EVIDENCE FOR AEGILOPS SHARONENSIS EIG AS THE DONOR OF THE B GENOME OF WHEAT

Abstract

A number of lines of evidence are advanced for the candidacy of Aegilops sharonensisEig as the donor of the B genome of wheat. The cytoplasm of Ae. shuronensis iscompatible with tetraploid wheat Triticum turgidum dicoccoides,as evidenced bythe high level of chromosome pairing and fertility of the amphiploid Ae. sharonensisx T. turgidum dicoccoides. Ae. sharonensischromosomes exhibit high levels of pairing with those of the B genome of wheat in hybrids with Ph-deficient hexaploid wheat and low levels of homoeologous pairing with T. monocmcumchromosomes.——The amphidiploid between Ae. sharonensisand T. monococcumis very similar to T. turgidum dicoccoidesin spike, spikelet and grain morphology. The karyotype of Ae. sharonensisresembles more closely that of extrapolated Bgenome karyotypes of wheat than do the karyotypes of other proposed B-genome donor species of Aegilops. Because of distinctiveness in cytological aftinity and karyotype morphology between Ae. sharonensisand Ae. longissima,a separate genome symbol S_shis proposed for the former species.