Haploidy and plant breeding

1981 ◽  
Vol 292 (1062) ◽  
pp. 499-507 ◽  
Keyword(s):  
Plant Breeding ◽  
Doubled Haploids ◽  
Chromosome Complement ◽  
Basic Research ◽  
Breeding Value ◽  
Additive Variance ◽  
Ploidy Levels ◽  
Breeding Programmes ◽  
Dh Lines

A haploid is an organism that looks like a sporophyte, but has the chromosome complement of a reduced gamete. There are several ways in which haploids can occur or be induced in vivo : spontaneously, mostly associated with polyembryony, and through abnormal processes after crosses, like pseudogamy, semigamy, preferential elimination of the chromosomes of one parental species, and androgenesis. In the crops described, haploids are or are near to being used in basic research and plant breeding. The application of haploids in breeding self-pollinated crops is based on their potential for producing fully homozygous lines in one generation, which can be assessed directly in the field. Early generation testing of segregating populations is possible through haploids, because doubled haploids (DH) possess additive variance only. Haploids can also be applied in classical breeding programmes to make these more efficient through improved reliability of selection. The application of haploids in cross-pollinated crops is also based on a rapid production of DH-lines, which can be used as inbred lines for the production of hybrid varieties. By means of haploids all natural barriers to repeated selfing are bypassed. In autotetraploid crops there are two types of haploid. One cycle of haploidization leads to dihaploids; a second cycle produces monohaploids. The significance of dihaploids is in their greatly simplified genetics and breeding and in the possibility of estimation of the breeding value of tetraploid cultivars by assessing their dihaploids. The main drawback of dihaploids is their restriction to two alleles per locus. Also, after doubling, it is impossible to achieve tetra-allelism at many loci, the requirement for maximal performance of autotetraploid cultivars. Tetra-allelism can be obtained when improved dihaploids have a genetically controlled mechanism of forming highly heterozygous restitution gametes with the unreduced number of chromosomes. Monohaploids, after doubling or twice doubling, may lead to fully homozygous diploids and tetraploids. These are important for basic research, but not yet for practical application. Meiotic data of potato homozygotes at three ploidy levels are presented.

Performance of isolated microspore-derived doubled haploids of wheat (Triticum aestivum L.)

1997 ◽  
Vol 77 (4) ◽  
pp. 549-554 ◽  
Author(s):  
Tianci Hu ◽  
Ken J. Kasha
Keyword(s):  
In Vitro Selection ◽  
Nuclear Dna ◽  
Chromosome Doubling ◽  
Microspore Culture ◽  
Doubled Haploids ◽  
Spontaneous Mutation ◽  
Nuclear Dna Content ◽  
Root Tip ◽  
Ploidy Levels ◽  
Dh Lines

Ploidy level, genetic stability and field performance of isolated microspore-derived wheat plants were evaluated. The ploidy levels of isolated microspore-derived wheat plants from cv. Chris and reciprocal crosses of Chris × Sinton were determined by two methods, namely chromosome counts of root tip cells and flow cytometric measurement of nuclear DNA content from leaves. Both methods gave similar results with the frequencies of spontaneous chromosome doubling and completely fertile plants among microspore-derived H0 plants of wheat being about 80% and 75%, respectively, based on two H0 populations. Only 1.7% were aneuploid and 16% were haploid. Spontaneous mutation frequencies were low with 1 of 124 Chris DH plants having a recessive mutant for lemma awns while three were grass-like plants in the H0 generation. The field-measured traits of microspore-derived DH lines were similar to the check by the third generation. Ninety-two percent and 70% of Chris DH lines had 1000-kernel weights and yields similar to the check, respectively. These results indicate that microspore-derived DH lines should have good potential for applications in plant breeding, in vitro selection, plant transformation and genetic studies. Key words: Wheat, microspore, culture, haploidy, performance, stability

Ploidy of Regenerated Broccoli Derived from Microspore Culture Versus Anther Culture

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 533g-534
Author(s):  
Min Wang ◽  
Mark W. Farnham
Keyword(s):  
Anther Culture ◽  
Doubled Haploid ◽  
Direct Method ◽  
Microspore Culture ◽  
Doubled Haploids ◽  
Chromosome Complement ◽  
Culture Method ◽  
Lower Percentage ◽  
Ploidy Levels ◽  
Culture Techniques

Anther and microspore culture are commonly utilized to produce doubled-haploid (diploid), homozygous lines in broccoli (Brassica oleracea L. Italica Group). It is well-documented that doubled-haploid regenerants are produced by means of polyploidization during anther culture. However, polyploidization may not occur at all, or it may involve a tripling or quadrupling of the chromosome complement. As a consequence, regenerated populations from anther culture contain diploids, but also haploids, triploids, and tetraploids. Microspore culture represents a simpler and more direct method for producing doubled-haploids. Although a similar mix of ploidy types is likely to be observed among regenerants derived from microspore culture, the actual ploidy levels of such regenerants have not been documented for broccoli. Thus, the objectives of this study were to compare ploidy levels of regenerants developed using both anther and microspore culture in broccoli, and to examine phenotypic variation in ploidy makeup of populations developed from both anther and microspore culture using different F1 hybrids. Broccoli regenerants were derived simultaneously from both anther and microspore cultures using the same four F1 hybrids, including Everest, Patriot, Greenbelt and Major. Ploidy level was determined by flow cytometry. A majority of regenerants derived from both anther and microspore culture, were determined to be diploids or tetraploids. Significant differences in ploidy makeup of populations were observed among hybrid varieties for both culture techniques. Regardless of the culture method used, `Everest' produced a greater percentage of diploids and a lower percentage of tetraploids than `Patriot' did. Haploids were observed more frequently from microspore culture than from anther culture when `Everest' and `Major' served as parents.

Molecular markers and doubled haploids in European plant breeding programmes

Euphytica ◽  
2006 ◽  
Vol 158 (3) ◽  
pp. 305-312 ◽  
Author(s):  
Stine Tuvesson ◽  
Christophe Dayteg ◽  
Per Hagberg ◽  
Outi Manninen ◽  
Pirjo Tanhuanpää ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Plant Breeding ◽  
Doubled Haploids ◽  
Breeding Programmes

scholarly journals Distant hybridization as a method of haploid production in cereals

2019 ◽  
Vol 2 (2) ◽  
pp. 44-52
Author(s):  
T. I. Djatchouk ◽  
V. N. Akinina ◽  
O. V. Khomyakova ◽  
E. V. Кalashnikova
Keyword(s):  
Doubled Haploids ◽  
Chromosome Complement ◽  
Imperata Cylindrica ◽  
Chromosome Engineering ◽  
Distant Hybridization ◽  
Time Period ◽  
Efficient Alternative ◽  
Dh Lines ◽  
Time Required ◽  
Haploid Plants

Elimination of chromosomes is a phenomenon widespread in distant hybrids. It ranges from the loss of one or two chromosomes to elimination of whole chromosome complement of one of the parents. Such elimination leads to the production of haploid plants, which then are treated with colchicine to double the chromosome number and to develop DH‑lines. Homozygosity of doubled haploids serves as a basis for their wide use in plant genetics and breeding. The use of this approach reduces the time required for obtaining homozygous lines by 5 years on the average. It leads to savings in human resources, energy and acreage. The development of the “bulbosum” method for haploid barley production had a strong influence on the chromosome engineering in cereals and its implementation in plant breeding. However, the method developed on that basis could not be used effectively for producing haploids of wheat, triticale, etc. because of Hordeum bulbosum L. pollen sensitivity to genes inhibiting wheat crossability (Kr genes). The crosses with Imperata cylindrica (L.) Raeusch. is an efficient alternative to the widely used wheat × maize and triticale × maize crosses due to abundant pollen supply within a longer time period, significantly higher frequency of embryos formation and haploid plants regeneration.

scholarly journals Microspore embryogenesis in vitro: the role of stresses

2019 ◽  
Vol 23 (1) ◽  
pp. 86-94 ◽  
Author(s):  
T. I. Djatchouk ◽  
O. V. Khomyakova ◽  
V. N. Akinina ◽  
I. A. Kibkalo ◽  
A. V. Pominov
Keyword(s):  
Microspore Culture ◽  
Doubled Haploids ◽  
Embryo Sac ◽  
Microspore Embryogenesis ◽  
Gametic Embryogenesis ◽  
Chemical Pretreatments ◽  
Dh Lines

Gametic embryogenesis is one form of totipotency of plant cells, in which either male or female gametes are induced to form embryoids (sporophytes). Regeneration of haploid plants from embryoids and subsequent chromosome duplication result in doubled haploids and DH-lines. The production of haploids and doubled haploids (DHs) through gametic embryogenesis allows a single-stage development of complete homozygous lines from heterozygous plants. The development of effective haploid protocols to produce homozygous plants has a significant impact on plant breeding, shorting the time and costs required to establish new cultivars. There are several available methods to obtain haploids and DHs-lines, of which anther or isolated microspore culture in vitro are the most effective. Microspore embryogenesis is more commonly applied. This is in part because more male gametophytes are contained in a single anther compared to the single female gametophyte per embryo sac. Microspore embryogenesis is regarded as one of the most striking examples of plant cell totipotency. The switch of cultured microspores from gametophytic to sporophytic mode of development has been induced by stress treatments of various kinds applied to donor plants, inflorescences, buds, anthers or isolated microspores both in vivo and in  vitro. Physical or chemical pretreatments (cold and heat shock, sugar starvation, colchicine, n-butanol, gametocydes) act as a trigger for inducing the sporophytic pathway, preventing the gametophytic pathway development of microspore. The recent investigations have revealed that cold pretreatment during microspore reprogramming acts rather as an anti-stress factor alleviating the real stress caused by nutrient starvation of anthers or microspores isolated from donor plants. Under stress pretreatment a vacuolated and polarized microspore transformed into a depolarized and dedifferentiated cell, which is an obligatory condition for reprogramming their development. We summarize data concerning the role of various stresses in the induction of microspore embryogenesis and possible mechanisms of their action at cellular and molecular levels. Identification of new stresses allows creating efficient protocols of doubled haploid production for end-user application in the breeding of many important crops.

Hybrid maize breeding with doubled haploids: Comparison between selection criteria

2006 ◽  
Vol 54 (3) ◽  
pp. 343-350 ◽  
Author(s):  
C. F. H. Longin ◽  
H. F. Utz ◽  
A. E. Melchinger ◽  
J.C. Reif
Keyword(s):  
Selection Criteria ◽  
Doubled Haploids ◽  
Optimum Allocation ◽  
Finite Sample ◽  
Sample Sizes ◽  
Maize Breeding ◽  
Selection Gain ◽  
Breeding Programmes ◽  
Hybrid Maize ◽  
Breeding Resources

The optimum allocation of breeding resources is crucial for the efficiency of breeding programmes. The objectives were to (i) compare selection gain ΔGk for finite and infinite sample sizes, (ii) compare ΔGk and the probability of identifying superior hybrids (Pk), and (iii) determine the optimum allocation of the number of hybrids and test locations in hybrid maize breeding using doubled haploids. Infinite compared to finite sample sizes led to almost identical optimum allocation of test resources, but to an inflation of ΔGk. This inflation decreased as the budget and the number of finally selected hybrids increased. A reasonable Pk was reached for hybrids belonging to the q = 1% best of the population. The optimum allocations for Pk(q) and ΔGkwere similar, indicating that Pk(q) is promising for optimizing breeding programmes.

Improvement of effectiveness in maize breeding

2006 ◽  
Vol 54 (3) ◽  
pp. 351-358 ◽  
Author(s):  
P. Pepó
Keyword(s):  
Recurrent Selection ◽  
Genetic Manipulation ◽  
Field Testing ◽  
Tissue Cultures ◽  
Maize Breeding ◽  
Breeding Programmes ◽  
Speed Up ◽  
Selection For

Plant regeneration via tissue culture is becoming increasingly more common in monocots such as maize (Zea mays L.). Pollen (gametophytic) selection for resistance to aflatoxin in maize can greatly facilitate recurrent selection and the screening of germplasm for resistance at much less cost and in a shorter time than field testing. In vivo and in vitro techniques have been integrated in maize breeding programmes to obtain desirable agronomic attributes, enhance the genes responsible for them and speed up the breeding process. The efficiency of anther and tissue cultures in maize and wheat has reached the stage where they can be used in breeding programmes to some extent and many new cultivars produced by genetic manipulation have now reached the market.

Doubled haploid production in maize under Sub-montane Himalayan conditions using R1-nj-based haploid inducer TAILP1

2020 ◽  
Vol 80 (03) ◽  
Author(s):  
R. K Khulbe ◽  
A. Pattanayak ◽  
Lakshmi Kant ◽  
G. S. Bisht ◽  
M. C. Pant ◽  
...  
Keyword(s):  
Doubled Haploid ◽  
Sweet Corn ◽  
Haploid Induction ◽  
Maize Breeding ◽  
Line Production ◽  
Haploid Inducer ◽  
Breeding Programmes ◽  
Source Populations ◽  
Developmental Phases

The use of in vivo haploid induction system makes the doubled haploid (DH) technology easier to adopt for the conventional maize breeders. However, despite having played an important role in the initial developmental phases of DH technology, Indian maize research has yet to harvest its benefits. Haploid Inducer Lines (HILs) developed by CIMMYT are being widely used in maize breeding programmes in many countries including India. There, however, is no published information on the efficiency of DH line production using CIMMYT HILs in Indian maize breeding programmes. In the present study, the efficiency of DH production using CIMMYT’s tropically adapted inducer line TAILP1 was investigated with eight source populations including two of sweet corn. The average haploid induction rate (HIR) of TAILP1 was 5.48% with a range of 2.01 to 10.03%. Efficiency of DH production ranged from 0.14 to 1.87% for different source populations with an average of 1.07%. The information generated will be useful for maize breeders intending to use DH technology for accelerated development of completely homozygous lines.

scholarly journals The TRACE-Seq method tracks recombination alleles and identifies clonal reconstitution dynamics of gene targeted human hematopoietic stem cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rajiv Sharma ◽  
Daniel P. Dever ◽  
Ciaran M. Lee ◽  
Armon Azizi ◽  
Yidan Pan ◽  
...  
Keyword(s):  
Genetic Diseases ◽  
Basic Research ◽  
Gene Correction ◽  
Coding Region ◽  
Hematopoietic Stem ◽  
Hematopoietic Reconstitution ◽  
Exon 1 ◽  
Template Library ◽  
Donor Template

AbstractTargeted DNA correction of disease-causing mutations in hematopoietic stem and progenitor cells (HSPCs) may enable the treatment of genetic diseases of the blood and immune system. It is now possible to correct mutations at high frequencies in HSPCs by combining CRISPR/Cas9 with homologous DNA donors. Because of the precision of gene correction, these approaches preclude clonal tracking of gene-targeted HSPCs. Here, we describe Tracking Recombination Alleles in Clonal Engraftment using sequencing (TRACE-Seq), a methodology that utilizes barcoded AAV6 donor template libraries, carrying in-frame silent mutations or semi-randomized nucleotides outside the coding region, to track the in vivo lineage contribution of gene-targeted HSPC clones. By targeting the HBB gene with an AAV6 donor template library consisting of ~20,000 possible unique exon 1 in-frame silent mutations, we track the hematopoietic reconstitution of HBB targeted myeloid-skewed, lymphoid-skewed, and balanced multi-lineage repopulating human HSPC clones in mice. We anticipate this methodology could potentially be used for HSPC clonal tracking of Cas9 RNP and AAV6-mediated gene targeting outcomes in translational and basic research settings.

scholarly journals Additive genetic variance and covariance between relatives in synthetic wheat crosses with variable parental ploidy levels

Genetics ◽  
2021 ◽  
Vol 217 (2) ◽  
Author(s):  
L E Puhl ◽  
J Crossa ◽  
S Munilla ◽  
P Pérez-Rodríguez ◽  
R J C Cantet
Keyword(s):  
Hexaploid Wheat ◽  
Variance Components ◽  
Bayesian Model ◽  
Synthetic Hexaploid Wheat ◽  
Data Sets ◽  
Hierarchical Bayesian Model ◽  
Additive Variance ◽  
Ploidy Levels ◽  
Breeding Values ◽  
Synthetic Hexaploid

Abstract Cultivated bread wheat (Triticum aestivum L.) is an allohexaploid species resulting from the natural hybridization and chromosome doubling of allotetraploid durum wheat (T. turgidum) and a diploid goatgrass Aegilops tauschii Coss (Ae. tauschii). Synthetic hexaploid wheat (SHW) was developed through the interspecific hybridization of Ae. tauschii and T. turgidum, and then crossed to T. aestivum to produce synthetic hexaploid wheat derivatives (SHWDs). Owing to this founding variability, one may infer that the genetic variances of native wild populations vs improved wheat may vary due to their differential origin and evolutionary history. In this study, we partitioned the additive variance of SHW and SHWD with respect to their breed origin by fitting a hierarchical Bayesian model with heterogeneous covariance structure for breeding values to estimate variance components for each breed category, and segregation variance. Two data sets were used to test the proposed hierarchical Bayesian model, one from a multi-year multi-location field trial of SHWD and the other comprising the two species of SHW. For the SHWD, the Bayesian estimates of additive variances of grain yield from each breed category were similar for T. turgidum and Ae. tauschii, but smaller for T. aestivum. Segregation variances between Ae. tauschii—T. aestivum and T. turgidum—T. aestivum populations explained a sizable proportion of the phenotypic variance. Bayesian additive variance components and the Best Linear Unbiased Predictors (BLUPs) estimated by two well-known software programs were similar for multi-breed origin and for the sum of the breeding values by origin for both data sets. Our results support the suitability of models with heterogeneous additive genetic variances to predict breeding values in wheat crosses with variable ploidy levels.

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