Comparative mapping of the wheat 5B short chromosome arm distal region with rice, relative to a crossability locus

2002 ◽  
Vol 105 (5) ◽  
pp. 759-765 ◽  
Author(s):  
D. Lamoureux ◽  
C. Boeuf ◽  
F. Regad ◽  
O. Garsmeur ◽  
G. Charmet ◽  
...  
Keyword(s):  
Comparative Mapping ◽  
Distal Region ◽  
Short Chromosome ◽  
Chromosome Arm

Genetic and physical characterization of chromosome 4DL in wheat

Genome ◽  
2001 ◽  
Vol 44 (5) ◽  
pp. 883-892 ◽  
Author(s):  
MA Rodriguez Milla ◽  
J P Gustafson
Keyword(s):  
Recombinant Inbred Lines ◽  
Dominant Gene ◽  
Triticum Aestivum L ◽  
Distal Region ◽  
Population Coding ◽  
Accurate Information ◽  
Al Tolerance ◽  
Chromosome Arm ◽  
Different Types

The long arm of chromosome 4D in wheat (Triticum aestivum L.) has been shown in previous studies to harbor genes of agronomic importance. A major dominant gene conferring Aluminum (Al) tolerance (Alt2 in 'Chinese Spring' and AltBH in 'BH 1146'), and the Kna1 locus controlling the K+/Na+ discrimination in saline environments have been mapped to this chromosome arm. However, accurate information on the genetic and physical location of markers related to any of these genes is not available and would be useful for map-based cloning and marker-assisted plant breeding. In the present study, using a population of 91 recombinant inbred lines segregating for Al tolerance, we provide a more extensive genetic linkage map of the chromosome arm 4DL based on RFLP, SSR, and AFLP markers, delimiting the AltBH gene to a 5.9-cM interval between markers Xgdm125 and Xpsr914. In addition, utilizing a set of wheat deletion lines for chromosome arm 4DL, the AltBH gene was physically mapped to the distal region of the chromosome, between deletion breakpoints 0.70 and 0.86, where the kilobase/centimorgan ratio is assumed to be low, making the map-based cloning of the gene a more realistic goal. The polymorphism rates in chromosome arm 4DL for the different types of markers used were extremely low, as confirmed by the physical mapping of AFLPs. Finally, analysis of 1 Mb of contiguous sequence of Arabidopsis chromosome 5 flanking the gene homologous to the BCD1230 clone (a cosegregating marker in our population coding for a ribulose-5-phosphate-3-epimerase gene), revealed a previously identified region of stress-related and disease-resistance genes. This could explain the collinearity observed in comparative mapping studies among different species and the low level of polymorphism detected in the chromosome arm 4DL in hexaploid wheat.Key words: wheat, aluminum, mapping, AFLP, SSR.

Genetic mapping of the Lr20–Pm1 resistance locus reveals suppressed recombination on chromosome arm 7AL in hexaploid wheat

Genome ◽  
2002 ◽  
Vol 45 (4) ◽  
pp. 737-744 ◽  
Author(s):  
Christina Neu ◽  
Nils Stein ◽  
Beat Keller
Keyword(s):  
Powdery Mildew ◽  
Leaf Rust ◽  
Hexaploid Wheat ◽  
Molecular Mapping ◽  
Population Based ◽  
Distal Region ◽  
Resistance Locus ◽  
Physical Linkage ◽  
Chromosome Arm ◽  
Suppressed Recombination

The Lr20–Sr15–Pm1 resistance locus in hexaploid wheat confers resistance to three different fungal wheat pathogens (leaf rust, stem rust, and powdery mildew). It was previously localized in the distal region of chromosome arm 7AL. As a first step towards the isolation of this complex locus, we performed molecular mapping of the Lr20 and Pm1 genes in three F2 populations. In two populations, a cluster of 8 and 12 markers, respectively, cosegregated with the resistance genes. In a third population based on a cross between a susceptible lr20 mutant and a resistant cultivar, all clustered markers were monomorphic. However, in this population the recombination frequency proximal to the Lr20 gene was up to 60 times higher, indicating that the complete genetic linkage of the clustered markers is not due to a close physical linkage of the probes but is caused by suppressed recombination. This was supported by the analysis of Triticum monococcum BAC clones where no physical linkage between cosegregating probes was observed. Suppressed recombination at the Lr20–Pm1 locus is likely the result of an alien introgression of chromatin from an unidentified wild relative species or is due to chromosomal rearrangements.Key words: wheat, leaf rust, powdery mildew, resistance, suppressed recombination.

Prediction and analysis of spatial order in haploid chromosome complements

1983 ◽  
Vol 218 (1211) ◽  
pp. 211-223 ◽  
Keyword(s):  
Three Dimensions ◽  
Haploid Genome ◽  
Short Chromosome ◽  
Spatial Order ◽  
General Application ◽  
Computer Aided Analysis ◽  
Computer Aided ◽  
Chromosome Arm ◽  
A Cell ◽  
Sum Of Distances

Bennett has proposed a model that predicts a mean ordered arrangement of all the chromosomes in a simple haploid genome, based on associations of pairs of most similar long, and pairs of most similar short, chromosome arms. The model orders a complete simple haploid genome so that each chromosome is associated with two constant neighbours. This paper describes a test of the model with two types of data obtained from the same reconstructed serially sectioned somatic metaphases examined in the electron microscope. First, chromosome arm volumes were estimated and used to identify the chromosomes and to predict their mean spatial order. Secondly, centromere positions in three dimensions were established. In the species and hybrids used, all with 14 chromosomes, there are so many ways of positioning the chromosomes within haploid sets that a computer-aided analysis was developed. With use of only centromere identities and positions, the programs generated all possible orders of centromeres in haploid sets (where each centromere has two neighbours) and computed the sum of distances between centromeres for each order within a cell. Orders were ranked in ascending sequence of sums of distances. Orders that ranked highest were taken as ‘best’. After results for replicate cells had been pooled, orders were ranked from best to worst. A test of the predicted order was then made by finding its position on this summary. In all the four grasses examined, the predicted order was among the 5% of orders judged best by the analysis. To demonstrate and confirm the predicted order in these grasses, only seven to ten reconstructed nuclei were required. Presumably this test is suitable for general application to other materials whose simple haploid genomes contain between six and about ten biarmed chromosomes.

Genetic Effects of 1BS Chromosome Arm on the Main Agronomic Traits in Chuanmai 42

2009 ◽  
Vol 35 (12) ◽  
pp. 2167-2173 ◽  
Author(s):  
Jun LI ◽  
Hui-Ting WEI ◽  
Su-Jie YANG ◽  
Chao-Su LI ◽  
Yong-Lu TANG ◽  
...  
Keyword(s):  
Agronomic Traits ◽  
Genetic Effects ◽  
Chromosome Arm

scholarly journals Effects of Interspecific Chromosome Substitution in Upland Cotton on Cottonseed Macronutrients

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1158
Author(s):  
Nacer Bellaloui ◽  
Sukumar Saha ◽  
Jennifer L. Tonos ◽  
Jodi A. Scheffler ◽  
Johnie N. Jenkins ◽  
...  
Keyword(s):  
South Carolina ◽  
Upland Cotton ◽  
Field Experiments ◽  
Seed Quality ◽  
Recurrent Parent ◽  
Chromosome Substitution ◽  
Substitution Lines ◽  
Chromosome Substitution Lines ◽  
Macronutrient Content ◽  
Chromosome Arm

Nutrients, including macronutrients such as Ca, P, K, and Mg, are essential for crop production and seed quality, and for human and animal nutrition and health. Macronutrient deficiencies in soil lead to poor crop nutritional qualities and a low level of macronutrients in cottonseed meal-based products, leading to malnutrition. Therefore, the discovery of novel germplasm with a high level of macronutrients or significant variability in the macronutrient content of crop seeds is critical. To our knowledge, there is no information available on the effects of chromosome or chromosome arm substitution on cottonseed macronutrient content. The objective of this study was to evaluate the effects of chromosome or chromosome arm substitution on the variability and content of the cottonseed macronutrients Ca, K, Mg, N, P, and S in chromosome substitution lines (CS). Nine chromosome substitution lines were grown in two-field experiments at two locations in 2013 in South Carolina, USA, and in 2014 in Mississippi, USA. The controls used were TM-1, the recurrent parent of the CS line, and the cultivar AM UA48. The results showed major variability in macronutrients among CS lines and between CS lines and controls. For example, in South Carolina, the mean values showed that five CS lines (CS-T02, CS-T04, CS-T08sh, CS-B02, and CS-B04) had higher Ca level in seed than controls. Ca levels in these CS lines varied from 1.88 to 2.63 g kg−1 compared with 1.81 and 1.72 g kg−1 for TM-1 and AMUA48, respectively, with CS-T04 having the highest Ca concentration. CS-M08sh exhibited the highest K concentration (14.50 g kg−1), an increase of 29% and 49% over TM-1 and AM UA48, respectively. Other CS lines had higher Mg, P, and S than the controls. A similar trend was found at the MS location. This research demonstrated that chromosome substitution resulted in higher seed macronutrients in some CS lines, and these CS lines with a higher content of macronutrients can be used as a genetic tool towards the identification of desired seed nutrition traits. Also, the CS lines with higher desired macronutrients can be used as parents to breed for improved nutritional quality in Upland cotton, Gossypium hirsutum L., through improvement by the interspecific introgression of desired seed nutrient traits such as Ca, K, P, S, and N. The positive and significant (p ≤ 0.0001) correlation of P with Ca, P with Mg, S with P, and S with N will aid in understanding the relationships between nutrients to improve the fertilizer management program and maintain higher cottonseed nutrient content.

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