scholarly journals Phenotypic selection under two contrasting environments in wild sunflower and its crop–wild hybrid

2019 ◽  
Vol 12 (8) ◽  
pp. 1703-1717
Author(s):  
Alejandro Presotto ◽  
Fernando Hernández ◽  
Kristin L. Mercer
Keyword(s):  
Phenotypic Selection ◽  
Wild Sunflower ◽  
Wild Hybrid

Recurrent Phenotypic Selection for Resistance to Brown Leaf Spot in Smooth Bromegrass 1

Crop Science ◽  
1986 ◽  
Vol 26 (3) ◽  
pp. 533-536 ◽  
Author(s):  
Clyde C. Berg ◽  
Robert T. Sherwood ◽  
Kenneth E. Zeiders
Keyword(s):  
Leaf Spot ◽  
Phenotypic Selection ◽  
Smooth Bromegrass ◽  
Brown Leaf Spot ◽  
Brown Leaf ◽  
Selection For

scholarly journals Increasing selection gain and accuracy of harvest prediction models in Jatropha through genome-wide selection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adriano dos Santos ◽  
Erina Vitório Rodrigues ◽  
Bruno Galvêas Laviola ◽  
Larissa Pereira Ribeiro Teodoro ◽  
Paulo Eduardo Teodoro ◽  
...  
Keyword(s):  
Prediction Models ◽  
Block Design ◽  
Phenotypic Selection ◽  
Breeding Population ◽  
Breeding Cycle ◽  
Selection Cycle ◽  
Genome Wide ◽  
Random Block ◽  
Random Block Design ◽  
Number Of Individuals

AbstractGenome-wide selection (GWS) has been becoming an essential tool in the genetic breeding of long-life species, as it increases the gain per time unit. This study had a hypothesis that GWS is a tool that can decrease the breeding cycle in Jatropha. Our objective was to compare GWS with phenotypic selection in terms of accuracy and efficiency over three harvests. Models were developed throughout the harvests to evaluate their applicability in predicting genetic values in later harvests. For this purpose, 386 individuals of the breeding population obtained from crossings between 42 parents were evaluated. The population was evaluated in random block design, with six replicates over three harvests. The genetic effects of markers were predicted in the population using 811 SNP's markers with call rate = 95% and minor allele frequency (MAF) > 4%. GWS enables gains of 108 to 346% over the phenotypic selection, with a 50% reduction in the selection cycle. This technique has potential for the Jatropha breeding since it allows the accurate obtaining of GEBV and higher efficiency compared to the phenotypic selection by reducing the time necessary to complete the selection cycle. In order to apply GWS in the first harvests, a large number of individuals in the breeding population are needed. In the case of few individuals in the population, it is recommended to perform a larger number of harvests.

scholarly journals Marker-Assisted Introgression in Backcross Breeding Programs

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1923-1932 ◽  
Author(s):  
Peter M Visscher ◽  
Chris S Haley ◽  
Robin Thompson
Keyword(s):  
Quantitative Trait ◽  
Genetic Model ◽  
Phenotypic Selection ◽  
Inbred Lines ◽  
Breeding Programs ◽  
Coupling Phase ◽  
Breed Difference ◽  
Backcross Populations ◽  
Backcross Breeding ◽  
Marker Spacing

The efficiency of marker-assisted introgression in backcross populations derived from inbred lines was investigated by simulation. Background genotypes were simulated assuming that a genetic model of many genes of small effects in coupling phase explains the observed breed difference and variance in backcross populations. Markers were efficient in introgression backcross programs for simultaneously introgressing an allele and selecting for the desired genomic background. Using a marker spacing of 10–20 cM gave an advantage of one to two backcross generations selection relative to random or phenotypic selection. When the position of the gene to be introgressed is uncertain, for example because its position was estimated from a trait gene mapping experiment, a chromosome segment should be introgressed that is likely to include the allele of interest. Even for relatively precisely mapped quantitative trait loci, flanking markers or marker haplotypes should cover ∼10–20 cM around the estimated position of the gene, to ensure that the allele frequency does not decline in later backcross generations.

scholarly journals A New Breeding Strategy towards Introgression and Characterization of Stay-Green QTL for Drought Tolerance in Sorghum

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 598
Author(s):  
Nasrein Mohamed Kamal ◽  
Yasir Serag Alnor Gorafi ◽  
Hanan Abdeltwab ◽  
Ishtiag Abdalla ◽  
Hisashi Tsujimoto ◽  
...  
Keyword(s):  
Phenotypic Expression ◽  
Phenotypic Selection ◽  
Breeding Strategy ◽  
Stay Green ◽  
Breeding Programs ◽  
The Public ◽  
Drought Tolerant ◽  
Selection Step ◽  
The Cost

Several marker-assisted selection (MAS) or backcrossing (MAB) approaches exist for polygenic trait improvement. However, the implementation of MAB remains a challenge in many breeding programs, especially in the public sector. In MAB introgression programs, which usually do not include phenotypic selection, undesired donor traits may unexpectedly turn up regardless of how expensive and theoretically powerful a backcross scheme may be. Therefore, combining genotyping and phenotyping during selection will improve understanding of QTL interactions with the environment, especially for minor alleles that maximize the phenotypic expression of the traits. Here, we describe the introgression of stay-green QTL (Stg1–Stg4) from B35 into two sorghum backgrounds through an MAB that combines genotypic and phenotypic (C-MAB) selection during early backcross cycles. The background selection step is excluded. Since it is necessary to decrease further the cost associated with molecular marker assays, the costs of C-MAB were estimated. Lines with stay-green trait and good performance were identified at an early backcross generation, backcross two (BC2). Developed BC2F4 lines were evaluated under irrigated and drought as well as three rainfed environments varied in drought timing and severity. Under drought conditions, the mean grain yield of the most C-MAB-introgression lines was consistently higher than that of the recurrent parents. This study is one of the real applications of the successful use of C-MAB for the development of drought-tolerant sorghum lines for drought-prone areas.

scholarly journals Fruit Quality Characters of Myrtle (Myrtus communis L.) Selections: Review of a Domestication Process

2021 ◽  
Vol 13 (16) ◽  
pp. 8785
Author(s):  
Silvia Medda ◽  
Maurizio Mulas
Keyword(s):  
Raw Materials ◽  
Phenotypic Selection ◽  
Second Step ◽  
Myrtus Communis ◽  
Wild Populations ◽  
Phenotypic Characters ◽  
Myrtus Communis L ◽  
Mother Plants ◽  
Domestication Process ◽  
Fruit Characters

Interest in myrtle (Myrtus communis L.) by food, cosmetics, and pharmaceutic industries generated the integration of biomasses harvested from wild populations as raw materials with yields of cultivated orchards. The domestication process is reviewed considering shoot, fruit, and leaf biometric characters of selections obtained in three steps of the program. The first step started in Sardinia (Italy) in 1995 by the analysis of wild germplasm variability. Seventy accessions were the object of the first studied population of mother plants. Agamic propagation tests, as well quality evaluations of fruit and leaves, were integrated into the first step. In the second step, a field of comparison of forty-two agamically propagated cultivars functional to biomass production and to food uses was planted and evaluated for phenotypic characters. In the third step, a new population of twenty selections was obtained by open cross-pollination of some of the cultivars and further phenotypic selection in seedling population. In this review, the three populations are compared for biometric shoot, leaves and fruit characters, in order to verify the pressure of domestication process on these traits. Wild populations showed high variability only partially used during the first step, while the hybridization may create new variability for use in the genetic improvement of myrtle.

scholarly journals Developing green super rice varieties with high nutrient use efficiency by phenotypic selection under varied nutrient conditions

2019 ◽  
Vol 7 (3) ◽  
pp. 368-377 ◽  
Author(s):  
Zilhas Ahmed Jewel ◽  
Jauhar Ali ◽  
Yunlong Pang ◽  
Anumalla Mahender ◽  
Bart Acero ◽  
...  
Keyword(s):  
Nutrient Use Efficiency ◽  
Phenotypic Selection ◽  
Rice Varieties ◽  
Nutrient Use ◽  
High Nutrient ◽  
Use Efficiency ◽  
Nutrient Conditions

Phenotypic selection in a population of Crepis tectorum ssp. pumila (Asteraceae)

1992 ◽  
Vol 70 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Stefan Andersson
Keyword(s):  
Life History ◽  
Multiple Regression ◽  
Large Scale ◽  
Demographic Data ◽  
Phenotypic Selection ◽  
Direct Selection ◽  
Surprising Result ◽  
Regression Analyses ◽  
Ecotypic Differentiation ◽  
Crepis Tectorum

A 3-year demographic study was conducted to reveal targets of selection on morphology and life history in a population of Crepis tectorum ssp. pumila, a winter annual plant confined to calcareous grasslands (alvars) on the Baltic island of Öland (south Sweden). I calculated the selection differential to describe the change in the mean value of a character due to selection and used multiple regression analyses to partition the direct effect of selection on the trait from indirect responses of selection on other traits. Rosette leaf number, a convenient measure of plant size, was strongly correlated with both viability and fertility (fitness). There was also a strong relationship between fitness and the extent to which the plants expressed traits characterizing this particular taxon. Multiple regression analyses indicated direct selection favouring plants with deeply lobed leaves and a densely branched stem, two distinctive traits of ssp. pumila believed to be adaptive in the alvar habitat. Only stem height was subject to both direct and indirect selection in the wrong direction; taller individuals were more successful than those with a shorter stem, a surprising result considering the inferred advantage of a short stature in the exposed alvar habitat. Selection on other traits assumed to be ecologically important (germination time, flowering time, and seed size) was found to be either absent or variable in direction when other traits were held constant. The failure of plants to survive to the flowering stage in the last two summers indicates strong selection for plants that produce a high percentage of dormant seeds. Overall, the contemporary selection regime as revealed by demographic data was only partly congruent with predictions regarding historical selection pressures based on large-scale patterns of variation (ecotypic differentiation). Key words: Crepis tectorum, ecotypic differentiation, life history, morphology, phenotypic selection.

scholarly journals GWAS revealed effect of genotype × environment interactions for grain yield of Nebraska winter wheat

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Shamseldeen Eltaher ◽  
P. Stephen Baenziger ◽  
Vikas Belamkar ◽  
Hamdy A. Emara ◽  
Ahmed A. Nower ◽  
...  
Keyword(s):  
Linkage Disequilibrium ◽  
Winter Wheat ◽  
Grain Yield ◽  
Genome Wide Association Study ◽  
Phenotypic Selection ◽  
Wheat Breeding ◽  
Wheat Genotypes ◽  
Genome Wide ◽  
Genomic Regions ◽  
Significant Linkage

Abstract Background Improving grain yield in cereals especially in wheat is a main objective for plant breeders. One of the main constrains for improving this trait is the G × E interaction (GEI) which affects the performance of wheat genotypes in different environments. Selecting high yielding genotypes that can be used for a target set of environments is needed. Phenotypic selection can be misleading due to the environmental conditions. Incorporating information from phenotypic and genomic analyses can be useful in selecting the higher yielding genotypes for a group of environments. Results A set of 270 F3:6 wheat genotypes in the Nebraska winter wheat breeding program was tested for grain yield in nine environments. High genetic variation for grain yield was found among the genotypes. G × E interaction was also highly significant. The highest yielding genotype differed in each environment. The correlation for grain yield among the nine environments was low (0 to 0.43). Genome-wide association study revealed 70 marker traits association (MTAs) associated with increased grain yield. The analysis of linkage disequilibrium revealed 16 genomic regions with a highly significant linkage disequilibrium (LD). The candidate parents’ genotypes for improving grain yield in a group of environments were selected based on three criteria; number of alleles associated with increased grain yield in each selected genotype, genetic distance among the selected genotypes, and number of different alleles between each two selected parents. Conclusion Although G × E interaction was present, the advances in DNA technology provided very useful tools and analyzes. Such features helped to genetically select the highest yielding genotypes that can be used to cross grain production in a group of environments.

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