Mapping a gene conferring resistance to Pseudocercosporella herpotrichoides on chromosome 4V of Dasypyrum villosum in a wheat background

Genome ◽  
1998 ◽  
Vol 41 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Ahmet Yildirim ◽  
Stephen S Jones ◽  
Timothy D Murray
Keyword(s):  
Distal Part ◽  
Dominant Gene ◽  
Rflp Markers ◽  
Addition Line ◽  
Dasypyrum Villosum ◽  
Pseudocercosporella Herpotrichoides ◽  
Eyespot Resistance ◽  
Double Recombination ◽  
Simultaneous Selection ◽  
Selection For

The objectives of this study were to map and tag the previously undescribed eyespot resistance gene PchDv on chromosome 4V of Dasypyrum villosum in a wheat background. The 82 F2 plants used for mapping were produced from a cross between a susceptible\i wheat 'Yangmai-5' (4V(4D)) substitution line and a resistant wheat 'Chinese Spring' disomic addition line of chromosome 4V of D. villosum. Segregation for resistance and susceptibility among F2 plants was 3:1, indicating that resistance was controlled by a single dominant gene. PchDv mapped to the distal part of chromosome 4V and was bracketed by two RFLP markers, Xcdo949 and Xbcd588, in a 33-cM interval. This distance could not be reduced, owing to a lack of polymorphic loci in this region. Theoretically, double recombination in this region occurs in 3.3% of the individuals; therefore, 96.7% of the selected genotypes would have PchDv, with simultaneous selection for both flanking markers. Double recombination between the flanking markers was observed in 2 out of 82 (2.4%) F2 individuals.

Simultaneous selection for high yield and stability in common bean (Phaseolus vulgaris) genotypes

2002 ◽  
Vol 138 (3) ◽  
pp. 249-253 ◽  
Author(s):  
F. MEKBIB
Keyword(s):  
Common Bean ◽  
Genotype By Environment Interaction ◽  
Yield Stability ◽  
High Yield ◽  
Environment Interaction ◽  
Yield Performance ◽  
Simultaneous Selection ◽  
Selection For ◽  
Stability Statistics ◽  
Selection Of

Phenotypic yield stability is a trait of special interest for plant breeders and farmers. This value can be quantified if genotypes are evaluated in different environments. Common bean is the main cash crop and protein source of farmers in many lowland and mid-altitude areas of Ethiopia. An experiment was undertaken to evaluate common bean genotypes for yield performance at Alemaya, Bako and Nazreth in Ethiopia for 3 years. The yield performance of genotypes was subjected to stability analysis and yield-stability statistics were generated to aid the selection of genotypes that were high yielding and very stable. The significant genotype by environment interaction indicated that the relative performance of the varieties altered in the different environments. Genotype yield performance varied ranging from 1511–2216 kg/ha. Simultaneous selection for yield and yield-stability statistics using YS(i) statistics indicated that A 410, GLP x92, Mx-2500-19, G 2816, A-195, 997-CH-1173, Diacol calima, ICA 15541 and AND 635 were both high yielding and stable. Following this study, using farmers’ evaluation and other criteria, GLP x92 and G-2816 were identified as preferred genotypes and were released for further production.

scholarly journals Simultaneous selection for dominant and recessive mutants

Heredity ◽  
1965 ◽  
Vol 20 (1) ◽  
pp. 142-144 ◽  
Author(s):  
J W James
Keyword(s):  
Simultaneous Selection ◽  
Selection For

Identification of an RFLP interval containing Pch2 on chromosome 7AL in wheat

Genome ◽  
1997 ◽  
Vol 40 (2) ◽  
pp. 249-252 ◽  
Author(s):  
Robert C. de la Peña ◽  
Timothy D. Murray ◽  
Stephen S. Jones
Keyword(s):  
Chinese Spring ◽  
Wheat Chromosome ◽  
Distal Portion ◽  
Rflp Markers ◽  
Substitution Lines ◽  
Eyespot Disease ◽  
Single Marker ◽  
Double Recombination ◽  
Recombinant Substitution Line ◽  
Selection Of

The gene Pch2 in 'Cappelle Desprez' is one of two genes found in hexaploid wheat known to confer resistance to eyespot disease. This study was conducted to develop an RFLP linkage map of the distal portion of wheat chromosome 7AL, and to locate and identify markers closely associated with Pch2 for use in marker-assisted selection. Ten loci in addition to Pch2 were mapped on chromosome 7AL, using segregation data from 102 homozygous chromosome 7A recombinant substitution lines derived from 'Chinese Spring' × 'Chinese Spring' ('Cappelle Desprez' 7A). The Pch2 locus was bracketed by two RFLP markers, one 11.0 cM distal to Xcdo347 and the other 18.8 cM proximal to Xwg380. The position of Pch2 on chromosome 7AL is similar to that of Pch1 on chromosome 7DL, suggesting that these resistance genes are homoeoloci. Although no single marker was closely linked to Pch2, simultaneous selection of the flanking RFLP markers Xcdo347 and Xwg380 could be used for selecting Pch2, since double recombination occurred in only 3% of the recombinant population. The use of the flanking RFLP markers to select for Pch2, in combination with previously identified Pch1-linked markers, would facilitate the development of cultivars carrying two genes for resistance to eyespot.Key words: Triticum aestivum, Pseudocercosporella herpotrichoides, recombinant substitution line.

Relationships between body weight and some follicle and fleece characters in an Australian fine-wool Merino flock

1969 ◽  
Vol 20 (6) ◽  
pp. 1177 ◽  
Author(s):  
T Nay ◽  
RH Hayman
Keyword(s):  
Body Weight ◽  
Correlation Coefficient ◽  
Unit Area ◽  
Additive Effect ◽  
Phenotypic Correlations ◽  
Close Relationship ◽  
Simultaneous Selection ◽  
Selection For ◽  
Fleece Weight ◽  
Highly Correlated

Phenotypic correlations between body weight, follicle characters, and fleece characters have been investigated in a flock of 95 fine-wool non-Peppin Merino wethers, reared in the same locality under the same conditions. The results indicated that three follicle characters, follicle chord, follicle depth, and the index of follicle bending, were independent of body weight. It was found, in agreement with the results of other workers, that body weight was highly correlated with both greasy and clean wool weights (r = 0.53 and 0.51 respectively). It was also found that follicle characters were significantly correlated with most of the fleece characters which contribute to the clean fleece weight per unit area of skin. The correlation coefficient of wool weight per unit area of skin with follicle chord was 0.33, with follicle depth 0.28, and with follicle bending index –0.35. The follicle characters were also correlated with greasy and clean fleece weights. Crimp number per inch was predicted for individual animals by using as criterion the length of the follicle chord. A highly significant correlation coefficient of 0.67 was obtained between predicted and observed crimp number. The close relationship between crimp chord and follicle chord reported in previous work was confirmed. It is suggested that simultaneous selection for body weight and certain follicle characters may have an additive effect on the production of clean wool. It is also suggested that the genetic antagonism between clean wool weight and number of crimps per inch can be explained in anatomical terms.

scholarly journals The evolution of bacterial mutation rates under simultaneous selection by interspecific and social parasitism

2013 ◽  
Vol 280 (1773) ◽  
pp. 20131913 ◽  
Author(s):  
Siobhán O'Brien ◽  
Antonio M. M. Rodrigues ◽  
Angus Buckling
Keyword(s):  
Mutation Rate ◽  
Social Parasitism ◽  
Mutation Rates ◽  
Bacterial Populations ◽  
Simultaneous Selection ◽  
Bacterial Mutation ◽  
Selection For ◽  
Intraspecific Parasitism ◽  
Theory And Experiments ◽  
Mutation Rate Evolution

Many bacterial populations harbour substantial numbers of hypermutable bacteria, in spite of hypermutation being associated with deleterious mutations. One reason for the persistence of hypermutators is the provision of novel mutations, enabling rapid adaptation to continually changing environments, for example coevolving virulent parasites. However, hypermutation also increases the rate at which intraspecific parasites (social cheats) are generated. Interspecific and intraspecific parasitism are therefore likely to impose conflicting selection pressure on mutation rate. Here, we combine theory and experiments to investigate how simultaneous selection from inter- and intraspecific parasitism affects the evolution of bacterial mutation rates in the plant-colonizing bacterium Pseudomonas fluorescens. Both our theoretical and experimental results suggest that phage presence increases and selection for public goods cooperation (the production of iron-scavenging siderophores) decreases selection for mutator bacteria. Moreover, phages imposed a much greater growth cost than social cheating, and when both selection pressures were imposed simultaneously, selection for cooperation did not affect mutation rate evolution. Given the ubiquity of infectious phages in the natural environment and clinical infections, our results suggest that phages are likely to be more important than social interactions in determining mutation rate evolution.

Simultaneous selection and counter-selection for the directed evolution of proteases inE. coliusing a cytoplasmic anchoring strategy

2015 ◽  
Vol 113 (6) ◽  
pp. 1187-1193 ◽  
Author(s):  
Zachary M. Carrico ◽  
Kathryn L. Strobel ◽  
Meera E. Atreya ◽  
Douglas S. Clark ◽  
Matthew B. Francis
Keyword(s):  
Directed Evolution ◽  
Counter Selection ◽  
Simultaneous Selection ◽  
Selection For

Simultaneous Selection for Yield and Stability in Sugarcane Using AMMI Model

2018 ◽  
Vol 6 (2) ◽  
pp. 206
Author(s):  
Gulzar S Sanghera ◽  
Arvind Kumar ◽  
Rajesh Kumar
Keyword(s):  
Ammi Model ◽  
Simultaneous Selection ◽  
Selection For
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