Construction of midget chromosomes in wheat

To test the usefulness of breakage–fusion–bridge (BFB) cycles in generating new chromosome aberrations in bread wheat (Triticum aestivum L.) and to extend the range of aberrations available, a series of midget chromosomes was produced from the long arm of chromosome 1B. Using a reverse tandem duplication initiated chromatid type BFB cycle, the 1BL arm was broken and fused with centromeres of either chromosome 5BL or 1RS to form dicentric chromosomes. The 1R and 5B centromeres were broken by centric misdivision. Among the progenies of plants with dicentric chromosomes, two classes of monocentric chromosomes were selected: deficient chromosomes 1B and chromosomes that had 1RS or 5BL for one arm and various fragments of 1BL for the other arm. Following centric misdivision of these monocentrics, midget chromosomes 1BL were isolated: deficient and deletion telocentrics and telocentrics derived from interstitial regions of 1BL. By chance, one deficient chromosome 1BS and one deletion chromosome 1BS were identified in unrelated lines of the same wheat. Following centric misdivision of these chromosomes, two midget chromosomes covering the whole of 1BS were added to the set.Key words: breakage–fusion–bridge cycle, centric misdivision, chromosome aberrations.

Download Full-text

Evaluation of bread wheat Triticum aestivum L. callus genotypes for water stress tolerance using Polyethylene Glycol (PEG)

Baghdad Science Journal ◽

10.21123/bsj.9.3.391-396 ◽

2012 ◽

Vol 9 (3) ◽

pp. 391-396

Author(s):

Baghdad Science Journal

Keyword(s):

Triticum Aestivum ◽

Polyethylene Glycol ◽

Water Stress ◽

Bread Wheat ◽

Triticum Aestivum L ◽

The Other ◽

Soluble Carbohydrates ◽

Soluble Carbohydrate ◽

Water Stress Tolerance ◽

Proline Concentration

A fixed callus weight of 150 mg was induced from immature embryos of three bread wheat Triticum aestivum L. genotypes (Tamos 2, El-izz and Mutant 1) cultured on nutrient medium {MS) containing Polyethylene glycol (PEG-6000) supplemented with concentrations (0.0, 3.0, 6.0, 9.0 or 12.0%) to evaluate their tolerance to water stress. Cultures were incubated in darkness at temperature of 25?1 ?C. Callus fresh and dry weights were recorded and soluble Carbohydrate and the amino acid Proline concentrations were determined. Results showed that there were significant differences in studied parameters among bread wheat genotypes of which Tamos 2 was higher in callus average fresh and dry weights which gave 353.33 and 38.46 mg/cultured tube respectively. Tamos 2 was also higher in soluble Carbohydrate and Proline concentrations which gave 189.84 and 12.30 mg/g respectively. Results also showed that there was significant reduction in callus average fresh and dry weights and soluble Carbohydrates concentration as concentrations of PEG increased in cultured medium, whereas average Proline concentration increased as PEG concentrations increased. The results also revealed significant interactions among the genotypes and PEG concentrations in all studied parameters. It can be concluded thatTamos 2 genotype showed better tolerance to drought than the other two genotypes

Download Full-text

Season Response of Bread Wheat Cultivars (Triticum Aestivum L.) to Different Planting Dates Under Samawa Desert Condition

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/923/1/012089 ◽

2021 ◽

Vol 923 (1) ◽

pp. 012089

Author(s):

Al-Burki Fouad Razzaq A. ◽

Mohsin Haider Abdulhussein ◽

Sarheed Abdullah F.

Keyword(s):

Triticum Aestivum ◽

Field Experiment ◽

Grain Yield ◽

Bread Wheat ◽

Yield Components ◽

Triticum Aestivum L ◽

The Other ◽

Wheat Cultivars ◽

Planting Dates

Abstract A field experiment was carried out in Samawa desert (70 km west of Samawa city, Al-Muthanna governorate), during the 2018-2019 and 2019-2020 agricultural seasons, to study the response of three Iraqi cultivars of wheat (Tamooz2, Ibaa99, Abu Ghraib3) to three planting dates (November 15, 1st December and December 15) under Samawa desert conditions. The results showed the superiority of Tamooz2 cultivar in all traits of the yield components, it gave the highest averages of grain yield, which amounted 5.75 and 5.89 tons/ha−1, weight of 1000 grains, which amounted 29.79 and 31.06 gm, and the number of grains per spike, which amounted 73.02 and 73.76 for the 2019 and 2019-2020 seasons, respectively. The date of December 15th also surpassed in the traits of grain yield, weight of 1000 grains, number of spike grains, and the highest grain yield reached 5.62 and 5.58 tons/ha−1 for the two seasons 2018-2019 and 2019-2020, respectively, and the combination (Tamooz 2 x December 15) gave superiority over the other combinations in terms of grain yield which amounted 6.05 tons ha−1 (2018-2019 season) and Ibaa99 × December 1 gave the highest grian yield about 6.10 tons ha-1 (2019-2020 season).

Download Full-text

Correlation and Path Coefficient Studies of Yield and Yield Associated Traits in Bread Wheat (Triticum aestivum L.) Genotypes

Advances in Plants & Agriculture Research ◽

10.15406/apar.2017.06.00226 ◽

2017 ◽

Vol 6 (5) ◽

Cited By ~ 1

Author(s):

Ermias Assefa

Keyword(s):

Triticum Aestivum ◽

Bread Wheat ◽

Triticum Aestivum L ◽

Path Coefficient

Download Full-text

Response of Yield and Grain Quality of some Bread Wheat (Triticum aestivum L.) Genotypes to Different Sowing Dates

Journal of Plant Production ◽

10.21608/jpp.2016.46876 ◽

2016 ◽

Vol 7 (10) ◽

pp. 1043-1051

Author(s):

Magda Abd El-Rahman ◽

Aml El-Saidy

Keyword(s):

Triticum Aestivum ◽

Bread Wheat ◽

Grain Quality ◽

Triticum Aestivum L ◽

Sowing Dates

Download Full-text

Effect of Cold Pretreatment and Incubation Temperature on Bread Wheat (Triticum aestivum L.) Anther Culture

Cereal Research Communications ◽

10.1007/bf03543678 ◽

2001 ◽

Vol 29 (3-4) ◽

pp. 331-338 ◽

Cited By ~ 15

Author(s):

I. N. Xynias ◽

I. A. Zamani ◽

E. Gouli-Vavdinoudi ◽

D. G. Roupakias

Keyword(s):

Triticum Aestivum ◽

Anther Culture ◽

Bread Wheat ◽

Incubation Temperature ◽

Triticum Aestivum L ◽

Cold Pretreatment

Download Full-text

Chromatid and chromosome type breakage-fusion-bridge cycles in wheat (Triticum aestivum L.).

Genetics ◽

10.1093/genetics/140.3.1069 ◽

1995 ◽

Vol 140 (3) ◽

pp. 1069-1085 ◽

Cited By ~ 2

Author(s):

A J Lukaszewski

Keyword(s):

Triticum Aestivum ◽

Ring Chromosome ◽

Triticum Aestivum L ◽

Aleurone Layer ◽

Meiotic Pairing ◽

Chromosome Type ◽

Root Tips ◽

Morphological Marker ◽

Bfb Cycle ◽

Tandem Duplications

Abstract During the development of disomic additions of rye (Secale cereale L.) chromosomes to wheat (Triticum aestivum L.), two reverse tandem duplications on wheat chromosomes 3D and 4A were isolated. By virtue of their meiotic pairing, the reverse tandem duplications initiated the chromatid type of the breakage-fusion-bridge (BFB) cycle. This BFB cycle continued through pollen mitoses and in the early endosperm divisions, but no clear evidence of its presence in embryo mitoses was found. The chromosome type of BFB cycle was initiated by fusion of two broken chromosome ends resulting in a dicentric or a ring chromosome. Chromosome type BFB cycles were detected in embryo mitoses and in root tips, but they did not persist until the next meiosis and were not transmitted to the progeny. Active BFB cycles induced breakage of other wheat chromosomes that resulted in additional reverse tandem duplications and dicentric and ring chromosomes. Four loci, on chromosome arms 2BS, 3DS, 4AL, and most likely on 7DL, were particularly susceptible to breakage. The BFB cycles produced high frequency of variegation for pigmentation of the aleurone layer of kernels and somatic chimeras for a morphological marker. With the exception of low mutation rate, the observed phenomena are consistent with the activity of a Ds-like element. However, it is not clear whether such an element, if indeed present, was of wheat or rye origin.

Download Full-text