High-frequency haploid production from Japanese wheat genotypes crossed with tetraploid hordeum bulbosum

The crossabilities of the three cultivars and their F₁ hybrids of Japanese wheat (Triticum aestivum L.) with two clones of tetraploid Hordeum bulbosum after the treatment of 2, 4-dichlorophenoxyacetic acid (2, 4-D) were investigated. The effect of 2, 4-D treatment was significantly advantageous for increasing seed set. The frequencies of seed set with embryo formation were 35.8% of florets pollinated when treated with 2,4-D. The crossability was also profoundly influenced by the genotypes of wheat and the clones of H. bulbosum. Immature embryos were aseptically regenerated to haploid plants at a frequency of 85.0%. As a result, the average frequency of haploid production was approximately 30% of florets pollinated. The potential of wheat haploids in breeding programmes was discussed.