Description
Cytogenetical and breeding studies of range grasses are in hand. Present article describes preliminary cytogenetical analysis of wheatgrass (Agropyron) and bromegrass (Bromus) taxa (Agropyron trichophorum n = 21, A. pectinoforome n = 21), two different populations of A. repens (n = 28) and Bromus stenostachyus (n = 14). The species varied with regard to chiasma number and distribution. The highest value occurred in A. repens (Mako population). Heterogenity test for the paired samples showed lack of heterogenity for chiasmata indicating homogenity of Agropyron taxa. However a test for ring and rod bivalents showed significant differences between the two populations of A. repens indicating genomic differences. Multivalents occurred regularly except in A. pectiniforome showing diplontic behaviour. B-chromosomes occurred in Bromus stenostachyus which moved to the poles, but were seen as laggard too. UPGMA cluster analysis separated two populations of A. repens, indicating their genomic differences. Other meiotic variations noticed were: occurrence of a synezetic knot and cytomixis causing aneuploidy in B.stenostachyus; clumping and laggards occurred frequently, indicating heterozygosity of the taxa due to cross pollination.
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Cytogenetical Studies in Range Grasses of Iran
Cytogenetical and breeding studies of range grasses are in hand. Present article describes preliminary cytogenetical analysis of wheatgrass (Agropyron) and bromegrass (Bromus) taxa (Agropyron trichophorum n = 21, A. pectinoforome n = 21), two different populations of A. repens (n = 28) and Bromus stenostachyus (n = 14). The species varied with regard to chiasma number and distribution. The highest value occurred in A. repens (Mako population). Heterogenity test for the paired samples showed lack of heterogenity for chiasmata indicating homogenity of Agropyron taxa. However a test for ring and rod bivalents showed significant differences between the two populations of A. repens indicating genomic differences. Multivalents occurred regularly except in A. pectiniforome showing diplontic behaviour. B-chromosomes occurred in Bromus stenostachyus which moved to the poles, but were seen as laggard too. UPGMA cluster analysis separated two populations of A. repens, indicating their genomic differences. Other meiotic variations noticed were: occurrence of a synezetic knot and cytomixis causing aneuploidy in B.stenostachyus; clumping and laggards occurred frequently, indicating heterozygosity of the taxa due to cross pollination.
