Influence of Isolation and Culture Media on Induction of Microspore Embryogenesis in Roses (Rosa hybrida)

Microspore culture was applied to induce embryogenesis in roses (Rosa hybrida) cv. HAV1. Important factors affecting viability of isolated microspores and formation of multi-cellular structures including isolation media (NLN, AB, B) and induction media were studied. The most responsive developmental stage of microspores (late unicellular) was determined using DAPI staining. The least infection of microspores was observed when microspores were sterilized with sodium hypochlorite (3.5%) for 15 minutes. The best isolation medium was B medium. Among induction media, the highest ratio of multi-cellular structures was formed in AT3(1). The presence of lactalbumin hydrolysate in the induction medium increased the frequency of divisions and formation of multi-cellular structures. Among various treatments tested, the highest frequency of multi-cellular structures was observed in microspores cultured in AT3(1) and stressed with heat shock(30°C) for 7 days, However they produced only very few pro-embryos. Hereby, microspore embryogenesis protocol for roses is introduced for the first time.