scholarly journals Analytical and numerical comparisons of two methods of estimation of additive × additive × additive interaction of QTL effects

2021 ◽  
Author(s):  
Adrian Cyplik ◽  
Jan Bocianowski
Keyword(s):  
Molecular Marker ◽  
Doubled Haploid ◽  
Numerical Comparison ◽  
Additive Interaction ◽  
Numerical Comparisons ◽  
Plant Phenotype ◽  
Dh Lines ◽  
Qtl Effects

AbstractThis paper presents the analytical and numerical comparison of two methods of estimation of additive × additive × additive (aaa) interaction of QTL effects. The first method takes into account only the plant phenotype, while in the second we also included genotypic information from molecular marker observation. Analysis was made on 150 doubled haploid (DH) lines of barley derived from cross Steptoe × Morex and 145 DH lines from Harrington × TR306 cross. In total, 153 sets of observation was analyzed. In most cases, aaa interactions were found with an exert effect on QTL. Results also show that with molecular marker observations, obtained estimators had smaller absolute values than phenotypic estimators.

Shoaling decisions in female swordtails: how do fish gauge group size?

Behaviour ◽  
2007 ◽  
Vol 144 (11) ◽  
pp. 1333-1346 ◽  
Author(s):  
Bob Wong ◽  
Gil Rosenthal ◽  
Jessica Buckingham
Keyword(s):  
Gauge Group ◽  
Group Size ◽  
Group Membership ◽  
Size Ratio ◽  
Numerical Comparison ◽  
Weber’S Law ◽  
Significant Preference ◽  
Xiphophorus Helleri ◽  
Weber's Law ◽  
Numerical Comparisons

AbstractLittle is known about the mechanisms individuals might use to compare group sizes when making decisions about group membership. One possibility is that animals use ratio to determine differences in group sizes. Weber's Law states that the ease of any numerical comparison is based on the ratio between the stimuli compared; as the ratio becomes smaller the comparison becomes more difficult. We set out to test this prediction by offering female green swordtails, Xiphophorus helleri, dichotomous choices between different shoal sizes, varying both in ratios and absolute numbers of fish. Swordtails attended to the ratio of group size between stimulus shoals, rather than the numerical difference between shoals, when making shoaling decisions. Where group size ratio was 2:1, subjects showed a significant preference for the larger shoal, independent of the numerical difference between the shoals. When the ratio was 1.5:1, subjects showed no preference. The ratio between group sizes may, thus, be an important factor in shoaling decisions. More broadly, ratio could prove to be a widespread mechanism for animals to make numerical comparisons in group assessments.

In vitro and in vivo screening for cold tolerance in winter × spring wheat-derived doubled haploids following the wheat × maize system

2007 ◽  
Vol 55 (3) ◽  
pp. 273-282
Author(s):  
S. Sharma ◽  
H. Chaudhary
Keyword(s):  
Grain Yield ◽  
Cold Tolerance ◽  
Spring Wheat ◽  
Doubled Haploid ◽  
Tetrazolium Chloride ◽  
Cold Tolerant ◽  
Dh Lines ◽  
Ttc Test

Seventy-eight doubled haploid (DH) lines, derived from 21 elite and diverse winter × spring wheat F 1 hybrids, following the wheat × maize system, were screened along with the parental genotypes under in vitro and in vivo conditions for cold tolerance. Under in vitro conditions, the 2,3,5-triphenyl tetrazolium chloride (TTC) test was used to characterize the genotypes for cold tolerance. Based on the TTC test, only one doubled haploid, DH 69, was characterized as cold-tolerant, seven DH and five winter wheat parents were moderately tolerant, while the rest were susceptible. Analysis of variance under in vivo conditions also indicated the presence of sufficient genetic variability among the genotypes (DH lines + parents) for all the yield-contributing traits under study. The correlation and path analysis studies underlined the importance of indirect selection for tillers per plant, harvest index and grains per spike in order to improve grain yield. It was also concluded that selection should not be practised for grain weight per spike as it would adversely affect the grain yield per plant. When comparing the field performance of the genotypes with the in vitro screening parameters, it was concluded that in addition to the TTC test, comprising a single parameter, other physiological and biochemical in vitro parameters should be identified, which clearly distinguish between cold-tolerant and susceptible genotypes and also correlate well with their performance under field conditions.

General and specific combining ability of in vitro doubled haploid maize lines in the field

2010 ◽  
Vol 58 (2) ◽  
pp. 167-177
Author(s):  
T. Spitkó ◽  
L. SÁgi ◽  
J. Pintér ◽  
C. Marton ◽  
B. Barnabás
Keyword(s):  
Doubled Haploid ◽  
Combining Ability ◽  
Field Performance ◽  
Control Line ◽  
Regeneration System ◽  
Sample Number ◽  
Maize Hybrids ◽  
Grain Moisture ◽  
Dh Lines

The breeding of hybrid maize now has a history of over 100 years. In 1908, George H. Shull was the first to report on the high yields, great uniformity and homogeneity of hybrids derived from a cross between two inbred lines. Following this discovery, consistent self-fertilisation over a period of six to eight generations was found to be an extremely efficient method for developing maize lines. From the mid-1970s, however, with the elaboration of the monoploid ( in vivo ) and microspore culture ( in vitro ) techniques, it became possible to develop homozygous lines within a year.With the help of an efficient plant regeneration system based on anther culture, large numbers of doubled haploid (DH) lines can be produced. In the course of the experiments the seed of DH plants selected over several years was multiplied and crossed with Martonvásár testers, after which the hybrids were included in field performance trials in three consecutive years (2005–2007). The aim was to determine whether the field performance of hybrids developed in this way equalled the mean yield of standards with commercial value. The data also made it possible to calculate the general (GCA) and specific (SCA) combining ability of the parental lines, indicating the usefulness of the parental components in hybrid combinations and expressing the extent to which a given line contributes to yield surpluses in its progeny.A total of 52 maize hybrids were evaluated in the experiments in terms of yield and grain moisture content at harvest. The combinations, resulting from crosses between 12 DH lines, one control line developed by conventional inbreeding and four testers, were found to include hybrids capable of equalling the performance of the standards, and four DH lines were identified as improving the yield level of their progeny. As the experiment was carried out on a very small number of genotypes, the results are extremely promising and suggest that, if the range of genotypes used to develop DH lines is broadened and the sample number is increased, it will be possible in the future to find maize hybrids, developed with in vitro DH parental components, that surpass the performance of commercial hybrids.

Growth and yield of doubled haploid lines of oilseed Brassica rapa

1998 ◽  
Vol 78 (4) ◽  
pp. 537-544 ◽  
Author(s):  
D. B. Dewan ◽  
G. Rakow ◽  
R. K. Downey
Keyword(s):  
Brassica Rapa ◽  
Seed Yield ◽  
Doubled Haploid ◽  
Field Tests ◽  
Field Evaluation ◽  
Growth And Yield ◽  
Consistent Performance ◽  
Delayed Flowering ◽  
Dh Lines ◽  
Number Of Seeds

The production of doubled haploid (DH) lines of Brassica rapa could be an efficient procedure for the development of inbred parents for hybrid production. A total of 162 B. rapa DH lines were evaluated in field tests at Saskatoon, Canada, in single row, replicated tests and 10 DH lines were tested in four-row plot, multilocation, replicated tests. Seed of DH lines was produced by bud selfing in the greenhouse. Approximately one-fifth of all DH lines tested were chlorophyll deficient, presumably due to the expression of recessive alleles. Inbreeding depression was evident in low seed and biological yields, low number of seeds per pod and delayed flowering. Seed yield of DH lines was positively associated with the number of seeds per pod, early flowering and a long pod-filling period. One DH line was equal in yield to its donor population (DP), suggesting that dominance deviation was the genetic basis for high seed yield in this species. The consistent performance of DH lines over years and locations indicated that DH lines may be selected after 1 year of evaluation for combining ability testing. Higher yielding DH lines of B. rapa must be selected before they can be used as parents for hybrid development. Key words: Brassica rapa, doubled haploid, field evaluation

scholarly journals Tradition, quality and biotechnology in Hungarian spice pepper ( Capsicum annuum L.) breeding

2010 ◽  
Vol 58 (3) ◽  
pp. 259-266 ◽  
Author(s):  
J. Pauk ◽  
C. Lantos ◽  
G. Somogyi ◽  
P. Vági ◽  
Z. Ábrahám Táborosi ◽  
...  
Keyword(s):  
Doubled Haploid ◽  
Microspore Culture ◽  
Isolated Microspore Culture ◽  
Culture Methods ◽  
Culture Techniques ◽  
New Genotype ◽  
Breeding Programmes ◽  
History Of ◽  
Dh Lines ◽  
Two Hybrid

Spice pepper production has a history of almost 300 years in the southern part of Hungary. In this study the results of two biotechnological improvements are summarized. Anther and isolated microspore culture techniques were improved to release haploid and doubled haploid (DH) lines for spice pepper breeding. Both the anther and isolated microspore culture methods were successfully used in spice pepper haploid production. Microspore culture-derived structures were analysed to identify their different parts. Green plantlets were regenerated from embryos derived from both anther and microspore cultures. Their doubled haploid analogues were integrated into Hungarian spice pepper hybrid seed breeding programmes. One hybrid, Sláger, was released as a new genotype for spice pepper production in 2008 and two hybrid candidates (Délibáb and Bolero) are now being tested in official trials.

Recurrent selection in doubled-haploid populations of barley (Hordeurn vulgare L.)

1985 ◽  
Vol 27 (2) ◽  
pp. 172-177 ◽  
Author(s):  
J. D. Patel ◽  
E. Reinbergs ◽  
S. O. Fejer
Keyword(s):  
Doubled Haploid ◽  
Recurrent Selection ◽  
Doubled Haploids ◽  
Additive Genetic Variance ◽  
Response To Selection ◽  
Hordeum Vulgare L ◽  
Doubled Haploid Lines ◽  
Days To Heading ◽  
High Selection ◽  
Dh Lines

Cycle zero (C0) of recurrent selection in barley (Hordeum vulgare L.) was initiated by diallel mating of seven highly selected parents. A total of 398 doubled-haploid (C0DH) lines were derived from 21 crosses and were evaluated along with their parents in C0 experiment. Seven doubled-haploid lines (DH) were selected from the cycle zero (C0) experiment and intercrossed to form cycle 1 (C1). From the 21 crosses of the diallel, 260 doubled-haploid lines (C1DH) were derived and were evaluated along with the C0 and C1 parents. The frequency distribution of the standardized means of the DH lines from C0 and C1 indicated a slight response to selection for seed yield. Genetic analysis of the C1DH population showed high additive genetic variance for yield per hill, plant height, and yield per spike, and a high proportion of additive × additive epistasis for spikes per hill, days to heading, and 100-seed weight. Seven doubled-haploid lines were selected from different high-yielding crosses represented by C1DH lines. High selection pressure was applied for yield per hill, yield per spike, and spikes per hill. Further response to selection is expected in later cycles. The seven selected doubled-haploid lines will be used as the parents of the next recurrent selection cycle.Key words: recurrent selection, doubled haploids, additive, epistasis, heritability, Hordeum.

scholarly journals Efficiency of generations for estimating marker-associated QTL effects by multiple regression.

Genetics ◽  
1993 ◽  
Vol 135 (1) ◽  
pp. 223-231
Author(s):  
J Moreno-Gonzalez
Keyword(s):  
North Carolina ◽  
Stepwise Regression ◽  
Additive Effects ◽  
Significance Level ◽  
Recombinant Inbreds ◽  
The North ◽  
Dh Lines ◽  
Genetic Standard Deviation ◽  
Better Than ◽  
Qtl Effects

Abstract Knowledge about the efficiency of generations for estimating marker-associated QTLs is needed for selection. The objective of this paper is to develop a theory to compare the efficiency of segregating generations and testcrosses from the cross of two inbred lines differing in value for a quantitative trait (P1 x P2) for estimating additive, dominance and heterotic effects of QTLs by stepwise regression. An equation that predicts the smallest gene effect in genetic standard deviation units that can be detected with 50% chance at a significance level as a function of the heritability (h2) and the recombination frequency (r) of markers was developed for the segregating generations and testcrosses. For estimating additive effects, the most efficient generation was the doubled-haploid (DH) lines; the most inefficient was the North Carolina Design III (NCD III), followed by selfed backcrosses (SB); the selfed families from F2 individual plants (F2:3 lines) are inferior to the recombinant inbreds (RI) for low r, but are better than RI for high h2 and r. Dominance effects are less efficiently estimated than additive effects. The NCD III is better than the SB and the F2:3 lines for detecting dominance effects. The RI and DH do not estimate dominance effects. The differential heterotic QTL effects of lines P1 and P2 when crossed with tester T can be estimated by evaluating testcrosses of individual F2 plants (F2T), recombinant inbreds (RIT) and double-haploid lines (DHT). The DHT is superior to the other generations. The F2T is better than the RIT for r > or = 0.20, but inferior for r < or = 0.1 or low heritability.

Sign in / Sign up

Export Citation Format

Share Document