Chromosomal location of genes for supernumerary spikelet in tetraploid wheat

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 515-520 ◽  
Author(s):  
D. L. Klindworth ◽  
N. D. Williams ◽  
L. R. Joppa

The supernumerary spikelet (SS) trait of durum wheat (Triticum turgidum L.), including the ramified and four-rowed spike traits, is characterized by an increased number of spikelets per spike. Chromosomal location of the SS gene(s) was determined by crossing the ramified spike line PI349056 to the set of 'Langdon' D-genome disomic substitution lines. Double monosomic F1 plants were backcrossed to PI349056 and the testcross F1 plants were classified for chromosome pairing and spike type. Segregation for spike type was observed in the testcross F2. Data indicated that the major SS gene was located on chromosome 2A. Subsequent crosses with the 'Langdon' 2A telosomics indicated that the major SS gene was located on the short arm of chromosome 2A. Segregation of the testcross F2 indicated that a minor SS gene was located on chromosome 2B. Results also indicated that inhibitors of SS may be located on the D-genome chromosomes and an additional experiment was designed to test this hypothesis. Eight D-genome monosomic addition lines were developed by backcrossing PI349056 from one to three times to plants containing D-genome univalents. The test populations contained two cytological types of plants, disomics having 14 pairs of durum chromosomes and D-genome monosomic additions having 14 pairs of durum chromosomes plus a D-genome monosome. Comparison of these two types of plants indicated that chromosome 2D (from 'Chinese Spring' wheat) had a strong inhibitor of SS expression.Key words: Triticum, branched spike, ramified spike, four-rowed spike, cytogenetics.

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 222-228 ◽  
Author(s):  
L. R. Joppa ◽  
N. D. Williams

A complete set of disomic substitution lines have been developed in the tetraploid wheat cultivar Langdon (Triticum turgidum L. var. durum). These aneuploid lines each have a pair of durum wheat homoeologues replaced by a pair of D-genome chromosomes transferred from 'Chinese Spring' hexaploid wheat. They can be used to determine the chromosomal location of genes, to transfer chromosomes from one cultivar or line of tetraploid wheat to another, to study the cytogenetics of tetraploid wheat, to determine gene linkages, and to identify chromosomes involved in translocations. Their phenotypic characteristics, their cytogenetic behavior, and suggested methods for their use are described.Key words: cytogenetics, monosomic, chromosome transmission, telosomic, chromosome substitution.


Genome ◽  
2006 ◽  
Vol 49 (12) ◽  
pp. 1545-1554 ◽  
Author(s):  
J. Li ◽  
D.L. Klindworth ◽  
F. Shireen ◽  
X. Cai ◽  
J. Hu ◽  
...  

The aneuploid stocks of durum wheat ( Triticum turgidum L. subsp. durum (Desf.) Husnot) and common wheat ( T. aestivum L.) have been developed mainly in ‘Langdon’ (LDN) and ‘Chinese Spring’ (CS) cultivars, respectively. The LDN-CS D-genome chromosome disomic substitution (LDN-DS) lines, where a pair of CS D-genome chromosomes substitute for a corresponding homoeologous A- or B-genome chromosome pair of LDN, have been widely used to determine the chromosomal locations of genes in tetraploid wheat. The LDN-DS lines were originally developed by crossing CS nulli-tetrasomics with LDN, followed by 6 backcrosses with LDN. They have subsequently been improved with 5 additional backcrosses with LDN. The objectives of this study were to characterize a set of the 14 most recent LDN-DS lines and to develop chromosome-specific markers, using the newly developed TRAP (target region amplification polymorphism)-marker technique. A total of 307 polymorphic DNA fragments were amplified from LDN and CS, and 302 of them were assigned to individual chromosomes. Most of the markers (95.5%) were present on a single chromosome as chromosome-specific markers, but 4.5% of the markers mapped to 2 or more chromosomes. The number of markers per chromosome varied, from a low of 10 (chromosomes 1A and 6D) to a high of 24 (chromosome 3A). There was an average of 16.6, 16.6, and 15.9 markers per chromosome assigned to the A-, B-, and D-genome chromosomes, respectively, suggesting that TRAP markers were detected at a nearly equal frequency on the 3 genomes. A comparison of the source of the expressed sequence tags (ESTs), used to derive the fixed primers, with the chromosomal location of markers revealed that 15.5% of the TRAP markers were located on the same chromosomes as the ESTs used to generate the fixed primers. A fixed primer designed from an EST mapped on a chromosome or a homoeologous group amplified at least 1 fragment specific to that chromosome or group, suggesting that the fixed primers might generate markers from target regions. TRAP-marker analysis verified the retention of at least 13 pairs of A- or B-genome chromosomes from LDN and 1 pair of D-genome chromosomes from CS in each of the LDN-DS lines. The chromosome-specific markers developed in this study provide an identity for each of the chromosomes, and they will facilitate molecular and genetic characterization of the individual chromosomes, including genetic mapping and gene identification.


Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 229-233 ◽  
Author(s):  
C. F. Konzak ◽  
L. R. Joppa

The durum wheat (Triticum turgidum L. var. durum) cultivar 'Vic' was treated with the chemical mutagen N-methyl-N′-nitrosourea and among the M2 progeny a mutant with "chocolate chaff" (designated cc) was identified. Genetic analyses indicated that chocolate chaff is due to a single recessive gene mutation. The penetrance of the gene for chocolate chaff was environmentally influenced and varied from dark blotches on the glumes to complete coloration of culms as well as spikes. To determine the chromosomal location of the gene, the mutant was crossed with a set of 'Langdon' durum disomic substitution lines in which each of the 14 A- and B-genome chromosomes of durum wheat were replaced by their respective D-genome homoeologues. The segregation of cc was normal in all of the crosses except for those with the 7D(7A) and 7D(7B) lines. Cytogenetic analysis indicated that the gene was located on chromosome 7B, and that chromosome 7D has a gene that prevents the expression of cc when present in one or more copies. It was shown that the 'Langdon' D-genome disomic substitution lines can be used to determine the chromosomal location of genes in tetraploid wheat.Key words: Triticum turgidum, aneuploid, chromosome substitution, monosomic, cytogenetics.


1995 ◽  
Vol 114 (1) ◽  
pp. 34-39 ◽  
Author(s):  
C.-Y. Liu ◽  
A. J. Rathjen ◽  
K. W. Shepherd ◽  
P. W. Gras ◽  
L. C. Giles

Genome ◽  
2004 ◽  
Vol 47 (5) ◽  
pp. 911-917 ◽  
Author(s):  
A Cenci ◽  
S Somma ◽  
N Chantret ◽  
J Dubcovsky ◽  
A Blanco

Carotenoids are essential components in all plants. Their accumulation in wheat seed determines the endosperm colour, which is an important quality trait in wheat. In this study, we report the isolation of BAC clones containing genes coding for three different enzymes of the carotenoid biosynthesis pathway: phytoene synthase (PSY), phytoene desaturase (PDS), and ζ-carotene desaturase (ZDS). Primers were designed on the basis of wheat ESTs similar to the sequences of these three genes in other species, and used to screen a BAC library from Triticum turgidum var. durum (2n = 28, genomes AABB). Eight, six, and nine 384-well plates containing at least one positive clone were found for PSY, PDS, and ZDS, respectively. BACs selected for each of these genes were then divided in two groups corresponding to the A and B genomes of tetraploid wheat, based on differences in the length of the PCR amplification products, conformation-sensitive gel electrophoresis (CSGE), or cleavage amplification polymorphisms. Positive clones were then assigned to chromosomes using a set of D genome substitution lines in T. turgidum var. durum 'Langdon'. PSY clones were localized on chromosomes 5A and 5B, PDS on chromosomes 4A and 4B, and ZDS on chromosomes 2A and 2B. The strategies used for the PCR screening of large BAC libraries and for the differentiation of BAC clones from different genomes in a polyploid species are discussed.Key words: wheat, carotenoid biosynthesis, BAC.


Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 509-514 ◽  
Author(s):  
D. L. Klindworth ◽  
N. D. Williams ◽  
L. R. Joppa

The supernumerary spikelet (SS) trait of durum wheat (Triticum turgidum L.), including the four-rowed and ramified spike types, is characterized by an increased number of spikelets per spike. To determine the inheritance of this trait, the tetraploid ramified spike cultivar PI349056 was crossed reciprocally to normal-spike 'Langdon' durum, and the F1 was backcrossed to each parent. The F1, F2, F3, BC1F1, and BC1F2 were classified for SS expression. Additionally, PI349056 was crossed to the 'Langdon' 2D(2A) disomic substitution line to study linkage of SS genes. The SS trait was recessive to normal spike, and both four-rowed spike and ramified spike progeny were observed in the segregating generations. Segregation in F3 and BC1F2 families indicated that SS in PI349056 was quantitatively inherited, controlled by a major recessive gene and numerous minor genes. Normal-spiked plants selected in families homozygous for the major gene indicated that the major gene did not produce SS when the minor genes were absent. Selection of normal-spiked plants in the F3 and F4 of 'Langdon' 2D(2A) disomic substitution/PI349056 indicated that the minor SS genes were not linked to the major gene on chromosome 2A.Key words: Triticum, branched spike, ramified spike, four-rowed spike.


Genome ◽  
1995 ◽  
Vol 38 (2) ◽  
pp. 332-338 ◽  
Author(s):  
H. Ma ◽  
G. R. Hughes

The genetic control of resistance, expressed as restricted lesion development in seedling plants, to septoria nodorum blotch of wheat was studied under controlled environmental conditions, using the parental, F1, F2, F3, BC1F1, and BC1F2 generations of crosses of Triticum timopheevii-derived resistant durum lines S3-6, S9-10, and S12-1 with the susceptible durum cv. Sceptre. The seedling resistance of these three resistant sources, derived from T. timopheevii (PI 290518), was monogenically controlled. The chromosomal location of the resistance gene identified was determined by crossing the complete set of 'Langdon' – 'Chinese Spring' D-genome disomic substitution lines with S12-1. Tests of the F1 and F2 generations of each cross indicated that only chromosome 3A was associated with resistance. Therefore, the resistance gene is considered to be located on chromosome 3A and has been designated temporarily as SnbTM.Key words: Leptosphaeria nodorum, Stagonospora nodorum, Phaeosphaeria nodorum, glume blotch, disease resistance, substitution lines, Triticum durum.


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