DOUBLED HAPLOIDS FOR ESTIMATING ADDITIVE EPISTATIC GENETIC VARIANCES IN SELF-POLLINATING CROPS

1980 ◽  
Vol 22 (1) ◽  
pp. 125-127 ◽  
Author(s):  
T. M. Choo
Keyword(s):  
Doubled Haploid ◽  
Genetic Variance ◽  
Doubled Haploids ◽  
Additive Genetic Variance ◽  
Genetic Variances ◽  
Doubled Haploid Lines

In this study it was shown that besides additive and additive × additive genetic variances, additive × additive × additive genetic variance can also be estimated from a diallel experiment in which each cross is represented by a number of doubled haploid lines.

Recurrent selection in doubled-haploid populations of barley (Hordeurn vulgare L.)

1985 ◽  
Vol 27 (2) ◽  
pp. 172-177 ◽  
Author(s):  
J. D. Patel ◽  
E. Reinbergs ◽  
S. O. Fejer
Keyword(s):  
Doubled Haploid ◽  
Recurrent Selection ◽  
Doubled Haploids ◽  
Additive Genetic Variance ◽  
Response To Selection ◽  
Hordeum Vulgare L ◽  
Doubled Haploid Lines ◽  
Days To Heading ◽  
High Selection ◽  
Dh Lines

Cycle zero (C0) of recurrent selection in barley (Hordeum vulgare L.) was initiated by diallel mating of seven highly selected parents. A total of 398 doubled-haploid (C0DH) lines were derived from 21 crosses and were evaluated along with their parents in C0 experiment. Seven doubled-haploid lines (DH) were selected from the cycle zero (C0) experiment and intercrossed to form cycle 1 (C1). From the 21 crosses of the diallel, 260 doubled-haploid lines (C1DH) were derived and were evaluated along with the C0 and C1 parents. The frequency distribution of the standardized means of the DH lines from C0 and C1 indicated a slight response to selection for seed yield. Genetic analysis of the C1DH population showed high additive genetic variance for yield per hill, plant height, and yield per spike, and a high proportion of additive × additive epistasis for spikes per hill, days to heading, and 100-seed weight. Seven doubled-haploid lines were selected from different high-yielding crosses represented by C1DH lines. High selection pressure was applied for yield per hill, yield per spike, and spikes per hill. Further response to selection is expected in later cycles. The seven selected doubled-haploid lines will be used as the parents of the next recurrent selection cycle.Key words: recurrent selection, doubled haploids, additive, epistasis, heritability, Hordeum.

COMPARAISON ENTRE DES LIGNEES PEDIGREES ET DES LIGNEES HAPLOIDES DOUBLEES CHEZ L’ORGE (HORDEUM VULGARE L.)

1980 ◽  
Vol 60 (1) ◽  
pp. 79-85 ◽  
Author(s):  
PIERRE TURCOTTE ◽  
C. A. ST-PIERRE ◽  
KEH MING HO
Keyword(s):  
Hordeum Vulgare ◽  
Doubled Haploid ◽  
Doubled Haploids ◽  
Block Design ◽  
Pure Line ◽  
Kernel Weight ◽  
Hordeum Vulgare L ◽  
Line Production ◽  
Doubled Haploid Lines ◽  
Time Required

Pedigree and doubled haploid lines from seven crosses of barley (Hordeum vulgare L.) were compared over 2 years. The lines were tested, in a randomized complete block design, in row plots at Ste-Foy in 1977 and in hill plots at Brawley, California in 1978. There are significant differences between the two methods of pure line production for grain yield, 1000-kernel weight, plant height, resistance to lodging and date of maturity. Furthermore, these significant differences between doubled haploid and pedigree lines seem to be tied to wide crosses. After showing that doubled haploids are superior for resistance to lodging, we conclude that the use of doubled haploid lines must be seriously considered in a barley breeding program on the basis of improved selection efficiency and the short time required to get homozygous lines.

Cytogenetic studies of progenies from crosses between 'Centurk' wheat and its doubled haploids derived from anther culture

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 622-628 ◽  
Author(s):  
Sawsan S. Youssef ◽  
R. Morris ◽  
P. S. Baenziger ◽  
C. M. Papa
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Doubled Haploid ◽  
Structural Changes ◽  
Meiotic Chromosome ◽  
Doubled Haploids ◽  
Triticum Aestivum L ◽  
Root Tips ◽  
Doubled Haploid Lines ◽  
A Minor

Karyotype stability, which is essential when using wheat (Triticum aestivum L.) doubled haploids in a breeding program, was evaluated in 14 anther-derived doubled-haploid lines after at least three generations of selfing, by crossing them as females with the parent cultivar 'Centurk' and doing cytological studies on the progenies. There were no deviations from the hexaploid chromosome number (2n = 42) in root tips. Meiotic chromosome pairing was as stable as that in the control ('Centurk' × 'Centurk') in most progenies. Chromosomal structural changes and (or) behavioral deviations were detected at the metaphase I, anaphase I, telophase I, and quartet stages of meiosis in a minor proportion of the cells. The frequencies of multivalents, lagging bivalents and univalents, bridges, and micronuclei were higher in some progenies than in the control. Chromosomal fragments were infrequent. The ranges in percentages of normal cells were 72.4–90.0 at anaphase I, 76.4–92.6 at telophase I, and 82.6–93.2 at quartet stages in the doubled-haploid progenies, compared with 95–100, 92–100, and 94–96, respectively, in the control. On the basis of these results, the doubled-haploid lines should produce enough normal gametes to provide adequate seed supplies when they are used as parents in wheat cultivar and population improvement.Key words: Triticum aestivum, chromosome pairing, chromosome aberrations, gametoclonal variation.

scholarly journals In vitro androgenesis in triticale

2017 ◽  
Vol 1 (1) ◽  
pp. 99-100
Author(s):  
Oksana Ivanovna Zaitseva
Keyword(s):  
Genetic Variation ◽  
Anther Culture ◽  
Doubled Haploid ◽  
Doubled Haploids ◽  
External Factors ◽  
Hexaploid Triticale ◽  
Doubled Haploid Lines ◽  
In Vitro Androgenesis

Abstract The technology for in vitro anther culturing was optimized in hexaploid triticale using combination of external factors that allowed to obtain more than 100 doubled haploid lines. Investigation of genetic variation among anther culture derived doubled haploids of triticale showed the occurrence of heterozygous plants.

THE EFFICIENCY OF USING DOUBLED HAPLOIDS IN A RECURRENT SELECTION PROGRAM IN A DIPLOID, CROSS-FERTILIZED SPECIES

1978 ◽  
Vol 20 (4) ◽  
pp. 505-511 ◽  
Author(s):  
T. M. Choo ◽  
L. W. Kannenberg
Keyword(s):  
Doubled Haploid ◽  
Recurrent Selection ◽  
Doubled Haploids ◽  
Additive Genetic Variance ◽  
Significant Loss ◽  
Doubled Haploid Population ◽  
Mass Selection ◽  
Complete Dominance ◽  
Haploid Population ◽  
Selection Intensities

Mass selection in both doubled haploid and diploid populations was simulated for a 30-year period under additive and complete dominance models. The response to S1 selection was also included for the purpose of comparison. All selection programs were conducted at two selection intensities, 5% and 25%, under 0.2 heritability with a constant population size of 400. S1 lines were evaluated in 10-plant plots with four replications; use of a winter nursery was assumed. The character under selection was controlled by 20 major (A = 2) genes and 20 minor (A = 1) genes. The initial frequency of ten of the major genes and ten of the minor genes was 0.5; that of the remaining ten of each type was 0.1. The response to mass selection with doubled haploids was about 1.4 times faster than diploid mass selection and equal to S1 selection in terms of gain per year. If replicated trials were used to evaluate the doubled haploids, the rate of gain was faster than in S1 selection. The greater efficiency of using doubled haploids was due to doubling of the additive genetic variance and the elimination of dominance variance. However, significant loss of desirable genes occurred in the mass selected doubled haploid population under both the 5% and 25% selection intensities in the additive and complete dominance models.

scholarly journals Animal models with group-specific additive genetic variances: extending genetic group models

2018 ◽  
Author(s):  
Stefanie Muff ◽  
Alina K. Niskanen ◽  
Dilan Saatoglu ◽  
Lukas F. Keller ◽  
Henrik Jensen
Keyword(s):  
Animal Model ◽  
Animal Models ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Group ◽  
Breeding Value ◽  
Sampling Variance ◽  
Implicit Assumption ◽  
Genetic Variances ◽  
Genetic Groups

Abstract1. The animal model is a key tool in quantitative genetics and has been used extensively to estimate fundamental parameters, such as additive genetic variance, heritability, or inbreeding effects. An implicit assumption of animal models is that all founder individuals derive from a single population. This assumption is commonly violated, for instance in cross-bred livestock breeds, when an observed population receive immigrants, or when a meta-population is split into genetically differentiated subpopulations. Ignoring genetic differences among different source populations of founders may lead to biased parameter estimates, in particular for the additive genetic variance.2. To avoid such biases, genetic group models, extensions to the animal model that account for the presence of more than one genetic group, have been proposed. As a key limitation, the method to date only allows that the breeding values differ in their means, but not in their variances among the groups. Methodology previously proposed to account for group-specific variances included terms for segregation variance, which rendered the models infeasibly complex for application to most real study systems.3. Here we explain why segregation variances are often negligible when analyzing the complex polygenic traits that are frequently the focus of evolutionary ecologists and animal breeders. Based on this we suggest an extension of the animal model that permits estimation of group-specific additive genetic variances. This is achieved by employing group-specific relatedness matrices for the breeding value components attributable to different genetic groups. We derive these matrices by decomposing the full relatedness matrix via the generalized Cholesky decomposition, and by scaling the respective matrix components for each group. To this end, we propose a computationally convenient approximation for the matrix component that encodes for the Mendelian sampling variance. Although convenient, this approximation is not critical.4. Simulations and an example from an insular meta-population of house sparrows in Norway with three genetic groups illustrate that the method is successful in estimating group-specific additive genetic variances and that segregation variances are indeed negligible in the empirical example.5. Quantifying differences in additive genetic variance within and among populations is of major biological interest in ecology, evolution, and animal and plant breeding. The proposed method allows to estimate such differences for subpopulations that form a connected meta-population, which may also be useful to study temporal or spatial variation of additive genetic variance.

ESTIMATION OF ADDITIVE AND NONADDITIVE GENETIC VARIANCES IN NONINBRED POPULATIONS UNDER SIRE OR FULLSIB MODEL

1989 ◽  
Vol 69 (1) ◽  
pp. 61-68
Author(s):  
C. Y. LIN ◽  
A. J. LEE
Keyword(s):  
Animal Model ◽  
Maximum Likelihood ◽  
Least Squares ◽  
Key Words ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Restricted Maximum Likelihood ◽  
Animal Breeding ◽  
Genetic Variances ◽  
Reml Estimation

The separation of additive and nonadditive genetic variances has been a problem for animal breeding researchers because conventional methods of statistical analyses (least squares or ANOVA type) were not able to accomplish this task. Henderson presented computing algorithms for restricted maximum likelihood (REML) estimation of additive and nonadditive genetic variances from an animal model for noninbred populations. Unfortunately, application of this algorithm in practice requires extensive computing. This study extends Henderson's methodology to estimate additive genetic variance independently of nonadditive genetic variances under halfsib (sire), fullsib nested and fullsib cross-classified models. A numerical example illustrates the REML estimation of additive [Formula: see text] and additive by additive [Formula: see text] genetic variances using a sire model. Key words: Genetic variance, additive, nonadditive, dairy

A STUDY OF COMBINING ABILITY FOR SOME DEVELOPMENTAL TRAITS IN A DIALLEL SET OF CROSSES IN PEARL MILLET

1976 ◽  
Vol 18 (3) ◽  
pp. 429-435
Author(s):  
H. R. Chaudhary ◽  
S. Jana
Keyword(s):  
Pearl Millet ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Leaf Size ◽  
Diallel Cross ◽  
Pennisetum Typhoides ◽  
Genetic Variances ◽  
Considerable Impact ◽  
Nonallelic Interactions ◽  
Developmental Traits

A diallel cross involving ten selected inbred parents in pearl millet Pennisetum typhoides (Burm.) Staph and Hubb. was analyzed for the inheritance of number of functioning leaves and leaf size. The study revealed that both additive and dominance genetic variances were important for leaf size whereas additive genetic variance was of major importance for number of functioning leaves. However, nonallelic interactions evidently had considerable impact in the inheritance of both characters. Heritability for number of functioning leaves was higher than that for leaf size. Although specific and general combining abilities were significant for both characters, gca effect appeared to be more important than sca effect for both characters. It was proposed that a breeding procedure which could make an efficient use of both additive and nonadditive genetic variances would be appropriate for the improvement of pearl millet.

Sign in / Sign up

Export Citation Format

Share Document