THE EFFECT OF LOCATION ON NATURAL SELECTION IN BULK POPULATIONS OF BARLEY (HORDEUM VULGARE L.). II. QUANTITATIVE TRAITS

1980 ◽  
Vol 60 (1) ◽  
pp. 41-47 ◽  
Author(s):  
T. M. CHOO ◽  
H. R. KLINCK ◽  
C. A. ST-PIERRE
Keyword(s):  
Natural Selection ◽  
Quantitative Traits ◽  
Bulk Material ◽  
Flag Leaf ◽  
Selection Procedure ◽  
Distinct Pattern ◽  
Rate Of Change ◽  
Hordeum Vulgare L ◽  
Testing Environments ◽  
Segregating Population

The effects of natural selection on quantitative traits were compared in 17 single hybrid barley populations which had been developed either by growing the bulk material continuously in each of two locations, Macdonald College and La Pocatière, or by alternating between these locations annually or after 2–8 yr per location. Comparisons were made by testing the F10 and F15 generations of each of the 17 populations at the two locations for 2 yr. Natural selection favored longer awns, shorter spikes, smaller flag leaves, fewer spikes per plot, and, perhaps, heavier grains. Natural selection had very little effect, however, on the number of grains per spike or grain yield. Variation among populations was observed only for awn length, spike length, flag leaf area, and number of grains per spike in the F15 generation. This indicates that the rate of change for the four traits was affected by the propagation environments but was not affected by the frequency of alternation because no distinct pattern was found among these populations. These populations in both generations responded similarly to the testing environments except for awn length in F15. It is suggested that wider diversity of locality is needed in order to evaluate effectively the usefulness of a natural selection procedure involving the alternating of a segregating population.

Natural Selection on Quantitative Traits in the Bombina Hybrid Zone

Evolution ◽  
1995 ◽  
Vol 49 (6) ◽  
pp. 1224 ◽  
Author(s):  
Beate Nurnberger ◽  
Nick Barton ◽  
Catriona MacCallum ◽  
Jason Gilchrist ◽  
Michael Appleby
Keyword(s):  
Natural Selection ◽  
Hybrid Zone ◽  
Quantitative Traits

scholarly journals NATURAL SELECTION ON QUANTITATIVE TRAITS IN THE BOMBINA HYBRID ZONE

Evolution ◽  
1995 ◽  
Vol 49 (6) ◽  
pp. 1224-1238 ◽  
Author(s):  
Beate Nürnberger ◽  
Nick Barton ◽  
Catriona MacCallum ◽  
Jason Gilchrist ◽  
Michael Appleby
Keyword(s):  
Natural Selection ◽  
Hybrid Zone ◽  
Quantitative Traits

scholarly journals Selection in a growing bacterial/yeast colony biases results of mutation accumulation experiments

2021 ◽  
Author(s):  
Anjali Mahilkar ◽  
Sharvari Kemkar ◽  
Supreet Saini
Keyword(s):  
Natural Selection ◽  
Population Size ◽  
Effective Population Size ◽  
Colony Growth ◽  
Mutation Accumulation ◽  
Rate Of Change ◽  
Raw Material ◽  
Effective Population ◽  
The Face ◽  
Mean Fitness

AbstractMutations provide the raw material for natural selection to act. Therefore, understanding the variety and relative frequency of different type of mutations is critical to understanding the nature of genetic diversity in a population. Mutation accumulation (MA) experiments have been used in this context to estimate parameters defining mutation rates, distribution of fitness effects (DFE), and spectrum of mutations. MA experiments performed with organisms such asDrosophilahave an effective population size of one. However, in MA experiments with bacteria and yeast, a single founder is allowed to grow to a size of a colony (~108). The effective population size in these experiments is of the order of 10. In this scenario, while it is assumed that natural selection plays a minimal role in dictating the dynamics of colony growth and therefore, the MA experiment; this effect has not been tested explicitly. In this work, we simulate colony growth and perform an MA experiment, and demonstrate that selection ensures that, in an MA experiment, fraction of all mutations that are beneficial is over represented by a factor greater than two. The DFE of beneficial and deleterious mutations are accurately captured in an MA experiment. We show that the effect of selection in a growing colony varies non-monotonically and that, in the face of natural selection dictating an MA experiment, estimates of mutation rate of an organism is not trivial. We perform experiments with 160 MA lines ofE. coli, and demonstrate that rate of change of mean fitness is a non-monotonic function of the colony size, and that selection acts differently in different sectors of a growing colony. Overall, we demonstrate that the results of MA experiments need to be revisited taking into account the action of selection in a growing colony.

scholarly journals Spontaneous mutations and the origin and maintenance of quantitative genetic variation

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Wen Huang ◽  
Richard F Lyman ◽  
Rachel A Lyman ◽  
Mary Anna Carbone ◽  
Susan T Harbison ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Quantitative Traits ◽  
Spontaneous Mutation ◽  
Natural Populations ◽  
Empirical Work ◽  
Stabilizing Selection ◽  
Spontaneous Mutation Rate ◽  
Evolutionary Forces ◽  
Quantitative Genetic

Mutation and natural selection shape the genetic variation in natural populations. Here, we directly estimated the spontaneous mutation rate by sequencing new Drosophila mutation accumulation lines maintained with minimal natural selection. We inferred strong stabilizing natural selection on quantitative traits because genetic variation among wild-derived inbred lines was much lower than predicted from a neutral model and the mutational effects were much larger than allelic effects of standing polymorphisms. Stabilizing selection could act directly on the traits, or indirectly from pleiotropic effects on fitness. However, our data are not consistent with simple models of mutation-stabilizing selection balance; therefore, further empirical work is needed to assess the balance of evolutionary forces responsible for quantitative genetic variation.

scholarly journals Genetic variability, heritability for quantitative traits in upland rice (Oryza sativa L.) genotypes

2021 ◽  
Author(s):  
D.R. Meghawal ◽  
G.M. Lal ◽  
Ranjana Tiwari
Keyword(s):  
Plant Height ◽  
Quantitative Traits ◽  
Upland Rice ◽  
Oryza Sativa L ◽  
Flag Leaf ◽  
Crop Improvement ◽  
Leaf Length ◽  
Additive Gene ◽  
Field Experimentation ◽  
Flag Leaf Length

The present investigation consists of 34 genotypes with one local check (NDR-359) grown at field experimentation centre at the Department of Genetic and Plant Breeding, SHIATS, Allahabad evaluated for thirteen quantitative characters. All the genotypes differed significantly with respect to all the quantitative traits. High to moderate estimates of GCV and PCV were found for number of panicle per plant, number of tiller per plant, plant height and number of spikelet’s per panicle, indicating these traits could be use for selection in crop improvement. Plant height, number of spikelet’s per panicle, test weight and flag leaf length exhibited high values for broad sense heritability. Number of spikelet’s and plant height showed highest genetic advance coupled with high heritability, which is also exhibited by number of panicle per plant, number of tillers per plant and plant height suggesting pre dominance of additive gene action in the expression of these traits.

scholarly journals Genetic variability in elite barley genotypes based on the agro-morphological characteristics evaluated under irrigated system

2017 ◽  
Vol 41 (2) ◽  
pp. 147-158 ◽  
Author(s):  
Renato Fernando Amabile ◽  
Fábio Gelape Faleiro ◽  
Flávio Capettini ◽  
José Ricardo Peixoto ◽  
Ricardo Meneses Sayd
Keyword(s):  
Cluster Analysis ◽  
Genetic Variability ◽  
Protein Content ◽  
Leaf Area ◽  
Flag Leaf ◽  
Morphological Characteristics ◽  
Federal District ◽  
Group Method ◽  
Hordeum Vulgare L ◽  
Arithmetic Means

ABSTRACT Recently, researches have shown that the Brazilian savannah has a great potential to supply the demand for barley grains. The purpose of this study was to assess the genetic variability in 39 elite barley (Hordeum vulgare L.) genotypes based on the agro-morphological traits of a crop irrigated in the savannah system. An irrigation experiment in the design of complete randomized block with four replicates was conducted at Federal District - Brazil. The evaluated traits were: distance from the last knot to the rachis, distance from the flag leaf to rachis, spike length, number of grains by ear, flag leaf area, plant height, silking, lodging, grain yield, thousand-seed weight, protein content and grain commercial classification. After using analysis of variance the means were used to estimate the genetic dissimilarity among all genotypes pairs based on the Mahalanobis’ generalized distance. Cluster analysis using genetic distance matrix was performed having Unweighted Pair Group Method using Arithmetic Means method (UPGMA) as the criteria. Highly significant differences were found among the genotypes for all traits evaluated. The high coefficient of genetic variation indicates the possibility of having genetic gains for all traits. The traits that most contributed to the variability were the flag leaf area and silking, while the protein content and lodging were the traits that contributed the least. Based on the cluster analysis, at least three major groups of similarity were found. There was a clustering trend of two and six-rowed materials. The most divergent genotypes were PFC 2005123, Antártica-1, Nandi and FM 404.

scholarly journals Estimation of genetic diversity for quantitative traits of commercial wheat (Triticum aestivum)

2017 ◽  
Vol 1 ◽  
pp. 320
Author(s):  
Adnan Rasheed ◽  
Abdul Malik Solangi
Keyword(s):  
Plant Height ◽  
Quantitative Traits ◽  
Yellow Rust ◽  
Flag Leaf ◽  
Spike Length ◽  
Breeding Programme ◽  
Adult Plant ◽  
Augmented Design ◽  
Peduncle Length ◽  
Selection Of

This research was conducted to assess the performance of wheat genotypes and to detect genotypes with adult plant resistance by evaluating them in a trap nursery. 36 commercial wheat cultivar were used in experiment. Morocco was sown on four sides of trial. Material was sown in augmented design. The data was recorded on different quantitative like Plant height (cm), no. of tillers/plant, spike length (cm), no of spikelets/plant, peduncle length (cm), stem diameter (mm) and flag leaf area. Selection of genotypes could be done from two main clusters to make cross for improvement of traits. No of tillers/plant, peduncle length, spike/length, spikelets/plant and plant height showed large genetic variability in Biplot and these variables could be used as selection criteria. Pak-81, Sindh-81, Mexipak-65, Sarsabaz, Chakwal-86 and Kiran-95 so these cultivars could be potentially used in future breeding programme for improvement of several quantitative traits according to results of Biplot analysis. Following genotypes were found moderate resistant against yellow rust viz. Anmol-9, Bahawalpur-200 and Bakhtawar-92 and could be used further in future breeding programme to stand against yellow ruts pressure. Maxipak-65 and WL-711 need to improve by incorporating yellow rust resistant genes.

Influence of production systems on return and risk from malting barley production in western Canada

2016 ◽  
Vol 96 (3) ◽  
pp. 339-346 ◽  
Author(s):  
E.G. Smith ◽  
T.K. Turkington ◽  
J.T. O’Donovan ◽  
M.J. Edney ◽  
P.E. Juskiw ◽  
...  
Keyword(s):  
Field Data ◽  
Production Systems ◽  
Flag Leaf ◽  
Field Pea ◽  
Western Canada ◽  
Malting Barley ◽  
Hordeum Vulgare L ◽  
Previous Crop ◽  
Field Data Analysis ◽  
The Impact

Profitable malting barley (Hordeum vulgare L.) production systems are required to reverse the decline in area seeded to malting barley in western Canada. Systems that could increase the profitability of growing malting barley considered the previous crop, nitrogen (N) rate, and fungicide application. The net return (NR) and risk for these systems were computed from western Canada field data. Analysis of variance was used to evaluate the impact of systems on NR over 21 site-years of field data. Risk was evaluated with a stochastic simulation model. NR was higher and risk lower for malting barley when the preceding crop was field pea (Pisum sativum L.), when fungicide was applied at the flag leaf stage for leaf disease control, and when N was 50% of the recommended N rate. Therefore, malting barley should be grown on field pea stubble at a lower N rate, with fungicide applied when there are leaf diseases.

scholarly journals Deciphering signatures of natural selection via deep learning

2021 ◽  
Author(s):  
Xinghu Qin ◽  
Charleston W.K. Chiang ◽  
Oscar E Gaggiotti
Keyword(s):  
Deep Learning ◽  
Natural Selection ◽  
Quantitative Traits ◽  
Predictive Power ◽  
Spatial Location ◽  
Human Genetic Variation ◽  
Environmental Attributes ◽  
Wide Range ◽  
Candidate Regions ◽  
Genomic Regions

Identifying genomic regions influenced by natural selection provides fundamental insights into a wide range of problems including human health, animal and plant breeding, and the understanding of local adaptation. We propose a new method, DeepGenomeScan, that can be used to address all these problems. It is based on the principle that the genotypes of individuals can be used to predict any associated trait; not only their phenotype but also their spatial location or the environmental attributes of the habitat they live in. We, therefore,implemented a deep learning method to detect candidate regions under selection by identifying loci that contribute the most to the predictive power of the deep neural network. Using simulations, we show that our method can successfully identify loci underlying quantitative traits subject to complex spatial patterns of selection. We apply DeepGenomeScan to a European human genetic variation dataset and posit that the loci that contribute the most to the prediction of latitude and longitude are located in genomic regions under selection. Using this approach, we identified many SNPs located within well-known genes, some of which were not identified using existing population genetics approaches, e.g. MCM6, MGAT5, TMEM163.

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