EVOLUTION OF FERTILITY IN ADVANCED GENERATIONS OF AN ALFALFA SINGLE CROSS HYBRID

1971 ◽  
Vol 13 (4) ◽  
pp. 834-841 ◽  
Author(s):  
L. Dessureaux ◽  
A. Gallais
Keyword(s):  
Genetic Models ◽  
Mother Plant ◽  
Seed Setting ◽  
Three Generations ◽  
Single Cross ◽  
Selection For

Cross-fertility of a single cross hybrid was found to decrease gradually in advanced generations. When the same parents were selfed without selection for two or three generations, seed setting increased from Syn1 to Syn2, then decreased in Syn3 and Syn4. Interpretation of these data according to various genetic models, assuming no epistasis, indicates that fertility is influenced more by the mother plant than by the zygote, especially in the F1. Even with the best model, deviations from regression remain significant, except when the Syn1 generation is removed from the analysis.

FERTILITY OF BARLEY AUTOTETRAPLOIDS: I. FERTILITY IN SUCCESSIVE GENERATIONS OF FOUR AUTOTETRAPLOID BARLEY VARIETIES AND THE EFFECT OF SELECTION FOR FERTILITY IN THE O.A.C. 21 AUTOTETRAPLOID

1959 ◽  
Vol 39 (1) ◽  
pp. 98-107 ◽  
Author(s):  
E. Reinbergs ◽  
L. H. Shebeski
Keyword(s):  
Promising Method ◽  
Low Fertility ◽  
Fertility Level ◽  
Seed Setting ◽  
The Mean ◽  
Selection For ◽  
Successive Generations ◽  
Subsequent Selection

The differences in fertility of four colchicine-induced autotetraploid barley varieties (Brant, Montcalm, O.A.C. 21 and York) were determined and compared in four successive generations following the induction of tetraploidy. Despite a wide fertility range within each autotetraploid, the varieties tested varied considerably in their mean per cent fertility. Within each variety the mean per cent fertility remained relatively constant from generation to generation. The Montcalm tetraploid had the lowest mean fertility, fluctuating from generation to generation within a range of 6.0 to 10.1 per cent. The O.A.C. 21 tetraploid had the highest mean fertility, fluctuating within a range of 40.0 to 51.3 per cent.Significant differences in fertility of the four autotetraploid varieties were interpreted as indicating that seed-setting ability may be genetically controlled and, therefore, hybridization and subsequent selection could be a promising method for increasing fertility.Continuous selection for either high or low fertility from the C1 to C4 generation did not change the mean per cent fertility level in the O.A.C. 21 tetraploid.

SELECTION FOR SEED SET IN NONINBRED AND PARTLY INBRED POPULATIONS OF ALFALFA

1977 ◽  
Vol 57 (3) ◽  
pp. 873-881 ◽  
Author(s):  
R. MICHAUD ◽  
T. H. BUSBICE
Keyword(s):  
Medicago Sativa ◽  
Seed Set ◽  
Exponential Model ◽  
Seed Setting ◽  
Medicago Sativa L ◽  
Selection For ◽  
Inbred Populations ◽  
The Relationship ◽  
Advanced Generation ◽  
Coefficient Of Inbreeding

Alfalfa (Medicago sativa L.) is a highly heterozygous cross-pollinating species, and most breeding efforts have been conducted on noninbred populations. The purpose of this study was to determine whether greater breeding progress could be made by selecting within partly inbred populations rather than within noninbred ones. One hundred and twenty F1 (noninbred) and 120 S1 (partly inbred) plants that were issued from crossing and selfing four alfalfa clones were evaluated for self-fertility. The most self-fertile 10% of the plants from each family were selected in each population. The selected plants within each level of inbreeding were intercrossed to produce an advanced generation in which the effectiveness of the selection was evaluated. Selection increased both self- and cross-fertility in the advanced generation. Selection was more effective at the F1 level than at the S1 level. Fertility was reduced drastically by inbreeding. The average self-fertility of the S1’s was only about 7% of the cross-fertility of their parental clones. An exponential model was proposed to describe the relationship between seed setting and the coefficient of inbreeding in the developing zygote. This model explained 95% of the variation among 11 unselected populations having differing levels of inbreeding.

Allozyme variation in three generations of selection for whole weight in Sydney rock oysters (Saccostrea glomerata)

Aquaculture ◽  
2001 ◽  
Vol 193 (3-4) ◽  
pp. 213-225 ◽  
Author(s):  
L.J. English ◽  
J.A. Nell ◽  
G.B. Maguire ◽  
R.D. Ward
Keyword(s):  
Allozyme Variation ◽  
Three Generations ◽  
Saccostrea Glomerata ◽  
Selection For

scholarly journals RNA‐Seq Analysis of Genetic and Transcriptome Network Effects of Dual‐Trait Selection for Ethanol Preference and Withdrawal Using SOT and NOT Genetic Models

2020 ◽  
Vol 44 (4) ◽  
pp. 820-830
Author(s):  
Laura B. Kozell ◽  
Denesa Lockwood ◽  
Priscila Darakjian ◽  
Stephanie Edmunds ◽  
Karen Shepherdson ◽  
...  
Keyword(s):  
Network Effects ◽  
Genetic Models ◽  
Rna Seq ◽  
Ethanol Preference ◽  
Selection For

Response to three generations of selection for increased body weight in channel catfish, Ictalurus punctatus, grown in earthen ponds

Aquaculture ◽  
2003 ◽  
Vol 228 (1-4) ◽  
pp. 69-79 ◽  
Author(s):  
Mahmoud A Rezk ◽  
R.Oneal Smitherman ◽  
John C Williams ◽  
Amy Nichols ◽  
Huseyin Kucuktas ◽  
...  
Keyword(s):  
Body Weight ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Three Generations ◽  
Earthen Ponds ◽  
Selection For

scholarly journals Evolutionary Genetic Models of the Ovarian Time Bomb Hypothesis for the Evolution of Genomic Imprinting

Genetics ◽  
2002 ◽  
Vol 162 (1) ◽  
pp. 425-439 ◽  
Author(s):  
Anton E Weisstein ◽  
Marcus W Feldman ◽  
Hamish G Spencer
Keyword(s):  
Growth Factor ◽  
Genetic System ◽  
Early Embryogenesis ◽  
Genetic Models ◽  
Insulin Like Growth Factor ◽  
Deleterious Mutations ◽  
Trophoblastic Disease ◽  
Evolutionary Genetic ◽  
The Face ◽  
Selection For

Abstract At a small number of loci in eutherian mammals, only one of the two copies of a gene is expressed; the other is silenced. Such loci are said to be “imprinted,” with some having the maternally inherited allele inactivated and others showing paternal inactivation. Several hypotheses have been proposed to explain how such a genetic system could evolve in the face of the selective advantages of diploidy. In this study, we examine the “ovarian time bomb” hypothesis, which proposes that imprinting arose through selection for reduced risk of ovarian trophoblastic disease in females. We present three evolutionary genetic models that incorporate both this selection pressure and the effect of deleterious mutations to elucidate the conditions under which imprinting could evolve. Our findings suggest that the ovarian time bomb hypothesis can explain why some growth-enhancing genes active in early embryogenesis [e.g., mouse insulin-like growth factor 2 (Igf2)] have evolved to be maternally rather than paternally inactive and why the opposite imprinting status has evolved at some growth-inhibiting loci [e.g., mouse insulin-like growth factor 2 receptor (Igf2r)].

scholarly journals THE DYNAMICS OF GENETIC VARIABILITY IN THREE GENERATIONS OF MASS SELECTION FOR FAST GROWTH IN AFRICAN CATFISH, Clarias gariepinus ASSESSED BY MICROSATELLITE MARKERS

2015 ◽  
Vol 10 (2) ◽  
pp. 113
Author(s):  
Imron Imron ◽  
Bambang Iswanto ◽  
Huria Marnis ◽  
Rommy Suprapto ◽  
Narita Syawalia Ridzwan
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Genetic Differentiation ◽  
Clarias Gariepinus ◽  
Breeding Program ◽  
Fixation Index ◽  
Mass Selection ◽  
African Catfish ◽  
Three Generations ◽  
Selection For

Selective breeding aiming at improving the performance of economically important traits acts by exploiting population’s phenotypic variance. Due to the relationship between phenotype and genotype, selection on phenotype may also affect the profile of genotype. This study was aimed to monitor the impact of three generations of mass selection for fast growth in African catfish, Clarias gariepinus, on genetic variability, assessed by microsatellite. A total of 350 fish representing four populations, namely a composite base population (G-0), selected lines of the first generation (G-1) to the third generation (G-3), were sampled. The samples were screened for their genetic diversity using five microsatellite loci1 namely cga01, cga02, cga03, cga05, and cga09. Several genetic parameters including number of allele (A), allelic richness (AR), observed (Ho) and expected (He) heterozygosity, and fixation index (Fis) were evaluated. The results showed that there was a slight increase in the value of diversity indices in the G-1 relative to the G-0 and to the other two generations. Among these parameters, the number of allele seemed to be the most sensitive parameter in detecting genetic changes. All populations experienced heterozygote deficit and positive fixation index indicating the phenomena of inbreeding. Overall, selection for growth for three generations in African catfish breeding program resulted in significant genetic differentiation between populations. Further, the level of genetic differentiation seemed to accumulate along with the number of generaton in breeding program. However, selection did not result in a decline in genetic diversity within population. A relatively short period of the program, along with the use a high number of broodstock (mating pairs) to produce each generation seems to be able to maintain the stability of genetic diversity of the population.

Sign in / Sign up

Export Citation Format

Share Document