Abstract:

Using genomic DNA of I. trifida (2x) as probe, I. trifida (4x) lines 695104 and 697288 were analyzed with genome in situ hybridization (GISH). The results showed that the two liness were very closely related to I. trifida (2x) based on hybridization signals. Bright and even hybridization signals were observed on all chromosomes of 695104, showing that I. trifida (4x) 695104 should be from doubling of I. trifida (2x) chromosome set. Hybridization signals of 697288 differed from those of 695104 in brightness and region size. It displayed there types: the first was that 41 chromosomes appeared bright and even signals on whole chromosomal; the second was that 14 chromosomes presented even signals almost on whole chromosome but weaker than the first; the third was that 5 chromosomes displayed more weaker signals than those of both the first and the second. Therefore 697288 might derived from I. trifida (2x), but through recombination and variation.

Key words: Sweet potato, Ipomoea trifida, Genome in situ hybridization (GISH)