scholarly journals A Highly Sensitive Method to Detect Avocado Sunblotch Viroid for the Maintenance of Infection-Free Avocado Germplasm Collections

Viruses ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 512
Author(s):  
David N. Kuhn ◽  
Barbie Freeman ◽  
Andrew Geering ◽  
Alan H. Chambers
Keyword(s):  
Agricultural Research ◽  
Germplasm Collection ◽  
The United States ◽  
Persea Americana ◽  
Molecular Diagnostic ◽  
Taqman Assay ◽  
Research Station ◽  
United States Department ◽  
The Creation ◽  
Avocado Sunblotch Viroid

The United States Department of Agriculture (USDA) Agricultural Research Service (ARS) Subtropical Horticulture Research Station (SHRS) in Miami, FL holds a large germplasm collection of avocado (Persea americana). The recent threat of infection by laurel wilt has encouraged the creation of a backup collection at a disease-free site. Creating the backup collection is complicated by infection of some trees in the germplasm collection with avocado sunblotch viroid (ASBVd). Infected trees are frequently asymptomatic, necessitating the use of a molecular diagnostic assay. Although a reverse-transcription based assay already exists and has been used to assay all germplasm at the station, some trees showed inconsistent results. We have developed a more sensitive and specific assay involving pre-amplification of the entire viroid cDNA followed by detection using real-time PCR and a TaqMan assay. A second screening of all germplasm identified additional ASBVd -infected trees and allowed us to confidently remove these trees from the station. This method enables avocado germplasm curators to proceed with the creation of a viroid-free backup collection.

scholarly journals Detection and Classification of SPLCV Isolates in the U.S. Sweetpotato Germplasm Collection via a Real-Time PCR Assay and Phylogenetic Analysis

Plant Disease ◽  
2011 ◽  
Vol 95 (11) ◽  
pp. 1385-1391 ◽  
Author(s):  
N. A. Barkley ◽  
D. L. Pinnow ◽  
M. L. Wang ◽  
K. S. Ling ◽  
R. L. Jarret
Keyword(s):  
Phylogenetic Analysis ◽  
Real Time ◽  
Ipomoea Batatas ◽  
Agricultural Research ◽  
Germplasm Collection ◽  
The United States ◽  
United States Department ◽  
Potato Leaf ◽  
In Vitro Plantlets

The United States Department of Agriculture–Agricultural Research Service sweetpotato (Ipomoea batatas) germplasm collection contains accessions that were initially collected from various countries worldwide. These materials have been maintained and distributed as in vitro plantlets since the mid-1980s. The status of viral infection by the emerging Sweet potato leaf curl virus (SPLCV) and other Begomovirus spp. in this germplasm has yet to be determined. In order to minimize the potential distribution of virus-infected clones, all accessions in the collection were tested for SPLCV using a real-time polymerase chain reaction assay. In total, 47 of 701 accessions of in vitro plantlets tested positive for SPLCV. The presence of SPLCV detected in these materials was confirmed via biological indexing using the indicator plants I. nil and I. muricata. Symptoms appeared more rapidly on I. muricata than on I. nil. Nucleotide polymorphisms among the isolates were evaluated by sequencing the AV1 coat protein gene from 24 SPLCV-infected accessions. The results revealed that the SPLCV isolates shared high sequence identity. Ten nucleotide substitutions were identified, most of which were synonymous changes. Phylogenetic analysis was conducted on those 24 SPLCV isolates in combination with six described SPLCV species and various SPLCV strains from GenBank to evaluate the relationships among viral species or strains. The results from this analysis indicated that most of the AV1 genes derived from previously classified SPLCV species clustered together, some of which formed well-supported monophyletic clades, further supporting the current taxonomy. Overall, identification of SPLCV-infected germplasm will allow approaches to be employed to eliminate the virus from the collection and limit the distribution of infected materials.

scholarly journals Conservation and Utilization of Livestock Genetic Diversity in the United States of America through Gene Banking

Diversity ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 244 ◽  
Author(s):  
Harvey D. Blackburn ◽  
Carrie S. Wilson ◽  
Bethany Krehbiel
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Agricultural Research ◽  
Germplasm Collection ◽  
The United States ◽  
United States Department ◽  
Livestock Sector ◽  
Wide Range ◽  
The Status ◽  
Span 60

A germplasm collection curated by the United States Department of Agriculture (USDA), Agricultural Research Service (ARS), National Animal Germplasm Program contains of over one million samples from over 55,000 animals, representing 165 livestock and poultry breeds. The collection was developed to provide genetic conservation and security for the U.S. livestock sector. Samples in the collection span 60 years, suggesting a wide range of genetic diversity and genetic change is represented for rare and major breeds. Classifying breeds into four groups based upon registration or census estimates of population size of < 1000, < 5000, < 20,000, and > 20,000 indicated that 50% of the collection is comprised of rare breeds in the < 1000 category. As anticipated, collections for breeds in the < 20,000 and > 20,000 are more complete (86% and 98%, respectively) based upon an index combining the number of germplasm samples and the number of animals. For the rarest breeds (< 1000), collection completeness was 45%. Samples from over 6000 animals in the collection have been used for adding diversity to breeds, genomic evaluation, reconstituting populations, or various research projects. Several aspects of collecting germplasm samples from rare breeds are discussed. In addition, approaches that could be used to enhance the status of rare breeds via the repository use are presented. However, given the array of obstacles confronting rare breeds, the gene bank may be the most secure prospect for the long-term conservation of rare breed genetics.

scholarly journals Elucidation of the Genome of Bradyrhizobium sp. Strain USDA 3456, a Historic Agricultural Diazotroph from Cowpea (Vigna unguiculata)

2019 ◽  
Vol 8 (33) ◽  
Author(s):  
Richard Allen White ◽  
Jeffrey S. Norman ◽  
Emily E. Mclachlan ◽  
Joseph P. Dunham ◽  
Aaron Garoutte ◽  
...  
Keyword(s):  
Vigna Unguiculata ◽  
Agricultural Research ◽  
Draft Genome ◽  
Germplasm Collection ◽  
The United States ◽  
United States Department ◽  
Content Type ◽  
Agricultural Applications ◽  
Bradyrhizobium Sp ◽  
Strain Usda

Bradyrhizobium sp. strain USDA 3456 is a historic strain from the United States Department of Agriculture (USDA) Agricultural Research Service (ARS) National Rhizobium Germplasm Collection isolated from Vigna unguiculata (cowpea) in 1966. Strain USDA 3456 has been utilized in global agricultural applications, including improving soil nitrogen fertility. The draft genome sequence here provides a genetic reference of a novel diazotroph.

Armillaria novae-zelandiae.

2021 ◽  
Author(s):  
Ian Hood
Keyword(s):  
Agricultural Research ◽  
Disease Risk ◽  
Nutrient Recycling ◽  
The United States ◽  
Laboratory Culture ◽  
Root Disease ◽  
White Rot ◽  
United States Department ◽  
Planted Forests ◽  
Global Database

Abstract Armillaria novae-zelandiae is a white rot wood decay fungus and root disease pathogen that occurs in a number of countries in the Southern Hemisphere and in parts of tropical and subtropical Asia. It is not known to have been introduced to these regions, where it is presumed to be indigenous. Its designation as "invasive" is based on its propensity to establish colonies and disease centres in disease-free areas by dispersal of basidiospores from "toadstool" fruit bodies that appear on wood during the winter months. As a wood decomposer fungus A. novae-zelandiae contributes beneficially to carbon and nutrient recycling. Like many other Armillaria species it is recognized by characteristic white mycelial fans or ribbons produced beneath host bark and by its bootlace-like rhizomorphs by which it spreads vegetatively from colonized buried woody material or stump root systems to infect living host plants.Armillaria novae-zelandiae was the cause of substantial disease losses in plantations of Pinus radiata and orchards of kiwifruit vines (Actinidia deliciosa) in New Zealand from the 1970s to the 1990s. Its importance has since declined with changes in patterns of crop management, although it remains widely distributed. Much research into its control was undertaken during this period. In eastern states in Australia, A. novae-zelandiae is a minor cause of root disease in natural and planted forests, where it is of lesser importance than Armillaria luteobubalina. Its impact in other regions is unknown, but it has not been associated with reports of significant disease. Risk of unintended international spread appears to be low to negligible but should not be discounted. If intercepted, isolates of A. novae-zelandiae may be identified by laboratory culture testing or more rapidly and precisely by molecular sequencing procedures. A. novae-zelandiae is listed in the EPPO Global Database and features in the United States Department of Agriculture Agricultural Research Service fungal databases. It is considered a risk organism in Hawai'i.

scholarly journals Advances in fruit breeding in Nepal

2020 ◽  
Vol 3 (1) ◽  
pp. 301-319
Author(s):  
Tek P Gotame ◽  
Ishwori P Gautam ◽  
Surendra L Shrestha ◽  
Jiban Shrestha ◽  
Bal Krishna Joshi
Keyword(s):  
Fruit Development ◽  
Agricultural Research ◽  
National Level ◽  
Germplasm Collection ◽  
Gene Bank ◽  
Special Focus ◽  
Research Station ◽  
Fruit Breeding ◽  
Tropical Fruit ◽  
Protocol Standardization

Nepal has spent about six decades on fruit development and research in different species. Fruit breeding particularly local and exotic germplasm collection started after 1950s and has gained momentum after the formation of commodity programme in 1972 AD. Major researches in the past were focused on indigenous and exotic genotype collection, evaluation, selection, propagation protocol standardization and adoptive trials. Some good ground works have already been done in major fruits such as apple, pear, plum, persimmon, kiwifruit, citrus, litchi, guava, pomegranate, walnut, papaya, banana and mango. The major public institutions involved in fruit breeding are Nepal Agricultural Research Council (NARC) following Agriculture and Forestry University. Some of the private nurseries like Everything Organic Nursery, Kavre and Technology Demonstration Centre of ICIMOD, Lalitpur were also involved in introduction and maintenance of indigenous and exotic fruit species. National Centre for Fruit Development, Kirtipur; Tropical Region Horticulture Centre, Nawalpur; Temperate Horticulture Farm, Satbanj, and Horticulture Farm, Marpha collected many local and exotic fruits and maintained at field gene bank. Horticulture Research Station, Rajikot has introduced 25 spur type apple cultivars and maintained in field gene bank. National Citrus Research Programme, Paripatle has introduced, collected and maintained 130 genotypes including exotic and indigenous landraces of citrus. Two varieties of acid lime ‘Sunkagati-1’ and ‘Sunkagati-2’ have been released and one variety ‘Terhathum Local’ has been registered. ‘Khoku Selection’ of mandarin orange has also been registered. Banana varieties 'Malbhog', 'Willium Hybrid' and 'G9' has been selected by participatory varietal selection and registered.  To strengthen fruit breeding in the nation, NARC needs to be restructured with special focus on fruit researches. Establishment of national fruit commodity programs along with establishment of Tropical Fruit Research Station in Province 2 and Temperate Fruit Research Station in Province 5 at national level can streamline NARC's fruit breeding researches.

scholarly journals Incidence and Severity of Cavity Spot of Carrot as Affected by Pigmentation, Temperature, and Rainfall

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 929-936 ◽  
Author(s):  
C. Saude ◽  
P. W. Simon ◽  
M. R. McDonald
Keyword(s):  
Agricultural Research ◽  
Disease Incidence ◽  
Secondary Infection ◽  
Organic Soil ◽  
The United States ◽  
Field Trials ◽  
United States Department ◽  
Breeding Line ◽  
Total Rainfall ◽  
Cavity Spot

Field trials to determine the effect of carrot pigmentation and weather parameters on cavity spot (CS) of carrot were conducted in the Holland/ Bradford Marsh region of Ontario between 2002 and 2009. In all, 23 colored carrot cultivars from the United States Department of Agriculture (USDA) Agricultural Research Service breeding program at the University of Wisconsin (n = 5) and commercial seed companies (n = 18) were seeded in organic soil (pH 6 to 7, 45 to 75% organic matter) in late May to early June and harvested in late October or early November. Carrot roots were assessed for CS severity midseason and postharvest. Evaluations postharvest indicated that the purple pigmented carrot from breeding line ‘USDA 106-3’ and cultivars ‘Purple Rain’ and ‘Purple Haze’ consistently had low CS severity. The orange-pigmented ‘USDA 101-23’, ‘Cellobunch’, ‘YaYa’, and ‘Envy’ had moderate CS; and the red-pigmented carrot breeding line ‘USDA 104-3’ and cultivars ‘Atomic Red’, ‘Proline Red’, ‘Dragon’, and an unnamed line from India had high CS. Differences in CS severity in carrot cultivars between evaluations at midseason and postharvest suggest that some carrot cultivars are more susceptible to Pythium spp. inoculum in soil (alloinfection) and others to secondary infection (autoinfection) that can be attributed to the Pythium sp. involved in CS. CS severity was positively correlated with total rainfall 2 and 3 months after seeding, and was negatively correlated with number of days with air temperature ≥30°C 3 and 4 months after seeding. Soil temperature and total rainfall were the best predictors of CS incidence and severity. These results could allow a forecast of disease incidence and severity at harvest.

Wingnut (Juglandaceae) as a new generic host forPityophthorus juglandis(Coleoptera: Curculionidae) and the thousand cankers disease pathogen,Geosmithia morbida(Ascomycota: Hypocreales)

2015 ◽  
Vol 148 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Stacy M. Hishinuma ◽  
Paul L. Dallara ◽  
Mohammad A. Yaghmour ◽  
Marcelo M. Zerillo ◽  
Corwin M. Parker ◽  
...  
Keyword(s):  
United States ◽  
Los Angeles ◽  
United States Of America ◽  
Agricultural Research ◽  
The United States ◽  
United States Department ◽  
Department Of Agriculture ◽  
Geosmithia Morbida ◽  
Thousand Cankers Disease ◽  
First Occurrence

AbstractThe walnut twig beetle (WTB),Pityophthorus juglandisBlackman (Coleoptera: Curculionidae), vectors a fungus,Geosmithia morbidaKolařík, Freeland, Utley, and Tisserat (Ascomycota: Hypocreales), which colonises and kills the phloem of walnut and butternut trees,JuglansLinnaeus (Juglandaceae). Over the past two decades, this condition, known as thousand cankers disease (TCD), has led to the widespread mortality ofJuglansspecies in the United States of America. Recently the beetle and pathogen were discovered on severalJuglansspecies in northern Italy. Little is known about the extra-generic extent of host acceptability and suitability for the WTB. We report the occurrence of both the WTB andG. morbidain three species of wingnut,Pterocarya fraxinifoliaSpach,Pterocarya rhoifoliaSiebold and Zuccarini, andPterocarya stenopterade Candolle (Juglandaceae) growing in the United States Department of Agriculture-Agricultural Research Service, National Clonal Germplasm Repository collection in northern California (NCGR) and in the Los Angeles County Arboretum and Botanic Garden in southern California, United States of America. In two instances (once inP. stenopteraand once inP. fraxinifolia) teneral (i.e., brood) adult WTB emerged and were collected more than four months after infested branch sections had been collected in the field. Koch’s postulates were satisfied with an isolate ofG. morbidafromP. stenoptera, confirming this fungus as the causal agent of TCD in this host. A survey of the 37PterocaryaKunth accessions at the NCGR revealed that 46% of the trees had WTB attacks and/or symptoms ofG. morbidainfection. The occurrence of other subcortical Coleoptera associated withPterocaryaand the first occurrence of the polyphagous shot hole borer, a species nearEuwallacea fornicatusEichhoff (Coleoptera: Curculionidae), inJuglansare also documented.

Sign in / Sign up

Export Citation Format

Share Document