scholarly journals Genetic Variation and Effects of Individual Selection for Double Ovules and Bigerm Fruits of Monogerm Sugar Beet.

2002 ◽  
Vol 4 (4) ◽  
pp. 201-208
Author(s):  
Naoki Ogata ◽  
Masakatsu Tanaka
Keyword(s):  
Genetic Variation ◽  
Sugar Beet ◽  
Individual Selection ◽  
Selection For

Genetic variation in fatty acid composition of subcutaneous fat in cattle

2013 ◽  
Vol 53 (2) ◽  
pp. 129 ◽  
Author(s):  
M. J. Kelly ◽  
R. K. Tume ◽  
S. Newman ◽  
J. M. Thompson
Keyword(s):  
Fatty Acids ◽  
Genetic Variation ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Saturated Fatty Acids ◽  
Genetic Correlations ◽  
Subcutaneous Fat ◽  
Monounsaturated Fatty Acids ◽  
Selection For

Genetic parameters were estimated for fatty acid composition of subcutaneous beef fat of 1573 animals which were the progeny of 157 sires across seven breeds grown out on pasture and then finished on either grain or grass in northern New South Wales or in central Queensland. There was genetic variation in individual fatty acids with estimates of heritability for the proportions of C14 : 0, C14 : 1c9, C16 : 0, C16 : 1c9, C18 : 0 and C18 : 1c9 fatty acids in subcutaneous beef fat of the order of 0.4 or above. Also substantial correlations between some fatty acids were observed. Genetic correlations between fatty acids and fat depth at the P8 site suggested that much of the genetic variation in fatty acid composition was related to changes in fatness. Selection for decreased fatness resulted in decreased proportions of C18 : 1c9 with concomitant increases in C18 : 0, C14 : 0 and C16 : 0. This suggested that selection for decreased fatness at a given weight will result in a decrease in the proportions of monounsaturated fatty acids in the subcutaneous fat in the carcass with a corresponding increase in the proportions of saturated fatty acids.

Genetic parameters and responses to selection for pre-weaning growth in suffolk and texel sheep

1995 ◽  
Vol 1995 ◽  
pp. 48-48
Author(s):  
I.W. Purvis ◽  
J.P. Hanrahan
Keyword(s):  
Growth Rate ◽  
Genetic Variation ◽  
Genetic Gain ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Present Report ◽  
Growth Data ◽  
Genetic Trend ◽  
Breeding Objective ◽  
Selection For

In order to evaluate genetic gain in populations under selection it is necessary to be able to partition the observed response into genetic and environmental components. This requires estimates of the appropriate genetic and environmental (co)variances unless appropriate genetic controls are available. Growth rate is an important component of the breeding objective for sheep breeds used as terminal sires and, whereas older estimates of the contribution of genetic variation to differences in preweaning growth indicated heritabilities of the order of 0.1, more recent studies have indicated considerably higher values. The present report concerns analyses of preweaning growth data on purebred Suffolk and Texel sheep to estimate genetic parameters for preweaning growth traits and genetic trend in growth rate from birth to weaning.

scholarly journals Selection Criteria for Drought-Tolerant Bread Wheat Genotypes at Seedling Stage

2019 ◽  
Vol 11 (9) ◽  
pp. 2584 ◽  
Author(s):  
Hafiz Ahmed ◽  
Muhammad Sajjad ◽  
Mingju Li ◽  
Muhammad Azmat ◽  
Muhammad Rizwan ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Selection Criteria ◽  
Dry Weight ◽  
Shoot Length ◽  
Seedling Stage ◽  
Chlorophyll B ◽  
Fresh Weight ◽  
Drought Tolerant ◽  
Selection For ◽  
Thermo Stability

Diminishing water resources as a result of excessive use of water for irrigation and climate change posture a severe global threat to food security. Herein, an experiment was conducted to determine the selection criteria for drought-tolerant bread wheat genotypes at the seedling stage using morphological and photosynthetic pigmentation-related traits. A panel of 105 wheat landraces, historical Pakistani varieties, and advance breeding lines were evaluated under normal and drought stress using factorial completely randomized design. The root length, fresh weight, dry weight, cell membrane thermo-stability, and chlorophyll b were positively correlated among themselves under both normal and stress conditions. Hence, selection of any one of these traits enhances the performance of other traits. The shoot length was non-significant and negatively associated with all other studied characters except relative water content. The results suggested that selection for shoot length could not improve genetic gain for drought tolerance. Out of 10 principal components (PCs), the first three PCs were showed significant genetic variation under both conditions. The first three PCs showed 74.6% and 76% cumulative genetic variation under normal and drought conditions, respectively. Based on PCA, 10 drought-tolerant and five drought-susceptible genotypes were identified. Overall results suggested that selection for root length, fresh weight, dry weight, cell membrane thermo-stability, and chlorophyll b at the seedling stage would improve genetic gain for drought tolerance. The outperforming genotypes under drought stress conditions can be useful in future wheat breeding programs, and early selection for the traits recommended in this study will be effective for developing high-yielding and drought-tolerant wheat varieties.

scholarly journals Quantitative and molecular genetic variation in sympatric populations of Medicago laciniata and M. truncatula (Fabaceae): relationships with eco-geographical factors

2007 ◽  
Vol 89 (2) ◽  
pp. 107-122 ◽  
Author(s):  
MOUNAWER BADRI ◽  
HOUCINE ILAHI ◽  
THIERRY HUGUET ◽  
MOHAMED ELARBI AOUANI
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Local Adaptation ◽  
Quantitative Traits ◽  
Gene Diversity ◽  
Sympatric Populations ◽  
Widespread Species ◽  
Geographical Factors ◽  
Significant Difference ◽  
Selection For

SummaryMedicago laciniata is restricted to south of the Mediterranean basin and it extends in Tunisia from the inferior semi-arid to Saharan stages, whereas M. truncatula is a widespread species in such areas. The genetic variability in four Tunisian sympatric populations of M. laciniata and M. truncatula was analysed using 19 quantitative traits and 20 microsatellites. We investigated the amplification transferability of 52 microsatellites developed in M. truncatula to M. laciniata. Results indicate that about 78·85% of used markers are valuable genetic markers for M. laciniata. M. laciniata displayed significantly lower quantitative differentiation among populations (QST=0·12) than did M. truncatula (QST=0·45). However, high molecular differentiations, with no significant difference, were observed in M. laciniata (FST=0·48) and M. truncatula (FST=0·47). Several quantitative traits exhibited significantly smaller QST than FST for M. laciniata, consistent with constraining selection. For M. truncatula, the majority of traits displayed no statistical difference in the level of QST and FST. Furthermore, these traits are significantly associated with eco-geographical factors, consistent with selection for local adaptation rather than genetic drift. In both species, there was no significant correlation between genetic variation at quantitative traits and molecular markers. The site-of-origin explains about 5·85% and 11·27% of total quantitative genetic variability among populations of M. laciniata and M. truncatula, respectively. Established correlations between quantitative traits and eco-geographical factors were generally more moderate for M. laciniata than for M. truncatula, suggesting that the two species exhibit different genetic bases of local adaptation to varying environmental conditions. Nevertheless, no consistent patterns of associations were found between gene diversity (He) and environmental factors in either species.

Genetic variability in time to germination of sugar-beet clusters

1971 ◽  
Vol 76 (1) ◽  
pp. 27-32 ◽  
Author(s):  
J. P. Battle ◽  
W. J. Whittington
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Sugar Beet ◽  
Maternal Effects ◽  
Diallel Cross ◽  
Wild Form ◽  
Maternal Parent ◽  
Germination Characteristics ◽  
Heritability Estimates

SUMMARYAn analysis of germination characteristics of progeny from a diallel cross between five sugar-beet plants showed that the genotype of the maternal parent controlled to a marked extent the behaviour of the progeny. This may be related to the presence in the fruits of inhibitory substances.Some evidence was found for genie and maternal interactions but these were always of less importance than the maternal effects. Heritability estimates from parent, off spring regression and analysis of half-sib family variances demonstrated that genetic variation for germination characteristics had not been eliminated during the improvement of sugar beet from the wild form.

scholarly journals Non-random X-chromosome inactivation in the mouse: difference of reaction to imprinting

1982 ◽  
Vol 39 (3) ◽  
pp. 237-259 ◽  
Author(s):  
D. S. Falconer ◽  
J. H. Isaacson ◽  
I. K. Gauld
Keyword(s):  
Genetic Variation ◽  
Chromosome Inactivation ◽  
Enzyme Assays ◽  
Linked Gene ◽  
Percentage Points ◽  
High Line ◽  
Liver And Kidney ◽  
Selection For ◽  
The Difference ◽  
Activation Probability

SummarySelection for increased and for decreased expression of the sex-linked gene brindled (Mobr) in heterozygous females produced two lines with non-random X chromosome inactivation. In the High line the X chromosome marked by brindled was active in about 60% of cells, while in the Low line it was active in about 25% of cells. The whole of the difference was caused by the chromosomes carrying brindled: neither the unmarked X chromosome nor the autosomes were differentiated. There was a positive correlation between the expression of brindled in daughters and mothers. This was probably not caused by residual genetic variation, but was more probably a maternal effect similar to that described by Cattanach & Papworth (1981). On this assumption the daughters' scores were adjusted to a standard maternal score. Enzyme assays on females doubly heterozygous for brindled and for the sex-linked Pgk-1 locus proved that the percentage of brindled in the coat provided an accurate measure of the X-inactivation proportions in the blood, liver and kidney. The accuracy was improved by adjustment for maternal score. In the selection lines, brindled was always inherited from the mother. When brindled was transmitted by male parents the probability of activation of its chromosome was increased by 8 percentage points in the High line and 18 in the Low line. This effect of the parental source is much greater than has previously been reported. The responses to selection can be interpreted in terms of the Xce locus controlling the activation probability, different alleles on the chromosomes carrying brindled being selected in the two lines. If this interpretation is correct, the alleles on one or both of the chromosomes carrying brindled were different from any of the three known alleles. The different effects of male transmission in the two lines can be described as a difference between the two chromosomes in their reactions to imprinting. This difference might possibly also be due to the Xce locus.

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