bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistanceto Cucurbit Leaf Crumple Virus in Melon
Authors: McCreight James D. , Liu Hsing-Yeh , Turini Thomas A.
Published: February 2019

Cucurbit leaf crumple geminivirus (CuLCrV) is transmitted by sweet-potato whitefly (Bemisia tabaci) biotype B (SPWF-B) and occurs on cucurbits in Arizona, California, Texas, and Mexico. This virus is identical to Cucurbit leaf curl virus, and their symptoms are similar to Squash leaf curl virus on squash (Cucurbita sp.) and Melonleaf curl virus on melon (Cucumis melo L.). Melon has been reported to be either susceptible to CuLCrV, or to have the ability to recover from infection. Twenty-three melon cultigens were inoculated with CuLCrV in greenhouse tests using SPWF-B. Eighteen of the cultigens tested were highly susceptible to CuLCrV (≥60% infected plants) and generally exhibited pronounced CuLCrV symptoms: `Amarillo', `Edisto 47', `Esteem', `Fuyu 3', `Impac', `Moscatel Grande', `Negro', `Perlita', PI 234607, PI 236355, PI 414723, `PMR 5', `Seminole', `Sol Dorado', `Sol Real', `Top Mark', `Vedrantais', and WMR 29. Five cultigens were resistant to CuLCrV (<40% infected plants that exhibited restricted, mild symptoms): MR-1, PI 124111, PI 124112, PI 179901, and PI 313970. Symptoms abated with time in both groups although infected plants remained positive for the virus. Ten of the cultigens (`Edisto 47', `Fuyu 3', `Impac', MR-1, PI 124112, PI 313970, PI 414723, `PMR 5', `Top Mark', and WMR 29) were included in field tests in 2003 and 2004 that were naturally infected with CuLCrV. With the exception of PI 414723, the greenhouse and field data were consistent for reaction to CuLCrV.
Identified Resistance in Lettuce Germplasm to Verticillium Wilt Caused by Verticillium dahliae
Authors: Vallad G.E. , Qin Q.M. , Grube R. , Hayes R.J. , Ryder E. , Subbarao K.V.
Published: February 2019

Since its appearance in 1995, Verticillium wilt of lettuce has spread through the Salinas River Valley, where nearly 60% of California's lettuce acreage is located. A replicated field trial was conducted to assess various modern and heirloom lettuce (Lactuca sativa) cultivars, plant introductions, and L. virosa lines for resistance to Verticillium wilt. Based on horticultural type, lettuce plants were destructively sampled at harvest maturity and assessed for the incidence of Verticillium wilt. Of the L. sativa cultivars, only the iceberg type displayed pronounced foliar symptoms of stunting and wilting. Disease incidence based on root symptoms ranged from 0% to 100%, with continuous variation found across and within lettuce types. Most cos, crisphead, and leaf cultivars exhibited 20% or greater disease incidence. Butter cultivars exhibited the lowest disease incidence among the major lettuce types examined, and Latin and Batavia type cultivars exhibited the lowest disease incidence overall. Disease progression was further monitored for 10 select lettuce cultivars for 2 weeks past harvest maturity. Disease intensity increased over the 2-week period for some cultivars, demonstrating the need to assess plants for Verticillium wilt past harvest maturity to avoid misclassifying plants. The L. sativa plant introduction lines tested, predominantly stem and oil-seed horticultural types, were quite susceptible and exhibited distinct symptoms of wilt and defoliation, possibly due to their elongated growth habit. The variation in disease incidence among the L. virosa lines tested was discontinuous, with discrete differences in susceptibility. Overall, the results reflected trends found in previous greenhouse and field trials.
Collection and Preliminary Evaluation of Turkish Strawberry Germplasm
Authors: Serçe Sedat , Gündüz Kazim , Paydas Sevgi , Kaska Nurettin , Özdemir Emine , Hancock Jim
Published: February 2019

Fragaria species are in different plodiy levels (from 2n = 2x = 14 to 2n = 8x = 56) and distributed in almost all parts of the arable areas of the world. The flora of Turkey has wild strawberries, some of which are harvested for their small, but very aromatic berries. There are also old cultivars found in Turkey that are known for their aromatic fruits. We made collection trips to the Marmara and Black Sea areas to collect both wild strawberries and old cultivars in Summer 2004. During these trips, we sampled 50 populations from the altitudes of 6 to 2007 m, lat. 35°91'N to 41°76'N latitudes, and long. 26°81'E to 42°65'E. The samples were propagated in a greenhouse and evaluated in a replicated trail for both taxonomic and horticultural traits in an unheated greenhouse. The chromosome numbers of the genotypes were also determined. The results indicate that Turkish strawberry germplasm consists of both diploid and octoploid species. The principal components and cluster analysis separated the genotypes into three groups: octoploid cultivars and/or derivatives (e.g., `Madame Moutot'), and two diploid Fragaria species, vesca and viridis. Further relationships of the genotypes will be discussed.
Influence of Tillage Method and Insecticide on Asian Eggplant Production
Authors: Range Kurt T. , Walters S. Alan , Taylor Bradley H.
Published: February 2019

Many growers in the St. Louis metro east area in Illinois are growing a diversity of vegetable products to satisfy local market demand, including many Asian vegetables. In 2003 and 2004, an experiment was conducted at a grower location in Belleville, Ill., to evaluate the effect of tillage method (tillage vs. no-tillage) following no-tillage corn (Zea mays) and insecticide treatment (imidacloprid, carbaryl, and none) on growth and productivity of three Asian eggplant (Solanum melongena) cultivars (`Ichiban', `Little Fingers', and `Millionaire'). Regardless of cultivar, imidacloprid resulted in greater plant growth for most of the growing season, resulting in higher early and total-season yields compared to the other insecticide treatments. Flea beetle (numerous species, including Epitrix fuscula and Epitrix cucumeris) damage to eggplants can be severe during the early part of the growing season in southern Illinois, which can drastically reduce plant growth and subsequent yields. Although carbaryl was applied at 10-d intervals for most of the growing season, flea beetle damage was similar to the no insecticide treatment and resulted in significant growth reduction and yield loss compared to imidacloprid. Tillage methods did not differ (P > 0.05) for Asian eggplant productivity or flea beetle damage. Cultivar performance was similar over the tillage method and insecticide treatment as no significant interactions (P > 0.05) were detected. However, cultivars differed for productivity with `Millionaire' and `Ichiban' generally providing higher marketable and total yields than `Little Fingers'.
Fall Cover Crops for Reducing Nitrate Leaching in Cool Season Vegetable Production in the Salinas Valley
Authors: Smith Richard F. , Jackson Louise E. , Bensen Tiffany A.
Published: February 2019

Lettuce growers in the Salinas Valley are often not able to rotate to other crops due to economic pressure, such as high land rent. Winter-grown cover crops (October to March) provide a short-term rotation from lettuce and have been shown to reduce nitrate leaching by 75%. However, the use of winter-grown cover crops is low due to the extended time these cover crops tie up the ground. As a result, growers are interested in the potential of fall-grown cover crops (September to October) to reduce nitrate leaching through the winter. Fall-grown cover crops are incorporated into the soil prior to the onset of winter rains and leave the soil bare over the winter; however, during fall growth, the cover crop has the potential to capture excess nitrate that may leach during the fallow period, but how much has not been previously measured. A long-term trial was established in Fall 2003 using treatments of Indian mustard (B. juncea) `ISCI 61', White mustard (S. alba) `Ida Gold', Cereal rye (Secale cereale) `Merced', and a no cover crop control. All cover crops contained ≈224 kg·ha-1 N upon incorporation. Anion resin bags were installed 90 cm deep in the soil following incorporation to trap leaching nitrate; they were left in place until planting of the lettuce the following spring. First-year results indicated that the mustard cover crops and `Merced' rye all reduced nitrate leaching to the 90-cm depth by 67% to 82% over the bare fallow treatment. These results indicate that fall-grown cover crops have the potential to reduce nitrate leaching in lettuce production systems in the Salinas Valley.
Using Polyacrylamide (PAM) for Reducing Sediment and Nutrient Losses from Cool Season Vegetable Fields
Authors: Cahn Michael D. , Ajwa Husein A.
Published: February 2019

Agricultural runoff is a source of nutrients and sediments in surface water on the central coast of California. Treating soils with high molecular weight anionic polyacrylamide (PAM) may reduce sediments and P lost from furrow and sprinkler irrigated fields by maintaining infiltration and stabilizing soil aggregates. We conducted column and field studies to quantify the effect of PAM on infiltration rate, run off, and sediment and nutrient (ortho and total P, NO3, K) loss from cool season vegetable fields. Column studies demonstrated a reduction in infiltration for 10 soil types when PAM was continuously applied in the irrigation water at 10 ppm. Recirculating infiltrometer studies showed that in furrow systems, PAM, applied only in the initial water at 10 ppm, had no significant effect on infiltration at four of six sites evaluated. Turbidity and total suspended solids were significantly reduced in the PAM treated water. Across all sites, treatment with PAM reduced suspended solids by 85% compared to the untreated control. Additionally, soluble and total P, and total N were reduced in the PAM treated water. PAM had no effect on nitrate or salt levels in the runoff. PAM applied through sprinklers at a 5 ppm concentration was able to significantly reduce the turbidity and the suspended solids in the tailwater. Similar to the results obtained with the recirculation infiltrometer trials, PAM reduced soluble and total P and total N in the runoff, but had no significant effect on NO3-N. Total sediment loss under sprinklers was reduced by as much as 95% using PAM.
Tomato Yield Stability during Five-year Transition to Conservation Tillage and Cover Cropping
Authors: Mitchell Jeffrey P. , Horwath William R. , Klonsky Karen K. , Southard Randal J. , DeMoura Rich , Munk Daniel S. , Hembree Kurt J.
Published: February 2019

Eliminating tillage passes is a means to reduce production costs and dust emissions in California's San Joaquin Valley tomato production region. Inserting winter cover crops between summer crops may be a way to add organic matter to the soil and thereby improve soil quality. From 1999, we evaluated conservation tillage (CT) and cover cropping (CC) in a tomato/cotton rotation in Five Points, Calif. During the course of the study, tillage operations were reduced an average of 50% in the CT system relative to the standard tillage (ST) approach. Yields in the CT no cover crop (NO) system matched or exceeded yields in the STNO system in each year. Tomato yields in the CTCC and STCC systems were comparable to the STNO except in the first year, when stand establishment and early season vigor were problems. Weed management and machine harvest efficiency in high surface residue systems are issues requiring additional work in order to make CT adoption more widespread.
Biofumigation and Soil Conditioning Effects of Cover Crops in Processing Tomato
Authors: Johnstone P. R. , Hartz T. K. , Miyao E. M. , Davis R. M.
Published: February 2019

Mustard cover crop residue has been reported to have a “biofumigant” action when incorporated into the soil, potentially providing significant disease suppression and yield improvement for the succeeding crop. Such activity could be particularly useful in processing tomato rotations, where consecutive cropping invariably results in yield decline. Agronomic and environmental effects of growing over-winter mustard cover crops preceding tomato production were investigated in three field trials between 2002 and 2004. Two mustard cover crops [`Pacific Gold', a brown mustard (Brassica juncea), and `Caliente', a blend of brown and white mustard (Sinapis alba)] were compared to a legume cover crop mix, a fallow bed treatment (the standard grower practice in this region), and, in two of the three trials, a fumigation treatment using metam sodium. No suppression of soil populations of Verticillium dahliae or Fusarium spp. was observed with the mustard cover crops, nor was there any visual evidence of disease suppression on subsequent tomato crops. In these fields, the mustard either had no effect, or reduced tomato yield, when compared to the fallow treatment. At one of two sites, metam sodium fumigation significantly increased tomato yield. The presence of a cover crop, whether mustard or legume, reduced winter runoff by an average of 50% over two years of trials. No benefit of mustard cover cropping beyond this reduction in winter runoff was observed.
Vegetable Science International Network (VEGINET)
Authors: Nath Prem
Published: February 2019

At the International Conference on Vegetables held 11–14 Nov. 2002 in Bangalore, India, about 700 participants from 37 countries across the globe discussed more than 600 papers and posters presented on its 13 theme areas of scientific, technological, and economic importance. It was recognized that this phenomenal knowledge and much more of it that is globally available and will be available in the future should be collected, consolidated and easily retrieved and shared for appropriate use by the stakeholders. Therefore, the General Assembly of the Conference ICV-2002 decided to establish the Vegetable Science International Network (VEGINET). The goal of VEGINET will be to strengthen partnership and inter-institutional cooperation among the member organizations of the vegetable sector toward improved production and utilization of vegetables. The main objectives will be to strengthen/promote vegetable research and development by facilitating inter- and intra-regional and inter-institutional cooperation; promote partnership between public and private sectors for improving vegetable production; facilitate development of human resources; promote improved and sustainable production of vegetables for food; develop a collaborative network for dissemination of information among the member organizations; and facilitate building of a sustainable infrastructure from the farm to the consumer and processor. The rising challenge, structure and membership, partnership, human resource development, mandate and strategy, activities, and resource generation of the VEGINET will be explained during the presentation.
Water and Phosphorus Efficiency in Containerized Crop Production of Cotoneaster dammeri `Skogholm' with an Industrial Mineral Aggregate Amended Pine Bark Substrate
Authors: Owen James S. , Warren Stuart L. , Bilderback Ted E. , Albano Joseph P.
Published: February 2019

The physical and chemical properties of pine bark yield low water and nutrient efficiency; consequently, an engineered substrate altering the substrate properties may allow greater water and nutrient retention. Past research has focused on controlling the quantity and rate of water and nutrient inputs. In this study, pine bark was amended at 8% (by volume) with a Georgiana palygorksite-bentonite blended industrial mineral aggregate with a particle size of 850 μm-4.75 mm or 300 μm-710 μm to improve water and nutrient efficiency. Each particle size was pretreated at temperatures of ≈140 °C (pasteurized) or ≈390 °C (calcined). The study was a 2 (particle size) × 2 (heat pretreatment) factorial in a randomized complete-block design with four replications. The control was a pine bark substrate amended with 11% sand (by volume). Containers (14 L) were topdressed with 17–5–12 controlled release fertilizer. A 0.2 leaching fraction was maintained by biweekly monitoring container influent from spray stakes and effluent volume measured daily. An aliquot of the daily collected effluent was analyzed for phosphorus (P). After 112 days, tops and roots were harvested, dried, and weighed for dry weight comparisons. Compared to pine bark amended with sand the 300 μm-710 μm particle size mineral decreased mean daily water application by ≈0.4 L/day per container. The calcined mineral reduced P leaching by ≈10 mg of P per container or 60% over the course of the study compared to pine bark: sand. Top and root dry weights were unaffected. These results suggest 300 μm–710 μm calcined mineral provided the most significant decreases in water use and P leaching while growing an equivalent plant.
Interactive Web-based Technology Has Wide Applications for Extension Programs
Authors: Pennisi Bodie
Published: February 2019

The Internet has become a valuable tool in education in the traditional classroom. Although electronic publications and other visual information in the form of PowerPoint presentations, with or without streaming video, have proven very effective in disseminating information, these forms lack interaction with clientele. Horizon Wimba software circumvents this limitation by allowing interaction between presenter and remote audience as well as between individual students while the lecture is in progress. This Web-based tool was evaluated in two Extension programs, Master Gardener and county agent trainings. With both types of audience, evaluations showed high satisfaction and effectiveness of the delivery of information. Evaluations also showed that Master Gardeners who use the Internet on a regular basis considered the Web-delivered interactive lecture format similar to face-to-face interaction. Master Gardeners who do not use the Internet on a regular basis listed that Web-delivered interactive training could be used as a supplement to traditional face-to-face interaction. County agents were very comfortable with the format and indicated high interest in participating in future trainings via the Internet.
Acceptable Risks—In Science vs. Farming
Authors: Murray Mike , Ashcroft Bill , Top B. M. , Ashburner G. R.
Published: February 2019

University of California Extension field staff are well educated and highly trained to conduct sound applied research. Part of this training includes statistical classes. Data that fail to attain a 95% confidence level are considered “risky.” This is inconsistent with “risk” assumed in almost every other aspect of our lives. There are ample examples of people willingly taking “high” risks. Examples include legalized gambling, marriage, insurance actuarial tables, etc. Most of us are willing to take calculated risks, depending on the importance and cost of making an incorrect assumption. This is directly applicable to agricultural production enterprises. While the comfortable level of risk will vary among producers, there is interest in technologies that have confidence levels below 95%. Australian processing tomato researchers have developed a Residual Maximum Likelihood (REML) analysis tool to address this issue. REML was designed to simplify interpretation of a relatively complex data set, including statistics, so a farmer can make choices at a risk level they find appropriate. The model incorporates pairwise t tests, an interactive computer program, and a gambling analogy in its analyses. Multiple variables can be entered and the model provides odds that the desired result will be attained. The user can determine the relative importance of each variable as part of the determination. This model, and implications for adoption by producer clientele, will form the basis for the presentation.
Classification and Identification of S-haplotypes Using PCR-RFLP and Measuring the Self-incompatibility Activity in Radish (Raphanus sativus L.)
Authors: Park Su-Hyoung , Kim Ki-Taek , Lim Sun-Hyoung , Yoon Moo-Kyoung , Lee Soo-Seong , Chun Changhoo , Park Hyo-Geun
Published: February 2019

Self-incompatibility (SI) in Brassicaceae vegetables prevents self-pollination by recognizing self-pollens and rejecting them at the stigmatic surfaces. The S-haplotypes of 47 hybrid radish cultivars that are commercially available in Korea were classified and identified using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Twelve kinds of S-haplotypes were identified from the cultivars: S1, S8, S11, S17, S18, S30, and S31 haplotypes in class-I S-haplotype and S4, S5, S13, S21, and S26 haplotypes in class-II S-haplotypes. Even though the class-II S-haplotypes are supposed to exhibit weak and/or leaky SI activity, the class-II S-haplotypes showed the same allele frequency of class-I S-haplotypes in 38 fully classified commercial cultivars. The SI activity was examined using the pollen tube germination test, flower pollination test, and the seed set ratio analysis. The pollen tube test showed low correlation (R2 = 0.13) with the flower pollination test, a conventional method. The results of seed set ratio analysis varied from 0% to 159%, and thus could distinguish the weak and strong SI activity clearly and showed high correlation with the flower pollination test (R2 = 0.69). The seed set ratios of the cultivars possessing the class-I/class-I, class-I/class-II, and class-II/class-II genotypes were 0.6%, 17.4%, and 38.1%, respectively. Among the eight class-II/class-II cultivars, three cultivars showed strong SI activity. The SI activity of the S4S17, S5S8, and S4S26 genotypes varied among cultivars, but the S1S17, S5S17, and S8S26 genotypes showed constant strong, intermediate, and strong activity, respectively, among the cultivars. Results indicate that the SI activity of Brassicaceae vegetables depends not only on the S-haplotypes, but also on the genetic background of cultivars.
Genetics and Breeding of Early Blight Resistance in Tomato
Authors: Foolad Majid R. , Sharma Arun , Ashrafi Hamid , Lin Guoyang
Published: February 2019

Early blight (EB), caused by the fungus Alternaria solani, is a destructive disease of tomato (Lycopersicon esculentum) worldwide. Sources of genetic resistance have been identified within related wild species, including green-fruited L. hirsutum and red-fruited L. pimpinellifolium. We have employed traditional protocols of plant breeding and contemporary molecular markers technology to discern the genetic basis of EB resistance and develop tomatoes with improved resistance. Backcross breeding has resulted in the development of germplasm with improved resistance; however, linkage drag has been a major obstacle when using L. hirsutum as a donor parent. To identify and map QTLs for EB resistance, we used several filial and backcross populations derived from interspecific crosses between L. esculentum and either L. hirsutum or L. pimpinellifolium. In each population, an average of seven resistance QTLs were detected. While similar QTLs were detected in different generations of the same cross, generally different QTLs were identified in populations derived from different crosses. The results suggested stability of QTLs across environments and generations but variation in QTLs in different interspecific populations. It is expected that marker-assisted pyramiding of QTLs from different sources results in development of germplasm with strong and durable resistance. Further inspection of the results led to the identification and selection of six QTLs with stable and independent effects for use in marker–assisted selection (MAS). However, to facilitate “clean” transfer and pyramiding of these QTLs, near-isogenic lines (NILs) containing individual QTLs in a L. esculentum background should be developed.
Screening and Breeding for Leafminer Resistance in Spinach
Authors: Mou Beiquan
Published: February 2019

Leaf miner(Liriomyza spp.) is a major insect pest of many important vegetable crops, including spinach (Spinacia oleracea). Chemical control is not long lasting, and it is well documented that leafminers can develop a high degree of resistance to insecticides. Resistant varieties remain the most economical means of insect control. The purposes of the present experiments were to evaluate differences in spinach genotypes to leafminer damage, to compare results obtained from insect cages and from the field, and to study the association among different resistant traits. We screened 345 spinach genotypes from the USDA germplasm collection and 441 genotypes from CGN (Holland) and IPK (Germany) spinach collections for leafminer resistance in an outdoor insect cage and in the field. Significant genotypic differences were found for leafminer stings per unit leaf area, mines per plant, and mines per 100 g of plant weight. The sting result from the field was highly correlated (r = 0.770) with the result from the insect cage, demonstrating that a cage test could be used to screen for leafminer resistance in the field. Mines per plant were not correlated with plant weight, suggesting that leafminer flies did not lay their eggs randomly and oviposition-nonpreference occurred in these plants. Stings per unit leaf area was not correlated with mines per plant or per 100 g plant weight, which suggests that feeding-nonpreference does not necessarily mean oviposition-nonpreference for a spinach genotype and these two traits can be improved independently. These findings suggest that genetic improvement of spinach for leafminer resistance is feasible. A phenotypic recurrent selection method is used to increase the level of leafminer resistance in spinach.
Small Heat Shock Proteins, Morphological and Physiological Characteristics Associated with Heat Tolerance in Salvia (Salvia splendens)
Authors: Natarajan Seenivasan , Kuehny Jeff
Published: February 2019

Small heat shock proteins (sHSP) are a specific group of highly conserved proteins produced in almost all living organisms under heat stress. These sHSP have been shown to help prevent damage at the biomolecular level in plants. One of the greatest impediments to production of marketable herbaceous plants and their longevity is high temperature stress. The objectives of this experiment were to study the plant responses in terms of sHSP synthesis, single leaf net photosynthesis, total water-soluble carbohydrates (WSC), and overall growth for two S. splendens cultivars differing in performance under heat stress. `Vista Red' (heat tolerant) and `Sizzler Red' (heat sensitive) were exposed to short duration (3 hours) high temperature stresses of 30, 35, and 40 °C in growth chambers. Increasing the temperature to about 10 to 15 °C above the optimal growth temperature (25 °C, control) induced the synthesis of sHSP 27 in S. splendens. Expression of these proteins was significantly greater in the heat-tolerant vs. the heat-sensitive cultivar. Soluble carbohydrate content was greater in `Vista Red', and in both the cultivars raffinose was the primary soluble carbohydrate in heat-stressed plants. Overall growth of plants was significantly different in the two cultivars studied in terms of plant height, stem thickness, number of days to flower, and marketable quality. The better performance of `Vista Red' under heat stress was attributed to its morphological characteristics, including short stature, thicker stems and leaves. sHSPs and WSC are also found to be associated with heat tolerance and heat adaptation in S. splendens.
Effect of External Nitrate Concentration on Nitrate and Iron Uptake and Assimilation in Vaccinium Species
Authors: Darnell Rebecca
Published: February 2019

Most Vaccinium species, including V. corymbosum, have strict soil requirements for optimal growth, requiring low pH, high iron, and nitrogen, primarily in the ammonium form. V. arboreum is a wild species adapted to high pH, low iron, nitrate-containing soils. This broader soil adaptation in V. arboreum may be related to increased efficiency of iron or nitrate uptake/assimilation compared with cultivated Vaccinium species. To test this, nitrate and iron uptake, and nitrate reductase (NR) and ferric chelate reductase (FCR) activities were compared in two Vaccinium species, V. arboreum and the cultivated V. corymbosum. Plants were grown hydroponically for 15 weeks in either 1.0 or 5.0 mm NO3 with 0.09 mm Fe. Root FCR activity was greater in V. arboreum compared with V. corymbosum, especially at the lower external nitrate concentration. However, this was not reflected in differences in iron uptake. Nitrate uptake and root NR activity were greater in V. arboreum compared with V. corymbosum. The lower nitrate uptake and assimilation in V. corymbosum was reflected in decreased plant dry weight compared with V. arboreum. V. arboreum appears to be more efficient in acquiring nitrate compared with V. corymbosum, possibly due to increased NR activity, and this may partially explain the wider soil adaptation of V. arboreum.
Alternatives to Fish Oil for Thinning Apples with Lime Sulfur
Authors: Schupp James R. , McFerson James R. , Robinson Terence L.
Published: February 2019

A tank mix of fish oil plus liquid lime sulfur has proven to be an effective chemical thinner for apples in the bloom and postbloom periods. This combination was labeled for use as a chemical thinner in Washington State in 2003. There are several concerns with fish oil when used in this thinning mixture. Phytotoxicity is one concern. Apple growers have a reluctance to utilize this oil because of its expense and repulsive odor. Research to date has been conducted using oil from a single small source in Washington State. Shipping fish oil across the country is expensive and the consistency and purity of fish oil from other sources is unknown. Fish oil may function as a surfactant and penetrant, and it may also have a direct thinning effect. The objective of these studies was to evaluate the efficacy of several surfactants and oils in combination with lime sulfur for thinning apples. Lime sulfur has been less effective as a thinner when used alone than when used with oil in our studies. Regulaid, LI-700, and Silwet L-77 were shown to be less effective than oils for achieving thinning. Vegetable oil has been very effective in the thinning combination, while petroleum oils have been effective in some eastern U.S. trials, but less effective in the west. Tank mixing fish oil with lime sulfur has remained among the best treatments in our trials, while vegetable oil also shows promise.
Changes in Gluconasturtiin Content in Chinese Cabbage with Increasing Cabbage Looper Density
Authors: De Villena Fernando , Fritz Vincent , Cohen Jerry , Hutchison William
Published: February 2019

Gluconasturtiin (2-phenylethyl glucosinolate), an aromatic glucosinolate, was used to evaluate the response of Chinese cabbage (Brassica campestris L. ssp. pekinensis) cv. Green Rocket to three and five cabbage looper (Trichoplusia ni Hubner) larvae per plant. Plants were harvested 0, 10, and 17 days after infestation. The change in gluconasturtiin content due to decreased light and leaf area removed was also studied. All samples were assayed for gluconasturtiin content using high performance liquid chromatography (HPLC). The gluconasturtiin content of plants subjected to five larvae/plant had a 59% increase, compared to noninfested plants 10 days after infestation. The effect of larval feeding was also dependent on harvest time. The levels of gluconasturtiin increased by 52% from the first harvest (prior to infestation) to the second harvest (10 days after infestation) in both larval feeding densities. Seventeen days after infestation (final harvest), gluconasturtiin content experienced a nonsignificant 6% decrease, compared to the previous harvest.
Biological Control of Crucifer Crop Pests and Participatory IPM in Thailand
Authors: Rowell Brent , Bunsong Nittayaporn , Satthaporn Kosin , Phithamma Sompian , Doungsa-ard Charnnarong
Published: February 2019

Larvae of the diamondback moth (DBM), Plutella xylostella L. (Lepidoptera: Ypeunomutidae) and other crucifer pests cause severe economic damage to cabbage, Brassica oleracea L. var. capitata (Brassicaceae) and related vegetables in Thailand and elsewhere in Southeast Asia. Overuse of pesticides is a serious problem in most vegetable growing areas of the country. Six species of parasitoids were reared from DBM larvae and pupae collected in northern Thailand in 1989–90 and 2003–04. The larval parasitoid Cotesiaplutellae Kurdjumov (Braconidae) appears to be the most important parasitoid of DBM in Thailand; other native or naturalized parasitoids may play supplementary roles. These natural enemies can and should be conserved in well thought out, participatory IPM programs. Field experiments comparing local farmer practice (weekly sprays of synthetic pyrethroid insecticides) to a simple IPM protocol using Bt and neem demonstrated superior control and higher yields of undamaged cabbage from the IPM treatment. This information on DBM parasitoids and other natural enemies of crucifer pests has been developed into a poster and other extension materials currently used in national “training of trainer” (for vegetable IPM) programs throughout Thailand. Farmer-centered IPM programs focused on conservation of local DBM parasitoids and on greater implementation of biological control will help alleviate growing public concerns regarding the effects of pesticides on vegetable growers and consumers.
Changes in Kale Pigment Profiles during Leaf Ontogeny
Authors: Lefsrud Mark G. , Kopsell Dean A.
Published: February 2019

Chlorophyll and carotenoid pigments were measured with high-performance liquid chromatography (HPLC) during leaf development in kale (Brassicaoleracea L. var. acephala D.C). Lutein and β-carotene are two plant-derived carotenoids that possess important human health properties. Diets high in these carotenoids are associated with a reduced risk of cancer, cataracts, and age-related macular degeneration. Kale plants were growth-chamber grown in nutrient solution culture at 20 °C under 500 μmol·m-2·s-1 of irradiance. Pigments were measured in young (<1 week), immature (1-2 weeks), mature (2-3 weeks), fully developed (3-4 weeks) and senescing (>4 weeks) leaves. Significant differences were measured for all four pigments during leaf development. Accumulation of the pigments followed a quadratic trend, with maximum accumulation occurring between the first and third week of leaf age. The highest concentrations of lutein were recorded in 1- to 2-week-old leaves at 15.1 mg per 100 g fresh weight. The remaining pigments reached maximum levels at 2-3 weeks, with β-carotene at 11.6 mg per 100 g, chlorophyll a at 251.4 mg per 100 g, and chlorophyll b at 56.9 mg per 100 g fresh weight. Identifying changes in carotenoid and chlorophyll accumulation over developmental stages in leaf tissues is applicable to “baby” leafy greens and traditional production practices for fresh markets.
Sensory Quality Ratings and Mineral and Glycoalkaloid Concentrations in Organically and Conventionally Grown Redskin Potatoes (Solanumtuberosum)
Authors: Wszelaki Annette , Delwiche Jeannine , Walker Sonia , Liggett Rachel , Scheerens Joseph , Kleinhenz Matthew
Published: February 2019

Sensory evaluations (triangle tests) were used to determine if panelists could distinguish, by tasting, cooked wedges of potatoes grown organically, either with or without compost, and conventionally. Mineral and glycoalkaloid analyses of tuber skin and flesh were also conducted. When the skin remained on the potatoes, panelists detected differences between conventional potatoes and organic potatoes, regardless of soil treatment. However, they did not distinguish between organic treatments (±compost) when samples contained skin or between any treatments if wedges were peeled prior to preparation. Glycoalkaloid levels tended to be higher in organic potatoes. In tuber skin and flesh, potassium, magnesium, phosphorus, sulfur, and copper concentrations were also significantly higher in the organic treatments, while iron and manganese concentrations were higher in the skin of conventionally grown potatoes.
Response of Total Polyphenol Content to Nitrogen, Phosphorus, and Potassium Nutrition of Bush Tea (Athrixia phylicoides)
Authors: Mudau Nixwell , Soundy Puffy , du Toit Elsa
Published: February 2019

Bush tea (Athrixia phylicoides) belongs to the Asteraceae family. It is a popular beverage, commonly used as an herbal tea and for medicinal purposes. In some parts of South Africa, people consume or drink it as an aphrodisiac. Bush tea was grown under varying nitrogen (N), phosphorus (P) and potassium (K) levels in the four seasons to determine the seasonal nutrient requirements for improved quality. Treatment consisted of 0, 100, 200, 300, 400, or 500 kg·ha–1 N, P, or K in a randomized complete-block design under 50% shade nets. Three N, P, and K parallel trials were conducted per season (autumn, winter, spring, and summer). Total polyphenols were extracted using Folin-Ciaocalteau reagents and analyzed in a spectrophotometer. Results for the N trial suggested that total polyphenols increased quadratically in response to N nutrition during summer, winter, and spring, but not in autumn. The optimum N level was 300 kg·ha–1. The highest total polyphenol was 51.1 mg·g–1 in winter. For the P trial, total polyphenols also increased quadratically in response to P nutrition regardless of season. Again winter had the highest total polyphenols (46.8 mg·g–1). The optimum P level was 300 kg·ha–1. In the K trial, regardless of season, total polyphenols plateaued at 200 kg·ha–1 and the highest polyphenols were in winter (43.3 mg·g–1). Therefore, for improved total polyphenol content, 300 kg·ha–1 N and P and 200 kg·ha–1 K are recommended regardless of season.
Rooting Osha Crown Cuttings Using IBA and NAA
Authors: Sondeno Bennett J. , Panter Karen L.
Published: February 2019

Osha (Ligusticum porteri) is a Rocky Mountain native frequently used as a medicinal herb. It is currently harvested largely from the wild. Studies have been under way since 2001 to find ways to propagate and produce the plant. To potentially increase rooting success of crown cuttings of osha, two different rooting hormones were used, each at two concentrations. Treatments were controls, 2500 ppm, and 5000 ppm solutions each of indole-3-butyric acid (IBA) and α-naphthalene acetic acid (NAA). Cuttings were soaked in deionized water or treatment solutions for 2 min. After soaking cuttings were stuck in sterilized sand in 725-mL2 containers, one cutting per container. Containers were placed on a mist propagation bench at 21 °C in a completely randomized design under natural light and day lengths. Data taken were days to visible root and shoot, and presence or absence of root formation after 50 days. Results indicated only one of 70 cuttings (<1%) produced a shoot. Roots formed on 14% of control cuttings, 64% in 2500 ppm IBA, 86% in 5000 ppm IBA, 36% in 2500 ppm NAA, and 14% in 5000 ppm NAA. Days to rooting ranged from 14.9 (2500 ppm IBA) to 29.0 (5000 ppm NAA). Due to considerable variation in days to rooting, and the number of cuttings that did not root, analysis of variance showed no differences among treatments. Frequency analysis indicated differences among treatments in root presence or absence. The 2500 and 5000 ppm IBA treatments showed more root formation than the controls or either NAA treatment. This indicates IBA may enhance rooting of osha crown cuttings.
Propagation by Stem Cuttings and Response of Seeds to Light and Temperature of Fever Tea (Lippiajavanica)
Authors: Soundy Puffy , Mpati Winnie , Toit Elsadu
Published: February 2019

Fever tea (Lippiajavanica) is one of the important medicinal plants belonging to the Verbenaceae family. The first objective of this investigation was to study the propagation of fever tea using stem cuttings. The main variables studied were cutting position, rooting media and rooting hormone. The germination requirement of fever tea seed is also not known. Therefore, the second objective was to investigate the ideal seed germination temperature and light combinations. Germination was tested at constant temperature regimes (15, 20, 25 and 30 °C) with a continuous light or dark period and at alternate temperatures of 20/30 °C and 16/8 hour (light/dark) combinations, respectively. For the stem cutting investigation, sampling was done every 5, 10, 15, and 20 days from plant establishment. Apical cuttings took less time to root than basal cuttings regardless of growing medium. Response of cuttings to rooting hormone was growing medium-related. With rooting hormone, it took 10 days to root most of the apical cuttings, whereas basal cuttings showed more roots in 15 to 20 days after plant establishment. Cuttings in sand took 5 days longer to root than in pine bark, regardless of rooting hormone. Therefore, for quicker establishment of fever tea stem cuttings, rooting hormone and pine bark should be used for propagation of both apical and basal cuttings. In the germination investigation, it was found that fever tea seeds are positively photoblastic. Regardless of temperature, seeds failed to germinate in continuous darkness. The germination percentage was improved at continuous or alternating temperatures above 20 °C with continuous light. However, the germination percentage decreased with alternating light and dark treatments.
Application of Molecular Data on Ornamental Peach Systematics
Authors: Hu Dongyan , Zhang Donglin , Zhang Zuoshuang , Zhang Qixiang , Li Jianhua
Published: February 2019

Ornamental peach [Prunuspersica (L.) Batsch.] is a well-known ornamental plant for the garden. However, the genetic relationship among ornamental peach cultivars is not clear, which limits further studies of its molecular systematics and breeding. A group of 16 taxa of ornamental peach, originated from Prunuspersica and Prunusdavidiana (Carr.) Franch., had been studied using AFLPs and ISSRs. A total of 243 useful markers between 75 to 500 base pairs were generated from six EcoRI/MseI AFLP primer combinations (ACC/CAT, AGG/CAT, ACT/CAT, ACC/CTC, AGG/CTC, and ACT/CTC). The average readable bands were 41 per primer combination. Among them, 84% of the bands were polymorphic markers. A total of 132 useful markers between 300 to 1400 base pairs were generated from 10 ISSR primers (UBC818, UBC825, UBC834, UBC855, UBC817, UBC868, UBC845, UBC899, UBC860, and UBC836). The mean reliable bands were 14 per primer. Among them, 62% of the bands were polymorphic markers. Both methods generated very similar phenograms with consistent clades. From these results we concluded that AFLP and ISSR analysis had a great potential to identify ornamental peach cultivars and estimate their phylogeny. The application of these molecular techniques may elucidate the hierarchy of ornamental peach taxa.
Detection of Genetic Variation among Camellia Parents and Hybrids Using Random Amplified Polymorphic DNA (RAPD) Markers
Authors: Chen Lianghong , Wang Shizhou , Nelson Mack
Published: February 2019

The reliability of the random amplified polymorphic DNA (RAPD) technique in amplifying polymorphisim among the hybrids and their parents' genomes of the genus Camellia was evaluated. Three hybrids (`Londontowne Blush', `Ashton's Snow', and `Ashton's Cameo') and one of the parents, C. oleifrea`Plain Jane', provided by the America Camellia Society, Fort Valley, Ga., were investigated. Twenty 10-based random primers were tested in this study. Five out of 20 primers were selected for RAPD analysis based on the ability to produce unambiguously scoreable RAPD bands for evaluation and comparison of the genotypes under investigation. The five primers were selected because they produced distinct patterns of amplified bands for each tested genotype. A total of 162 RAPD bands were produced. Among the 162 bands, 86 bands showed polymorphisms. The amplified band sizes ranged from 236 to 1656 bp. These data indicate that in the three hybrids and one of the parents exist unique genomic regions. Our investigation results showed that the RAPD molecular approach can be used to discriminate genetic variation among hybrids and their parents.
Genetic Diversity Study of Green Bean [Phaseolus vulgaris (L.)] using Morphological, Allozyme, and RAPD Markers
Authors: Luan Feishi , Sun Zhanyong
Published: February 2019

The purpose of this study was to analyze the genetic relationship by using morphological, biochemical, and molecular markers. Sixty accessions of green bean [Phaseolusvulgaris (L.)], including 43 from North China, 13 from the International Center for Tropic Agriculture, and four from Poland, were collected and divided into three groups: cultivated determinate (35), cultivated indeterminate (12), and semi-wild determinate (13). Dendrograms were constructed based on the genetic similarity and distance analysis of these 60 accessions by using biological characters, allozyme, and random amplified polymorphic DNA (RAPD) markers. The 60 accessions were classified into two groups based on the genetic relationship examined in their biological characters. The cultivated indeterminate formed one group, and cultivated determinate and semi-wild determinate belonged to another group. Ten allozymes with 25 polymorphic loci divided the 60 accessions into nine groups, i.e., five groups for cultivated determinate, two groups for cultivated indeterminate, and two groups for semi-wild determinate. Twenty-nine RAPD markers with 314 polymorphic loci divided the 60 accessions into 13 groups, i.e., nine groups for cultivated determinate, three groups for cultivated indeterminate, and one group for semi-wild determinate. The average genetic similarities and genetic distance of intra-group and inter-groups were 0.81 and 0.75, and 0.19 and 0.24, respectively. Ten bands were characterized as specifically associated with cultivated determinate, one band specific for cultivated indeterminate, and one band for semi-wild. These biochemical and molecular markers provided more information than morphological markers. Allozyme and RAPD markers can be used as an available tool to exploit green bean germplasm in the future.
Microsatellite Markers Developed from `Bluecrop' Reveal Polymorphisms in the Genus Vaccinium and Are Suitable for Cultivar Fingerprinting
Authors: Boches Peter , Rowland Lisa J. , Hummer Kim , Bassil Nahla V.
Published: February 2019

Microsatellite markers for blueberry (Vaccinium L.) were created from a preexisting blueberry expressed sequence tag (EST) library of 1305 sequences and a microsatellite-enriched genomic library of 136 clones.

Microsatellite primers for 65 EST-containing simple sequence repeats (SSRs) and 29 genomic SSR were initially tested for amplification and polymorphism on agarose gels. Potential usefulness of these SSRs for estimating species relationships in the genus was assessed through cross-species transference of 45 SSR loci and cluster analysis using genetic distance values from five highly polymorphic EST-SSR loci. Cross-species amplification for 45 SSR loci ranged from 17% to 100%, and was 83% on average in nine sections. Cluster analysis of 59 Vaccinium species based on genetic distance measures obtained from 5 EST-SSR loci supported the concept of V. elliotii Chapm. as a genetically distinct diploid highbush species and indicated that V. ashei Reade is of hybrid origin. Twenty EST-SSR and 10 genomic microsatellite loci were used to determine genetic diversity in 72 tetraploid V. corymbosum L. accessions consisting mostly of common cultivars. Unique fingerprints were obtained for all accessions analyzed. Genetic relationships, based on microsatellites, corresponded well with known pedigree information. Most modern cultivars clustered closely together, but southern highbush and northern highbush cultivars were sufficiently differentiated to form distinct clusters. Future use of microsatellites in Vaccinium will help resolve species relationships in the genus, estimate genetic diversity in the National Clonal Germplasm Repository (NCGR) collection, and confirm the identity of clonal germplasm accessions.