Identification Of Chromosome Aberrations In Hybrids Between Hexaploid And Octoploid Triticale

Triticale is an artificial crop produced by crossing wheat and rye,which combines the characteristics of both parents with large spikes,many grains,high biological yield,rich protein and lysine content,strong resistance to biotic and abiotic stresses and wide adaptability,indicating potential crop in future.However,octoploid triticale usually has shrunken grain and low fertility,while the hexaploid triticale has limited processing quality being lack of D genome chromosomes.Hybridization between the two different ploidy triticale will not only help to breed secondary triticale with improved agronomic traits,but also to produce aneuploids based on the hexaploid triticale background which can be used for studying wheat-rye chromosome interactions.In this study,a hexaploid triticale Woh1084(AABBRR)was crossed with an octoploid triticale Jinghui 1(AABBDDRR),their hybrids F4-F5 were sequentially identified using oligonucleotide multiplex painting and genomic in situ hybridization(GISH),the major results was as following.Oligonucleotide multiplex painting combined rye GISH clearly distinguishes the chromosomes of two triticale parents.Woh1084 contains 28 wheat chromosomes and 14 rye chromosomes involving DS6D(6A),Jinghui 1 contains 42 wheat chromosomes and 14 rye chromosomes,but its 7D has obvious deletion of terminal signals in 7DL.Chromosomes 2B and 5A also showed polymorphism between two parents,while no other variation was found in other chromosomes.Based on identification of 74 F4-F6 families and 285 plants chromosome variation of different generations were detected.Among 9 F4 families,four lines showed similar chromosome constitution to Woh1084 all with DS6D(6A),while the other five lines contained 9 chromosome variations,which included 3 structural variation such as homozygous and heterozygous translocation T3DS·3RL and 3R telosome,and six chromosome number variations involving chromosome losses or gain of 4B,6D,6A,7B,and 7D.Three plants 227-3,227-4,and 230-3 were identified as AABBRR without DS6D(6A).Among 58 F5 families,48 shared similar constitutions to Woh1084,6 were regular AABBRR types without DS6D(6A),the other 4 lines contained chromosomal changes,which included one plant as DS6D(6A)-DS7D(7B),4 involved chromosome losses or gains of 2A,2B,4D,4B,7B,and 7D and one plant 16cxj254-5 involved translocation T1DS·1DL-3RL.Among 38 plants in 7 F6 families with varied chromosomes in corresponding F5 plants,37 plants with chromosome variations were identified,which included chromosome number variations involved losses or gains of 3A,6A,2A,4A,1B,2B,4B,7B,2D,4D,6D,7D,1R and 2R,and structural variations including 2R telosomes,homozygous and heterozygous translocation T1DS·1DL-3RL.Two lines showed similar karyotypes with Woh 1084,one line was regular AABBRR.In addition to develop 15 stable secondary triticale F6 lines with promise agronomic traits,32 aneuploids based on hexaploid tricticale background were also identified,which included chromosome additions(4D and 7D),substitutions(2D,4D,6D and 7D)and translocations(T1DS·1DL-3RL and T3DS·3RL).