Genetic parameters from a clonally replicated test of black spruce (Piceamariana)

1992 ◽  
Vol 22 (1) ◽  
pp. 24-36 ◽  
Author(s):  
T. J. Mullin ◽  
E. K. Morgenstern ◽  
Y. S. Park ◽  
D. P. Fowler
Keyword(s):  
Genetic Gain ◽  
Genetic Variance ◽  
Genetic Model ◽  
Black Spruce ◽  
Clonal Selection ◽  
High Standard ◽  
Height Growth ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Growth And Survival

A clonally replicated field test of full-sib black spruce (Piceamariana (Mill.) B.S.P.) progeny was established at four locations in Nova Scotia. Estimated variance components for 5-year height growth and survival were interpreted according to an additive–dominance–epistasis genetic model and used to derive estimates of gain from various selection and deployment strategies. Five years after striking, 64% of the total genetic variance for height growth was due to additive variance. Virtually all of the remaining nonadditive variance was composed of epistatic variances; dominance variance was negligible. Narrow-sense heritability for 5-year height growth was low at 0.059. Substantial nonadditive variance contributed to a somewhat higher estimate of broad-sense heritability at 0.093. Family-mean heritabilities were much higher: 0.823 and 0.697 for half-sib and full-sib family means, respectively. Comparable heritabilities for survival were estimated with high standard errors and were considered unreliable. Results from this study indicate that clonal selection may provide large increases in genetic gain by capturing (i) genetic variance due to epistasis and (ii) a greater portion of the additive variance. Genetic gains for 5-year height growth in the order of 22.6% might be achieved using the best 1% of tested clones for operational planting. Clonal propagation may also be a preferred method to capture substantial genetic gain (about 11%) from selection at the family level, resulting in simplified management of breeding populations while reducing costs associated with conventional soil-based orchards.

scholarly journals Genetic variance for body size in a natural population of Drosophila buzzatii.

Genetics ◽  
1991 ◽  
Vol 128 (4) ◽  
pp. 739-750
Author(s):  
A Ruiz ◽  
M Santos ◽  
A Barbadilla ◽  
J E Quezada-Díaz ◽  
E Hasson ◽  
...  
Keyword(s):  
Genetic Variance ◽  
Genetic Model ◽  
Phenotypic Variance ◽  
Total Phenotypic Variance ◽  
Fourth Chromosome ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Thorax Length ◽  
Drosophila Buzzatii ◽  
F2 Generation

Abstract Previous work has shown thorax length to be under directional selection in the Drosophila buzzatii population of Carboneras. In order to predict the genetic consequences of natural selection, genetic variation for this trait was investigated in two ways. First, narrow sense heritability was estimated in the laboratory F2 generation of a sample of wild flies by means of the offspring-parent regression. A relatively high value, 0.59, was obtained. Because the phenotypic variance of wild flies was 7-9 times that of the flies raised in the laboratory, "natural" heritability may be estimated as one-seventh to one-ninth that value. Second, the contribution of the second and fourth chromosomes, which are polymorphic for paracentric inversions, to the genetic variance of thorax length was estimated in the field and in the laboratory. This was done with the assistance of a simple genetic model which shows that the variance among chromosome arrangements and the variance among karyotypes provide minimum estimates of the chromosome's contribution to the additive and genetic variances of the trait, respectively. In males raised under optimal conditions in the laboratory, the variance among second-chromosome karyotypes accounted for 11.43% of the total phenotypic variance and most of this variance was additive; by contrast, the contribution of the fourth chromosome was nonsignificant. The variance among second-chromosome karyotypes accounted for 1.56-1.78% of the total phenotypic variance in wild males and was nonsignificant in wild females. The variance among fourth chromosome karyotypes accounted for 0.14-3.48% of the total phenotypic variance in wild flies. At both chromosomes, the proportion of additive variance was higher in mating flies than in nonmating flies.

Genetic parameters and age–age correlations in a clonally replicated test of black spruce after 10 years

1994 ◽  
Vol 24 (12) ◽  
pp. 2330-2341 ◽  
Author(s):  
T.J. Mullin ◽  
Y.S. Park
Keyword(s):  
Variance Components ◽  
Genetic Model ◽  
Black Spruce ◽  
Genetic Correlations ◽  
Field Performance ◽  
Field Testing ◽  
Height Growth ◽  
Phenotypic Variance ◽  
Narrow Sense Heritability ◽  
Greenhouse Study

Height growth at 10 years from striking was assessed for clonally replicated full-sib black spruce (Piceamariana (Mill.) B.S.P) families tested at three locations in central Nova Scotia. Variance components were interpreted according to an additive–dominance–epistasis genetic model and used to derive comparative estimates of gain from various selection and deployment strategies. Field performance at 5 and 10 years was compared with that of the original ortets and families growing in a 25-week greenhouse study, by means of phenotypic and genetic correlation, and rank-change analyses. Between age 5 and 10, the additive portion of the total genetic variance for height decreased from 66 to 38%, while the dominance portion increased from less than 3 to 13%, and the epistatic portion from 31 to almost 49%. As a consequence, narrow-sense heritability estimates were lower at age 10 and gain estimates also decreased, particularly for those strategies that capture gain primarily from additive effects. Although correlations between field performance and early growth measurements were generally poor, the strongest were found at the half-sib level; full-sib correlations were somewhat weaker and those between clone means and early ortet performance were small and not statistically significant. The strongest age–age correlations were those that involved family mean seedling weight in the greenhouse. Family rankings based on early oven-dry biomass production also showed the most consistent agreement with ranking after 5 and 10 years of field testing, although the analyses suggest that effective early selection is probably limited to culling the worst 25% of the families based on biomass. Genotype–environment interactions were statistically significant, although these were limited to only 2% of the phenotypic variance in height growth; furthermore, strong genetic correlations between environments suggested that these interactions have little impact on selection efficiency.

scholarly journals Components of genetic variability and heritability of grain yield of silage maize

Genetika ◽  
2004 ◽  
Vol 36 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Mile Secanski ◽  
Tomislav Zivanovic ◽  
Goran Todorovic ◽  
Gordana Surlan-Momirovic
Keyword(s):  
Genetic Variability ◽  
Grain Yield ◽  
Genetic Variance ◽  
Block Design ◽  
Inbred Lines ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Silage Maize ◽  
V Genes ◽  
Set Up

The aim of the present study was to evaluate the following parameters for the grain yield of silage maize: variability of inbred lines and their diallel hybrids, superior-parent heterosis and components of genetic variability and heritability on the basis of the diallel set. The two-year four-replicate trial was set up according to the randomized complete-block design at Zemun Polje. It was determined that a genotype, year and their interaction significantly affected variability of this trait. The highest. i.e. the lowest grain yield, on the average for both investigation years. was recorded in the silage maize inbred lines ZPLB402 and ZPLB405. respectively. The analysis of components of genetic variance for grain yield shows that the additive component (D) was lower than the dominant (H1 and H2) genetic variance, while a positive component F and the frequency of dominant (u) and recessive (v) genes for this observed trait point to prevalence of dominant genes over recessive ones. Furthermore. this is confirmed by the ratio of dominant to recessive genes in parental genotypes for grain yield (Kd/Kr> 1) that is greater than unity in both years of investigation. The estimated value of the average degree of dominance (H1/D)1/2 exceeds unity, pointing out to superdominance in inheritance of this trait in both years of investigation. Results of Vr/Vr regression analysis indicate superdominance in inheritance of grain yield. Moreover. a registered presence of non-allelic interaction points out to the need to study effects of epistasis, as it can have a greater significance in certain hybrids. A greater value of dominant than additive variance resulted in high values of broad-sense heritability for grain yield in both investigation years (98.71%, i.e. 97.19% in 1997, i.e. 1998, respectively). and low values of narrow-sense heritability (11.9% in 1997 and 12.2% in 1998).

scholarly journals Generation means analysis of traits related to lodging using two crosses of durum×emmer wheat

2021 ◽  
Author(s):  
Majid Mohammadi ◽  
Aghafakhr Mirlohi ◽  
Mohammad Mahdi Majidi ◽  
Zahra Khedri ◽  
Vahid Rezaei
Keyword(s):  
Plant Height ◽  
Genetic Gain ◽  
Stem Diameter ◽  
Lodging Resistance ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Generation Means ◽  
Generation Means Analysis ◽  
Additive Gene ◽  
Final Yield

Abstract Lodging is one of the most important factors that affect wheat final yield. Emmer is a likely gene source to improve durum wheat; however, it is highly susceptible to lodging. The genetic studies of traits related to lodging in crosses of durum×emmer remains largely understudied. Here, we used progenies (six generations) derived from two crosses of durum×emmer in a generation means analysis (GMA) to determine gene action, inheritance, and genetic gain from selection in respect to plant height and its related traits. The results indicated that lodging resistance was significantly and negatively correlated with plant height and positively correlated with grain yield and mainly influenced by stem diameter. GMA results indicated that epistasis did not play an essential role in the genetic control of lodging related traits and almost the major portion of the genetic variation in these crosses resulted from additive gene actions. Also for all of the studied traits, the additive variance was higher than the dominance one. Narrow sense heritability was higher than 0.60 for most of the traits, and the genetic gain after one cycle of selection was positive for plant height and its components in both crosses. It was found that, selection in early generations may result in simultaneous reduction of plant height and increased stem diameter to improve lodging resistance in durum×emmer crossings.

scholarly journals Efficiencies of Clonally Replicated and Seedling Testing for Spruce Breeding and Deployment Strategies

2009 ◽  
Vol 58 (1-6) ◽  
pp. 292-300
Author(s):  
Y. H. Weng ◽  
Y. S. Park ◽  
D. Simpson ◽  
T. J. Mullin
Keyword(s):  
Genetic Variance ◽  
Gene Diversity ◽  
Additive Genetic Variance ◽  
Seed Orchard ◽  
Narrow Sense ◽  
Family Selection ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Clonal Seed Orchard ◽  
Seedling Test

AbstractGenetic gains based on a genetic test using clonal replicates were compared to those based on a test using seedlings at the same gene diversity and testing effort levels using POPSIM™ Simulator. Three testing and deployment strategies targeting for white spruce (P. glauca [Moench] Voss) and black spruce (P. mariana (Mill.) B.S.P.) in New Brunswick were compared: seedling test with clonal seed orchard deployed as seedlings (CSO_ST), clonally replicated test with clonal seed orchard deployed as seedlings (CSO_CRT), and clonally replicated test deployed as a clone mix (MVF). The breeding populations (BP) were formed by balanced within-family selection and the production populations (PP) were selected by strong restriction on relatedness, i.e., no parent in common. Compared to the seedling test, the clonally replicated test resulted in faster accumulation of additive effects but quicker loss of additive variance in the BP, and this is particular true in the case of lower narrow-sense heritability or less non-additive genetic variance. The quicker loss in BP additive variance was overcompensated for by its faster accumulation in BP additive effect, resulting in higher gain in the clonally replicated test based PPs. Compared to the CSO_ST, the gain superiority of the CSO_CRT increased with generations, decreasing narrow-sense heritability or reducing the amount of non-additive variance. Implementing MVF was the most effective in terms of gain in most simulated cases and its superiority over the CSO_ST increased with generations, decreasing narrowsense heritability, or increasing non-additive genetic variance. Overall results demonstrated significant advantages of using clonally replicated test both for BP advancement and PP selection in most of the scenarios, suggesting that clonally replicated test should be incorporated into current spruce breeding strategies.

scholarly journals Narrow-Sense Heritability of Selected Sensory Descriptors in Virginia-Type Peanut (Arachis hypogaea L.)1

2003 ◽  
Vol 30 (1) ◽  
pp. 64-66 ◽  
Author(s):  
T. G. Isleib ◽  
H. E. Pattee ◽  
F. G. Giesbrecht
Keyword(s):  
Arachis Hypogaea ◽  
Genetic Variance ◽  
Genetic Model ◽  
Additive Genetic Variance ◽  
Narrow Sense ◽  
Roasted Peanut ◽  
Narrow Sense Heritability ◽  
Breeding Lines ◽  
Arachis Hypogaea L ◽  
F2 Generation

Abstract The sweet, bitter and roasted peanut attributes of roasted peanut (Arachis hypogaea L.) flavor have been shown to be heritable traits. Previous research has estimated broad-sense heritability (H) and breeding values of numerous peanut cultivars and breeding lines for these attributes, but no study has estimated narrow-sense heritability (h2) in a specific population derived through hybridization and inbreeding. A population of 120 F3-derived families was developed without selection from the cross of NC 7/NC Ac 18431, a virginia-type line identified in 1990 as having a good flavor profile. The parents and F3:5 families were grown at two locations in North Carolina in 1995. SMK samples from each plot were roasted, ground to paste, tasted by a sensory panel, and scored for roasted peanut, sweet, bitter and astringent attributes. Additive and nonadditive genetic variances were estimated by equating variances among F2-derived families and among F3-derived families within F2-derived families to genetic covariances among inbred relatives. Regardless of whether the genetic model included dominance or additive-by-additive epistasis, the estimates of additive genetic variance for flavor attributes were small compared to those for nonadditive genetic variance. Narrow-sense heritability in the F2 generation was estimated at 0 for roasted peanut and astringent, 0.02 to 0.04 for sweet, and 0.01 to 0.03 for bitter, depending on the model used. Because of the low values of h2, which are specific to this population, gain from selection in early generations is expected to be limited within this population. Selection in this population should be practiced in late generations. Other parents have been identified whose crosses should produce greater improvement in sensory quality than can be expected from the NC 7 / NC Ac 18431 population.

scholarly journals The source of additive genetic variance of evolutionarily important traits

2019 ◽  
Author(s):  
Li Liu ◽  
Yayu Wang ◽  
Di Zhang ◽  
Xiaoshu Chen ◽  
Zhijian Su ◽  
...  
Keyword(s):  
Natural Selection ◽  
Fundamental Theorem ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Adaptive Divergence ◽  
Population Admixture ◽  
Strong Positive Correlation ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Fisher’S Fundamental Theorem

AbstractFisher’s fundamental theorem of natural selection predicts no additive variance of fitness in a natural population. Consistently, observations in a variety of wild populations show virtually no narrow-sense heritability (h2) for traits important to fitness. However, counterexamples are occasionally reported, calling for a deeper understanding on the evolution of additive variance. In this study we propose adaptive divergence followed by population admixture as a source of the additive genetic variance of evolutionarily important traits. We experimentally tested the hypothesis by examining a panel of ~1,000 yeast segregants produced by a hybrid of two yeast strains that experienced adaptive divergence. We measured over 400 yeast cell morphological traits and found a strong positive correlation between h2 and evolutionary importance. Because adaptive divergence followed by population admixture could happen constantly, particularly in some species such as humans, the finding reconciles the observation of abundant additive variances in evolutionarily important traits with Fisher’s fundamental theorem of natural selection. It also suggests natural selection may effectively promote rather than suppress additive genetic variance in species with wide geographic distribution and strong migratory capacity.

scholarly journals Components of genetic variability and heritability of the number of rows per ear in silage maize

2005 ◽  
Vol 21 (1-2) ◽  
pp. 109-121 ◽  
Author(s):  
Mile Secanski ◽  
Tomislav Zivanovic ◽  
Goran Todorovic
Keyword(s):  
Genetic Variability ◽  
Genetic Variance ◽  
Inbred Lines ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Partial Dominance ◽  
Silage Maize ◽  
V Genes ◽  
Recessive Genes ◽  
Allelic Interaction

The aim of this study was to estimate the following components for the number of rows per ear in silage maize: variability of inbred lines and their diallel hybrids, superior-parent heterosis and components of genetic variability and heritability on the basis of diallel hybrids. It was determined that the variability of this trait was significantly affected by a genotype, year and their interaction. Inbred lines ZPLB 402, ZPLB 403 and ZPLB 405 had a higher number of rows per ears than majority of hybrids in both years of investigation, which resulted in negative values of heterosis. The analysis of components of genetic variance indicates that the additive component (D) was higher that the dominant (Hi and H2) genetic variance while a positive value of the component F and frequency of dominant (u) and recessive (v) genes for the observed trait point out that dominant genes prevailed over recessive ones. Furthermore, this is confirmed by a dominant to recessive genes ratio in parental genotypes for the number of rows per ear (Kd/Kr>l) in both years. The evaluated average degree of dominance a/h^7d was below 1, indicating to a partial dominance in heritability of this trait in both years. Results of the Vr/Wr regression analysis point out to a partial dominance in heritability of the number of rows per ear. Moreover, a presence of non-allelic interaction was detected, which indicates to a need to study effects of epistasis as it can be more important in certain hybrids. The greater value of additive variance resulted in greater narrow-sense heritability for the number of rows per ear in both years of investigation (86.83% and 69.44%, respectively).

ADDITIVE AND NONADDITIVE GENETIC VARIANCES AND GENOTYPIC CORRELATIONS FOR YIELD AND OTHER TRAITS IN OATS

1971 ◽  
Vol 13 (4) ◽  
pp. 864-872 ◽  
Author(s):  
D. R. Sampson
Keyword(s):  
Seed Weight ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Heading Date ◽  
Stem Diameter ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Plot Yield ◽  
Panicle Number

The oat cultivate 'Dorval', 'Kelsey', 'Stormont', 'Orbit', 'Goodfield', 'Tyler' and 'Egdolon' and two numbered lines were crossed in a 3 × 6 factorial design. F1's, F2's and bullied F2 progenies were grown in successive years at seeding rates of 2.7, 9.5 and at the commercial rare of 76 Kg/ha, respectively; the F1's in irrigated cages, the F2's and F3's in nonirrigated fields. Additive genetic variance was the most important component of the phenotypic variances among progenies. Major differences occurred between the F1's and F2's, but the F2's and F3's agreed closely. The percentages of additive variance (narrow sense heritability) for the joint F2, F3 analyses were: height (91); heading date (87); seed weight (74); yield per panicle (71); seeds per panicle (63); panicle number (58); stem diameter (55); plot yield (52). Important nonadditive variance was present in the F2, F3 data for plot yield (17%), stem diameter (15%) and seed weight (12%). All traits were positively correlated with each other in the F1's. Correlations were weaker in the F2 and F3 and reversed for panicle number. Seed weight showed the least correlation with other traits. These results are discussed from the practical viewpoint of combining strong straw with high grain yield. The usefulness of selecting for seed weight and panicle yield to improve plot yield is underlined.

Genotype–nitrogen interactions in full-sib seedlings of black spruce

1985 ◽  
Vol 15 (6) ◽  
pp. 1031-1038 ◽  
Author(s):  
T. J. Mullin
Keyword(s):  
Genetic Variation ◽  
Combining Ability ◽  
Genetic Variance ◽  
Black Spruce ◽  
Height Growth ◽  
General Combining Ability ◽  
Narrow Sense ◽  
Components Of Variance ◽  
Nitrogen Fertility ◽  
Growth Characters

Genotype–environment interactions were investigated in 40 full-sib black spruce (Piceamariana (Mill.) B.S.P.) families grown in a greenhouse for 25 weeks under three levels of nitrogen fertility. Large general combining ability components of variance indicated that much of the genetic variance was additive. Heritability estimates were also high, with narrow-sense heritabilities of 0.35 for 25-week height growth and 0.15 for ovendry weight. Specific combining ability, reciprocal, and maternal effects were negligible for all but very early seed and growth characters. Statistically significant family × nitrogen interaction components were detected for all growth variables. Stability analysis using regression suggested that these interactions were due more to differences in degree of expression of genetic variation than to extreme changes in rank. Generally, the families that ranked in the top 10% at the highest nitrogen level were above average at all other levels.

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