scholarly journals Genetic analysis and clonal stability of two yellow cypress clonal populations in British Columbia

2013 ◽  
Vol 62 (1-6) ◽  
pp. 173-186 ◽  
Author(s):  
B. S. Baltunis ◽  
J. H. Russell ◽  
A.Van Niejenhuis ◽  
J. Barker ◽  
Y. A. El-Kassaby
Keyword(s):  
British Columbia ◽  
Genetic Analysis ◽  
Combining Ability ◽  
Variance Components ◽  
Genetic Variance ◽  
Genetic Correlations ◽  
Specific Combining Ability ◽  
Type B ◽  
Height Range ◽  
Coastal British Columbia

AbstractGenetic analysis of height and form at age 12 years of 697 yellow cypress (Callitropsis nootkatensis [D. Don] Oerst.) clones tested across seven sites in coastal British Columbia (BC) were explored in populations: Population 1 - No Pedigree and Population 2 - Reconstructed Pedigree. Genetic variances were statistically significant but generally higher σ̂g2was observed for Population 2. Height and form were under low to moderate genetic control as indicated by clonal repeatability and estimates were relatively similar between populations. For example, average Ĥ2in Population 2 was 0.31 for height (range: 0.18-0.45) and 0.22 for form (range: 0.06-0.32). While average Ĥ2in Population 1 was 0.25 for height (range: 0.19-0.35) and 0.18 for form (range: 0.09-0.27). The reconstructed pedigree in Population 2 allowed partitioning the genetic variance (σ̂g2) into component parts of additive (σ̂a2), specific combining ability (σ̂s2), and clone (σ̂c2); however, general lack of structure within the population resulted in variance components to be estimated with little precision for additive and specific combining ability. The majority of genetic variation was associated with clone for both traits. For example, σ̂c2accounted for 57.6% and 62.5% of the total genetic variance for height and form, respectively. Growth and form responses of clones across test environments were relatively stable and overall type-B genetic correlations were in excess of 0.8 for both traits implying clones selected for production populations should respond favorably across the seed planning zone for yellow cypress in coastal BC.

A diallel cross in black spruce

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 180-186 ◽  
Author(s):  
T. J. B. Boyle
Keyword(s):  
Combining Ability ◽  
Variance Components ◽  
Genetic Variance ◽  
Black Spruce ◽  
Diallel Cross ◽  
Specific Combining Ability ◽  
Environment Interaction ◽  
Forest Genetics ◽  
Data Set ◽  
Dominance Genetic Variance

A complete 7 × 7 diallel of black spruce (Picea mariana (Mill.) B.S.P.), without selfs, planted in three locations, was measured for height growth at several ages. Analysis using Griffing's method 3, model II, demonstrated that general combining ability (GCA) was the dominant genetic component of variation, although specific combining ability (SCA) appeared to be proportionately increasing in importance with age. When data from all locations were combined, the GCA × environment interaction proved to be highly significant. If the trend of increasing proportional importance of SCA continues, existing improvement strategies exploiting only GCA may need to be radically altered. Greater genetic gain would result from crosses among a few clones of high specific combining ability. Whatever approach is used, it appears likely that genotypes will have to be carefully matched to sites. Imbalance in the data set appeared to invalidate F-tests. As a result of heterozygosity in the parents and the likely presence of epistasis and linkage disequilibrium, the interpretation of GCA and SCA variance components in terms of additive and dominance genetic variance cannot be made. Key words: diallel cross, combining ability, black spruce, forest genetics.

scholarly journals Performance of testers with different genetic structure for evaluation of maize inbred lines

2012 ◽  
Vol 42 (5) ◽  
pp. 770-776 ◽  
Author(s):  
Lauro José Moreira Guimarães ◽  
Glauco Vieira Miranda ◽  
Rodrigo Oliveira DeLima ◽  
Ciro Maia ◽  
Lucimar Rodrigues de Oliveira ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Combining Ability ◽  
Genetic Variance ◽  
Inbred Lines ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Genetic Base ◽  
Maize Inbred Lines ◽  
Single Cross ◽  
Single Cross Hybrids

The objective of this study was to evaluate four maize testers for identification of superior inbreed lines in testcross. The four testers evaluated are cultivars with narrow or wide genetic base (single-cross hybrids and open pollinated varieties) and two kernel types (flint or dent). SynD and SynF testers are open pollinated varieties with dent and flint kernels, respectively, and FSH and DSH testers are single-cross hybrids with flint and dent kernels, respectively. SynD tester showed the biggest genetic variance among the maize inbreed lines in crosses. The effects of general combining ability (GCA) for lines and specific combining ability (SCA) for lines x testers were significant, whereas GCA effects for testers were not significant. SynD and SynF testers identified the largest number of lines with higher GCA. The DSH and FSH testers showed suitable to identify lines with high SCA. It was concluded that SynD and SynF testers are adequate to identify inbreed lines with high GCA effects, and it's possible to identify new lines with high heterotic potential in each one of the four testers.

Studies on Combining Ability for Seed Yield and Its Related Traits in Blackgram [Vigna mungo (L.) Hepper]

2020 ◽  
Author(s):  
Ranjana Patial ◽  
R. K. Mittal ◽  
V. K. Sood ◽  
Shahnawaz Ahmed
Keyword(s):  
Seed Yield ◽  
Combining Ability ◽  
Genetic Variance ◽  
Gene Action ◽  
Specific Combining Ability ◽  
Breeding Programme ◽  
Plant Seed ◽  
Ability Estimates ◽  
Additive Gene ◽  
Transgressive Segregants

An experiment was carried out in blackgram using line x tester mating design to estimate the GCA effect of parents and SCA effect of 54 hybrids for yield and its traits using 27 lines and two testers. The relative estimates of variance due to specific combining ability (SCA) were higher than general combining ability (GCA) variances for all twelve traits, indicating predominance of non-additive gene action. Combining ability estimates showed significant genetic variance in lines for all traits whereas testers had significant genetic variance for nine traits. On the basis of GCA effects, among the lines and testers IC-436910, IC-413306, IC-398973, IC-343885 and HPBU-111 respectively, were good combiners for most of the traits and can be used in future breeding programme. Specific combining ability studies indicated cross IC-436910 x HPBU-111 as best specific combiner for the economically important traits viz., plant height, branches per plant, seed yield per plant and days to 75% maturity. Such crosses could be further exploited to obtain transgressive segregants in future breeding programme.

COMBINING ABILITY FOR YIELD OF SYNTHETIC HEXAPLOID WHEATS

1974 ◽  
Vol 54 (2) ◽  
pp. 235-239 ◽  
Author(s):  
R. J. BAKER ◽  
P. L. DYCK
Keyword(s):  
Triticum Aestivum ◽  
Seed Yield ◽  
Combining Ability ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Triticum Aestivum L ◽  
Kernel Weight ◽  
Specific Combining Ability ◽  
Synthetic Hexaploid Wheats ◽  
Synthetic Hexaploid

Four hexaploid spring wheats (Triticum aestivum L.), which differ only in their D genomes, were crossed in all combinations. Heterosis was expressed in F1 and F2 for number of spikes, kernel weight, and seed yield. Failure to detect significant specific combining ability among F1 progeny suggests that only additive genetic variance is involved in the inheritance of these traits. Competition between single-spaced plants was detected.

Effect of milk fat to protein ratio on genetic variance for milk yield in Thai tropical Holstein cattle

2016 ◽  
Vol 96 (3) ◽  
pp. 410-415 ◽  
Author(s):  
S. Puangdee ◽  
M. Duangjinda ◽  
W. Boonkum ◽  
S. Buaban ◽  
S. Katawatin
Keyword(s):  
Milk Fat ◽  
Variance Components ◽  
Legendre Polynomials ◽  
Bayesian Method ◽  
Genetic Variance ◽  
Genetic Correlations ◽  
Random Regression ◽  
Third Order ◽  
Protein Ratio ◽  
Regression Test

The objective of this research was to investigate the optimum fat to protein ratio (FPR) in Thai tropical Holstein dairy cattle. First parity data consisting of 20 492 milk yields (MY) records for 24 891 cows for the period 2001 and 2011, were used in the analysis. The analysis used a random regression test-day animal model of third-order Legendre polynomials through the creation of a covariance function based on different FPRs. Variance components were estimated using the Bayesian method via the Gibbs sampling. The estimated heritability of MY in relation to FPR ranged from 0.19 to 0.27 with the pattern being similar to the genetic variances. Genetic correlations of MY at different FPRs were high at consecutive FPRs and then declined to negative in response to greater differences in FPR. Based on the results, it is concluded that the optimum FPR is in the range of 0.9 to 1.9, corresponding to the genetically controlled energy balance for MY in tropical Holsteins.

Combining ability in Glycine javanica

1968 ◽  
Vol 19 (3) ◽  
pp. 411 ◽  
Author(s):  
JG Wutoh ◽  
WM Hutton ◽  
AJ Pritchard
Keyword(s):  
Combining Ability ◽  
Genetic Correlations ◽  
Diallel Cross ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Forage Yield ◽  
Maturity Date ◽  
Stolon Length ◽  
Breeding Programmes ◽  
Stolon Development

A diallel cross of five accessions was used to estimate general and specific combining ability for nine traits in Glycine javanica L. Variation due to both general and specific combining ability was highly significant but the general combining ability component of variance was larger than the specific combining ability component for flowering time, maturity date, and seed weight. For yield, stolon length, stolon number, and percentage of stolons rooted the specific combining ability component was the larger. The cultivar Tinaroo had a high general combining ability and a low specific combining ability for most traits associated with forage yield and should be a valuable parent in future breeding programmes. Negative genetic correlations between yield and some traits associated with stolon development indicate that it may not be possible to produce a variety with all desirable characters from a breeding programme based on the five accessions used.

scholarly journals Genetic analysis of four main flavonoids in barley grain

2019 ◽  
Vol 48 (2) ◽  
pp. 231-237
Author(s):  
Tao Yang ◽  
Yawen Zeng ◽  
Juan Du ◽  
Shuming Yang ◽  
Xiaoying Pu
Keyword(s):  
Genetic Analysis ◽  
Combining Ability ◽  
Interspecific Hybrids ◽  
Barley Grain ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Barley Breeding ◽  
Hybrid Combination ◽  
Half Diallel

Genetic analysis of 4 major flavonoids in barley interspecific hybrids which were used as parents for half diallel crossingwas carried out. Compared with seven parents, the highest general combining ability of catechin content was Clipper barley, the higest general combining ability (GCA) of myricetin content were Schooner barley and Huangchangguang barley, the highest general combining ability of quercetin content were Ziguangmang barley and Kuanying barley, the highest general combining ability of kaempferol content were Ziguangmang barley and Schooner barley, the highest general combining ability of flavonoids are Schooner barley and Huangchangguang barley. The hybrid combination of a good matching were Clipper barley, Schooner barley, Ziguangmang barley and Kuanying barley, as a comprehensive general combining ability, specific combining ability, and combinations of which can be used as flavonoids in barley breeding.

scholarly journals The inheritance of plant height in winter wheat -Triticum aestivum L.-

Genetika ◽  
2005 ◽  
Vol 37 (2) ◽  
pp. 173-179 ◽  
Author(s):  
Veselinka Zecevic ◽  
Desimir Knezevic ◽  
Danica Micanovic ◽  
Milanko Pavlovic ◽  
Dusan Urosevic
Keyword(s):  
Winter Wheat ◽  
Plant Height ◽  
Combining Ability ◽  
Variance Components ◽  
Genetic Variance ◽  
Regression Line ◽  
Triticum Aestivum L ◽  
Wheat Varieties ◽  
F2 Generation ◽  
Mode Of Inheritance

Four winter wheat varieties (Srbijanka, Partizanka, KG-56 and PKB-111) have been selected for diallel crossing in other to study the mode of inheritance, gene effect and genetic variance components for the plant height in F2 generation. Sixty plants of parents and F2 generation were used for analysis. The mode of inheritance was done on the basis of the significance of components of genetic variance and the regression analysis. The inheritance of plant height in the most crossing combinations was superdominance. The combining ability analysis was found to be highly significant, which means both additive and non-additive type of gene actions. The best general combining ability manifested KG-56 variety, and the best specific combining ability have shown hybrids KG-56 x PKB-111, Srbijanka x PKB-111 and Partizanka x KG-56. The genetic variance components, average degree of dominance and regression line indicated superdominance in the inheritance of plant height. The dominant alleles frequency was higher than recessive alleles frequency, which confirmed the ratio of dominant/recessive alleles.

Evaluation of repeatability and pre-structured repeatability models for genetic analyses of repeated records of fat and protein contents of milk in Iranian Holstein cows

2018 ◽  
Vol 58 (11) ◽  
pp. 1983
Author(s):  
M. Asadi Fozi
Keyword(s):  
Genetic Analysis ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Holstein Cows ◽  
Phenotypic Correlation ◽  
Genetic Covariance ◽  
Future Studies ◽  
Phenotypic Correlations ◽  
Variance Structure

Fat and protein content of milk measurements from first to fifth lactations of Iranian Holstein cows were analysed using repeatability and several pre-structured repeatability models that varied in additive genetic variance structure and fitted heterogeneous residual co (variance). For this research, a total of 257 197 fat and 218 688 protein records were used. The records were measured on 116 531 cows born between 2010 and 2014. The animals originated from 2355 sires and 91 212 dams. Pre-structured repeatability models with heterogeneous residual co (variance) and the respective genetic variance structure were the best models for genetic analysis of the fat and protein data. The results derived from these models showed that heritability of both fat and protein are decreased from first to fifth lactations. Heritability of fat measured at first, second, third, fourth and fifth locations were between 0.10 and 0.19 and those for protein were between 0.07 and 0.24. Moderate to high phenotypic correlations were estimated between the repeated records of the fat and protein. Values of 0.13 and 0.16 were estimated for heritability of fat and protein using repeatability model. Phenotypic correlations among the repeated records of fat and protein were estimated to be 0.30 and 0.33, respectively when this model was applied. The results showed the genetic variance, heritability and phenotypic correlation of the fat and protein are changed over the lactations but the genetic parameters derived from the repeatability model are homogenous whereas in both models unity genetic correlations are assumed among the repeated records. The results of this study show that the repeatability model is not an appropriate model for genetic analysis of the repeated records of fat and protein in the population investigated and can be improved when pre-structured repeatability model is used. In the present study homogenous genetic covariance was assumed among the fat and protein taken at the different lactations which can be modelled in future studies for more improving the models.

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