Efficiency of Selection for Increased or Decreased Recombination

1968 ◽  
Vol 102 (923) ◽  
pp. 90-93 ◽  
Author(s):  
Masatoshi Nei ◽  
Yoko Imaizumi
Keyword(s):  
Selection For ◽  
Efficiency Of Selection

scholarly journals Efficiency of Selection for Broiler Growth at Various Ages

1953 ◽  
Vol 32 (4) ◽  
pp. 716-720 ◽  
Author(s):  
G.A. Martin ◽  
E.W. Glazener ◽  
W.L. Blow
Keyword(s):  
Selection For ◽  
Efficiency Of Selection

RECURRENT SELECTION FOR FORAGE AND SEED YIELD IN ZIGZAG CLOVER

1984 ◽  
Vol 64 (1) ◽  
pp. 119-130 ◽  
Author(s):  
NORMAN L. TAYLOR ◽  
PAUL L. CORNELIUS ◽  
ROY E. SIGAFUS
Keyword(s):  
Recurrent Selection ◽  
Selection Process ◽  
Linear Increase ◽  
Rate Of Change ◽  
Forage Yield ◽  
Annual Basis ◽  
Phenotypic Recurrent Selection ◽  
Winter Temperatures ◽  
Selection For ◽  
Efficiency Of Selection

Phenotypic recurrent selection on an annual basis was conducted with zigzag clover (Trifolium medium L.) to determine the efficiency of selection for improved seed and forage yield and the relationships among these characters. Seedlings were exposed to winter temperatures in a cold frame before they were transplanted in a field in the spring. The undesirable types were mowed prior to flowering and the selected plants were allowed to cross. Heads and seeds were harvested from each plant, and after seed threshing and counting, plants were further selected on the basis of numbers of seeds and heads. The effectiveness of four cycles of selection was evaluated over a 2-yr period in an experiment initiated with remnant seed and with management similar to that imposed during the selection process. Recurrent selection was effective in increasing vigor, seeds per head, heads per plant, and seeds per plant. A significant linear increase over cycles was found for each character. Vigor was not correlated with seeds per head, but was correlated with the other characters. The more vigorous plants also exhibited less stand reduction. Data from the two evaluation years were correlated suggesting that materials selected on an annual basis performed similarly to those grown in a 2-yr stand. Although recurrent selection was effective for improving all traits, the rate of change, particularly for seeds per head, was limited. Many more cycles of such selection would be required to change zigzag clover into a useful forage species. It was suggested that the phenotypic recurrent selection program should be continued on an annual basis, but modified if possible to select against the vernalization requirement for flowering which may be associated with poor seedling growth and low aftermath vigor.Key words: Trifolium medium, recurrent selection, vigor, persistance, heads and seeds per plant

Identification and selection for salt tolerance in lucerne (Medicago sativa L.)

1984 ◽  
Vol 35 (2) ◽  
pp. 239 ◽  
Author(s):  
CL Noble ◽  
GM Halloran ◽  
DW West
Keyword(s):  
Salt Tolerance ◽  
Medicago Sativa ◽  
Recurrent Selection ◽  
Leaf Damage ◽  
Shoot Number ◽  
Two Generations ◽  
Medicago Sativa L ◽  
Selection For ◽  
Efficiency Of Selection ◽  
Chloride Concentrations

Variation existed between plants of the lucerne (Medicago sativa L.) cultivar CUF 101 for dry matter production, shoot number and length, and leaf damage when grown for 70 days under 250 mM NaCl (15 h photoperiod, 20�C day, 10�C night). Salt tolerance evaluation using the criteria percentage leaf damage (percentage of total number of leaves with complete or partial necrosis) and length of the main shoot, isolated plants which showed salt tolerance of reasonably high heritability (h2=0.41). Two generations of recurrent selection for tolerance significantly increased the mean population tolerance without decreasing production under non-saline conditions. While both sodium and chloride concentrations of the shoot were lower in the tolerant than in less tolerant plants, chloride was more closely associated with salt tolerance than sodium. Sodium and chloride concentrations in the roots did not vary with the level of salt tolerance. No association of shoot and root potassium concentration with tolerance was evident. Selection for salt tolerance in lucerne plants using percentage leaf damage of less than 10% as the main criterion should give a rapid response to selection. The efficiency of selection may be increased if selection is based on the efficiency of chloride exclusion from the shoots and/or the level of chloride tolerated by the shoots prior to leaf damage becoming evident.

GENETIC RELATIONSHIPS BETWEEN GRAIN YIELD AND YIELD COMPONENTS IN A SYNTHETIC MAIZE POPULATION AND THEIR IMPLICATIONS IN SELECTION

2001 ◽  
Vol 49 (4) ◽  
pp. 337-342 ◽  
Author(s):  
N. VASIC ◽  
M. IVANOVIC ◽  
L. A. PETERNELLI ◽  
D. JOCKOVIC ◽  
M. STOJAKOVIC ◽  
...  
Keyword(s):  
Grain Yield ◽  
Genetic Correlation ◽  
Yield Components ◽  
Genetic Relationships ◽  
Maize Population ◽  
Selection Indices ◽  
Ear Height ◽  
Selection For ◽  
Efficiency Of Selection ◽  
Simple Selection

The synthetic maize population 316PO2 was subjected to genetic correlation analyses between grain yield, yield components and morphological traits. The purpose was to enable estimates to be made of the advantage of using selection indices compared with selection based on grain yield only, and if that advantage was present, to choose enough simple selection indices for practical use. Selection indices were constructed out of four traits highly significantly correlated with grain yield, in addition to yield itself. Grain yield exhibited a highly significant additive genetic correlation with ear diameter (ra=0.588**), kernels row-1 (ra=0.643**), ears plant-1 (ra=0.871**) and ear height (ra=0.427**). The most efficient index was Index No. 14 (R.E.I12345= 108.83%), which included all four traits and grain yield. Index No. 3, one of the simplest forms of index, including only ears plant-1 and grain yield, showed slightly less relative efficiency (R.E.I35=107.24%) than Index No. 14. Using this simple form of index with two characters (Index No. 3) could improve the efficiency of selection for grain yield. The estimated advantage from its use is 179.6 kg/selection cycle for grain yield over selection based only on grain yield.

Effect of sampling errors on efficiency of selection indices. 2. Use of information on associated traits for improvement of a single important trait

1976 ◽  
Vol 23 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Jill Sales ◽  
W. G. Hill
Keyword(s):  
Selection Index ◽  
Heritability Estimate ◽  
Parameter Estimates ◽  
Response To Selection ◽  
Sampling Errors ◽  
Estimation Of Parameters ◽  
Selection Indices ◽  
Important Trait ◽  
Selection For ◽  
Efficiency Of Selection

SUMMARYAn analysis is undertaken of the effect of errors in estimates of parameters on the response to selection for an economically important trait (trait 1) when one or more additional traits are added in a selection index. The detailed analysis is confined to one additional trait (trait 2) which contributes useful information unless the genetic and phenotypic regressions of trait 1 on trait 2 are equal.If there are errors in parameter estimates the extra response obtained by including trait 2 will usually be over-predicted. When trait 2 actually contributes no useful information the predicted benefit equals the real loss in efficiency from its inclusion.The loss in efficiency from poor estimation of parameters, whether or not the second trait makes a contribution, is roughly one-quarter of the squared coefficient of variation of a heritability estimate of trait 1 in the same experiment.

scholarly journals Variability of the «mass of seeds from a plant» sign in the soybeans hybrids of the different groups of ripeness

2019 ◽  
Vol 24 ◽  
pp. 53-58
Author(s):  
R. A. Vozgegova ◽  
Y. O. Lavrynenko ◽  
V. V. Bazaliy ◽  
T. Y. Marchenko ◽  
V. O. Borovik ◽  
...  
Keyword(s):  
Seed Yield ◽  
Seed Weight ◽  
Seed Mass ◽  
Comparative Methods ◽  
Hybrid Population ◽  
Genotypic Variability ◽  
Effective Selection ◽  
Selection For ◽  
Efficiency Of Selection ◽  
Population Yield

Aim. The purpose of the research is to determine the manifestation of the feature “seed weight from a plant” (the, parental forms) and hybrids, to establish the level of variability behind the soybean varieties in the F2–F5 hybrid combinations, to determine the effectiveness of selections for productivity in terms of the “seed weight from a plant” indicator from the hybrid populations of the F2–F5. Methods. The field, selection and genetic, calculation and comparative methods of the research were used. The varieties that are different in terms of fecundity and origin, also hybrids F1 and hybrid populations F2–F5 were studied. Selections on the basis of the “seed weight from a plant” were carried out in the F2–F5 populations. Results. It has been established that in soy characteristic “seed mass from a plant” has significant genotypic variability and has significant differences in varieties of different groups of ripeness, which may be a prerequisite for predicting the effective selection for this factorial trait. A high correlation of this trait with seed yield was also established. The proportion of the families from the selections, that were carried out in the F3 populations, exceeded the seed yield standard and was in the range of 28.0–37.5%. In the second generation of hybrids the efficiency of selection was 1.5–2 times lower. Conclusions. The highest yield of high-yielding genotypes, reached by the “seed mass from a plant” indicator was obtained from the F3 populations. To create the new high-yielding soybean varieties with a 3.5–5.5 t/ha yield under irrigation conditions, it is promising to use in the crossings the variety samples which are contrastive by groups of ripeness and genetic pedigree. Keywords: variety, soybean, hybrid, population, yield, irrigation.

scholarly journals Efficiency of selection in early generations of potato families with a view toward heat tolerance

2015 ◽  
Vol 15 (4) ◽  
pp. 210-217 ◽  
Author(s):  
Izabel Cristina Rodrigues de Figueiredo ◽  
César Augusto Brasil Pereira Pinto ◽  
Guilherme Henrique Martins Rodrigues Ribeiro ◽  
Leandro de Oliveira Lino ◽  
Danilo Hottis Lyra ◽  
...  
Keyword(s):  
Heat Tolerance ◽  
Tuber Shape ◽  
Family Selection ◽  
Clonal Generation ◽  
Seedling Generation ◽  
The Mean ◽  
Selection For ◽  
Efficiency Of Selection ◽  
Tuber Specific Gravity ◽  
Selection Of

Abstract The aim of this study was to evaluate the efficiency of selection of potato families in early generations for heat tolerance. Thirty families were evaluated in the seedling generation (SG), first clonal generation (FCG) in the field and greenhouse under high temperature conditions, and second clonal generation (SCG) under mild temperatures. The mean of the families was obtained in each generation. The 16 most productive families in FCG were selected, and the clones of these families were evaluated in experiments in the winter and rainy crop seasons. The results showed that family selection for tuber shape may be applied as of the SG. It was also observed that family selection in the FCG and SCG for yield and tuber specific gravity contributed to identification of clones tolerant to heat and responsive to environmental improvement.

Efficiency of selection–biotechnological system of selection for creation of breeding source material of sunflower resistant to herbicides and broomrape

Helia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Viktoria Babych ◽  
Mykola Kuchuk ◽  
Yaroslava Sharipina ◽  
Miroslav Parii ◽  
Yaroslav Parii ◽  
...  
Keyword(s):  
High Resistance ◽  
Normal Development ◽  
Source Material ◽  
Immature Embryos ◽  
Hybrid Combination ◽  
Selection For ◽  
The Creation ◽  
Efficiency Of Selection ◽  
Tribenuron Methyl

Abstract The sunflower is a strategically important oil crop. Every year the area under this crop grows, and the rapid returning of sunflowers back to the fields provokes the formation of new more aggressive races of broomrape (Orobanche cumana Wallr.). Broomrape is a parasite that interferes with the normal development of sunflower and can lead to significant crop losses. For creating a sunflower hybrid (F1) it is needed to cross the parental components, which have a complex of important traits, among which there is a resistance to the herbicides and a broomrape. Considering that the creation of each of the components of the hybrid involves many years of painstaking work in the breeding process, modern approaches and methods are used to accelerate the creation of a new source material. Thus, using the technology of cultivating immature embryos in vitro culture, it is possible to reduce the time to create lines resistant to herbicides, for example. And during selection for resistance to pathogenic organisms, testing is most often used against an artificial infectious background, both in the field and in laboratory conditions, in order to differentiate the material on this basis. The aim of this work was to establish the effectiveness system when creating an initial breeding material resistant to herbicides and broomrape. As a result of testing the lines on an artificial infectious background, was identified plants which have high resistance to the G-race broomrape and were isolated from hybrid combinations resistant to tribenuron-methyl and imidazolinones. Thus, among the analyzed plants which are resistant to tribenuron‐methyl, four lines were isolated, which are highly resistant to the G-race broomrape from a hybrid combinations BH0118/SURES–2 (101/1, 101/4, 101/6, 101/7), and BH0318/SURES–2 (101/21, 101/24, 101/28, 101/30), and five lines (101/11, 101/12, 101/16, 101/17, 101/18) from a hybrid combination BH0218/SURES–2. Among imidazolinone-resistant sunflower lines – line 3 was isolated as highly resistant to the G-race broomrape.

Sign in / Sign up

Export Citation Format

Share Document