Inheritance of scald resistance in barley. II.* Resistance genes of group B barley cultivars

1975 ◽  
Vol 26 (2) ◽  
pp. 251 ◽  
Author(s):  
SM Ali
Keyword(s):  
Environmental Factors ◽  
Resistance Genes ◽  
Genetic Basis ◽  
Rhynchosporium Secalis ◽  
Inheritance Of Resistance ◽  
West China ◽  
Barley Cultivars ◽  
Group B

The genetic basis of resistance to Rhynchosporium secalis (Oud.) Davis of barley cultivars La Mesita, West China and Sakigake differentiated as group B were determined from F2, F3 and BC1 progenies. The resistance genes identified are situated at different loci from each other. The effectiveness of the identified resistance genes to two isolates of Rhynchosporium secalis was studied under glasshouse conditions in winter and in summer, and also in the field. The inheritance of resistance genes of group B cultivars was found to be greatly influenced by environmental factors. *Part I, Aust. J. Agric. Res., 26: 243 (1975).

Inheritance of scald resistance in barley. I. Resistance of genes of group A barley cultivars

1975 ◽  
Vol 26 (2) ◽  
pp. 243 ◽  
Author(s):  
SM Ali
Keyword(s):  
Western Australia ◽  
Resistance Genes ◽  
Genetic Basis ◽  
Rhynchosporium Secalis ◽  
Common Gene ◽  
Resistant Cultivars ◽  
Barley Cultivars ◽  
Group A ◽  
The Common

The genetic basis of resistance and susceptibility of barley cultivars to Rhynchosporium secalis (Oud.) Davis was determined from F2 and F3 progenies of crosses among five resistant and four susceptible cultivars. The resistant cultivars Psaknon, Atlas 46, Atlas 57, Hudson and Turk were found to share a common gene in addition to other genes for resistance. No race of the pathogen found in Western Australia was able to overcome the resistance conferred by the common gene. The effectiveness of the identified resistance genes to two isolates of R. secalis was studied under glasshouse conditions in winter and summer, and in the field during winter.

Barley grass as a source of pathogenic variation in Rhynchosporium secalis

1981 ◽  
Vol 32 (1) ◽  
pp. 21 ◽  
Author(s):  
SM Ali
Keyword(s):  
Resistance Genes ◽  
Genetic Basis ◽  
Rhynchosporium Secalis ◽  
Pathogenic Variation ◽  
Pathogenic Variability ◽  
F2 Progeny

The pathogenic variability of 150 isolates of Rhynchospovium secalis collected in southern Australia was examined on 20 biotypes of barley grass (Hordeum lepovinum). The isolates were differentiated into 20 pathotypes on the basis of the reactions of the barley grass. The genetic basis of resistance and susceptibility of barley grass to R. secalis was determined from F2 progeny of crosses among three resistant and two susceptible biotypes of barley grass. The resistance genes identified were all dominant.

scholarly journals Inheritance of Resistance to Iron Deficiency in Cowpea

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 841F-841
Author(s):  
H.M. Cortinas-Escobar ◽  
Douglas C. Scheuring ◽  
Thomas J. Gerik ◽  
J. Creighton Miller
Keyword(s):  
Iron Deficiency ◽  
Environmental Factors ◽  
Genetic Basis ◽  
Maternal Inheritance ◽  
Calcareous Soils ◽  
Inheritance Of Resistance ◽  
Chi Square ◽  
Reciprocal Crosses ◽  
Chi Square Analysis ◽  
Made In

Cowpea [Vigna unguiculata (L.) Walp.] cultivars differ in their response to iron deficiency when grown on calcareous soils. This response is influenced by environmental factors such as soil pH, soil texture, presence of bicarbonates, and temperature. The objective of this study was to determine the genetic basis for resistance to iron deficiency in cowpea. Crosses of `Texas Pinkeye Purple Hull' (resistant) and `Pinkeye Purple Hull' (susceptible) were made in the greenhouse during Spring 1994, and F2 seeds were obtained in the summer. Reciprocal crosses were made in order to test for maternal effects. Seed of the parental, F1, and F2 generations were planted near Temple, Texas, during Fall 1994. The color (greenness) of 1031 F2 plants was measured using a chlorophyll meter (Minolta SPAD-502) 35 days after planting. Chi-square analysis showed a good fit to a 3:1 ratio of susceptible: resistant plants. These results suggest simple inheritance of the response to iron deficiency in cowpea. Similar segregation of the reciprocal crosses indicated absence of maternal inheritance.

scholarly journals Pathogenic Variation in Rhynchosporium secalis on Barley in Ethiopia

2000 ◽  
Vol 5 (2) ◽  
pp. 75
Author(s):  
K. Meles ◽  
M. Hulluka ◽  
M.L. Deadman
Keyword(s):  
Resistance Genes ◽  
Geographical Location ◽  
Effective Resistance ◽  
Rhynchosporium Secalis ◽  
Malting Barley ◽  
Differential Host ◽  
Barley Cultivars ◽  
Pathogenic Variation ◽  
Pathogenic Variability

This paper presents the first detailed study on pathogenic variability in Rhynchosporium secalis in Ethiopia. Twenty four isolates of R. secalis, collected from Arsi, Bale and Shoa, major barley growing locations in Ethiopia, were tested on ten differential host cultivars, with known genes for resistance to the disease. The most frequent pathotypes were those inducing susceptible reactions on cvs Steudelli and Kitchen and the least complex pathotype identified was able to induce a susceptible reaction on these two cultivars only. Pathotypes 16 and 7 were the most complex and were able to induce susceptible reactions on 10 and 9 of the differential host cultivars respectively. These pathotypes were collected from research stations and were isolated from improved barley cultivars belonging to the malting barley type. The most frequent pathotype was pathotype 6 which was represented by four isolates from different locations in Arsi, Bale and Shoa. Pathogenic variation was detected amongst spores collected from the same field and from the same geographical location. The most effective resistance genes were those possessed by Turk, La-Mesita, Bey, Nigrinudum, Jet and Forrajera.   

Host range and physiologic specialization in Rhynchosporium secalis

1974 ◽  
Vol 25 (1) ◽  
pp. 21 ◽  
Author(s):  
SM Ali ◽  
WJR Boyd
Keyword(s):  
Genetic Diversity ◽  
Host Range ◽  
Environmental Conditions ◽  
Host Specialization ◽  
Rhynchosporium Secalis ◽  
Host Reaction ◽  
Genetic Studies ◽  
Barley Cultivars ◽  
Adequate Sampling ◽  
Pathogenic Variability

The pathogenic variability of isolates of R. secalis collected in Western Australia has been examined on different host genera of the Gramineae and on selected barley cultivars. Depending on the host-isolate combination and the conditions of the test, evidence has been obtained of inter- and intra-isolate variability in both host reaction and isolate pathogenicity. This complicates definitive interpretation of the results, militates against identification of conventional 'races' of the pathogen and shows that R. secalis does not exhibit strict host specialization. Hosts which consistently express resistance or susceptibility under different environmental conditions, and isolates which express their pathogenic characteristics consistently, have been identified. The need for more precise genetic studies and adequate sampling of genetic diversity is emphasized.

Seeds and seasons: interpreting germination timing in the field

2005 ◽  
Vol 15 (3) ◽  
pp. 175-187 ◽  
Author(s):  
Kathleen Donohue
Keyword(s):  
Environmental Factors ◽  
Genetic Basis ◽  
Genetic Material ◽  
Field Studies ◽  
Seed Maturation ◽  
Genetic Pathways ◽  
Ecological Conditions ◽  
Germination Phenology ◽  
Transgenic Lines ◽  
Germination Timing

This paper discusses how field and laboratory experiments, using a variety of genetic material, can be combined to investigate the genetic basis of germination under realistic ecological conditions, and it reviews some of our recent work on germination phenology ofArabidopsis thalianain the field. Our results indicate that the genetic basis of germination depends on the environment. In particular, the conditions during seed maturation interact with post-dispersal environmental factors to determine germination phenology, and these interactions have a genetic basis. Therefore genetic studies of germination need to consider carefully the environment – both during seed maturation and after dispersal – in which the experiments are conducted in order to characterize genetic pathways involved with germination in the field. Laboratory studies that explicitly manipulate ecologically relevant environmental factors can be combined with manipulative field studies. These studies can identify the particular environmental cues to which seeds respond in the field and characterize the genetic basis of germination responses to those cues. In addition, a variety of genetic material – including mutant and transgenic lines, intact natural genotypes, recombinant genotypes, and near isogenic lines – can be used in field studies as tools to characterize genetic pathways involved in germination schedules under natural ecological conditions.

scholarly journals The Molecular-Genetic Basis of Functional Hyperandrogenism and the Polycystic Ovary Syndrome

2005 ◽  
Vol 26 (2) ◽  
pp. 251-282 ◽  
Author(s):  
Héctor F. Escobar-Morreale ◽  
Manuel Luque-Ramírez ◽  
José L. San Millán
Keyword(s):  
Environmental Factors ◽  
Polycystic Ovary Syndrome ◽  
Diagnostic Criteria ◽  
Genetic Basis ◽  
Polycystic Ovary ◽  
Molecular Genetic ◽  
Ovary Syndrome ◽  
The Metabolic Syndrome ◽  
Molecular Genetic Basis ◽  
Functional Hyperandrogenism

The genetic mechanisms underlying functional hyperandrogenism and the polycystic ovary syndrome (PCOS) remain largely unknown. Given the large number of genetic variants found in association with these disorders, the emerging picture is that of a complex multigenic trait in which environmental influences play an important role in the expression of the hyperandrogenic phenotype. Among others, genomic variants in genes related to the regulation of androgen biosynthesis and function, insulin resistance, and the metabolic syndrome, and proinflammatory genotypes may be involved in the genetic predisposition to functional hyperandrogenism and PCOS. The elucidation of the molecular genetic basis of these disorders has been burdened by the heterogeneity in the diagnostic criteria used to define PCOS, the limited sample size of the studies conducted to date, and the lack of precision in the identification of ethnic and environmental factors that trigger the development of hyperandrogenic disorders. Progress in this area requires adequately sized multicenter collaborative studies after standardization of the diagnostic criteria used to classify hyperandrogenic patients, in whom modifying environmental factors such as ethnicity, diet, and lifestyle are identified with precision. In addition to classic molecular genetic techniques such as linkage analysis in the form of a whole-genome scan and large case-control studies, promising genomic and proteomic approaches will be paramount to our understanding of the pathogenesis of functional hyperandrogenism and PCOS, allowing a more precise prevention, diagnosis, and treatment of these prevalent disorders.

scholarly journals Analysis of Antibiotic Resistance Genes, Environmental Factors, and Microbial Community From Aquaculture Farms in Five Provinces, China

2021 ◽  
Vol 12 ◽  
Author(s):  
Xu Cheng ◽  
Yitong Lu ◽  
Yanzhen Song ◽  
Ruifang Zhang ◽  
Xinyan ShangGuan ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Environmental Factors ◽  
Bacterial Community ◽  
Correlation Analysis ◽  
Resistance Genes ◽  
Environmental Risk ◽  
Antibiotic Resistance Genes ◽  
Community Diversity ◽  
Sediment Samples ◽  
Positive Correlation

The excessive use of antibiotics speeds up the dissemination and aggregation of antibiotic resistance genes (ARGs) in the environment. The ARGs have been regarded as a contaminant of serious environmental threats on a global scale. The constant increase in aquaculture production has led to extensive use of antibiotics as a means to prevent and treat bacterial infections; there is a universal concern about the environmental risk of ARGs in the aquaculture environment. In this study, a survey was conducted to evaluate the abundance and distributions of 10 ARGs, bacterial community, and environmental factors in sediment samples from aquatic farms distributed in Anhui (AP1, AP2, and AP3), Fujian (FP1, FP2, and FP3), Guangxi (GP1, GP2, and GP3), Hainan (HP1, HP2, and HP3), and Shaanxi (SP1, SP2, and SP3) Province in China. The results showed that the relative abundance of total ARGs was higher in AP1, AP2, AP3, FP3, GP3, HP1, HP2, and HP3 than that in FP1, FP2, GP1, GP2, SP1, SP2, and SP3. The sul1 and tetW genes of all sediment samples had the highest abundance. The class 1 integron (intl1) was detected in all samples, and the result of Pearson correlation analysis showed that the intl1 has a positive correlation with the sul1, sul2, sul3, blaOXA, qnrS, tetM, tetQ, and tetW genes. Correlation analysis of the bacterial community diversity and environmental factors showed that the Ca2+ concentration has a negative correlation with richness and diversity of the bacterial community in these samples. Of the identified bacterial community, Proteobacteria, Firmicutes, Chloroflexi, and Bacteroidota were the predominant phyla in these samples. Redundancy analysis showed that environmental factors (TN, TP, Cl–, and Ca2+) have a positive correlation with the bacterial community (AP1, GP1, GP2, GP3, SP1, SP2, and SP3), and the abundance of ARGs (sul1, tetW, qnrS, and intl1) has a positive correlation with the bacterial community (AP2, AP3, HP1, HP2, and HP3). Based on the network analysis, the ARGs (sul1, sul2, blaCMY, blaOXA, qnrS, tetW, tetQ, tetM, and intl1) were found to co-occur with bacterial taxa from the phyla Chloroflexi, Euryarchaeota, Firmicutes, Halobacterota, and Proteobacteria. In conclusion, this study provides an important reference for understanding the environmental risk associated with aquaculture activities in China.

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