Ethylene inhibitors improve efficiency of microspore embryogenesis in hexaploid triticale

Doubled haploid technology is an important tool in plant breeding and research, but routine application requires the establishment of efficient protocols. Microspore culture is an attractive approach although its efficiency is strongly dependent on the genotype. In this study we evaluated the effects of the three ethylene inhibitors aminooxyacetic acid, 2,5-norbornadiene, and silver thiosulphate (STS) on embryogenesis, regeneration rate and green plant rate in triticale microspore culture. Our results show that STS at 20 A mu M in particular had a positive effect on the embryogenesis rate, suggesting that for many genotypes ethylene accumulates in the culture vessel above a critical threshold where it becomes inhibitory for embryogenesis. In addition, STS also appears to positively influence the green plant rate. Taken together, our results show that the addition of ethylene inhibitors at defined concentrations can counteract the negative effect of ethylene, increase the embryogenesis rate and potentially also the green plant rate in microspore culture.