Phenetic relationships among different races of Striga gesnerioides (Willd.) Vatke from West Africa

Genome ◽  
2006 ◽  
Vol 49 (11) ◽  
pp. 1351-1365 ◽  
Author(s):  
Christopher J. Botanga ◽  
Michael P. Timko
Keyword(s):  
Genetic Variability ◽  
West Africa ◽  
Profile Analysis ◽  
Differential Resistance ◽  
Clustering Methods ◽  
Resistance Response ◽  
Breeding Lines ◽  
Root Hemiparasite ◽  
Striga Gesnerioides ◽  
Phenetic Relationships

Striga gesnerioides is a root hemiparasite that primarily parasitizes dicotyledonous species, including cowpea ( Vigna unguiculata L.) and other legumes. Based on the differential resistance response of various cultivars, landraces, and breeding lines, it has been proposed that several distinct races of cowpea-parasitic S. gesnerioides exist in West Africa. In this study, we used amplified fragment length polymorphism profile analysis to examine the genetic variability within and among populations of cowpea-parasitic S. gesnerioides within the suspected distribution range of a particular race, and statistical clustering methods to define the phenetic relationships of the various races in West Africa. Our data indicate that genetic variability within and among populations of each of the previously recognized races of cowpea-parasitic S. gesnerioides is extremely low. On the basis of genotypic profile and host differential resistance responses, 2 previously unknown races were identified. Of the 7 races now identifiable, races SG1 (from Burkina Faso) and SG5 (from Cameroon) are the most closely related, and SG4 (from Benin) and SG3 (from Niger/Nigeria) are the most divergent. SG6, a new race of the parasite identified in Senegal, was found to be the most genetically similar to SG4 from Benin. We also demonstrate that a hypervirulent isolate of the S. gesnerioides from Zakpota, in the Republic of Benin, is genotypically distinct from other populations of SG4, thereby warranting designation as a separate race, which we called SG4z. To further support our race classification scheme, we identified a group of molecular markers that effectively discriminate each of the various races. Finally, we show that an isolate (designated SG4i) of the wild legume Indigofera hirsuta –parasitic S. gesnerioides is genetically distinct and significantly diverged from the various races of cowpea-parasitic S. gesnerioides. Our data suggest that both geographic isolation and host-driven selection are critical factors defining race formation in S. gesnerioides in West Africa.

scholarly journals Race structure of cowpea witchweed (Striga gesnerioides) in West Africa and its implications for Striga resistance breeding of cowpea

Weed Science ◽  
2020 ◽  
Vol 68 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Erik W. Ohlson ◽  
Michael P. Timko
Keyword(s):  
West Africa ◽  
Resistance Genes ◽  
Broad Spectrum ◽  
Genetic Relatedness ◽  
Durable Resistance ◽  
Resistance Breeding ◽  
Differential Resistance ◽  
African Countries ◽  
Sources Of Resistance ◽  
Striga Gesnerioides

AbstractCowpea witchweed [Striga gesnerioides (Willd.) Vatke] is a primary constraint of cowpea [Vigna unguiculata (L.) Walp.] production in West Africa. Previously, seven S. gesnerioides races were classified based upon host specificity and genotypic profiling. Because race number and distribution are dynamic systems influenced by gene flow, genetic drift, and natural selection, a thorough investigation of S. gesnerioides diversity and the effectiveness of known sources of resistance in cowpea is needed to develop varieties with durable and broad-spectrum Striga resistance. In this study, we screened seven cowpea lines against 58 unique S. gesnerioides populations collected from across nine West African countries. Individuals from 10 S. gesnerioides populations were genotyped with simple sequence repeat (SSR) markers. We identified six races of S. gesnerioides based on their parasitism of the seven cowpea lines with known differential resistance genotypes. No cowpea line was resistant to all 58 Striga populations and none of the Striga populations were able to overcome the resistance of all seven lines. A novel race, SG6, of the parasite collected from Kudu, Nigeria, was found to overcome more cowpea resistance genes than any previously reported race. SSR analysis indicates that Striga populations are highly differentiated and genetic relatedness generally corresponds with geographic proximity rather than their host compatibility. Due to the dearth of broad-spectrum resistance found among Striga-resistant cowpea lines, there exists a need to stack multiple Striga resistance genes in order to confer broad-spectrum and durable resistance.

scholarly journals Genetic Structure and Analysis of Host and Nonhost Interactions of Striga gesnerioides (Witchweed) from Central Florida

2005 ◽  
Vol 95 (10) ◽  
pp. 1166-1173 ◽  
Author(s):  
Christopher J. Botanga ◽  
Michael P. Timko
Keyword(s):  
United States ◽  
Genetic Structure ◽  
West Africa ◽  
The United States ◽  
Genetic Distances ◽  
Polymorphism Analysis ◽  
Root Hemiparasite ◽  
Striga Gesnerioides ◽  
Central Florida ◽  
High Level

Striga gesnerioides is a root hemiparasite of wild and cultivated legumes, among which cowpea (Vigna unguiculata) and Indigofera hirsuta are suitable hosts. In this study, we examined the genetic structure and host-parasite interaction of a strain of S. gesnerioides parasitizing I. hirsuta (SGFL) from central Florida (United States). Amplified fragment length polymorphism analysis was used to compare genetic profiles from 71 individual S. gesnerioides plants (SGFL) representing four different populations in central Florida. Our results showed that these individuals are genetically similar, with pairwise genetic distances ranging from 0.00 to 0.037. A cluster analysis grouped all four S. gesnerioides populations from Florida, separating them from S. gesnerioides isolates parasitic on I. hirsuta and cowpea collected from West Africa. One EcoRI and MseI selective primer combination generated a 510-bp fragment present in individuals from the SGFL and the West African isolate parasitic on I. hirsuta, but absent in isolates parasitic on cowpea. Germination of seed from individuals of all four populations of S. gesnerioides parasitic on I. hirsuta from Florida was stimulated by root exudates from cowpea genotypes Blackeye and TVX-3236, known to be highly susceptible to all races of S. gesnerioides parasitic on cowpea in West Africa. SGFL seedlings failed to parasitize cowpea, with the development of attached SGFL seedlings arrested at the tubercle stage. The very high level of genetic uniformity observed within and among the central Florida populations suggests that there was likely a single introduction of the parasite or strong host-driven selection to genetic uniformity.These findings are important in assessing the potential of the parasite as an agronomically significant pest in the United States.

Characterization of Resistance of Peanut to Puccinia arachidis

2013 ◽  
Vol 14 (1) ◽  
pp. 31 ◽  
Author(s):  
Imana L. Power ◽  
Albert K. Culbreath ◽  
Barry L. Tillman
Keyword(s):  
Genetic Variability ◽  
Ssr Markers ◽  
Collaborative Research ◽  
Field Studies ◽  
The United States ◽  
Breeding Lines ◽  
Plant Introductions ◽  
Puccinia Arachidis ◽  
Arachis Hypogaea L

Peanut rust, caused by Puccinia arachidis Speg, is an important foliar disease of peanut (Arachis hypogaea L.) in tropical countries. The best option for disease management is host resistance. The objectives of this project included characterizing peanut genotypes for resistance to P. arachidis, assessing the genetic variation of newly developed Collaborative Research and Support Program (CRSP) peanut breeding lines, and assessing genetic variability among P. arachidis populations. In field studies conducted over 2010-2011, several CRSP breeding lines demonstrated varying levels of rust resistance. Detached leaf assays were used to examine the components of resistance to P. arachidis. Few significant differences were observed in these studies. We used SSR markers to characterize newly developed CRSP breeding lines, plant introductions, and commonly grown cultivars. The SSR markers used detected polymorphisms but were not able to distinguish resistant from susceptible peanut genotypes. Sequences of the 5.8S-ITS2-28S region of P. arachidis isolates collected from different regions in the United States and other countries do not indicate high genetic variability among the populations. Accepted for publication 23 September 2013. Published 25 November 2013.

Genetic Variability for Pod Yield and Component Traits in Sugar Snaps (Pisum sativum var. saccharatum)

2020 ◽  
Author(s):  
Ajay Chauhan ◽  
Akhilesh Sharma ◽  
Parveen Sharma ◽  
Viveka Katoch ◽  
Sanjay Chadha ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Block Design ◽  
Internodal Length ◽  
Breeding Lines ◽  
Pod Yield ◽  
Horticultural Traits ◽  
Component Traits ◽  
Additive Gene ◽  
High Heritability ◽  
Positive Direct

Background: Edible podded pea is an oriental vegetable crop which shares the cultivation pattern with the garden pea. Fresh tender pods lacking parchment layer are consumed whole like beans. It is a newly introduced crop in India and therefore, it would be imperative to identify the most promising genotypes vis-à-vis traits of interest, those contributing towards maximization of yield. The present investigation was, therefore, planned to assess the genetic parameters of variability for pod yield and related horticultural traits in order to identify the most promising edible pod pea genotypesMethods: Thirty six genotypes comprising of 29 F7 advanced breeding lines and nine lines from different institutes including three checks namely, ‘Arka Apoorva’, ‘Arka Sampoorna’ and ‘Mithi Phali’ were evaluated in randomized complete block design over three replications during winters 2016-2017 at C.S.K. Himachal Pradesh Krishi Vishvavidyalaya, Palampur for pod yield and related horticultural traits.Result: Sufficient genetic variability was observed for all morphological and yield contributing attributes. The magnitude of phenotypic (PCV) and genotypic (GCV) coefficients of variation were high for pod yield while branches per plant, internodal length, harvest duration and pods per plant showed high PCV and moderate GCV. High heritability along with high genetic advance was observed for internodal length, plant height, average pod weight and pod yield per plant indicating the importance of additive gene action. Pod yield per plant revealed positive correlation at both phenotypic and genotypic levels with pods per plant, average pod weight, pod length and pod breadth. Pods per plant and average pod weight at both phenotypic and genotypic levels had maximum positive direct and indirect effects to the total association of component traits suggesting the importance of these traits towards pod yield. 

scholarly journals GENETIC VARIABILITY FOR GRAIN NUTRIENTS CONTENT IN COASTAL RICE COLLECTIONS OF BANGLADESH

2021 ◽  
Vol 9 (11) ◽  
pp. 182-201
Author(s):  
F Shahrin ◽  
P Roy ◽  
M S Raihan ◽  
M M Haque ◽  
M G Rasul
Keyword(s):  
Genetic Variability ◽  
Grain Yield ◽  
Rice Grain ◽  
Clustering Methods ◽  
Gene Effects ◽  
Mean Values ◽  
Nutrient Contents ◽  
Additive Gene ◽  
High Heritability ◽  
Rice Genotypes

Overcoming malnutrition through biofortification breeding in rice is aimed to assist nutritional food security in Bangladesh. So to select parents for nutritional improvement, estimation and exploitation of mineral nutrients reserves of rice grain and their variability assessment in different genotypes is essential. Eighty-five (85) T. aman rice genotypes collected from different coastal regions of Bangladesh were evaluated at the Advanced Plant Breeding laboratory, GPB of BSMRAU to estimate the grain nutrients content and to elucidate their genetic variability among the genotypes. Considerable significant variation (0.1% level of probability) was noted among the genotypes for studied different grain nutrient contents and yield per hill. The mean values of N, P, K, Ca, Mg, Na, Zn, Fe, Cu, Mn and grain yield/ hill were 10788.24 mg/kg, 804.85 mg/kg, 3798.58 mg/kg, 13795.29 mg/kg, 2778.87 mg/kg, 3771.17 mg/kg, 7.25 mg/kg, 5.01 mg/kg, 1.05 mg/kg, 1.90 mg/kg and 433.29 g, respectively. Box and whisker plots analysis were done to represent data graphically for better understanding. Histogram was used to present the frequency distribution of genotypes for N, P, K, Ca, Mg, Na, Zn, Fe, Cu, Mg and Grain yield/hill content in 85 diverged rice genotypes All the traits had equality in genotypic and phenotypic variances with high heritability and high genetic advance which indicated preponderance of additive gene effects for these traits. The genotype R080 (Chinigura) contained the highest content of grain P, Fe and Cu. The R030 (Mota Dhan), R040 (Dudh Kalam) and R019 (Chikon Dhan) were noted for the highest Ca, Mg and Na content, respectively. The maximum N and Zn content were observed in R029 (Dudh Kolom) and R075 (Gopal Bogh), respectively. R083 (Lal Dhan) was marked for the highest grain yield/ hill and K content. Genetic variability parameters, heat map analysis and neighbor joining clustering methods indicated these genotypes including R079 can be considered for biofortification program and used as parents for the improvement of those grain nutrients in rice breeding.

scholarly journals Yield and physicochemical quality of Physalis peruviana L. fruit related to the resistance response against Fusarium oxysporum f. sp. physali

2019 ◽  
Vol 37 (2) ◽  
pp. 120-128
Author(s):  
Franklin Mayorga-Cubillos ◽  
Jorge Argüelles-Cárdenas ◽  
Edwin Rodríguez-Velásquez ◽  
Carolina González-Almario ◽  
Claudia Ariza-Nieto ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Crop Improvement ◽  
Physicochemical Characterization ◽  
Principal Component ◽  
Differential Resistance ◽  
Resistance Response ◽  
Physalis Peruviana ◽  
Fruit Cracking ◽  
Medicinal Value ◽  
Cape Gooseberry

Cape gooseberry (Physalis peruviana L.) is a fruit of great interest, due to its high nutritional and potential medicinal value. Vascular wilt disease caused by the fungus Fusarium oxysporum f. sp. Physali (Foph) is responsible for crop losses of up to 100% which makes necessary to identify resistant cultivars. To contribute to crop improvement processes, a physicochemical characterization was performed on fruits of 33 cape gooseberry genotypes using 18 quantitative descriptors. The genotypes were planted in the field under high and no pressure of Foph. The Student’s t test detected statistically significant differences (P<0.05) between the two conditions for yield, fruit cracking (%) and fruit juice pH. The principal component analysis explained in five factors 84.96% of the total variance, in which the fruit physical variables were the major contributor to the first component (41.65%). Cluster analysis grouped the genotypes under high and no pressure in seven and eight clusters, respectively. Two contrasting genotypesshowing differential resistance response to the pathogen wereanalyzed for fruit antioxidant capacity, in which DPPH and ORAC methods presented significant differences (P<0.05) between the two genotypes with greater antioxidant activity in the susceptible material.

Reaction of Selected Peanut Varieties and Breeding Lines to Southern Stem Rot1

1997 ◽  
Vol 24 (1) ◽  
pp. 6-9 ◽  
Author(s):  
B. A. Besler ◽  
W. James Grichar ◽  
O. D. Smith
Keyword(s):  
Disease Resistance ◽  
West Africa ◽  
Burkina Faso ◽  
Disease Incidence ◽  
Sclerotium Rolfsii ◽  
Field Conditions ◽  
Breeding Line ◽  
Breeding Lines ◽  
Yield Increase

Abstract Eight Texas and one Georgia breeding lines, four accessions from Burkina Faso (West Africa), and six runner and two spanish-type cultivars were compared for yield, grade, and susceptibility to Sclerotium rolfsii Sacc. for 3 yr under irrigated field conditions. The spanish-type cultivar Tamspan 90 and runner-type breeding line TX896100 (recently released as Tamrun 96) consistently had the lowest disease incidence for all 3 yr. Averaged over years, TX896100 was the highest yielding entry. Four breeding lines resulted in a 2 to 16% yield increase over Okrun, the highest yielding cultivar. The African accessions, in general, produced low yields and low grades with no advantages in disease resistance.

Genetic and cytogenetic analyses of the A genome of Triticum monococcum L. V. Inheritance and linkage relationships of genes determining the expression of 12 qualitative characters

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 869-881 ◽  
Author(s):  
J. Kuspira ◽  
J. Maclagan ◽  
R. N. Bhambhani ◽  
R. S. Sadasivaiah ◽  
N.-S. Kim
Keyword(s):  
Triticum Aestivum ◽  
Genetic Variability ◽  
Major Gene ◽  
Morphological Characters ◽  
Triticum Monococcum ◽  
Chromosomal Mapping ◽  
Allelic Series ◽  
Einkorn Wheat ◽  
Breeding Lines ◽  
A Genome

Our investigation of 460 true-breeding lines confirms a long-standing observation that natural phenotypic and genetic variability in the diploid wheat Triticum monococcum L. is limited. The modes of inheritance of 12 morphological characters are discussed in light of the extensive information available on the genetics and cytogenetics of many of these characters in the related wheat Triticum aestivum. Analysis of data from appropriate crosses, complementation studies, and observations of phenotypes of F1s and F2s from crosses between lines expressing dominant traits indicate that each of these characters is determined by one major gene. A multiple allelic series exists at each of the Hg (glume pubescence) and Hn (node pubescence) loci. The genes for six of these characters fall into two closely linked groups. Genes Bg (glume colour) and Hg are the same distance apart as in Triticum aestivum, indicating that at least this segment of chromosome 1A has been highly or completely conserved since the origin of the polyploid wheats. The genes Sg (glume hardness), La (lemma awn length), Fg (false glume), and Lh (head type) are also very closely linked, with the outside markers being only 4 map units apart. The dominant and recessive alleles of genes determining these characters should serve as excellent markers for linkage and chromosomal mapping because of their complete penetrance and constant expressivity. Tentative assignments of genes and linkage groups identified in this investigation to specific chromosomes of T. monococcum have been made on the basis of known chromosomal locations of A genome genes in T. aestivum. The tentative assignments could be verified using a variety of genetic and cytogenetic approaches. It is suggested that a thorough study of the genetic heritage of einkorn wheat will require the use of induced mutants since natural genetic variability is low in this species.Key words: Triticum, characters, inheritance, linkage, mapping, A genome.

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