DIFFERENTIAL FERTILITY AND TRANSMISSION OF MALE AND FEMALE GAMETES IN ALLOPLASMIC WHEAT HYBRIDS

1981 ◽  
Vol 23 (2) ◽  
pp. 337-348 ◽  
Author(s):  
Seiichi Tsuji ◽  
S. S. Maan
Keyword(s):  
Seed Set ◽  
Triticum Aestivum L ◽  
Aegilops Species ◽  
D Genome ◽  
Differential Fertility ◽  
Male And Female ◽  
Cytoplasmic Effects ◽  
Male Gametes ◽  
Alloplasmic Wheat ◽  
Wheat Hybrids

Alloplasmic Triticum aestivum L. cv. Selkirk lines having cytoplasms of five D-genome Aegilops species were crossed reciprocally with euplasmic T. durum Selection 56-1 to study differential cytoplasmic effects on pentaploid hybrids. Pollen fertility of the alloplasmic and euplasmic pentaploid hybrids ranged from 23.0% to 46.6%, and from 84.9% to 91.1%, respectively. Significant differences in seed-set and in the viability of backcrossed seed were observed between the euplasmic and alloplasmic pentaploids as well as among the five alloplasmic pentaploids. The pentaploid with Ae. squarrosa cytoplasm did not transmit 14-chromosome male gametes. The cytoplasms of Ae. squarrosa, Ae. cylindrica and Ae. ventricosa were similar to one another in their differential effects on the transmission of euploid and aneuploid male gametes numbers, and similarly the cytoplasms of Ae. crassa and Ae. juvenalis resembled each other.

CYTOLOGY AND FERTILITY OF PENTAPLOID WHEAT HYBRIDS WITH INDUCED PAIRING BETWEEN HOMOEOLOGOUS CHROMOSOMES

1982 ◽  
Vol 24 (4) ◽  
pp. 397-408 ◽  
Author(s):  
U. Kushnir ◽  
G. M. Halloran
Keyword(s):  
Chromosome Pairing ◽  
Hexaploid Wheat ◽  
Triticum Turgidum ◽  
Triticum Aestivum L ◽  
The Other ◽  
Homoeologous Chromosome ◽  
D Genome ◽  
Homoeologous Chromosome Pairing ◽  
Wheat Hybrids ◽  
Homoeologous Chromosomes

Two mutants, each promoting homoeologous chromosome pairing in hexaploid wheat (Triticum × aestivum L. emend gr. aestivum), in the cultivar Chinese Spring, ph1b at the Ph locus on chromosome 5BL and the other, ph2, on chromosome 3DS, were compared for their influence on chromosome pairing and fertility in pentaploid hybrids with Triticum turgidum L. emend var. dicoccoides (Korn. in litt. in Schweinf.). The mutants induced increased multivalent frequency over the normal pentaploid. Lower univalent frequencies in the ph2-pentaploid, compared with the normal pentaploid, indicated that D-genome chromosomes of the former were substantially involved in homoeologous pairing. Certain differences in other meiotic processes and fertility among the pentaploids may reflect differences in the activity of the pairing genes. There appeared to be a higher level of univalent elimination in pollen and egg cells in the ph2-, compared with the ph1b-pentaploid. Tetrad formation was close to normal in the ph2- pentaploid but exhibited high levels of abnormality (monads, dyads, triads and apolar tetrads) in the ph1b-pentaploid. Fertility levels in crosses of the pentaploids with hexaploid wheat, while low, were much lower for the ph1b-, compared with the ph2-pentaploid.

Hybrid breeding in wheat: how shaping floral biology can offer new perspectives

2020 ◽  
Vol 47 (8) ◽  
pp. 675 ◽  
Author(s):  
Caterina Selva ◽  
Matteo Riboni ◽  
Ute Baumann ◽  
Tobias Würschum ◽  
Ryan Whitford ◽  
...  
Keyword(s):  
Control Systems ◽  
Floral Development ◽  
Seed Set ◽  
Fertility Control ◽  
Triticum Aestivum L ◽  
Floral Biology ◽  
Wheat Breeding ◽  
Hybrid Breeding ◽  
Hybrid Wheat ◽  
Male And Female

Hybrid breeding in wheat (Triticum aestivum L.) has the potential to deliver major yield increases. This is a requisite to guarantee food security for increasing population demands and to counterbalance the effects of extreme environmental conditions. Successful hybrid breeding in wheat relies on forced outcrossing while preventing self-pollination. To achieve this, research has been directed towards identifying and improving fertility control systems. To maximise cross-pollination and seed set, however, fertility control systems need to be complemented by breeding phenotypically distinct male and female lines. This review summarises existing and novel male sterility systems for wheat hybridisation. We also consider the genetic resources that can be used to alter wheat’s floral development and spike morphology, with a focus on the genetic variation already available. Exploiting these resources can lead to enhanced outcrossing, a key requirement in the progress towards hybrid wheat breeding.

scholarly journals A Microsatellite Map of Wheat

Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 2007-2023 ◽  
Author(s):  
Marion S Röder ◽  
Victor Korzun ◽  
Katja Wendehake ◽  
Jens Plaschke ◽  
Marie-Hélène Tixier ◽  
...  
Keyword(s):  
Bread Wheat ◽  
Reference Population ◽  
Triticum Aestivum L ◽  
Wheat Genome ◽  
D Genome ◽  
B Genome ◽  
Microsatellite Map ◽  
A Genome ◽  
Polymorphic Microsatellite ◽  
Primer Sets

Abstract Hexaploid bread wheat (Triticum aestivum L. em. Thell) is one of the world's most important crop plants and displays a very low level of intraspecific polymorphism. We report the development of highly polymorphic microsatellite markers using procedures optimized for the large wheat genome. The isolation of microsatellite-containing clones from hypomethylated regions of the wheat genome increased the proportion of useful markers almost twofold. The majority (80%) of primer sets developed are genome-specific and detect only a single locus in one of the three genomes of bread wheat (A, B, or D). Only 20% of the markers detect more than one locus. A total of 279 loci amplified by 230 primer sets were placed onto a genetic framework map composed of RFLPs previously mapped in the reference population of the International Triticeae Mapping Initiative (ITMI) Opata 85 × W7984. Sixty-five microsatellites were mapped at a LOD >2.5, and 214 microsatellites were assigned to the most likely intervals. Ninety-three loci were mapped to the A genome, 115 to the B genome, and 71 to the D genome. The markers are randomly distributed along the linkage map, with clustering in several centromeric regions.

POLLEN PRODUCTION AND DISSEMINATING PROPERTIES OF TRITICALE RELATIVE TO WHEAT

1972 ◽  
Vol 52 (4) ◽  
pp. 569-574 ◽  
Author(s):  
K. C. YEUNG ◽  
E. N. LARTER
Keyword(s):  
Seed Set ◽  
Marker Gene ◽  
Pollen Grains ◽  
Triticum Aestivum L ◽  
Hybrid Seed Production ◽  
Pollen Production ◽  
Hexaploid Triticale ◽  
Anther Length ◽  
Anther Extrusion ◽  
Wide Range

A study of the pollen production properties of three hexaploid triticale strains (Triticale hexaploide Lart.) showed that their anther length was significantly greater than that of wheat anthers (Triticum aestivum L. em Thell.) and the estimated number of pollen grains per anther ranged from 15,000 to 21,000. In comparison, a total of 8000 grains per anther was estimated for wheat, cult Manitou. Eighty-nine percent anther extrusion occurred in triticale cult Rosner, while Manitou averaged 70% anther extrusion. The period of anthesis of triticale varied according to strain but generally was of longer duration than in Manitou and thereby promoted outcrossing. Using a triticale strain carrying a dominant marker gene, 50% seed-set was obtained at a distance of 12 m leeward of the pollen source; however, a small percentage was still obtained at a distance of 30 m. It would appear from the limited number of triticales used in this study that a wide range of variability exists within this species in its pollen production and disseminating properties. With appropriate selection pressures, strains with an outbreeding habit could be developed for the purpose of hybrid seed production.

The genomic inheritance of aluminum tolerance in 'Atlas 66' wheat

Genome ◽  
1992 ◽  
Vol 35 (4) ◽  
pp. 689-693 ◽  
Author(s):  
William A. Berzonsky
Keyword(s):  
Root Growth ◽  
Aluminum Tolerance ◽  
Triticum Aestivum L ◽  
Nuclear Genes ◽  
D Genome ◽  
Hard Red Spring Wheat ◽  
Al Stress ◽  
Soft Red Winter Wheat ◽  
B Genome ◽  
Segregation Ratios

Toxicity to aluminum (Al) limits wheat (Triticum aestivum L. em. Thell.) yields. 'Atlas 66', a soft red winter wheat classified as tolerant (root growth ≥ 0.5 cm after Al stress) to 0.44 mM Al, was hybridized with tetraploid (4x) and hexaploid (6x) 'Canthatch', a hard red spring wheat classified as sensitive (root growth < 0.5 cm after Al stress) to 0.44 mM Al. Progenies produced from these hybridizations were tested for tolerance to 0.44 mM Al in solution to ascertain the number of genes and the genomes of 'Atlas 66', which determine tolerance to aluminum. Tests of 'Atlas 66', 6x-'Canthatch', and the F1's resulting from hybridizations between the parents indicated that dominant, nuclear genes carried by 'Atlas 66' determine tolerance to 0.44 mM Al. Segregation ratios for the F2 significantly differed from ratios expected for a dominant, duplicate genetic mechanism. F1 backcross segregation ratios did not significantly differ from ratios expected for dominant, duplicate nuclear genes for tolerance to aluminum. The expression of genes for tolerance to 0.44 mM Al for 'Atlas 66' appears to be more complex than is predicted by the existence of two dominant genes. A crossing scheme, which involved hybridizing 4x-'Canthatch' with 'Atlas 66', was executed to produce 42-chromosome plants having recombinant A- and B-genome chromosomes and D-genome chromosomes derived exclusively from 'Atlas 66'. Eleven F6 and F7 lines, developed from these plants, were selfed and plants in the F6 generation were backcrossed to 'Atlas 66' and 6x-'Canthatch'. The F6 and F7 lines were subjected to 0.44 mM Al in solution as were the backcrosses. While none of the lines had more than 50% of their seedlings classified as sensitive to Al in the F6 generation, four lines exhibited such a response in the F7 generation. In general, backcrossing the F6 lines to 6x-'Canthatch' increased sensitivity to Al, while backcrossing to 'Atlas 66' increased tolerance. Results suggest that genes for tolerance to Al in 'Atlas 66' wheat are not all located on D-genome chromosomes.Key words: aluminum tolerance, genomic inheritance, Triticum.

A cytological and molecular analysis of D-genome chromosome retention following F2–F6 generations of hexaploid×tetraploid wheat crosses

2018 ◽  
Vol 69 (2) ◽  
pp. 121 ◽  
Author(s):  
Sriram Padmanaban ◽  
Peng Zhang ◽  
Mark W. Sutherland ◽  
Noel L. Knight ◽  
Anke Martin
Keyword(s):  
Durum Wheat ◽  
Tetraploid Wheat ◽  
Triticum Aestivum L ◽  
Food Crops ◽  
Cytological Analysis ◽  
Genome Chromosome ◽  
D Genome ◽  
Ploidy Levels ◽  
F2 Generation ◽  
Global Food

Both hexaploid bread wheat (AABBDD) (Triticum aestivum L.) and tetraploid durum wheat (AABB) (T. turgidum spp. durum) are highly significant global food crops. Crossing these two wheats with different ploidy levels results in pentaploid (AABBD) F1 lines. This study investigated the differences in the retention of D chromosomes between different hexaploid × tetraploid crosses in subsequent generations by using molecular and cytological techniques. Significant differences (P < 0.05) were observed in the retention of D chromosomes in the F2 generation depending on the parents of the original cross. One of the crosses, 2WE25 × 950329, retained at least one copy of each D chromosome in 48% of its F2 lines. For this cross, the retention or elimination of D chromosomes was determined through several subsequent self-fertilised generations. Cytological analysis indicated that D chromosomes were still being eliminated at the F5 generation, suggesting that in some hexaploid × tetraploid crosses, D chromosomes are unstable for many generations. This study provides information on the variation in D chromosome retention in different hexaploid × tetraploid wheat crosses and suggests efficient strategies for utilising D genome retention or elimination to improve bread and durum wheat, respectively.

Chilling injury and chlorotic reactions of euploids and aneuploids of the group 6 homoeologues of common wheat

Genome ◽  
1992 ◽  
Vol 35 (3) ◽  
pp. 468-473 ◽  
Author(s):  
Ernest D. P. Whelan ◽  
G. B. Schaalje
Keyword(s):  
Triticum Aestivum ◽  
Common Wheat ◽  
Chinese Spring ◽  
Prolonged Exposure ◽  
Chilling Injury ◽  
Triticum Aestivum L ◽  
Recessive Trait ◽  
Cytoplasmic Effects ◽  
Group 6 ◽  
Winter Wheat Cultivars

Aneuploid seedlings of the common wheat (Triticum aestivum L.) cv. Chinese Spring (CS) that are nullisomic or telosomic for the long arm of chromosome 6D are susceptible to chilling injury under prolonged exposure to 6 °C; normal euploids or telosomics for the short arm are not. Studies of seedling grown for various durations at 20 °C prior to growth at 6 °C showed that chilling injury was a juvenile phenomenon and that the extent of injury was inversely proportional to the duration of growth at 20 °C to a maximum of about 14 days. When reciprocal crosses were made between susceptible 6D nullisomics or long-arm ditelocentrics of CS and resistant 6D nullisomics of three spring and one winter wheat cultivars, progenies from aneuploid F1 hybrids all segregated for susceptibility as a recessive trait and at a frequency approximating a dihybrid ratio; no cytoplasmic effects were detected. Aneuploids of the group 6 homoeologues of the spring wheat cvs. Cadet and Rescue were resistant, as were group 6 whole-chromosome substitutions of eight different donor wheats in the recipient parent CS and 56 other euploids tested. Genes for resistance to chilling injury appear to involve the group 6 chromosomes and the short arm of 6D in Chinese Spring. In contrast with chilling injury, all aneuploid lines with only four doses of the "corroded" loci on group 6 chromosomes exhibited chlorotic symptoms.Key words: Triticum aestivum, chilling injury.

Potential for gene transfer between wheat (Triticum aestivum) and jointed goatgrass (Aegilops cylindrica)

Weed Science ◽  
1998 ◽  
Vol 46 (3) ◽  
pp. 313-317 ◽  
Author(s):  
R. S. Zemetra ◽  
J. Hansen ◽  
C. A. Mallory-Smith
Keyword(s):  
Seed Set ◽  
Management Plan ◽  
Female Fertility ◽  
Recurrent Parent ◽  
D Genome ◽  
Aegilops Cylindrica ◽  
Herbicide Resistant ◽  
Jointed Goatgrass ◽  
Transfer Genes ◽  
Parent Female

Jointed goatgrass is a major weed in the wheat-producing areas of the western U.S. It shares the D genome with wheat, and interspecific hybrids between the two species occur in the field. The objective of this research was to determine if wheat X jointed goatgrass hybrids could serve to transfer genes from wheat to jointed goatgrass. A backcrossing program was initiated in the greenhouse between wheat X jointed goatgrass hybrids and either jointed goatgrass or wheat to determine the potential for seed set and the restoration of self-fertility. Seed was set by backcrossing with either species as the recurrent parent. Female fertility increased from 2% in the hybrid to 37% in the BC2 plants with jointed goatgrass as the recurrent parent. Partial self-fertility was restored in the second backcross (BC2) generation using jointed goatgrass as the recurrent parent. This indicates that genes could be transferred between wheat and jointed goatgrass after only two backcrosses. The number of bivalents observed in the plants during meiosis appeared to be key to increasing female fertility and self-fertility. Based on the results of this study, it is possible for genes to move from wheat to jointed goatgrass. Any release of a herbicide-resistant wheat should be accompanied by a management plan that would minimize the potential for gene movement between these species.

INHERITANCE OF THE TYPE OF SOLID STEM IN GOLDEN BALL (TRITICUM DURUM): II. CYTOGENETICS OF THE RELATION BETWEEN SOLID STEM AND OTHER MORPHOLOGICAL CHARACTERS IN HEXAPLOID F5 LINES OF A HYBRID WITH RESCUE (T. AESTIVUM)

1959 ◽  
Vol 37 (6) ◽  
pp. 1207-1216 ◽  
Author(s):  
Ruby I. Larson
Keyword(s):  
Triticum Aestivum ◽  
Triticum Durum ◽  
Triticum Aestivum L ◽  
Morphological Characters ◽  
Genome Chromosome ◽  
D Genome ◽  
Stem Solidness ◽  
Pentaploid Hybrid ◽  
Golden Ball ◽  
Solid Stem

Cytogenetic analysis of selected F5 lines of the pentaploid hybrid, Rescue (Triticum aestivum L. emend. Thell.) × Golden Ball (T. durum Desf.) showed that chromosome XVI is the member of the D genome of Rescue that prevents transfer of the more solid top culm internode of Golden Ball to hexaploid segregates. It also produces a lax spike. Chromosome XX, which is the D-genome chromosome mainly responsible for the hollowness of hollow-stemmed hexaploids, probably has little effect in Rescue. Long awns were associated with low chromosome number but not with stem solidness or dense spike; therefore, the chromosome that suppresses awn development is probably not XVI.Three 42-chromosome segregates from the cross were more solid in the top internode than Rescue, presumably because of segregation of genes in the A and B genomes. It is unlikely, however, that a fully hexaploid segregate with a top internode as solid as that of Golden Ball can be selected from this hybrid.

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