Attempted Gene Transfer From Tetraploids to Diploids Intriticum

The possibility of introgression from tetraploid (2n = 28) AABB to diploid (2n = 14) AA wheats was investigated. Reciprocal crosses were made between tetraploid Triticum turgidum L. var. durum Desf. and diploids T. monococcum L. var. boeoticum Boiss., or T. urartu Tum.; and between T. turgidum var. carthlicum Nevski and T. monococcum L., or boeoticum, or urartu. The triploid F1hybrids were backcrossed to diploid parents. All backcross derivatives were lethal at BC1or BC2except those of durum × boeoticum which were carried to BC4. However, neither fertile plants nor plants with the diploid chromosome number were obtained up to BC4generation. As backcross generations advanced, backcross seed set, seed development, seed viability and plant vigor decreased. The failure of introgression from tetraploid to diploid wheats may be due to differential selection for unreduced gametes and adverse nucleo-cytoplasmic interactions.