Features of the F1 Hybrids of Hystrix longe-Aristata and Two Japanese Elymus Species

Hybrids between species of Elymus and Hystrix were obtained by the embryo‐rescue technique. The two Elymus species E. ciliaris and E. yezoensis were used in combinations with H. longe‐aristata. All three species involved are indigenous to Japan. The hybrids had mainly a single spikelet per node like the Elymus parents, and the spikelets had few florets as in Hystrix. The microsporogenesis of the hybrids was highly anomalous, and the hybrid plants were completely sterile. In combination with E. yezoensis the anther development was inhibited at an early stage and microsporocytes were not found. The results indicate that the two genera are distantly related.