bluuebunny/crossref_metadata_2025 huggingface dataset:
The Production of Callus, Shoot, and Rooted Plantlets of Rhododendron catawbiense ‘English Roseum’ from Florets
Authors: Sicuranza Jenna , Mitkowski Nathaniel A.
Published: February 2019

The Rhododendron catawbiense (Michx.) varieties ‘Roseum Elegans’ and ‘English Roseum’ are the primary varieties of rhododendron sold in the northeastern United States; however, very little research has been published on their ability to produce shoots, roots, or plantlets in tissue culture. The suitability of two rhododendron varieties (including ‘English Roseum’) was examined using two different combinations of cytokinin and auxin in Anderson's rhododendron medium. It was determined that the variety ‘Scintillation’ performed poorly regardless of the media conditions used; however, ‘English Roseum’ produced callus and shoots using Anderson's medium and 4.0 mg·L−
1 IAA and 15 mg·L−
1 2iP. Rooted plantlets were produced using a rooting medium containing Anderson's medium and 4 mg·L−
1 NAA. The ability of ‘English Roseum’ to produce 35% successful plantlets under these conditions suggests that this variety is moderately suitable for micropropagation purposes.
Empirical Models of Phosphorus Uptake under Different Nitrogen Sources in Dieffenbachia amoena ‘Tropic Snow’
Authors: Jiménez Silvia , Pérez Mónica , Plaza Blanca María , Salinas Roberto , Lao María Teresa
Published: February 2019

The study of models for better nutrient uptake estimation can help to improve integrated fertigation management, allowing enhanced water and fertilization use efficiency. The aim of this work was the development of empirical models that permit the prediction of the phosphorus (P) nutritional needs of Dieffenbachia amoena to increase P use efficiency in a recycled system. To achieve this, P uptake was correlated to climate parameters, such as temperature (T), vapor pressure deficit, and global radiation (Rg), and to growth parameters such as leaf area index (LAI). In addition, the influence of the N form supply (NO3
–-N or NH4
+-N) on P uptake was studied. The trial was carried out with Dieffenbachia amoena ‘Tropic Snow’ plants growing in a recycled system with expanded clay as substrate. The crop was placed in an INSOLE buried solar greenhouse, with the plants supplied with equal amounts of N, differing in the percentage of the N form applied: Ta (100 NO3
– : 0 NH4
+), Tb (50 NO3
– : 50 NH4
+) and Tc (0 NO3
– : 100 NH4
+). The N form applied to Dieffenbachia amoena ‘Tropic Snow’ plants affects P and N uptake, but it does not influence K uptake. Nitrogen and P uptake rates are higher in the plants supplied with NH4
+ or NO3
– + NH4
+ than in the plants provided with NO3
– alone. The supply of a combination 50 NO3
– : 50 NH4
+ improves P use efficiency. The study also indicates the possibility of predicting the P uptake rate and P uptake concentration using the proposed models. Phosphorus uptake can be estimated with a model dependent on the LAI in the NO3
–-N treatments and on the LAI and Rg in the NH4
+-N treatments. The P uptake concentration can be calculated with the P uptake, estimated through the previous model, and the experimental water uptake. This parameter would permit the nutritive solutions design, decreasing nutrient losses in open systems.
Penstemon: A Summary of Interspecific Crosses
Authors: Lindgren Dale T. , Schaaf Daniel M.
Published: February 2019

Documenting the successful interspecific crosses in a genus is a valuable tool in making decisions in developing strategies for plant breeding activities. However, summarizing the breeding and hybridization can be confusing because of incomplete or lost breeding records and the failure to register the parentage of new cultivar names. A summary of interspecific crosses in the genus Penstemon at the University of Nebraska–Lincoln West Central Research and Extension Center over 10 years provides insight into both successful and unsuccessful crosses. The results, based on seed production and percent of successful crosses, would suggest that interspecific crosses are more likely to be successful when the parent species are more closely related.
Yield and Russeting of Greenhouse Tomato as Influenced by Leaf-to-fruit Ratio and Relative Humidity
Authors: Demers Dominique-André , Dorais Martine , Papadopoulos Athanasios P.
Published: February 2019

Three experiments were conducted in greenhouses 1) to determine the optimal leaf-to-fruit ratio for minimizing the incidence of russeting (miniature cuticle cracks on fruit) while optimizing fruit yield of greenhouse tomato (Lycopersicon esculentum Mill.) and 2) to investigate the effect of day/night relative humidity (RH) regimens on the development of russeting. Leaf-to-fruit ratio treatments (0.5–2.0) were achieved by varying the number of fruit (two to six fruit) per cluster and the number of leaves (two to four leaves) between clusters. In one experiment, plants were also subjected to either high day/low night or low day/high night RH regimens (low RH, 60% to 70%; high RH, 85% to 95%). Results showed that russeting of greenhouse tomato was mostly influenced by the number of fruit per cluster (total fruit load), and very little by the number of leaves between clusters. In general, decreasing the number of fruit per cluster resulted in a progressive increase in the occurrence of russeting. Furthermore, as the number of fruit per cluster decreased, the percentage of fruit with no russeting and with little russeting decreased whereas the percentage of fruit with the more severe russeting increased (except for the summer). For beefsteak cultivars Trust and Rapsodie grown under southwestern Ontario conditions, the best pruning practices for minimizing russeting and optimizing yield was to prune clusters to three fruit in early spring and late fall, to four fruit during spring and fall, and to five fruit during the summer, with three leaves between clusters all year long. In the current study, no significant effect of day/night RH regimens on fruit russeting was observed. Of the cultivars used, Rz 74/56 was less sensitive to russeting than ‘Trust’, whereas ‘Rapsodie’ was not different from the two other cultivars. However, all three cultivars had a very high incidence of russeting (>65% of fruit affected), and none should be regarded as russeting resistant. Breeding programs and genetic investigations with the objective of developing greenhouse tomato cultivars resistant to russeting are needed.
Floral Competence of Primocane-fruiting Blackberries Prime-Jan and Prime-Jim Grown at Three Temperature Regimens
Authors: Stanton Michele A. , Scheerens Joseph C. , Funt Richard C. , Clark John R.
Published: February 2019

We investigated the responses of staminate and pistillate floral components of Prime-Jan and Prime-Jim primocane-fruiting blackberry (Rubus L. subgenus Rubus Watson) to three different growth chamber temperature regimens, 35.0/23.9 °C (HT), 29.4/18.3 °C (MT), and 23.9/12.8 °C (LT). Temperature was negatively related to flower size, and morphologically abnormal floral structures were evident in 41% and 98% of the MT- and HT-grown plants, respectively. Anthers of LT- and MT-grown plants dehisced. The viability of pollen (as deduced through staining) from Prime-Jan grown at LT or MT exceeded 70%, whereas that of Prime-Jim pollen was significantly reduced (<40%) by the MT regimen. In vitro pollen germinability (typically <50%) was negatively influenced by temperature but was unaffected by cultivar. Pollen useful life was diminished under HT conditions; LT-grown pollen held at 23.9 °C retained 63% of its original germinability over a 32-h period, while the germinability of that held at 35.0 °C for 16 hours decreased by 97%. Virtually all flowers cultured under HT conditions were male sterile, exhibiting structural or sporogenous class abnormalities including petaloidy and malformation of tapetal cells or microspores; HT anthers that were present, failed to dehisce. Stigma receptivity, pistil density, and drupelet set were also negatively influenced by increased temperature; values for these parameters of floral competency among control plants were reduced by 51%, 39%, and 76%, respectively, in flowers cultured under HT conditions. In this study, flowering and fruiting parameters, and presumably the yield potential of Prime-Jan and Prime-Jim, were adversely affected by increased temperature. However, their adaptive response to heat stress under field conditions awaits assessment.
Occurrence of 23-epi-26-deoxyactein and Cimiracemoside A in Various Black Cohosh Tissues Throughout the Growing Season
Authors: Thomas Andrew L. , Crawford Richard J. , Rottinghaus George E. , Tracy John K. , Applequist Wendy L. , Schweitzer Besa E. , Havermann Larry J. , Woodbury Scott F. , Miller James S. , Ellersieck Mark R. , Gray Dean E.
Published: February 2019

Black cohosh [Actaea racemosa L.; Cimicifuga racemosa (L.) Nutt.] is a perennial herb native to North America that is commonly used for the treatment of menopausal symptoms. The plant is almost exclusively harvested from the wild and is being threatened by overharvesting in some regions. As demand for this plant continues to increase, the potential for profitable cultivation of this species is becoming realistic. Little is known about the effect of various cultivation practices, soils, environments, and harvest times on the multitude of phytochemicals that occur in black cohosh. Furthermore, although the rhizome is the organ that is traditionally consumed, other tissues also contain various quantities of important phytochemicals, but this has not been well documented. The objectives of this study, therefore, were to ascertain any environmental effects on the production of two representative phytochemicals (23-epi-26-deoxyactein and cimiracemoside A) and to elucidate any season-long patterns or variations in the production of these compounds within five black cohosh tissues (leaf, rachis, rhizome, root, and inflorescence). All black cohosh tissues contained 23-epi-26-deoxyactein with substantially more, as a percentage of dry weight, detected in inflorescence (28,582 to 41,354 mg·kg−1) and leaf (8250 to 16,799 mg·kg−1) compared with rhizome (2688 to 4094 mg·kg−1), and all tissues experienced a linear season-long decrease in occurrence of this compound. Cimiracemoside A was not detected in leaf tissues. The highest levels were found in rhizome (677 to 1138 mg·kg−1) and root (598 to 1281 mg·kg−1), which likewise experienced a significant season-long decrease in this compound, whereas levels in the rachis (0 to 462 mg·kg−1) increased over time. In general, environmental factors did not affect production of either compound. Varying seasonal patterns in phytochemical production, combined with differences in phytochemical content among plant tissues, point to the potential for more targeted horticultural production of these and other medicinal compounds within black cohosh.
Effect of Substrate Depth on Initial Growth, Coverage, and Survival of 25 Succulent Green Roof Plant Taxa
Authors: Durhman Angela K. , Rowe D. Bradley , Rugh Clayton L.
Published: February 2019

Because of greater interest in green roofs in the United States, it is critical to increase the number and geographic range of proven plant resources for long-term survival on rooftops. Successful plant taxa for extensive green roofs must establish themselves quickly, provide high groundcover density, and tolerate extreme environmental conditions. Furthermore, dead load weight restrictions on many buildings may limit the substrate depth that can be applied. The objective of this study was to evaluate the effect of substrate depth on initial establishment and survival of 25 succulent plant taxa for green roof applications in the midwestern United States. Survival, initial growth, and rate of coverage were compared for plants grown in three substrate depths (2.5, 5.0, and 7.5 cm) on 24 roof platforms. Plant coverage was determined from image analysis of weekly digital photographs. Results indicate deeper substrates promote greater survival and growth; however, in the shallowest depth of 2.5 cm, several species continued to persist. Of the 25 species initially planted, only 47% survived in the deepest substrate of 7.5 cm. Recommended species at the depths tested for climates similar to southern Michigan include Phedimus spurious Raf. ‘Leningrad White’, Sedum acre L., S. album L. ‘Bella d'Inverno’, S. middendorffianum L., S. reflexum L., S. sediforme J., and S. spurium Bieb. ‘Summer Glory’. Subsidiary species that are present at specific substrate depths but may not exhibit an ability to cover large areas include S. dasyphyllum L. ‘Burnatii’, S. dasyphyllum L. ‘Lilac Mound’, S. diffusum W., S. hispanicum L., and S. kamtschaticum Fisch. The primary deterrent for these subsidiary species was little to no survival at 2.5 cm. Deeper substrates promoted greater survival and growth for nearly all species tested.
Somatic Embryogenesis and Plant Development in Centella asiatica L., a Highly Prized Medicinal Plant of the Tropics
Authors: Joshee Nirmal , Biswas Bipul K. , Yadav Anand K.
Published: February 2019

Past research experience with Centella asiatica micropropagation suggests a very high rate of contamination during the culture establishment stage. We demonstrate protocols for successful sterilization of Centella explants prepared from field-grown plants with an abundance of fungal and bacterial contamination. Sequential steps during sterilization and explant preparation process included a dip for 30 s in 70% ethyl alcohol, weak bleach treatment for 12 min, and a 60-min soak in plant preservative mixture before establishing cultures. We also report a reproducible system for somatic embryogenesis in Centella using leaf and stolon tip explants collected from naturally growing populations. Somatic embryos were induced within 3 to 4 weeks of culture in the dark on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D). Initial embryogenic mass appeared as nodular callus, which eventually developed into actual somatic embryos exhibiting globular, heart-shaped, and cotyledonary stages. Leaves produced embryogenic calli at 2.26 and 4.52 μm 2,4-D, whereas stolon tips were responsive only in the 9.04 μm 2,4-D treatment. Withdrawal of 2,4-D/growth regulators from the induction medium resulted in the maturation and further development of the embryos into plantlets. Regular subculturing of the embryogenic calli into MS medium sustained their regenarability for more than 1 year. Somatic embryos were individually encapsulated in sodium alginate and calcium chloride-based encapsulation matrix to produce artificial or synthetic seeds (synseeds). Synseeds with 2% sodium alginate were found best for the survival and germination recorded after their storage at 5 to 8 °C for 30 and 60 days. We report protocols for C. asiatica to reduce explant contamination before establishment of cultures on somatic embryo induction medium and efficient somatic embryogenesis to facilitate conservation and mass production of elite germplasm. This may further assist rapid dissemination of superior clones needed for research and commercial production.
Bell Pepper Fruit Yield and Quality as Influenced by Solar Radiation-based Irrigation and Container Media in a Passively Ventilated Greenhouse
Authors: Jovicich Elio , Cantliffe Daniel J. , Stoffella Peter J. , Haman Dorota Z.
Published: February 2019

Frequent fertigation of soilless-grown bell pepper (Capsicum annuum L.) can increase fruit production, but development of fruit disorders may offset the increase in yield of first-quality (blemish-free) fruit in greenhouses with minimal environmental control. Fruit yield and quality were studied as affected by water volumes and nutrient concentration levels, delivered with irrigation events initiated after determined cumulative solar radiation levels, in ‘HA3378’ bell pepper from October to May in north–central Florida. Irrigation events occurred after solar radiation integral levels (SRI; ±SD) 1.7 ± 0.42, 3.7 ± 0.42, 5.7 ± 0.42, 7.7 ± 0.42, and 9.7 ± 0.42 kW·min−1·m−2, which led to mean number of daily irrigation events of 61 ± 31, 26 ± 12, 17 ± 8, 12 ± 5, and 10 ± 4 respectively. In peat mix, perlite, and pine bark media, volume per irrigation event and concentration levels of the nutrient solution were, in the first experiment, 74 mL standard (74-s), and in a second concurrent experiment, 74 mL half-standard (74-½s) or 3) 37 mL standard (37-s). In both studies, combined marketable fruit yields of first quality and second quality (minor cracking patterns and yellow spots) increased linearly with decreasing SRI (increased events per day). First-quality fruit weight with 74-s was unaffected by media and, in a quadratic response to SRI, reached 5.4 kg·m−2 at 5.7 kW·min−1·m−2. First-quality weight with 74-½s and 37-s did not differ. Weight was unaffected by SRI in peat mix and perlite, and a quadratic response was recorded in pine bark, with yields of ≤3.6 kg·m−2. Fruit cracking incidence decreased with increased SRI, and was generally greater in pine bark. Incidence of yellow spots doubled with 74-½s compared with 37-s, and decreased linearly with increased SRI; the disorder was minor with 74-s. Compared with 37-s, 74-½s decreased fruit with blossom-end rot by 14%, increased marketable fruit weight by 10% in media with the lowest water-holding capacity (perlite, pine bark), and increased nutrient use efficiency. With any media used, the SRI set point of 5.7 kW·min−1·m−2 (daily mean of 17 irrigation events) and 74 mL, at standard nutrient concentration levels, appeared to produce greater blemish-free fruit yield than delivering 37 mL/event or half-concentrated 74 mL/event within the range of SRI means of 1.7 to 9.7 kW·min−1·m−2 (61–10 irrigation events/day). Disorder-tolerant pepper cultivars, better temperature control, and August plantings are additional suggestions for irrigation management to increase first-quality fruit yield.
Effects of Nitrogen, Phosphorus, and Potassium Rates and Fertilizer Sources on Yield and Leaf Nutrient Status of Short-day Onions
Authors: Boyhan George E. , Torrance Reid L. , Hill C. Randy
Published: February 2019

This is a compilation of several studies that were performed to address specific grower concerns or questions about onion fertilization, to assess onion fertility, to make adjustments in soil test recommendations, and to test specific fertilizers for clients covering the 1999–2000 to 2004–2005 seasons. The synthesis of these studies was to evaluate levels of nitrogen (N), phosphorus (P), and potassium (K) fertilizers and their effect on yield, graded yield, and leaf tissue nutrient status in short-day onions over 6 years. In addition, various fertilizers were evaluated for their effect on these parameters. There was a significant increasing quadratic effect on yield from increasing N fertilizer from 0 to 336 kg·ha−1 with an R2 of 0.926. Maximum calculated yield was at 263 kg·ha−1 N fertilizer; however, the yield at this rate did not differ, based on a Fisher's least significant difference (P ≤ 0.05), from our current recommendations of 140 to 168 kg·ha−1 N. Jumbo (7.6 cm or greater) yield performed in a similar fashion. Phosphorus fertilizer rates from 0 to 147 kg·ha−1 had no effect on total yield, but did affect jumbo yields, which decreased linearly with an R2 of 0.322. Evaluations of P fertilizer in the 2001–2002 and 2002–2003 seasons only, when the exact same P fertilizer rates were used, showed a decreasing quadratic effect for jumbo yields with the lowest jumbo yields at 83 kg·ha−1 P fertilizer and jumbo yields increasing with 115 and 147 kg·ha−1 P fertilizer rates. Potassium fertilizer rates from 0 to 177 kg·ha−1 had a quadratic affect on total yield, with the highest yield of 52,361 kg·ha−1 with 84 kg·ha−1 K fertilizer rate. As would be expected, N and P fertilizer rates affected leaf tissue N and P levels, respectively. In addition, N fertilizer rates affected leaf tissue calcium (Ca) and sulfur levels. Potassium fertilizer rates had a significant linear effect on leaf tissue K 3 of 6 years. In addition, K fertilizer rates had a significant effect on leaf tissue P levels. Several fertilizers, including Ca(NO3)2 and NH4NO3, along with complete fertilizers and liquid fertilizers, were used as part of a complete fertilizer program and showed no differences for total yield or jumbo yield 4 of 5 years of evaluation when applied to supply the same amount of N fertilizer. Based on the results of this study, soil test P and K recommendations for onions in Georgia have been cut 25% to 50% across the range of soil test levels.
Postemergent Annual Bluegrass Control in Dormant Nonoverseeded Bermudagrass Turf
Authors: Toler Joe E. , Willis Thomas G. , Estes Alan G. , McCarty Lambert B.
Published: February 2019

Annual bluegrass (Poa annua L.) can be a troublesome weed to control in established turfgrass stands; it has developed herbicide resistance after repeated use of products with similar modes of action, and several new herbicides have been registered for use on turfgrasses. Four field studies were conducted near Clemson, S.C., from 2003 through 2005 to evaluate postemergence annual bluegrass control in dormant, nonoverseeded bermudagrass [Cynodon dactylon (L.) Pers.] turf using various herbicides applied in either December or February of each year and rated in the spring. Annual bluegrass control can be accomplished in dormant, nonoverseeded bermudagrass turf using a wide range of products applied in either December or February. Flazasulfuron, foramsulfuron, glufosinate, glufosinate + clethodim, glufosinate + glyphosate, glyphosate + clethodim, glyphosate + diquat, pronamide, rimsulfuron, and trifloxysulfuron provided 87% or greater annual bluegrass control regardless of application timing. Imazaquin and simazine controlled annual bluegrass greater than 85% when applied in December but less than 80% when applied in February. Glyphosate provided 93% annual bluegrass control when applied in February but only 72% control with December applications. No detrimental effects on bermudagrass spring greenup were observed for any herbicide treatment or application time. The availability of several effective herbicide options with differing modes of action provides turfgrass managers with the opportunity to use herbicide rotations that may prevent, or at least delay, the development of resistant annual bluegrass populations to these chemical products.
Establishment and Survival of Endophyte-infected and Uninfected Tall Fescue and Perennial Ryegrass Overseeded into Existing Kentucky Bluegrass Lawns in Northeastern North America
Authors: Rochefort Sophie , Desjardins Yves , Shetlar David J. , Brodeur Jacques
Published: February 2019

Overseeding of tall fescue and perennial ryegrass into pre-existing stands of kentucky bluegrass is viewed as a strategy to enhance the quality and durability of turfgrass lawns. In a 3-year study, the authors investigated the winter survival and establishment of tall fescue (‘Bonsai 2000’), with or without Neotyphodium coenophialum, and perennial ryegrass (‘Palmer III’), with or without N. lolii, in the province of Quebec, Canada (≈lat., 54ºN), a region characterized by rigorous winter conditions. Grass species were overseeded in June 2003 at two different rates (90 and 180 kg·ha−1), in experimental plots from two bioclimatological conditions: Quebec City and Boucherville. Turfgrass establishment and endophyte infection were evaluated during the following two spring and fall periods. Both tall fescue and perennial ryegrass had the capacity to establish and survive winter conditions, but performed best when snow cover was thick and present throughout the winter. The proportion of overseeded plants in the turfgrass stand rarely reached 30% over the years. Although the proportion of tall fescue and perennial ryegrass plants was much reduced in the spring, some tillers survived and were able, later in the season, to compete with kentucky bluegrass as tall fescue and perennial ryegrass populations returned to initial establishment populations each summer in mixed stands. Overwinter endophyte survival was species specific, with N. lolii being able to survive the cold winter but not N. coenophialum, which had a low percent of infection. For the perennial ryegrass–N. lolii association, competition with kentucky bluegrass is a primary factor limiting the increase over time in the proportion of endophyte-infected plants in a turfgrass mixture. Seeding rates did not influence the establishment of either grass species.
‘Marketmore 97’: A Monoecious Slicing Cucumber Inbred with Multiple Disease and Insect Resistances
Authors: Cavatorta Jason , Moriarty George , Henning Mark , Glos Michael , Kreitinger Mary , Munger Henry M. , Jahn Molly
Published: February 2019

‘Marketmore 97’ is the most recent addition to a series of disease-resistant slicing cucumbers developed in the Cornell University Department of Plant Breeding. The fruit have green skin with white spines and an average length and diameter of 18.8 cm and 4.8 cm, respectively. Broad resistance to a number of destructive diseases and insects makes this cultivar well-suited to low-input agricultural systems at the scale of the home gardener or the commercial grower. In addition to the cucumber mosaic virus (CMV), cucumber scab (Cladosporium cucumerinum Ell. & Arth.), downy mildew (Pseudoperonospora cubensis Berk & Curtis), and powdery mildew (Sphaerotheca fuliginea Schl. ex Fr.) resistances of ‘Marketmore 76’, ‘Marketmore 97’ contains resistance to alternaria leaf spot [Alternaria alternata (Fr.) Keis.], Ulocladium leaf spot (Ulocladium cucurbitae Let. & Roum.), target leaf spot (Corynespora cassiicola Berk. & Curt.), watermelon mosaic virus, papaya ringspot virus, and zucchini yellow mosaic virus. Furthermore, the bitterfree character of this cultivar is responsible for nonpreference of the striped cucumber beetle (Acalymma vittatum Fab.) and spotted cucumber beetle (Diabrotica undecimpunctata howardi Barber). Finally, a near isogenic line of ‘Marketmore 97’ is available that is gynoecious. A replicated trial of ‘Marketmore 97’ conducted in New York in 2006 confirmed comparable yield and quality to other Marketmore cultivars.
Evaluation of Warm-season Turfgrasses for Resistance to the Chinch Bug, Blissus occiduus
Authors: Eickhoff Thomas E. , Heng-Moss Tiffany M. , Baxendale Frederick P.
Published: February 2019

The chinch bug, Blissus occiduus Barber, has been documented as a serious pest of buffalograss, Buchloë dactyloides (Nutall) Engelmann, and zoysiagrass, Zoysia japonica Steudel, turf grown in the Midwest. In addition to these two warm-season turfgrasses, several other warm-season grasses, including bermudagrass, Cynodon dactylon (L.) Pers., may also be at risk of B. occiduus infestations. This research evaluated selected bermudagrass and zoysiagrass cultivars for resistance to B. occiduus. Eleven zoysiagrass and four bermudagrass cultivars were evaluated for resistance to B. occiduus using no-choice studies under greenhouse conditions. Based on turfgrass damage ratings, the zoysiagrasses ‘Diamond’, ‘Zoro’, and ‘Emerald’, and bermudagrass ‘Mini Verde’ were identified as moderately resistant to B. occiduus. The zoysiagrasses ‘Zenith’, ‘Meyer’, and ‘Crowne’, and bermudagrasses ‘Tifway 419’ and ‘Tifsport” were characterized as highly to moderately susceptible to B. occiduus. These results provide the first report of resistance to B. occiduus in zoysiagrass and bermudagrass germplasm.
Fruits of the Bibles
Authors: Janick Jules
Published: February 2019

The sacred writings of three religions (Judaism, Christianity, and Islam) are contained in the Hebrew Bible (referred to by Christians as the Old Testament), the Christian Bible (New Testament), and the Qur'an (Koran). These writings encompass events occurring over a period of more than two millennia and taken together represent a broad picture of mideastern peoples, describing their interactions with the sweep of events of that era. The writings include the sacred and profane, prose and poetry, history and myth, legend and fable, love songs and proverbs, parables and revelations. The basic agricultural roots of desert people are infused in the texts. Plants, plant products, and agricultural technology are referred to in hundreds of verses. References to fruits are abundant so that these bibles can be read almost as a pomological text in addition to the religious and sacred meanings that still inspire billions of people.
The Date Palm (Phoenix dactylifera L.): Overview of Biology, Uses, and Cultivation
Authors: Chao ChihCheng T. , Krueger Robert R.
Published: February 2019

Date palm (Phoenix dactylifera L.) is one of the oldest fruit crops grown in the arid regions of the Arabian Peninsula, North Africa, and the Middle East. The most probable area of origin of the date palm was in or near what is now the country of Iraq, but date cultivation spread to many countries starting in ancient times. Dates are a major food source and income source for local populations in the Middle East and North Africa, and play significant roles in the economy, society, and environment in these areas. In addition to serving directly as a food source, dates are packed and processed in a number of ways, and other parts of the tree are used for various purposes. The date palm is a diploid, perennial, dioecious, and monocotyledonous plant adapted to arid environments. It has unique biological and developmental characteristics that necessitate special propagation, culture, and management techniques. Thousands of date palm cultivars and selections exist in different date-growing countries. Different genetic marker systems have been used to study genetic relationships among date palm cultivars. The long life cycle, long period of juvenility, and dioecism of date palms make breeding challenging. Worldwide date production has grown from 1,809,091 t in 1962 to 6,924,975 t in 2005. Worldwide date production will continue to grow, especially in the Middle East, despite current and future challenges.
Rhizoeconomics: The Roots of Shoot Growth Limitations
Authors: Lynch Jonathan P.
Published: February 2019

The growth of terrestrial plants is primarily limited by edaphic factors such as drought, nutrient deficiencies, and mineral toxicities. Roots express an array of adaptive traits that help plants cope with these stresses, but such traits often incur significant costs, including direct metabolic costs, tradeoffs for contrasting resources, opportunity costs, and increased risks of biotic and abiotic stress. As an example, root cortical aerenchyma appears to improve crop growth under drought and low soil fertility by reducing the metabolic costs of soil exploration. Production of root cortical aerenchyma, however, may involve tradeoffs by reducing radial transport, mycorrhizal colonization, and by increasing disease susceptibility. A better understanding is needed of the full costs associated with specific root traits if we are to develop crops with better growth and yield in the stressful soil environments that increasingly dominate the earth's surface.
Interactions Between Root and Shoot Competition and Plant Traits
Authors: Cahill James F. , Lamb Eric G.
Published: February 2019

A plant's performance depends on its ability to deal with numerous, simultaneous ecological challenges. In both natural and production systems, dominant challenges include competition for soil resources and light, herbivory, and general abiotic stress. A central goal of research is to understand how these processes interact with each other and with plant phenotype (above- and belowground) to influence overall plant performance. Complicating these efforts is the reality that plants are phenotypically plastic with the phenotypic response to one challenge potentially altering the impact of a different challenge. Furthermore, factors external to the plant (e.g., the genotypic and phenotypic composition of the surrounding plants) can also influence the consequence of various ecological pressures. We have been using Arabidopsis thaliana as a model organism to help disentangle this complicated web of ecological interactions. Competitive ability can be influenced by small genotypic changes. A plant's ability to suppress competitors is driven mainly by size-related traits and soil fertility and a plant's ability to withstand harm coming from numerous sources. The relative importance of competition is contingent not only on the match between genotype and environment, but also on the diversity of genotypes within a given population. There is a need to consider alternative effects of plant traits along with the cascading consequences of plant responses to biotic and abiotic challenges.
Priorities for Sweetpotato Research in Developing Countries: Results of a Survey
Authors: Fuglie Keith O.
Published: February 2019

International institutions like the International Potato Center (CIP) strive to provide “global public goods” in the form of improved technologies applicable to large regions of the developing world. To identify priorities for sweetpotato improvement, CIP conducted a survey of knowledgeable scientists in developing countries to elicit their perspectives on the most important constraints facing poor and small-scale sweetpotato growers in their countries. Respondents scored productivity and other constraints according to their importance in the region or country where they worked. Mean and weighted mean scores were estimated to provide a group judgment of the most important constraints facing sweetpotato farmers in developing countries. The survey results showed that there are a few key needs facing farmers in all major sweetpotato producing areas, but there are other very important needs specific to certain regions. The needs that scored highest in all or most of the major sweetpotato producing areas in developing countries are: i) control of viruses (through varietal resistance, quality planting material, and crop management); ii) small-enterprise development for sweetpotato processing; iii) improvement in availability and quality of sweetpotato planting material; and iv) improved cultivars exhibiting high and stable yield potential. Some differences emerged, however, in priority needs of the two major centers of sweetpotato production: Additional priorities for sub-Saharan Africa include improved control of the sweetpotato weevil and cultivars with high β-carotene content to address vitamin A deficiency. For China, other top needs are: i) conservation and characterization of genetic resources; ii) prebreeding; iii) cultivars with high starch yield; and iv) new product development. The different sets of priorities reflect differences in the role of sweetpotato in the rural economy and also different capacities of the agricultural research system in these regions of the world. Compared with earlier surveys, there now seems to be a greater need for postharvest utilization research, especially in sub-Saharan Africa, partly reflecting a demand constraint due to the crop's status as an inferior food.
Overdominance and Epistasis Are Important for the Genetic Basis of Heterosis in Brassica rapa
Authors: Dong De-Kun , Cao Jia-Shu , Shi Kai , Liu Le-Cheng
Published: February 2019

To investigate the genetic basis of heterosis in Brassica rapa, an F2 population was produced from the cross of B. rapa L. subsp. chinensis (L.) Hanelt and B. rapa L. subsp. rapifera Metzg. Trait performances of the F1 hybrid showed evident mid parent heterosis, which varied from 18.55% to 101.62% for the 11 traits investigated. A total of 23 main effect quantitative trait loci (QTLs) were detected for biomass and its component traits, which could explain 4.38% to 47.80% of the phenotypic variance, respectively. Sixty-five percent of these QTLs showed obvious overdominance. Epistasis analysis detected 444 two-locus interactions for the 11 traits at the threshold of P < 0.005. Some of them remained significant when more stringent threshold were set. These results suggested that overdominance and epistasis might play an important role as the genetic basis of heterosis in B. rapa.
Effect of Timing and Rates of Application of Glyphosate and Carfentrazone Herbicides and Their Mixtures on the Control of Some Broadleaf Weeds
Authors: Sharma S.D. , Singh M.
Published: February 2019

Greenhouse and field trials were carried out to evaluate carfentrazone as a potential tank mix with glyphosate to control weeds. Application of active ingredient glyphosate at 1.15 kg·ha−1 provided 44%, 50%, 19%, and 17% control of ivyleaf morning-glory, milkweed vine, hemp sesbania, and field-bind weed (stage 1), respectively, and increased to 45%, 51%, 31%, and 76%, respectively, with active ingredient of 2.30 kg·ha−1. Carfentrazone as active ingredient at 17.7 g·ha−1 achieved 53%, 90%, and 99% control of hemp sesbania, ivyleaf morning-glory, and milkweed vine (stage 1), and increased to 88%, 98% in first two weed plants, respectively, with active ingredient at 52.2 g·ha−1. Either rate of carfentrazone at any stages of field-bind weed yielded ≈100% control. Application of tank-mixed glyphosate and carfentrazone to ivyleaf morning-glory and hemp sesbania (stage 1) demonstrated greater control than their sole applications. A complete control of milkweed vine and field-bind weed (stage 1) was achieved by tank-mixed glyphosate and carfentrazone. Corresponding to percent control values a reduction in biomass value was also recorded. Biomass reduction with glyphosate at either stage of ivyleaf morning-glory was only 14%–24% and reduction with carfentrazone was 40%–47%. Biomass was further reduced with the tank-mixed glyphosate and carfentrazone. A similarly trend in biomass reduction was noted in milkweed vine and hemp sesbania. However, ivyleaf morning-glory was found to be the most tolerant weed to glyphosate followed by hemp sesbania, milkweed vine, and field-bind weed. Tank-mixed applications of these two herbicides further increased the percent control and biomass reduction. In all weed species, there was a significant decrease in percent biomass reduction with age. Although the types of weed were different in the field experiment and greenhouse, a similar trend was observed in the percent control achieved with glyphosate, carfentrazone, and their tank-mixed application. Tank-mixed applications achieved 93%–95% control of Brazil pusley and 75%–83% control of passion flower. These values were significantly higher than the percent control achieved with application of only glyphosate. Therefore, tank-mixed application of glyphosate and carfentrazone may be beneficial than sole application to control broadleaf weeds.
Improving Multiple Shoot Proliferation in Bamboo Mosaic Virus-free Bambusa oldhamii Munro Propagation by Liquid Culture
Authors: Lin Choun-Sea , Kalpana Krishnan , Chang Wei-Chin , Lin Na-Sheng
Published: February 2019

An in vitro method for obtaining bamboo mosaic virus (BaMV)-free plantlets of Bambusa oldhamii Munro was developed. BaMV-free meristems were incubated on MS basal medium supplemented with 0.45 μm thidiazuron (TDZ) to induce the development of multiple shoots. Multiple shoot proliferation was higher in stationary liquid culture than on semisolid medium. Cytokinin was the key component for inducing proliferation, and TDZ was the stable and effective cytokinin for proliferation in long-term subcultures. Multiple shoots rooted after 1 month in MS basal medium containing 10.74 to 26.85 μm α-naphthaleneacetic acid with a rooting efficiency of 83%. Healthy, well-developed plantlets were transferred to soil in pots and raised in a greenhouse. Those plants derived from tissue culture were more vigorous than the ones derived from the traditional in vivo vegetative propagation method, air layering. The tissue culture-derived plants could produce the culms after 15 months. Fifteen of 38 plants flowered 2 years after being transplanted to the field.
In vitro Propagation and Plantlet Regeneration from Doritaenopsis Purple Gem ‘Ching Hua’ Flower Explants
Authors: Vendrame Wagner A. , Maguire Ian , Carvalho Virginia S.
Published: February 2019

The effects of four types of explants removed from 10-cm flower stalks of Doritaenopsis Purple Gem ‘Ching Hua’ (immature apical flower buds, immature lateral flower buds, flower stem nodes, and flower pedicel sections) and combinations of two plant growth regulators [naphthalene acetic acid (NAA) and thidiazuron (TDZ)] on direct in-vitro shoot induction and multiplication were studied. Immature apical flower buds were the only explants that showed induction and multiplication of shoots in vitro. NAA at 5.4 and 10.7 μm combined with either 4.5 or 9.1 μm TDZ provided the fastest and greatest percentages of shoot induction (27% to 40%) and the greatest numbers of shoot multiplication (111–160 shoots per explant). In vitro–induced shoots were rooted on medium containing 5.4 μm NAA and developed into plantlets with normal vegetative and reproductive morphology. Regenerated plantlets were acclimatized, showing 100% survival and establishment in greenhouse. Plantlets were grown to maturity and showed normal flower morphology. No floral off-types were observed. The high rates of shoot multiplication obtained offer a means for mass clonal propagation of this and possibly other related Doritaenopsis hybrids.
Effects of Light, Scarification, and Gibberellic Acid on Seed Germination of Eight Pedicularis Species from Yunnan, China
Authors: Li Ai-Rong , Guan Kai-Yun , Probert Robin J.
Published: February 2019

Seeds of most Pedicularis species do not germinate easily and uniformly, which hinders the process of seeking solutions for successful cultivation of these taxa. In an attempt to determine optimal conditions and effective methods for uniform, rapid, and high-percent germination, the effects of light, scarification, and gibberellic acid (GA3) were tested on seed germination of eight Pedicularis species from nine sites in the northwestern Yunnan Province of China. There were some differences in germination characteristics among the tested species. Seed germination of some species was promoted by light, but not in others. Wet-habitat species generally had positive photoblastic responses. For many species, scarification was effective to promote seed germination, but neither 100 nor 500 mg·L−1 GA3 had consistent promoting effects.
Particle Size and Hydraulic Properties of Pumice Affect Growth and Yield of Greenhouse Crops in Soilless Culture
Authors: Gizas George , Savvas Dimitrios
Published: February 2019

Four successive trials with gypsophila, rose, cucumber, and lettuce grown on different pumice grades were conducted in a heated glasshouse. In the gypsophila experiment, three grades of pumice (0 to 2, 0 to 5, and 0 to 8 mm) were tested, whereas in the rose, cucumber, and lettuce experiments, four pumice grades (0 to 2, 0 to 5, 0 to 8, and 4 to 8 mm) were compared. In each experiment, these pumice grades were combined with two growing systems, specifically placement of the same media volume either in pots or in bags. Furthermore, the physical properties of the tested pumice grades were determined. Overall, gypsophila and cucumber gave the highest yields when grown in pots filled with the two finest pumice grades, whereas the yield obtained from plants grown in bags was poor regardless of particle size range. Coarse pumice restricted gypsophyla and cucumber yield in pot culture to nearly the same degree as in bags. In contrast, lettuce, and to a greater degree roses, exhibited a weaker response to the different pumice grades and growing systems. The two finer pumice grades were characterized by relatively low air-filled porosity, which presumably restricted plant growth and yield as a result of poor root aeration when the media were placed in bags with a height of 8 cm. The coarsest pumice grades were characterized by a steep drop in the water content as the suction increased only a few centimeters above zero, which imposed an appreciable lowering of the overall water content in the pots in comparison with the bags (≈12.5%), as a result of the increased height of the former. Our results indicate that gypsophila and cucumber respond more strongly than roses and lettuce to the variations in the air-to-water ratio in the root zone originating from differences in the physical properties of the growing media.
Field-portable Analysis of Anthocyanin Concentration in Sepals of Hydrangea macrophylla
Authors: Schreiber Henry D. , Wade Nicholas A.
Published: February 2019

A field-portable method, adapting commercially available chlorophyll content meters, has been developed to measure the anthocyanin concentration in red and blue sepals of Hydrangea macrophylla. The meters were calibrated to total extractable anthocyanin concentration. The strength of the linear relationship (anthocyanin content index vs. extractable anthocyanin concentration) was better for red than blue sepals, due perhaps to the inclusion of purplish sepals in the blue data set or perhaps to more than one mechanism for the bluing of sepals. The meters were demonstrated to be an effective tool for the measurement of relative anthocyanin concentration in hydrangea sepals as a function of bloom stage.
Controlled Deterioration and Accelerated Aging Tests Predict Relative Seedling Emergence Potential of Melon Seed Lots
Authors: Mavi Kazim , Demir Ibrahim
Published: February 2019

The emergence of 22 commercial seed lots (12 in 2005 and 10 in 2006) of melon (Cucumis melo L.) with laboratory germinations greater than 90% were compared in low temperature (LTE), mechanical stress (MSE), high temperature (HTE), and salt stress (SSE) sowing conditions. The seedling emergence percentage ranged between 18% and 79% for LTE, 15% and 90% for MSE, 27% and 84% for HTE, and 49% and 92% for SSE in 2005; and 43% and 85% for LTE, 30% and 82% for MSE, 56% and 91% for HTE, and 49% and 89% for SSE in 2006. The germination of the lots was determined after controlled deterioration (CD) with 20% or 24% moisture content (MC) and accelerated aging (AA) at 40 and 45 °C in 2005; or at 45 and 47 °C in 2006 for 48, 72, 96, 120, and 144 h. Germination after various combinations of CD and AA was positively and significantly (P < 0.05) correlated with LTE, MSE, HTE, and SSE. Correlation values (0.17 to 0.78) of the initial laboratory germination were much lower than those of both aging tests. The optimum CD conditions of 48 h and 20% MC at 45 °C and AA conditions of 120 h at 45 to 47 °C are suggested as vigor tests to estimate relative seedling emergence of melon seeds.
Implications of Irrigation Method and Amount of Water Application on Phytophthora and Pythium Infection and Severity of Root Rot in Highbush Blueberry
Authors: Bryla David R. , Linderman Robert G.
Published: February 2019

A 2-year study was done in Oregon to determine the effects of irrigation method and level of water application on the development of root rot in northern highbush blueberry (Vaccinium corymbosum L. ‘Duke’). Plants were grown on mulched, raised beds and irrigated by overhead sprinklers, microsprays, or drip at 50%, 100%, and 150% of the estimated crop evapotranspiration requirement. Soil at the site was a silty clay loam. By the end of the first season, plants were largest with drip, intermediate-sized with microsprays and smallest with sprinklers; however, this was not the case the next season. By the end of year 2, plants irrigated by drip had less canopy cover, fewer new canes, lower pruning weights, and only half the shoot and root dry weight as plants irrigated by sprinklers or microsprays. Destructive sampling revealed that the field was infested by root rot. Less growth with drip was association with higher levels of infection by the root pathogen, Phytophthora cinnamomi. Phytophthora infection increased with water application, regardless of irrigation method, but averaged 14% with drip and only 7% with sprinklers and microsprays. Roots were also infected by Pythium spp. Pythium infection likewise increased with the total amount of water applied but, unlike P. cinnamomi, was similar among irrigation methods. Overall, drip irrigation maintained higher soil water content near the base of the plants than sprinklers and microsprays, resulting in conditions more favorable to root rot. Sprinklers and microsprays may be better alternatives than drip at sites prone to problems with the disease.