Genetic resistance of spruce to gall-forming adelgids (Hemiptera: Adelgidae)

2009 ◽  
Vol 39 (12) ◽  
pp. 2536-2541 ◽  
Author(s):  
B. Bains ◽  
F. Isik ◽  
W.B. Strong ◽  
B. Jaquish ◽  
J.A. McLean ◽  
...  
Keyword(s):  
Genetic Control ◽  
Genetic Resistance ◽  
Gall Formation ◽  
Narrow Sense Heritability ◽  
Seed Loss ◽  
Interior Spruce ◽  
High Heritability ◽  
Sib Families ◽  
Selection For ◽  
Partial Diallel

Adelgids (Hemiptera: Adelgidae) gall vegetative and reproductive shoots of interior spruce (Picea spp.), causing growth impairment, seed loss, and aesthetic decline. We tested the theory that susceptibility to galling is under genetic control in spruce. We assessed natural galling incidence in a spruce progeny test located in southern British Columbia. The experiment was composed of a replicated 13-parent incomplete, partial diallel with 42 full-sib families. Moderate evidence of genetic control of susceptibility–resistance was observed with individual narrow-sense heritability of 0.17. We observed considerable genetic variation among parents for resistance to gall formation as shown by high heritability (0.87) of family means. Breeding values for parental susceptibility to adelgid attack ranged between 0.25 and 0.76, indicating that selection for reduced susceptibility would be successful. The benefits of screening for resistance to adelgid attack are discussed in relation to adelgid pest management, insect’s life-cycle, and tree health.

Genetic control of wood density profile in young Douglas-fir

1991 ◽  
Vol 21 (6) ◽  
pp. 935-939 ◽  
Author(s):  
J. A. Loo-Dinkins ◽  
J. S. Gonzalez
Keyword(s):  
Relative Density ◽  
Genetic Control ◽  
Density Profile ◽  
Douglas Fir ◽  
Breast Height ◽  
Cambial Age ◽  
Sib Families ◽  
Progeny Tests ◽  
Selection For ◽  
The Difference

The relative density profile from pith to bark was examined in young Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stems at 1.3, 0.7, and 0.4 m above the ground. The trees represented 22 half-sib families growing at two progeny test locations. The objective was to evaluate the reliability of wood samples taken from below breast height (1.3 m) for selection for relative density in young coastal Douglas-fir progeny tests. The relative density profile appeared to be different for the first 6 or 7 years from the pith at the different sampling heights, but the difference decreased with cambial age. Genetic correlation estimates were sufficiently high to indicate identical genetic control at the three sampling heights, but heritability estimates were higher at 1.3 and 0.7 m than at 0.4 m. Sampling at 0.7 m is as effective as at 1.3 m. This allows reliable selection 1 to 2 years earlier than by sampling at 1.3 m.

scholarly journals Assessing gene action for hypoxia tolerance in cotton (Gossypium hirsutum L.)

2019 ◽  
pp. 51-62
Author(s):  
Altaf Hussain ◽  
Zafar Ullah Zafar ◽  
Habib-Ur-Rehman Athar ◽  
Jehanzeb Farooq ◽  
Saghir Ahmad ◽  
...  
Keyword(s):  
Genetic Effects ◽  
Hypoxia Tolerance ◽  
Narrow Sense Heritability ◽  
Partial Dominance ◽  
Additive Component ◽  
Hypoxic Environment ◽  
High Heritability ◽  
Selection For ◽  
Additive Genetic Effects ◽  
F1 Generation

Introduction. The inheritance studies on hypoxia tolerance in cotton are very scanty. Objective. The objective of this work was to study the inheritance pattern of seed cotton yield, ginning out-turn, and fiber length under normal and hypoxia conditions. Materials and Methods. An 8•8 diallel mating system was employed in F1 generation of cotton. The experiment was conducted during the years 2011-2012 at Cotton Research Institute, Multan, Pakistan. Results. Analysis of variance revealed significant variation (P<0.01) for all the traits under both non-stress and flooding stress conditions. The value of regression coefficient b deviated significantly from zero but not from unity for all the traits which enabled further analysis of the data. The additive component (D) was significant for all the traits and this has more values than the values of dominance components H1 and H2, which clearly indicates the preponderance of additive genetic effects. Under normal and hypoxia conditions the estimates of narrow sense heritability were higher. Conclusion. Predominance of additive genetic effects, high heritability along with partial dominance under both conditions suggested that selection for these traits under hypoxic environment at early generation will be useful.

Genetic control of mineral concentration and yield in perennial ryegrass (Lolium perenne L.), with special emphasis on minerals related to grass tetany

1999 ◽  
Vol 50 (1) ◽  
pp. 79 ◽  
Author(s):  
K. F. Smith ◽  
G. J. Rebetzke ◽  
H. A. Eagles ◽  
M. W. Anderson ◽  
H. S. Easton
Keyword(s):  
Genetic Correlation ◽  
Genetic Control ◽  
Perennial Ryegrass ◽  
Early Spring ◽  
Family Selection ◽  
Mineral Concentration ◽  
Sib Families ◽  
Selection For ◽  
Mineral Concentrations ◽  
Low K

Grass tetany is a common metabolic disorder of ruminants in southern Australia. To investigate the genetic control of mineral concentrations leading to this disorder, replicate populations of perennial ryegrass half-sib families were grown at Hamilton and Timboon in southern Australia. Variation in herbage yield, and Mg, P, K, Ca, Na, Cl, S, Mn, Fe, Cu, Zn, and K/(Mg+Ca) (tetany ratio) concentrations in the herbage of these families was measured in the early spring of 1994. Large environmental effects on herbage mineral concentration were detected, with location differences accounting for 60–80% of the total variance. Both the mean and range for mineral concentration were similar for each population. As expected, Mg, Ca, and K were significantly correlated with tetany ratio; however, the concentrations of other minerals were not consistently associated with tetany ratio. Tetany ratio and Mg showed a negative genetic correlation in both groups. The genetic correlation for tetany ratio with K or Ca was less repeatable across groups. Significant family variance components (σ2f) were detected for yield, Mg, Ca, K, and tetany ratio, and narrow-sense heritabilities for these traits were moderate to high (h2 = 0·46–0·81). However, family location interactions were also significant, with σ2fl often >σ2f. A large proportion of the family location interaction for K and Mg concentration was associated with non-rank family changes indicating that family selection for low K or high Mg concentration would be effective across environments. However, family × location effects for Ca and tetany ratio were associated with substantial rank changes across locations. Selection for increased Mg concentration would appear the most suitable strategy for reducing the tetany ratio of perennial ryegrass, with possibly different cultivars required for the environments represented by Hamilton and Timboon.

Genetic control of kraft pulp yield in Eucalyptus globulus

2010 ◽  
Vol 40 (5) ◽  
pp. 917-927 ◽  
Author(s):  
Desmond J. Stackpole ◽  
René E. Vaillancourt ◽  
Geoffrey M. Downes ◽  
Christopher E. Harwood ◽  
Brad M. Potts
Keyword(s):  
Genetic Control ◽  
Eucalyptus Globulus ◽  
Kraft Pulp ◽  
Near Infrared ◽  
Genetic Correlations ◽  
Basic Density ◽  
Pulp Yield ◽  
Narrow Sense Heritability ◽  
Selection Gradients ◽  
Economic Worth

Pulp yield is an important breeding objective for Eucalyptus globulus Labill., but evaluation of its genetic control and genetic correlations with other traits has been limited by its high assessment cost. We used near infrared spectroscopy to study genetic variation in pulp yield and other traits in a 16-year-old E. globulus trial. Pulp yield was predicted for 2165 trees from 467 open-pollinated families from 17 geographic subraces. Significant differences between subraces and between families within subraces were detected for all traits. The high pulp yield of southern Tasmanian subraces suggested that their economic worth was previously underestimated. The narrow-sense heritability of pulp yield was medium (0.40). The significant positive genetic correlation between pulp yield and diameter (0.52) was at odds with the generally neutral values reported. The average of the reported genetic correlations between pulp yield and basic density (0.50) was also at odds with our nonsignificant estimate. Pulp yield of the subraces increased with increasing latitude, producing a negative correlation with density (–0.58). The absence of genetic correlations within subraces between pulp yield and density suggests that the correlation may be an independent response of the two traits to the same or different selection gradients that vary with latitude.

scholarly journals Genetic characterization of carrot root shape and size using genome-wide association analysis and genomic-estimated breeding values

2021 ◽  
Author(s):  
Scott H. Brainard ◽  
Shelby L. Ellison ◽  
Philipp W. Simon ◽  
Julie C. Dawson ◽  
Irwin L. Goldman
Keyword(s):  
Image Analysis ◽  
Genetic Control ◽  
Digital Image Analysis ◽  
Genome Wide Association ◽  
Carrot Root ◽  
Size And Shape ◽  
Genome Wide ◽  
Market Class ◽  
Selection For ◽  
Estimated Breeding Values

Abstract Key message The principal phenotypic determinants of market class in carrot—the size and shape of the root—are under primarily additive, but also highly polygenic, genetic control. Abstract The size and shape of carrot roots are the primary determinants not only of yield, but also market class. These quantitative phenotypes have historically been challenging to objectively evaluate, and thus subjective visual assessment of market class remains the primary method by which selection for these traits is performed. However, advancements in digital image analysis have recently made possible the high-throughput quantification of size and shape attributes. It is therefore now feasible to utilize modern methods of genetic analysis to investigate the genetic control of root morphology. To this end, this study utilized both genome wide association analysis (GWAS) and genomic-estimated breeding values (GEBVs) and demonstrated that the components of market class are highly polygenic traits, likely under the influence of many small effect QTL. Relatively large proportions of additive genetic variance for many of the component phenotypes support high predictive ability of GEBVs; average prediction ability across underlying market class traits was 0.67. GWAS identified multiple QTL for four of the phenotypes which compose market class: length, aspect ratio, maximum width, and root fill, a previously uncharacterized trait which represents the size-independent portion of carrot root shape. By combining digital image analysis with GWAS and GEBVs, this study represents a novel advance in our understanding of the genetic control of market class in carrot. The immediate practical utility and viability of genomic selection for carrot market class is also described, and concrete guidelines for the design of training populations are provided.

scholarly journals Variability, Heritability, Genetic Advance and Interrelationships for Agronomic and Yield Traits of Sorghum B-Lines under Different Environments

2018 ◽  
pp. 1-13
Author(s):  
A. M. M. Al-Naggar ◽  
R. M. Abd El-Salam ◽  
M. R. A. Hovny ◽  
Walaa Y. S. Yaseen
Keyword(s):  
Grain Yield ◽  
Coefficient Of Variation ◽  
Block Design ◽  
Selection Criterion ◽  
Genetic Advance ◽  
Planting Dates ◽  
High Heritability ◽  
Selection For ◽  
Strength Of Association ◽  
B Lines

Information on heritability and trait association in crops assist breeders to allocate resources necessary to effectively select for desired traits and to achieve maximum genetic gain with little time and resources. The objectives of this investigation were to determine the amount of genetic variability, heritability, genetic advance and strength of association of yield related traits among sorghum lines under different environments in Egypt. Six environments with 25 sorghum B-lines were at two locations in Egypt (Giza and Shandaweel) in two years and two planting dates in one location (Giza). A randomized complete block design was used in each environment with three replications. Significant variation was observed among sorghum lines for all studied traits in all environments. Across environments, grain yield/plant (GYPP) showed positive and significant correlations with number of grains/plant (r = 0.71), days to flowering (r = 0.47), 1000-grain weight (r = 0.16) and plant height (PH) (r = 0.19). In general, the estimates of phenotypic coefficient of variation (PCV) were higher than genotypic coefficient of variation (GCV). Combined across the six environments, the highest PCV and GCV was shown by PH trait (95.14 and 43.57%) followed by GYPP (36.42 and 30.78%), respectively, indicating that selection for high values of these traits of sorghum would be effective. GYPP and PH traits showed high heritability associated with high genetic advance from selection, indicating that there are good opportunities to get success in improvement of these traits via selection procedures. Results concluded that PH is good selection criterion for GYPP and therefore selection for tall sorghum plants would increase grain yield.

Preliminary evaluation of genetic variation of weevil resistance in interior spruce in British Columbia

1991 ◽  
Vol 21 (2) ◽  
pp. 230-234 ◽  
Author(s):  
G. K. Kiss ◽  
A. D. Yanchuk
Keyword(s):  
British Columbia ◽  
Genetic Basis ◽  
Diameter Growth ◽  
Preliminary Evaluation ◽  
White Pine ◽  
North Central ◽  
Interior Spruce ◽  
Progeny Tests ◽  
Selection For ◽  
White Pine Weevil

White pine weevil (Pissodesstrobi (Peck)) damage in three interior spruce open-pollinated progeny tests in north central British Columbia was evaluated to examine the patterns of attack among families. While the overall incidence of damage was different across sites (i.e., Quesnel 9%, Red Rock 37%, and Aleza Lake 63%), correlations on a family-mean basis (percentage attacked per family) at Red Rock and Quesnel as well as Red Rock and Aleza Lake were significant (r = 0.63 and 0.71, respectively). Estimates of family heritability across sites for damage was high (hf = 0.77 ± 0.11), but individual heritability was only moderate (hi = 0.18 ± 0.03). More vigorous families, as determined by 10-year family mean height superiority prior to weevil attack, were damaged less frequently than those with average and poorer performance. Negative correlations of mean family height at 10 years of age with incidence of damage (on a family-mean basis) and mean family diameter with incidence of damage were significant (r = −0.51 and −0.44, respectively). These data suggest that there is a moderate genetic basis for resistance to weevil attack in interior spruce and that selection for height and diameter growth may improve resistance to weevil attack.

Modelling responses to selection for resistance to gastro-intestinal parasites in sheep

1997 ◽  
Vol 64 (3) ◽  
pp. 469-478 ◽  
Author(s):  
S. C. Bishop ◽  
M. J. Stear
Keyword(s):  
Intestinal Parasites ◽  
Genetic Resistance ◽  
Response To Selection ◽  
Disease Epidemiology ◽  
Count Distribution ◽  
Faecal Egg Count ◽  
Pasture Contamination ◽  
Selection For ◽  
Contamination Levels ◽  
Carry Over

AbstractThis paper describes a general framework which enables responses to selection for resistance to gastro-intestinal parasites in sheep to be stochastically modelled. The model incorporates between-animal variation for pasture intake, the proportion of larvae ingested from the pasture which survive to become adults, the fecundity of the mature worm, along with density-dependent control of this trait and the mortality rate of the worms. The between-animal variation for each component is partitioned into genetic, permanent and temporary environmental components which vary with age. Infection rates are estimated from existing pasture larval contamination and new contamination from infected animals. Using this framework, selection for reduced mean faecal egg count was practised, in silico, for a period of 10 years. Several general patterns emerged. First, a curvilinear response to selection was observed, with responses initially being large then declining over time. Mean faecal egg count declined from approximately 500 to 140 eggs per gin 10 years and worm burdens and pasture larval contamination showed similar patterns of response. The initial responses to selection were approximately 1·7 times that predicted by quantitative genetic theory because the epidemiology of the disease changed as the animals' genetic resistance improved. A method of partitioning selection responses into components due to the altered genotypes of the animals and components due to altered disease epidemiology is outlined. Secondly, the faecal egg count distribution became more aggregated, or skewed, as selection progressed. Thirdly, correlating pasture contamination levels across years (carry-over effects) resulted in even greater apparent responses to selection. Finally, regular anihelmintic treatment reduced mean faecal egg counts but did not alter the patterns of response to selection, indicating that selective breeding should be feasible under a variety of anthelmintic regimes.

scholarly journals Heritability for Yield and Glycoalkaloid Content in Potato Breeding under Warm Environments

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Manuel A. Gastelo Benavides ◽  
Luis Diaz ◽  
Gabriela Burgos ◽  
Thomas Zum Felde ◽  
Merideth Bonierbale
Keyword(s):  
Tuber Yield ◽  
Block Design ◽  
Potato Production ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Glycoalkaloid Content ◽  
High Heritability ◽  
Heat Tolerant ◽  
Broadsense Heritability ◽  
The Tropics

AbstractHigh temperatures affect potato production in the tropics, putting tuber yield and quality at risk and leading to increased glycoalkaloid concentration the cause of the bitter taste in potatoes and a cause for concern for human health. The International Potato Center (CIP), has developed new heat tolerant clones which are heat tolerant and also resistant to late blight. These clones offer an opportunity to evaluate yield and glycoalkaloid levels after growth under high temperature environments. We evaluated four sets of 16 full-sib families and 20 clones for tuber yield and glycoalkaloid content in order to estimate narrow-sense and broad-sense heritability respectively. We used a randomized complete block design replicated in three locations in Peru; San Ramon, La Molina and Majes At harvest, the number and weight of marketable and nonmarketable tubers were recorded. We analyzed samples of tubers from each clone for glycoalkaloid content using spectrophotometry. Narrow-sense heritability for tuber yield, tuber number and average tuber weight were 0.41, 0.50 and 0.83, respectively, indicating that further gains in breeding for heat tolerance will be possible. Broadsense heritability for glycoalkaloid content was 0.63 and correlation with tuber yield was weak, r=0.33 and R²=0.11 (P<0.01). High heritability and weak correlation will allow us to select clones with high tuber yield and low glycoalkaloid content, to serve as candidate varieties and parents in breeding programs.

GENETIC SOURCES OF RESISTANCE TO BLACKBIRD PREDATION IN SUNFLOWER

1986 ◽  
Vol 66 (1) ◽  
pp. 19-23 ◽  
Author(s):  
DAN E. PARFITT ◽  
GREGORY J. FOX
Keyword(s):  
Agelaius Phoeniceus ◽  
Narrow Sense ◽  
Sources Of Resistance ◽  
Bird Predation ◽  
Narrow Sense Heritability ◽  
The Third ◽  
Naturally Occurring ◽  
Xanthocephalus Xanthocephalus ◽  
Sib Families ◽  
Highly Correlated

Fifty-one sunflower (Helianthus annuus L.) inbreds were grown at three environments (locations) in North Dakota. Inbreds at two locations were subjected to naturally occurring bird predation by redwinged blackbirds (Agelaius phoeniceus L.) and yellowheaded blackbirds (Xanthocephalus xanthocephalus Bonaparte). The third sunflower plot was surrounded by a cage into which redwinged blackbirds were introduced. Bird damage was estimated as percent achenes removed from individual sunflower heads. Significant differences among environments were observed (P < 0.01). However, genotype performance among environments was highly correlated (P < 0.01). Half sib progeny from 36 of these inbreds were grown along with their maternal inbred parents to estimate narrow sense heritability (h2NS) of resistance to bird predation. Estimates of h2NS obtained by parent offspring regression and by covariance among half-sib families were h2NS = 0.69 and h2NS = 0.66, respectively. These estimates indicate a 67% level of heritability for resistance to bird predation, and suggest that it should be possible to develop sunflower lines with improved resistance.Key words: Sunflower, bird feeding, redwinged blackbird, yellowheaded blackbird

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