scholarly journals Genotyping of the Valencia Peanut Core Collection with a Molecular Marker Associated with Sclerotinia blight Resistance

2018 ◽  
Vol 45 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Kelly D. Chamberlin ◽  
Naveen Puppala

ABSTRACT Cultivated peanut, the second most economically important legume crop throughout the United States and the third most important oilseed in the world, is consistently threatened by various diseases and pests. Sclerotinia blight, (causal agents Sclerotinia sclerotiorum (S. sclerotiorum) and Sclerotinia minor Jagger (S. minor))is a major threat to peanut production in the Southwestern U.S., Virginia, and North Carolina and can reduce yield by up to 50% in severely infested fields. S. sclerotiorum has now been reported in areas of eastern New Mexico and west Texas where all U.S. grown Valencia peanuts are produced, commonly in organic cropping environments. Host plant resistance provides the most effective solution to managing Sclerotinia blight, especially in organic systems where pesticide use is not an option for disease control. To date, no Valencia cultivars with Sclerotinia blight resistance have been released. In this study, the Valencia peanut core germplasm collection was genotyped with a Simple Sequence Repeat (SSR) marker associated with Sclerotinia blight resistance in order to identify potential germplasm for use in breeding to develop Valencia peanut cultivars resistant to the disease. Thirty accessions from the Valencia peanut core collection have profiles consistent with other genotypes that exhibit less that 5% incidence of Sclerotinia blight under heavy disease pressure. The identified accessions, after field evaluation, may serve as potential sources of Sclerotinia blight resistance in Valencia peanut breeding programs.

2010 ◽  
Vol 37 (1) ◽  
pp. 1-11 ◽  
Author(s):  
J. P. Damicone ◽  
C. C. Holbrook ◽  
D. L. Smith ◽  
H. A. Melouk ◽  
K. D. Chamberlin

Abstract In 2001, entries from the peanut core collection, a subset of the USDA peanut germplasm collection, were planted in non-replicated plots in a field with a history of Sclerotinia blight caused by Sclerotinia minor. Variability existed among entries for reaction to Sclerotinia blight. Of the 744 entries evaluated, 11% had no disease, nearly 30% had <10% disease incidence, and only 21% had 50% disease incidence or more. Most of the resistant entries had an upright growth habit and were in early and mid-maturity groups. Many of the early maturing entries were susceptible to the foliar disease pepper spot which occurred throughout the study. Entries were selected for further evaluation in replicated plots based on a nil to low (<10%) incidence of Sclerotinia blight, adaptation and/or vigor, and other desirable characteristics such as an intermediate to prostrate growth habit and pepper spot resistance. Selected entries were retested in both 2002 and 2003 (n  =  62) and compared to resistant (Tamspan 90), moderately resistant (Tamrun 96), and susceptible (Okrun) reference cultivars. Most entries (55 in 2001 and 46 in 2003) had disease incidence less than Tamrun 96 and similar to Tamspan 90. In 2003 when disease incidence was highest, all 46 entries with resistant reactions similar to that of Tamspan 90 had erect plant growth habits except for entries 208 and 582 which were prostrate, and entries 273, 128, and 804 which were intermediate. Resistance to Sclerotinia blight and yield similar to Tamspan 90, plant habit, and/or reactions to pepper spot and web blotch were used to select the best entries. Entries 208, 128, 804, 582, and 273 combined resistance to Sclerotinia blight, pepper spot, and web blotch with less than erect growth habits. Entry 103 had good Sclerotinia blight resistance and yield, but an upright growth habit. Entry 92 had an upright growth habit and low yield, but good Sclerotinia blight resistance. Entries 92 and 103 had upright growth habits but were among the best entries for resistant to pepper spot and web blotch. Entries 426, 184, and 562 were upright and susceptible to pepper spot, but had resistance to web blotch and the best resistance to Sclerotinia blight. These entries appear to be useful sources of resistance to Sclerotinia blight for breeding programs and for increasing the probability of finding additional sources of resistance in clusters of germplasm identified within the entire USDA collection.


Crop Science ◽  
1994 ◽  
Vol 34 (1) ◽  
pp. 279-285 ◽  
Author(s):  
Noa Diwan ◽  
Gary R. Bauchan ◽  
Marla S. McIntosh

2020 ◽  
Vol 47 (1) ◽  
pp. 9-16
Author(s):  
K.D. Chamberlin ◽  
J.J. Baldessari ◽  
E.M.C. Mamani ◽  
M.V. Moreno

ABSTRACT Cultivated peanut, the third most important oilseed in the world, is consistently threatened by various diseases and pests. Sclerotinia minor Jagger (S. minor), the causal agent of Sclerotinia blight, is a major threat to peanut production in many countries and can reduce yield by up to 50% in severely infested fields. Host plant resistance will provide the most effective solution to managing Sclerotinia blight, but limited sources of resistance to the disease are available for use in breeding programs. Peanut germplasm collections are available for exploration and identification of new sources of resistance, but traditionally the process is lengthy, requiring years of field testing before those potential sources can be identified. Molecular markers associated with phenotypic traits can speed up the screening of germplasm accessions. The objective of this study was to genotype the peanut core collection of the Instituto Nacional de Tecnología Agropecuaria (INTA) Manfredi, Argentina, with a molecular marker associated with Sclerotinia blight resistance. One hundred and fifty-four (154) accessions from the collection were available and genotyped using the Simple Sequence Repeat (SSR) marker. Accessions from each botanical variety type represented in the core collection were identified as new potential sources of resistance and targeted for further evaluation in field tests for Sclerotinia blight resistance.


2020 ◽  
Vol 10 (11) ◽  
pp. 4013-4026
Author(s):  
Paul I. Otyama ◽  
Roshan Kulkarni ◽  
Kelly Chamberlin ◽  
Peggy Ozias-Akins ◽  
Ye Chu ◽  
...  

Cultivated peanut (Arachis hypogaea) is an important oil, food, and feed crop worldwide. The USDA peanut germplasm collection currently contains 8,982 accessions. In the 1990s, 812 accessions were selected as a core collection on the basis of phenotype and country of origin. The present study reports genotyping results for the entire available core collection. Each accession was genotyped with the Arachis_Axiom2 SNP array, yielding 14,430 high-quality, informative SNPs across the collection. Additionally, a subset of 253 accessions was replicated, using between two and five seeds per accession, to assess heterogeneity within these accessions. The genotypic diversity of the core is mostly captured in five genotypic clusters, which have some correspondence with botanical variety and market type. There is little genetic clustering by country of origin, reflecting peanut’s rapid global dispersion in the 18th and 19th centuries. A genetic cluster associated with the hypogaea/aequatoriana/peruviana varieties, with accessions coming primarily from Bolivia, Peru, and Ecuador, is consistent with these having been the earliest landraces. The genetics, phenotypic characteristics, and biogeography are all consistent with previous reports of tetraploid peanut originating in Southeast Bolivia. Analysis of the genotype data indicates an early genetic radiation, followed by regional distribution of major genetic classes through South America, and then a global dissemination that retains much of the early genetic diversity in peanut. Comparison of the genotypic data relative to alleles from the diploid progenitors also indicates that subgenome exchanges, both large and small, have been major contributors to the genetic diversity in peanut.


Author(s):  
Ze Peng ◽  
Huiqiong Chen ◽  
Lubin Tan ◽  
Hongmei Shu ◽  
Rajeev K Varshney ◽  
...  

Abstract Microbial symbiosis in legumes is achieved through nitrogen-fixing root nodules, which is important for sustainable agriculture. The molecular mechanisms underlying development of root nodules in polyploid legume crops are largely understudied. Through map-based cloning and QTL-seq approaches, we identified a pair of homoeologous GRAS transcription factor genes, Nodulation Signaling Pathway 2 (AhNSP2-B07 or Nb) and AhNSP2-A08 (Na), controlling nodulation in cultivated peanut (Arachis hypogaea L.), an allotetraploid legume crop, which exhibited non-Mendelian and Mendelian inheritance, respectively. The segregation of nodulation in the progeny of Nananbnb genotypes followed a 3:1 Mendelian ratio, in contrast to the 5:3 ~ 1:1 non-Mendelian ratio for nanaNbnb genotypes. Additionally, a much higher frequency of the nb allele (13%) than the na allele (4%) exists in the peanut germplasm collection, suggesting that Nb is less essential than Na in nodule organogenesis. Our findings provided the genetic basis of naturally occurred non-nodulating peanut plants, which can be potentially used for nitrogen fixation improvement in peanut. Furthermore, the results provided implications and insights into the evolution of homoeologous genes in allopolyploid species.


Crop Science ◽  
2018 ◽  
Vol 58 (3) ◽  
pp. 1306-1317 ◽  
Author(s):  
Rebecca S. Bennett ◽  
Kelly D. Chamberlin ◽  
John P. Damicone

2014 ◽  
Vol 41 (1) ◽  
pp. 42-49 ◽  
Author(s):  
K. D. Chamberlin

ABSTRACT Cultivated peanut, the second most economically important legume crop throughout the United States and the third most important oilseed in the world, is consistently threatened by various diseases and pests. Sclerotinia minor Jagger (S. minor), the causal agent of Sclerotinia blight, is a major threat to peanut production in the Southwestern U.S., Virginia, and North Carolina and can reduce yield by up to 50% in severely infested fields. Although host plant resistance would provide the most effective solution to managing Sclerotinia blight, limited sources of resistance to the disease are available for use in breeding programs. Peanut germplasm collections are available for exploration and identification of new sources of resistance, but traditionally the process is lengthy, requiring years of field testing before those potential sources can be identified. Molecular markers associated with phenotypic traits can speed up the screening of germplasm accessions. The objective of this study was to characterize the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) mini-core collection with regards to a molecular marker associated with Sclerotinia blight resistance. One hundred twenty-four (124) accessions from the collection were available and genotyped using the SSR marker and 67 were identified as potential new sources of resistance and targeted for further evaluation in field tests for Sclerotinia blight resistance.


2001 ◽  
Vol 28 (2) ◽  
pp. 84-89 ◽  
Author(s):  
C. C. Holbrook

Abstract An extensive working collection of Arachis germplasm is maintained by the USDA at the Southern Regional Plant Introduction Sta. in Griffin, GA. Much of this collection is maintained also under long-term seed storage at the Nat. Seed Storage Lab. in Ft. Collins, CO. The working collection consists of 9027 accessions of A. hypogaea and 684 accessions of Arachis species. About half of the A. hypogaea accessions are unimproved landraces collected in the crop's centers of diversity in South America. The other half is comprised of germplasm obtained from countries outside of South America. The U.S. germplasm collection of peanut was the first major germplasm collection to have a working core collection. Research has verified that this core collection can be used to improve the efficiency of germplasm utilization. This has stimulated a great amount of germplasm evaluation work and has resulted in the identification of numerous sources of resistance to several economically significant pathogens. Considerable efforts in the U.S. also have been devoted to the use of wild species of Arachis for sources of resistance to pathogens. Programs are ongoing to introgress high levels of resistance or immunity to early (Cercospora arachidicola Hori) and late (Cercosporidium personatum Berk. & M.A. Curtis) leaf spots, nematodes, and viruses. Genetic resources have been particularly useful in adding disease resistance to peanut cultivars. This has had a significant economic impact on U.S. peanut farmers. The largest impacts have been from the development of cultivars with resistance to Sclerotinia blight (Sclerotinia minor Jagger), the peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1], and tomato spotted wilt Tospovirus. Use of these resistant cultivars has an estimated economic impact of more that $200 million annually for U.S. peanut producers.


2021 ◽  
pp. 014556132110376
Author(s):  
Wei Wang ◽  
Xinxin Dong ◽  
Jianwen Qu ◽  
Yangyang Lin ◽  
Lei Liu

Objective: Microtia is a congenital auricular malformation with a hypoplastic external ear that ranges in severity from a slightly smaller auricle to complete the absence of the auricle. The present study was conducted to identify and analyze the characteristics of microtia-related articles published from 2006 to 2020 by using bibliometric analyses. Method: Microtia-related studies published from 2006 to 2020 were retrieved from the Web of Science Core Collection database. Keywords, first author, citations, date of publication, and publication journal were extracted and quantitatively analyzed using Bibliographic Item Co-Occurrence Matrix Builder software and the Bibliometric ( https://bibliometric.com/app ). VOSviewer was used to visualize research and form a network map on keywords and citations. Results: A total of 1031 articles from 2006 to 2020 were included. The number of articles showed an overall trend of growth over time. The United States and China are the top 2 countries in terms of the number of microtia-related articles. From the analysis of keyword clustering, keywords could be mainly divided into 4 clusters in the field of microtia research: surgery, tissue engineering, epidemiology, and rehabilitation including hearing-related treatments, evaluation of effects, and quality of life after surgery. The top 10 most frequently cited papers from 2006 to 2020 were also extracted and analyzed. Conclusion: A bibliometric research of microtia-related articles from 2006 to 2020 was conducted. This study may be helpful to understand the current research status of microtia and find the research trends in this field, thus proposing future directions for microtia research.


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