Alien Chromosome Addition in Wheat 1

Alien chromosome addition in the tetraploid wheat Triticum turgidum L. var. durum (AABB) is proposed. An Agrotricum with the constitution AABBII is anticipated. The I genome could consist of any group of seven chromosomes from Agropyron intermedium (Host) Beauv. The amphiploid derivative parent was an F 10 strain with an average chromosome number of 2n = 49 (range 25 to 66) resulting from chromosome elimination. Eleven first‐nuclear‐restoration backcross plants (RB 1 ) to the amphiploid of Triticum turgidum L. var. durum (2n = 28) ✕ A. intermedium (Host) Beauv. (2n = 42) have been established. The 11 RB 1 plants had a mean chromosome number per cell of 2n = 37.8, with a range of 25 to 50. The mean frequency of bivalent pairing per cell was 10.4 with a range of 0 to 21. The mean univalent number per cell was 17.0, ranging from 2 to 45. The RB 1 plants generally had morphological characteristics intermediate between the amphiploid and durum parents, pollen fertility of the RB 1 's averaged 8.1%, with a range of 0.3 to 35.6%. Further backcrossing of the RB 1 material with the durum parent is planned. Selection among RB 2 plants for high pollen fertility and a high stable number of univalents will be followed by RB 2 ✕ RB 1 intercrossing and finally selfing for the elimination of undesirable Agropyron univalents. A final product with 2n = 42 and genome formula AABBII is anticipated from this program.