Transfer of chromosomes of the A and B genomes of wheat to tetraploid rye
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Tetraploid rye was crossed with different tetraploid triticale lines. The F1 generation of tetraploid rye x 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 1A, 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 .
Publication order reference
B.Apolinarska, Institute of Plant Genetics, Polish Academy of Sciences, Strzeszynska 34, 60-479 Poznan, Poland