Spike preservation: A simple method to preserve pollen viability and in vitro germination in wheat

Abstract Background Wheat pollen grains have very short longevity and are non-viable after ~30 minute at room temperature and ~60 minutes at 4°C. Pollen grain viability can be preserved maximum to ~24 hrs with existing preservation methods. Results Herein, we developed two simple methods-anther preservation and spike preservation- to preserve the pollen grain viability in wheat. The methods were validated using viability and in vitro germination of pollen grains of 50 diverse spring wheat genotypes. Anthers and spikes were collected for anther preservation and spike preservation methods, respectively, and stored at room temperature (22°C) and fridge (4°C) for 0 and 1-week. Pollen viability were assessed using Alexander staining techniques at two storage temperatures 22°C and 4°C. In vitro germination was determined using liquid germination medium at 4°C. After 1 week, the pollen viability and in vitro germination as determined with Spike preservation method were higher as compared with those of anther preservation method at 4°C. In addition, in vitro pollen germination and pollen viability significantly reduced as storage duration increased. After 1-week, the pollen grains preserved with anther preservation method at 4°C failed to germinate. Conclusion The Spike preservation method is effective for preserving the pollen grain viability and in vitro germination in a large panel of wheat genotypes. This new method is instrumental to further our understanding on pollen grain viability and germination.