Submitted to: International Triticeae Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/19/1998
Publication Date: N/A
Interpretive Summary: Wheat grasses, the wild relatives of wheat, are excellent sources of genes for resistance to stem and leaf rusts, and barley yellow dwarf virus. We synthesized hybrids of these grasses with the highly crossable spring wheat cultivar, Fukuhokomugi (Fk), using the latter as the female parent. Several pentaploid hybrids of Fk with tetraploid wheat grass were produced, which had 14.0 to 15.6% of their chromosomes paired. Hybridization between Fk and diploid wheat grass also produced perennial hybrids, which were essentially intermediate between the two parents. Several of the synthetic hybrids showed pairing between the chromosomes of the parental species. This pairing will facilitate the transfer of alien genes into wheat.
Technical Abstract: Thinopyrum bessarabicum (2n = 2x = 14; JJ genome) and Th. curvifolium (2n = 4x = 28; J1J1J2J2) are valuable sources of genes for resistance to stem rust, leaf rust, and barley yellow dwarf virus, which could be introduced into bread wheat, Triticum aestivum L. (2n = 6x = 42; AABBDD). We synthesized hybrids with these perennial grasses using a highly crossable cultivar, Fukuhokomugi (Fk), as the female parent. Several pentaploid hybrids (2n = 5x = 35; ABDJ1J2) of Fk with Th. curvifolium were produced, which had 14.0-15.6% of their chromosome complement chiasmatically associated. Hybridization between Fk and Th. bessarabicum produced both tetraploid (2n = 4x = 28; ABDJ) and pentaploid (2n = 5x = 35; ABDJJ) hybrids. The latter arose as a result of functioning of the unreduced gamete of the male parent Th. bessarabicum. Unlike the female wheat parent the F1 hybrids were perennial. Morphologically, they were intermediate between the parental species. Even in the presence of Ph1, several hybrid showed some homoeologous chromosome pairing. Thus, in the tetraploid ABDJ hybrids, 17.7 to 23.5% of the complement showed association. Details of chromosome pairing are described and its implications in wheat breeding discussed.