Sadao Sakamoto

Cytogenetical studies on artificial hybrids amongElymus sibiricus, E. dahuricus andAgropyron tsukushiense in the tribe Triticeae, Gramineae

To explore the cytogenetical relationships ofElymus andAgropyron of the tribe Triticeae, Gramineae, two species of AsiaticElymus, E. sibiricus (2n=28) andE. dahuricus (2n=42), and a JapaneseAgropyron, A. tsukushiense (2n=42) were crossed. Pentaploid and hexaploid F1 hybrids were vigorous. All pollen grains were aborted and none of the hybrids produced seed.For the crossE. sibiricus × A. tsukushiense, the average chromosome pairing per cell at the MI of the PMCs in the F1 was 16.38 univalents, 8.93 bivalents, 0.25 trivalents and 0.01 quadrivalents; for the crossE. dahuricus × A. tsukushiense, it was 4.41 univalents, 17.67 bivalents, 0.32 trivalents, 0.28 quadrivalents and 0.04 quinquevalents; and for the crossE. dahuricus × E. sibiricus, it was 17.11 univalents, 8.74 bivalents, 0.04 trivalents and 0.07 quadrivalents. From the present results, it is concluded thatE. sibiricus contains one genome andE. dahuricus contains two genomes, which are homologous to those ofA. tsukushiense, and that the third genome ofE. dahuricus might be partially homologous to the remaining genome ofA. tsukushiense. This conclusion is also supported by the cytogenetical analysis ofE. dahuricus × E. sibiricus.

Variation and distribution of esterase isozymes inHeteranthelium andTaeniatherum of the tribe triticeae, gramineae

Esterase isozyme variations ofHeteranthelium piliferum, Taeniatherum asperum andT. crinitum collected in Iraq, Turkey and Iran were analysed by gel isoelectric focusing. InH. piliferum two types of esterase zymogram, H1 and H2, were found. It was demonstrated that a pair of allelic genes, which is shown in the heterozygotes, controls the difference between type H1 and H2. Two types of esterase zymogram, T1 and T2, were observed in two species ofTaeniatherum. The majority of strains having type H1 ofH. piliferum and type T1 ofT. crinitum was distributed in the highly elevated plateau of the Anatolian and Iranian highlands, while strains with H2 and T2 of these two species were found in the western foot-hills of the Zagros Mountains, the Tigris basin of Mesopotamia and the central Anatolian plateau.

Cytogenetic studies on an intergeneric hybrid betweenAgropyron tsukushiense andElymus mollis

Elymus mollis is distributed widely from Korea to Japan, Kamchatka and Alaska, the northern part of U.S.S.R., and Northern and Eastern Canada, Greenland and Iceland. This species is tetraploid (2n=28). A strain of this species collected in Hokkaido was crossed withAgropyron tsukushiense var.transiens collected in Mishima.From this cross, 22 F1 plants were produced. Crossability calculated from the number of hybrid plants produced and the number of floret pollinated was 30.6%. The shape of the F1 spikes was of theAgropyron type but the glumes were hairy as were those of theElymus parent. One of the characteristics distinguishingElymus fromAgropyron is the production of two spikelets at almost all nodes of the rachis. This character was not expressed in the F1 plants. All pollen grains of the F1 plants were completely abortive.The average chromosome pairing at the MI of the PMCs of the F1 amounted to 2.03 bivalents and 30.95 univalents. Almost all bivalents ranging from one to seven were rod-shaped connected with interstitial or terminal chiasma. These results indicate a lack of genomic homology between the three genomes ofA. tsukushiense and the two genomes ofE. mollis.