IDENTIFICATION OF THE APPARENT B–GENOME DONOR OF WHEAT

Abstract

More than 1450 accessions of wild wheats were collected throughout their area of endemism in the Near East. Two types of diploids were distinguished by their seed protein electrophoretic pattern. One of these, Triticum boeoticum Boiss., was prevalent in all wild wheat areas. The other, occurring over the entire range of the tetraploids, was identified as T. urartu Tum., a species previously known only from Transcaucasia. The tetraploid T. diococcoides Körn. Schweinf. (AeAeBeBe), occupying the western arc of the Fertile Crescent, and T. araraticum Jakubz. (AtAtBtBt) occurring in the eastern arc and Transcaucasia, gave dissimilar but remarkably uniform albumin patterns from ethanol extracts of the seeds. A different combination of boeoticum and urartu biotypes accounted for all of the albumin bands in each of the tetraploid patterns obtained from water extracts. The morphological characters of the diploids were combined in the tetraploids. Hybrids between the wild diploid species were sterile, and showed 7 II at meiosis. The synthetic amphiploid from such a hybrid showed 10 II + 2 IV or 12 II + 1 IV. The triploid hybrid T. dicoccum × T. urartu showed 6-7 II. These observations implicate T. urartu as the missing B-genome donor to both of the tetraploids.