Vigna unguiculata, are a popular vegetable in the southeastern United States. Southernpeas (cowpeas) are widely known by the many different horticultural types, i.e., blackeye, pinkeye, purple hull, cream, cowder, etc. `Elegance' was widely tested under the designation Ark 96-918. It was entered in the Regional Southernpea Cooperative Trials from 1997–2002, where it performed well. It is a root-knot nematode resistant cream that exhibits an upright bush habit with concentrated pod set and good yield potential. The seed are medium size and produce a high quality canned product. `Elegance' is unique in the fact that it is a purple hull cream with the pods turning from dark green to purple when the seed reach the green mature stage. The second release, Ark 98-348, is a selection out of `Chinese Red' that is less viney and has a more concentrated pod set and maturity than the `Chinese Red' types that are commercially grown. It was tested in the observational Regional Southernpea Cooperative Trials from 2000–02. In trials at the University of Arkansas Vegetable Substation, it outyielded industry standard `Chinese Red' types Ark 93-640 and 93-641, by 30%.
(273) Engineering Female Sterility for Horticultural Crops
Authors: Smith Alan , Gardner Nicole , Zimmermann Elizabeth S.
Published: February 2019

Female sterility is desirable in horticultural crops for many reasons, including decreasing invasiveness and weediness, reducing nuisance fruit production, promoting vegetative growth, and increasing flower longevity and number. This study tested a method of creating female sterility through genetic transformation of plants with a gene that ablates tissue necessary for female fertility and reproduction. A gene construct was created containing barnase, a cytotoxic RNAse, expressed with a transmitting tract specific promoter from the tobacco gene sP41. The sP41gene encodes a (1,3)-β-glucanase in the transmitting tract of the pistil of mature tobacco flowers. The construct also expressed barstar, a barnase inhibitor, driven by the CaMV 35S promoter to protect other plant tissues from unexpected barnase expression. Seed set data taken after controlled pollinations showed tobacco plants transformed with this construct had greatly reduced fertility in young flowers and female sterility in mature flowers relative to nontransformed controls. Light microscopy showed ablation of the transmitting tract tissue in transformed plants. The expression of barnase with a transmitting tract specific promoter is an effective way to reduce or eliminate female fertility. Due to the conservation of (1,3)-β-glucanase activity in the styles of other plant species, this construct has potential for producing female-sterile cultivars of other horticultural crops.