THE EFFICIENCY OF USING DOUBLED HAPLOIDS IN A RECURRENT SELECTION PROGRAM IN A DIPLOID, CROSS-FERTILIZED SPECIES

Mass selection in both doubled haploid and diploid populations was simulated for a 30-year period under additive and complete dominance models. The response to S1 selection was also included for the purpose of comparison. All selection programs were conducted at two selection intensities, 5% and 25%, under 0.2 heritability with a constant population size of 400. S1 lines were evaluated in 10-plant plots with four replications; use of a winter nursery was assumed. The character under selection was controlled by 20 major (A = 2) genes and 20 minor (A = 1) genes. The initial frequency of ten of the major genes and ten of the minor genes was 0.5; that of the remaining ten of each type was 0.1. The response to mass selection with doubled haploids was about 1.4 times faster than diploid mass selection and equal to S1 selection in terms of gain per year. If replicated trials were used to evaluate the doubled haploids, the rate of gain was faster than in S1 selection. The greater efficiency of using doubled haploids was due to doubling of the additive genetic variance and the elimination of dominance variance. However, significant loss of desirable genes occurred in the mass selected doubled haploid population under both the 5% and 25% selection intensities in the additive and complete dominance models.

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

Canadian Journal of Genetics and Cytology ◽

10.1139/g85-026 ◽

1985 ◽

Vol 27 (2) ◽

pp. 172-177 ◽

Cited By ~ 11

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.

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Gametophytic selection in a winter × spring barley cross

Genome ◽

10.1139/g91-141 ◽

1991 ◽

Vol 34 (6) ◽

pp. 918-922 ◽

Cited By ~ 9

Author(s):

C. C. Schön ◽

P. M. Hayes ◽

T. K. Blake ◽

S. J. Knapp

Keyword(s):

Segregation Distortion ◽

Doubled Haploid ◽

Doubled Haploids ◽

Spring Barley ◽

Population Based ◽

Doubled Haploid Population ◽

Dh Population ◽

Gametophytic Selection ◽

Segregation Ratios ◽

Haploid Population

Segregation distortion and the consequences of gametophytic selection were assessed in a winter × spring barley cross by comparing segregation of enzyme, storage protein, DNA, and morphological markers in three populations derived from the same cross: a control F2 (F2C), a doubled-haploid (DH) population, and an F2 derived from F1 plants self-pollinated at 10 °C (F2T). Segregation distortion was present in the F2T and the doubled-haploid population. Based on a comparison of the F2C and the F2T, gametophytic selection as a consequence of self-pollination at 10 °C was operative on chromosome 7 in regions linked to Rrn2. Segregation distortion in favor of the winter parent was found in the doubled-haploid population. There were significant deviations from expected segregation ratios at two loci, but only at one of the loci was the gene number significantly different from the F2C. Despite segregation distortion, the doubled-haploid population should be suitable for linkage analyses, as estimates of recombination based on F2 and doubled-haploid data were in close agreement.Key words: Hordeum vulgare, segregation distortion, doubled haploids, gametophytic selection, cold tolerance.

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Doubled haploids for locating polygenes

Canadian Journal of Genetics and Cytology ◽

10.1139/g83-065 ◽

1983 ◽

Vol 25 (5) ◽

pp. 425-429 ◽

Cited By ~ 6

Author(s):

T. M. Choo

Keyword(s):

Doubled Haploid ◽

Quantitative Trait ◽

Doubled Haploids ◽

Marker Gene ◽

Marker Genes ◽

Doubled Haploid Population ◽

Crossing Over ◽

Marker Loci ◽

Haploid Population ◽

Map Distance

A biometrical method, making use of one or two marker genes, was proposed for use in doubled-haploid populations to locate polygenes. A polygene, if located between two closely linked marker loci, can be detected in a doubled-haploid population derived from a cross of two diploid inbred parents. In addition, the presence of additive epistasis can be detected. If the map distance between the two marker loci is so close that the frequency of double crossing-over can be neglected, then the recombination values between the polygene and either marker gene can be estimated, and the additive effect of the polygene can be determined in the absence of pleiotropy. Further, the contribution of the polygene to the quantitative trait relative to all other polygenes can be measured from the experiment if double crossing-over and epistasis are absent. Note that the proposed method can be used as an adjunct to haploid breeding routines and other genetical experiments.

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DOUBLED HAPLOIDS FOR STUDYING THE INHERITANCE OF QUANTITATIVE CHARACTERS

Genetics ◽

10.1093/genetics/99.3-4.525 ◽

1981 ◽

Vol 99 (3-4) ◽

pp. 525-540

Author(s):

T M Choo

Keyword(s):

Doubled Haploid ◽

Doubled Haploids ◽

Doubled Haploid Population ◽

Breeding Methods ◽

Weighted Mean ◽

Quantitative Characters ◽

Haploid Population ◽

Parental Lines ◽

The Difference ◽

Two Populations

ABSTRACT By using a doubled-haploid population derived from F2 plants, additive and additive x additive genetic variances, as well as the number of segregating genes, can be estimated. An F2-derived doubled-haploid population may contain almost 50%more of the best recombinant than an F1-derived population. However, the best recombinant occurs in the same frequency in the two populations when there is no linkage between genes. The difference in the frequency of the best recombinant between F2- and F3-derived populations is small. This implies that the doubled-haploid method using F2 plants provides only slightly less opportunity for recombination than the conventional breeding methods of selfpollinating crops. In the absence of additive epistasis, a weighted mean of recombination values can be estimated using an F2-derived population and its parental lines. When additive epistasis is present, it can be estimated from doubled-haploid populations derived from two backcrosses. Studies on the linkage of quantitative characters are needed for determining whether doubled haploids should be produced from F2 or from F1 plants in a breeding program.

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