Abstract

SHW-L1 is a newly synthetic hexaploid wheat, which has a genomic combination analogous to that of natural common wheat. In the present study, intergeneric F₁ hybrids of SHW-L1 -Aegilops peregrina AS24 were produced without embryo rescue. Among the 31 F₁ hybrid plants observed, 20 had the expected chromosome number 2n = 35 and were euploids (genome ABDUS^l). The remainder 11 plants were aneuploids with 33, 34, 36 and 37 chromosomes, indicating that the neoallohexaploid SHW-L1 was cytologically instable and produced aneuhaploid gametes with 19, 20, 22 and 23 chromosomes, respectively. The hybrid plant lacking chromosome 5B carrying Ph1 showed a very high level of homoeologous chromosome pairing. The absence of Ph gene provides a potent cytological mechanism for DNA introgression among homoeologous chromosomes between newly synthetic wheat and wild species.

Key words: Aneuploids, common wheat, gene flow, neopolyploid, Ph1