Identification of the chromosome complement and the spontaneous 1R/1V translocations in allotetraploid Secale cereale × Dasypyrum villosum hybrids through cytogenetic approaches

Genome modifications that occur at the initial interspecific hybridization event are dynamic and can be consolidated during the process of stabilization in successive generations of allopolyploids. This study identifies the number and chromosomal location of ribosomal DNA (rDNA) sites between Secale cereale, Dasypyrum villosum, and their allotetraploid S. cereale × D. villosum hybrids. For the first time, we show the advantages of FISH to reveal chromosome rearrangements in the tetraploid Secale × Dasypyrum hybrids. Based on the specific hybridization patterns of ribosomal 5S, 35S DNA and rye species-specific pSc200 DNA probes, a set of genotypes with numerous Secale/Dasypyrum translocations of 1R/1V chromosomes were identified in successive generations of allotetraploid S. cereale × D. villosum hybrids. In addition we analyse rye chromosome pairs using FISH with chromosome-specific DNA sequences on S. cereale × D. villosum hybrids

Transfer of chromosomes of the A and B genomes of wheat to tetraploid rye

Tetraploid rye was crossed with different tetraploid triticale lines. The F₁ generation of tetraploid rye × tetraploid triticale hybrids was backcrossed with 4x rye. After backcrossing, all BC₁-F₁ plants were subjected to open pollination, whereas in the BC₁-F₂ generations only plants with wheat chromosomes in their karyotypes were open-pollinated. Substitution, addition and addition-substitution lines of wheat chromosomes in tetraploid rye were isolated from the F₂ and F₃ of BC₁. In 60 plants of BC₁-F₂, 59 chromosomes from the A genome and 9 from the B genome of wheat were recovered. The wheat chromosomes were monosomic except for five plants which were disomic, viz. 1A and 5A in two plants each, and a translocated 3AS/5AL in one plant. In 235 BC₁-F₃ plants, 174 wheat addition and substitution chromosomes were found, 143 from the A genome and 31 from the B genome. All wheat chromosomes except 3A from the A genome and four chromosomes from the B genome - 2B, 3B, 5B and 7B were recovered. The number of substitutions ranged from one to four per plant, only two plants having four. In the group of addition plants the number of added wheat chromosomes ranged from one to two, and in the case of addition-substitution plants — from two to four. Wheat chromosomes occurred in monosomic form, except 10 plants. Six substitution plants were disomic for 1 A, 2A, 5A, 7A, 2B and 3B, respectively. One was disomic for 1A and 5A in two addition plants. Two addition-substitution plants were double disomic: 1A and 5A - in one, and 1A and 3B in the other. In the BC₁-F₃ generation, 23 different translocations were found, four of which occurred between wheat chromosomes and the remaining 19 - between wheat and rye chromosomes. Translocated chromosomes were monosomic, except four plants. Two of them were disomic for 3AS/4RL, one for 4AS/4RS and one for 7AS/7RS. The fertility of both addition and substitution plants ranged from 0 to 38.0 seeds/spike, regardless of the chromosome number, with a mean of 9.61 seeds/spike. Plants with 28 chromosomes showed singnificantly higher fertility than plants with 29 and more chromosomes, except additoion plants with chromosomes 5A and 5B. The analysis of the influence of particular wheat chromosomes on plant fertility showed that both substitution and addition plants with chromosome 6A had the highest average fertility, while plants with chromosome 2B in substitution lines as well as plants with chromosome 2A in addition and addition-substitution lines had the lowest fertility

Introgression of wheat chromosomes into diploid rye by use of a hexaploid triticale with an ABRRRR genome

The objective of this study was to continue attempts to introduce wheat chromosomes, particularly those from the B genome, into diploid rye. An allohexaploid having 2 wheat mixogenomes (1B, 2A, 3B, 4B, 5B, 6A and 7B) and 4 rye genomes (RRRR) was crossed with substitution 2× rye containing the chromosomes of the wheat Agenome except 3A, and next backcrossed with substitution rye. Karyotypes were analysed by C-banding in the produced plants of the generations F 1 , BC 1 -F 1 , and BC 1 -F 2 . In nearly all plants of the F 1 generation (except one), 4–12 wheat chromosomes were found, mainly those of the B genome. A comparison of 2 successive generations indicates that both the mean and range of numbers of wheat chromosomes in the offspring of substitution plants and substitution-addition plants changed sometimes to the advantage of wheat chromosomes but sometimes to their disadvantage. A decline was observed in the contribution of B chromosomes and of chromosomes 2A and 6A, but pollen introduced some wheat chromosomes from the male parent: 1A, 4A, 5A and 7A. Wheat B chromosomes contributed to disturbances in plant development (lack of the spike emergence stage), but usually caused spike sterility, and even the single grains produced were usually unable to germinate. As a result, wheat chromosomes of the B genome were finally completely eliminated from the analysed material. The presence of wheat chromosomes of the A genome in fertile 2× rye plants, as well as their transfer to the next generations, indicate that the A genome is more closely related to the rye genome than the B genome. Positive introgression of wheat chromatin from the A genome into 2× rye depends to a large extent on chromosome engineering by means of appropriate crossing combinations, as A chromosomes from the male parent were much better tolerated than those from the female parent

Chromosome pairing in diploid substitution rye and addition rye with wheat chromosomes

Chromosome pairing was studied at metaphase I in PMCs by C-banding in diploid rye plants with 1–3 monosomic-substitution wheat chromosomes and 1 monosomic-addition wheat chromosome. In plants with chromosome 5A, no univalents were found. In other plants with 1 monosomic-substitution wheat chromosome (7A, 2A, or 1A), only rye univalents occurred, on average 0.02–0.18 per PMC. Wheat chromosomes paired with homoeologous rye chromosomes in bivalents. The addition chromosome 6A occurred as a univalent with a frequency of 0.92 per PMC. In plants with 2–3 monosomic-substitution wheat chromosomes, no univalents were found. In 2 diploid rye plants with substitution chromosomes 2A, 5A and in 1 plant with 2A, 7A, wheat chromosomes paired mainly with rye homoeologues, but sometimes they paired with each other, forming heteromorphic wheat bivalent. In the other 3 plants with wheat chromosomes 2A, 5A, 2 plants with 2A, 7A, and 4 plants with 5A, 7A, a reverse situation was observed: nonhomoeologous wheat chromosomes paired with one another (forming a heteromorphic bivalent) more frequently than with rye homoeologues. In plants with 3 substitution wheat chromosomes (2A, 5A, 7A), 2 of them paired with each other, forming first of all a heteromorphic ring bivalent, while the third wheat chromosome paired with a rye chromosome in a ring bivalent or rarely in a rod bivalent. Wheat chromosomes sporadically occurred in multivalents. The presented data show that the rye genome promotes both homoeologous pairing of wheat and rye chromosomes and nonhomoeologous pairing of wheat chromosomes

Cytogenetic characteristic and electrophoretic analysis of dwarf winter hexaploid Triticale mutants

Wykonano analizy cytologiczne kariotypów karłowych mutantów pszenżyta ozimego oraz ich form wyjściowych (kontrola) metodą C - prążkową, a także analizy białek zapasowych (glutenin wysokocząsteczkowych) metodą rozdziału elektroforetycznego na żelu poliakrymidowym z dodatkiem soli sodowej siarczanu dodecylu (SDS PAGE). Analizy cytologiczne wykazały, że wszystkie badane materiały miały pełny zestaw chromosomów heksaploidalnego pszenżyta. Wzór prążkowy chromosomów kontroli - 2088 i 51/59 zasadniczo nie różnił się od standardu. Jednakże w kontroli zaobserwowano różnice w strukturze chromosomów 1R i 4A. W karłowych mutantach zróżnicowane były chromosomy 1R, 3R oraz 4R. Niektóre obserwowane zmiany w strukturze rozmieszczenia prążków mogą świadczyć o delecji, translokacji i/lub duplikacji fragmentów ramion chromosomów. Badane mutanty, a także ich formy wyjściowe (kontrola) różniły się również pod względem składu podjednostek wysokocząsteczkowych glutenin. Mutanty linii 2088 - Tm 942, Tm 917 i Tm 1294 - były polimorficzne, natomiast mutanty rodu 51/59 - Tm 1297, Tm 1300 i Tm 1303 były identyczne i całkowicie różniły się od kontroli. Także kontrola 2088 różniła się od kontroli 51/59.The C-band karyotype of dwarf triticale mutants and their initial forms (control) as well as electrophoretic analysis of storage proteins (high molecular weight glutenins) using acid polyacrylamide gel with the addition of sodium dodecyl sulphate (SDS-PAGE) were performed. Cytological analysis showed that both controls and their mutants have a full set of chromosomes of hexaploid triticale, however, in the control chromosomes 1R and 4A and in mutants chromosomes IR, 3R as well as 4R were different. Some of the observed structural changes in chromosomes may indicate the deletions, translocations and/or duplications of the arm chromosome fragments. The studied mutants and their initial forms were also differentiated with regard to high molecular glutenin subunits. The mutants of 2088 - Tm 942, Tm 917 and Tm 1294 were polymorphic. On the other hand, the mutants of 51/59 - Tm 1297, Tm 1300 and Tm 1303 were homogenic and completely different than the control line. The breeding lines 2088 and 51/59 differed in subinits composition of high molecular glutenins

Effect of chromosomes of the wheat D genome on traits of hexaploid substitution triticale

The D genome of wheat (Triticum aestivum cv. Panda) was used in this study to improve traits of hexaploid winter triticale (×Triticosecale Wittmack). Genome D expression was studied in hexaploid triticale lines with single substitutions (1D/1A, 3D/3A, 4D/4A, 5D/5A, 6D/6A, 7D/7A) and a line with 4 substitutions (1D/1A + 3D/3A + 4D/4A + 6D/6D). Chromosomes 1D and 3D have introduced to the analysed substitution lines resistance to wheat leaf rust (Puccinia triticina, synonym P. recondita f. sp. tritici) and resistance to preharvest sprouting (which is very important in hexaploid triticale), reflected in a high expression of seed dormancy, a high falling number, and low alpha-amylase activity in grain