Breeding for creeping root in lucerne (Medicago sativa L.). I. The inital response to selection

1962 ◽  
Vol 13 (5) ◽  
pp. 813 ◽  
Author(s):  
H Daday
Keyword(s):  
Correlation Coefficients ◽  
Phenotypic Variance ◽  
Response To Selection ◽  
Gene Effects ◽  
Plant Vigour ◽  
Additive Gene ◽  
F2 Generation ◽  
Additive Genetic Effects ◽  
Short Days ◽  
F1 Generation

A lucerne-breeding programme was initiated in Canberra to combine the creeping-rooted habit of the variety Rambler with the summer and winter vigour of the varieties Hunter River, Hairy Peruvian, and African. The incidence of creeping-rooted plants in the "F1" generation was only 5%, which indicated marked non-additive gene effects concerned with the expression of the character. An "F2" generation, formed by interbreeding creeping plants from the "F1", showed only 6% of creeping individuals. Selection and recombination of the available creepers resulted in an average of 41% creeping-rooted plants in the "F3" families, with a range between families from 0 to 81%. In the "F2" generation approximately 50% of the phenotypic variance for creeping root was found to be additive genetic, and the response to selection was high. However, the persistence of non-additive genetic effects was indicated by a statistical analysis of the '"F3" generation. The genotypic correlation coefficients between creeping and summer forage scores, and creeping and winter forage scores, were –0.09 and 0.59 respectively, and that between summer and winter forage scores was 0.48. Thus an association between creeping rootedness and plant vigour is possible. For Rambler, both the incidence and degree of creep were found to be intensified by short days and low temperature, but this effect was not so apparent in the breeding material used in this study.

The Science of Breeding and Its Application to the Breeder Genetic Algorithm (BGA)

1993 ◽  
Vol 1 (4) ◽  
pp. 335-360 ◽  
Author(s):  
Heinz Mühlenbein ◽  
Dirk Schlierkamp-Voosen
Keyword(s):  
Genetic Algorithm ◽  
Genetic Variance ◽  
Response To Selection ◽  
Gene Effects ◽  
Fitness Functions ◽  
Additive Gene ◽  
Regression Techniques ◽  
Algorithm Theory ◽  
And Control ◽  
Theoretical Results

The breeder genetic algorithm (BGA) models artificial selection as performed by human breeders. The science of breeding is based on advanced statistical methods. In this paper a connection between genetic algorithm theory and the science of breeding is made. We show how the response to selection equation and the concept of heritability can be applied to predict the behavior of the BGA. Selection, recombination, and mutation are analyzed within this framework. It is shown that recombination and mutation are complementary search operators. The theoretical results are obtained under the assumption of additive gene effects. For general fitness landscapes, regression techniques for estimating the heritability are used to analyze and control the BGA. The method of decomposing the genetic variance into an additive and a nonadditive part connects the case of additive fitness functions with the general case.

scholarly journals Correlations and Heritability of the Characters Determining the Seed Yield of the Panicle Inflorescence Forms of Alfalfa (Medicago x varia T. Martyn)

2016 ◽  
Vol 74 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Zbigniew Bodzon
Keyword(s):  
Seed Yield ◽  
Correlation Coefficients ◽  
Yield Potential ◽  
Phenotypic Correlation ◽  
Phenotypic Variance ◽  
Selection For ◽  
Additive Genetic Effects ◽  
Pod Number ◽  
Number Of Seeds ◽  
Number Of Branches

Abstract Phenotypic correlation coefficients and heritability of the characters determining seed yield of panicle inflorescence forms of alfalfa was examined. Seed yield per plant, which was positively correlated with 10 generative and morphological traits, depended upon the number of pods per panicle and the number of seeds per pod. Variability of these characters determined about 60% of the variability of seed yield. Multiple linear regression and phenotypic correlations show that simultaneous selection for increased pod number per panicle and increased seed number per pod and number of branches per panicle resulted in enhanced seed yield potential. The share of the additive genetic effects in the phenotypic variance for number of pods per panicle was low and about 23%, while for number of seeds per pod and seeds per panicle amounted to about 75-77% and 56-57% respectively.

scholarly journals Inheritance of stem height and second-internode length in barley hybrids

Genetika ◽  
2009 ◽  
Vol 41 (3) ◽  
pp. 229-236 ◽  
Author(s):  
Milomirka Madic ◽  
Desimir Knezevic ◽  
Aleksandar Paunovic ◽  
Veselinka Zecevic
Keyword(s):  
Dominant Gene ◽  
Internode Length ◽  
Stem Height ◽  
Lodging Resistance ◽  
Gene Effects ◽  
Partial Dominance ◽  
Degree Of Dominance ◽  
Basal Internode ◽  
F2 Generation ◽  
F1 Generation

Stem height and second (basal) internode are highly important components of lodging resistance in barley. A diallel crossing of five divergent barley genotypes (KG-1/90, NS-293, Jagodinac, KG-15 and KG-10/90) was carried out in order to examine the modes of inheritance of stem height and second-internode length. The dominance of a parent with a higher stem was the prevailing mode of stem height inheritance in most of the combinations in F1 and F2 generations, the degree of dominance ranging from partial to superdominance. Partial dominance mostly occurred in the inheritance of second-internode length in most crossing combinations. An analysis of genetic variance components showed that the dominant gene effect was the most contributing factor to the inheritance of stem height. Additive effect genes prevailed in the inheritance of second-internode length in the F1 generation. Both additive and dominant gene effects played an important role in the F2 generation.

scholarly journals Demographic determinants of biometric heritability

2018 ◽  
Author(s):  
Julia A. Barthold ◽  
Floriane Plard ◽  
Jean-Michel Gaillard ◽  
Tim Coulson ◽  
Shripad Tuljapurkar
Keyword(s):  
Parental Effects ◽  
Phenotypic Variance ◽  
Confounding Factors ◽  
Response To Selection ◽  
Viability Selection ◽  
Integral Projection ◽  
Quantitative Characters ◽  
Demographic Processes ◽  
Additive Genetic Effects ◽  
Fertility Selection

AbstractThe response of quantitative characters to selection depends on their transmission from parents to offspring. A common estimate of this transmission is the biometric heritability defined as the slope of the regression of offspring phenotype on same-aged mid-parent phenotype (i.e. the ratio of the phenotypic parent-offspring covariance over the parental phenotypic variance). This slope is often interpreted as the percentage of phenotypic variation due to additive genetic effects after accounting for confounding factors such as environment, litter or parental effects. However, researchers seldom account for the possible influence of selection on this estimate. Here we study the effect on biometric heritability of fertility and viability selection, as well as phenotype ontogeny (growth) and inheritance from parents to offspring. We present exact formulas for the elasticities of biometric heritability in age-phenotype-structured integral projection models (IPMs), and illustrate these for two iteroparous long-lived species. We find that both viability and fertility selection can strongly affect heritability, mediated by growth and inheritance. Generally, demographic processes that result in parents reproducing at large phenotypes, regardless of their own birth phenotype, decrease heritability. Analysed at equilibrium, our models imply that a heritable character can show no response to selection, if parental phenotypes affect offspring phenotypes and if phenotypes develop with age. Our results further highlight the importance of accounting for demographic processes when estimating heritability.

Estimating the heritability of butterfat production

1961 ◽  
Vol 57 (3) ◽  
pp. 289-294 ◽  
Author(s):  
S. R. Searle
Keyword(s):  
Genetic Variation ◽  
New Zealand ◽  
Dairy Cows ◽  
Total Variance ◽  
Additive Effects ◽  
Narrow Sense ◽  
Sampling Errors ◽  
Gene Effects ◽  
Additive Gene Effects ◽  
Additive Gene

Part of the variation among butterfat yields in dairy cows arises from genetic differences among the animals. The proportion which this bears to the total variance is known as heritability. In the ‘narrow’ sense it is defined (Lush, 1940), as the proportion of the total variance that is due to additive gene effects; the ‘broad’ sense definition includes genetic variation arising from non-additive gene effects as well as that due to additive effects. Since related animals have a proportion of their genes in common the covariance among their production records can be used for estimating genetic variation and hence heritability. This paper discusses three groups of related animals most frequently used for this purpose, twins, daughter-dam pairs and paternal half-sibs, and presents the results of analysing production records of artificially bred heifers in New Zealand, including evidence of the magnitude of the sampling errors of the heritability estimates.

scholarly journals Genetic parameters and combining ability of some important traits in rice (Oryza sativa L.)

Genetika ◽  
2017 ◽  
Vol 49 (3) ◽  
pp. 1001-1014 ◽  
Author(s):  
Hasanalideh Haghighi ◽  
Ezatollah Farshadfar ◽  
Mehrzad Allahgholipour
Keyword(s):  
Combining Ability ◽  
Genetic Parameters ◽  
Amylose Content ◽  
Oryza Sativa L ◽  
Block Design ◽  
Regression Line ◽  
Diallel Cross ◽  
Combining Ability Analysis ◽  
Additive Gene ◽  
F2 Generation

In order to study the combining ability, genetic parameters and gene actions of yield, yield components and quality characters in rice, fifteen F2 generation of a 6?6 diallel cross, excluding reciprocals, was grown in a randomized complete block design (RCBD) with three replications. The results of analysis of variance showed significant differences between the genotypes for grain yield (GY), 100-grain weight (HGW), number of panicles per plant (PN), panicle length (PL), number of full grains per panicle (FGN) and for quality characters including amylose content (AC) and gel consistency (GC). The results of combining ability analysis revealed that general combining ability (GCA) and specific combining ability (SCA) were significant for characters GY, FGN, GC, AC, HGW and PN indicating the involvement of additive and non-additive effects in their inheritance, however high amounts of Bakers ratio remarked that additive gene effect had more portion in controlling these traits. The best combiners for GY, HGW, FGN, PN and PL, were RI18447-2, IR 50, Daylamani, RI18430-46 and Daylamani respectively. For AC and GC, the best combiner was Daylamani. Hayman's graphs showed that regression line passed below the origin cutting Wr axis in the negative region for HGW, PN, PL and GC, indicating the presence of over dominance. Estimates of genetic parameters showed significant amount of H1 and H2, and non-significant amount of D for the characters GY, PN, PL and GC, which confirmed the existence of dominance in the inheritance of these traits.

scholarly journals Identification of Heterotic Pairs by Full-Sib Reciprocal Recurrent Selection in Maize Synthetic Populations on Turda CompositeA(B)(2) x Turda CompositeB(A)(2)

2013 ◽  
Vol 70 (1) ◽  
pp. 208-213
Author(s):  
Andreea Daniela ONA ◽  
Ioan HAȘ ◽  
Ivan ILARIE ◽  
Voichița HAȘ ◽  
Nicolae TRITEAN ◽  
...  
Keyword(s):  
Recurrent Selection ◽  
Inbred Lines ◽  
Heterotic Group ◽  
Yield Potential ◽  
Reciprocal Recurrent Selection ◽  
Maize Breeding ◽  
Gene Effects ◽  
Synthetic Populations ◽  
Additive Gene ◽  
Selection Test

In the last 40 years, pre-breeding works induced, in more and more centers of maize breeding, full-sib reciprocal recurrent selection programmes to identify some heterotic pairs which can be sources for obtaining performance inbred lines. The aim is to identify the heterotic pairs with the best results according to the yield potential of maize, the breaking and falling resistance, and the grains moisture at the harvesting time. The creation programme of A and B composite population started at ARDS Turda in 1985. Inside of A composite came the next inbred lines: B73, A632, M117, TC209, T291, being from the B SSS heterotic group, and inside of B composite came the inbred lines Mo17, C103, TC 208, T248, W633, appreciated by us or being related to Lancaster Sure Crop heterotic group. The experimentation was done in two orientation comparative cultures, each one with 49 variants, in 4 repetitions; the comparative culture was a balanced quadratic grid of 7x7 type. From each culture were chosen the first six variants, which were evaluated according to the next characters: production potential, breaking and falling resistance, grains moisture at harvest. The presented results are a part from the second cycle of full-sib reciprocal recurrent selection. Test crosses and self-pollinations were made on plants from the two composites which had two cobs; on the first cob from A Composite realised the cross with the corresponding plant from the B Composite, and from the plant panicle of the B Composite was collected pollen to pollinate the chosen plant from the A Composite. At the both plants from the crossing, the second cob was self-pollinated and kept in reserve until 2010, when the test crosses was experimented and were selected the pairs with the best results according to the above characters. Using the full-sib reciprocal recurrent selection, we can successfully harnessing, simultaneously, the additive and non-additive gene effects.

scholarly journals Diallel Analysis for Area, Chlorophyll and Temperature of Flag Leaf in Bread Wheat under Well Watered and Drought Stress Conditions

2021 ◽  
Vol 13 (10) ◽  
pp. 45
Author(s):  
Naheif E. Mohamed ◽  
Ismail M. Bedawy ◽  
Yasser A. M. Hefny
Keyword(s):  
Drought Stress ◽  
Bread Wheat ◽  
Flag Leaf ◽  
Block Design ◽  
Diallel Analysis ◽  
Stress Conditions ◽  
F1 Hybrids ◽  
Gene Effects ◽  
Genetic Components ◽  
Additive Gene

To study genetic analysis of some physiological traits of drought stress in wheat using diallel techniques, an experiment was performed on ten bread wheat genotypes as parents and their 45 F1 hybrids in a randomized complete block design with three replicates under well-watered and drought stress conditions at the Research Farm of Faculty of Agriculture, Sohag University, Egypt during season of 2018/19. The results showed significant differences between the genotypes (G), Parents (P), F1 crosses, P vs. F1, GCA and SCA under well-watered and drought stress in the flag leaf area (FLA), flag leaf chlorophyll content (FLCC) and flag leaf temperature (FLT), except FLCC for F1 crosses exhibited insignificant differences. The significant differences were found in the interaction of SCA × Env., in all studied traits and GCA × Env., for FLT., indicating the involvement of both additive and dominance gene action in their inheritance. The most desirable heterotic effects were considered as the largest positive heterosis estimates for FLA and FLCC, and the lowest negative for FLT. The parent numbers P9, P8 and P3 were the best general combiner for FLA under normal irrigation and drought stress. While the parents P2, P7 and P9 were the best general combiner for FLCC, under normal irrigation and (P1, P2 and P3) under drought stress. Therefor the parents P1, P4 and P5 were the best general combiner for FLT under normal irrigation, also the P3, P4 and P5 were the best general combiner for FLT under drought stress conditions. Under normal irrigation and drought stress conditions as well as the combined data, the additive genetic components of variation (VA) in F1 ’s was much greater than dominance component (VD), as expressed by the (VA/VD) ratio which was more than unity for the FLA, and FLT under normal irrigation and their combined. This indicates that the additive gene effects in F1 crosses are more important than dominance and plays the major role in the inheritance of these studied traits.

scholarly journals Genetic variance of sunflower yield components - Heliantus annuus L.

Genetika ◽  
2003 ◽  
Vol 35 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Nada Hladni ◽  
Dragan Skoric ◽  
Marija Kraljevic-Balalic
Keyword(s):  
Leaf Area ◽  
Plant Height ◽  
Leaf Number ◽  
Total Leaf Area ◽  
Gene Effects ◽  
Partial Dominance ◽  
Mean Values ◽  
Total Leaf ◽  
Additive Gene ◽  
Mode Of Inheritance

The main goals of sunflower breeding in Yugoslavia and abroad are increased seed yield and oil content per unit area and increased resistance to diseases, insects and stress conditions via an optimization of plant architecture. In order to determine the mode of inheritance, gene effects and correlations of total leaf number per plant, total leaf area and plant height, six genetically divergent inbred lines of sunflower were subjected to half diallel crosses. Significant differences in mean values of all the traits were found in the F1 and F2 generations. Additive gene effects were more important in the inheritance of total leaf number per plant and plant height, while in the case of total leaf area per plant the nonadditive ones were more important looking at all the combinations in the F1 and F2 generations. The average degree of dominance (Hi/D)1/2 was lower than one for total leaf number per plant and plant height, so the mode of inheritance was partial dominance, while with total leaf area the value was higher than one, indicating super dominance as the mode of inheritance. Significant positive correlation was found: between total leaf area per plant and total leaf number per plant (0.285*) and plant height (0.278*). The results of the study are of importance for further sunflower breeding work.

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