Interaction between telocentric nucleolus-organizing chromosomes of two Agropyron species and their cytoplasms in alloplasmic lines of common wheat

Alloplasmic lines of common wheat (Triticum aestivum L. cultivars `Penjamo 62' and `Siete Cerros 66') with cytoplasms of two wheatgrass species (Agropyron glaucum and Ag. trichophorum) showed severe growth depression throughout their development and male sterility at maturity. Growth vigor of the alloplasmic lines was influenced more by cytoplasm donors than by nucleus donors, while male sterility was influenced more by nucleus donors. Short-arm telocentric, nucleolus-organizing chromosomes (telosomes) derived from Agropyron caused the restoration of growth vigor and male fertility of the alloplasmic lines in which cytoplasms and telosomes from the same Agropyron species were combined. The telosomes derived from Agropyron species different from the cytoplasm donors could also recover growth vigor and male fertility of the alloplasmic lines. The result indicates the presence of a common mechanism(s) which controls the nucleus-cytoplasmic incompatibility expressed in the alloplasmic lines with the two Agropyron cytoplasms. The Agropyron telosomes showed some dosage effects on growth vigor of the alloplasmic lines and affected fertility when added to the nuclear backgrounds of the two common wheat cultivars.