Variation of pollen viability and storability in asparagus (Asparagus officinalis L.) cultivars

The optimal culture condition for evaluating pollen viability of asparagus was studied. Sucrose was an effective constituent of the media for raising pollen germination rate. The medium containing 30% sucrose, 0.01% berate an d 3% agar was found to be optimum for assessing pollen viability. Effects o f temperature and light conditions during in vitro culture on pollen germin ation rate were not recognized in the range of 20-30 degrees C in this inve stigation. Varietal difference of pollen viability and storability was also investigated. Pollen germination rate was varied individually within each diploid cultivar, whereas it was uniformly low in triploid cultivar 'Hirosh ima Green'. Average percentage of pollen germination in each diploid cultiv ar was approximately the same, and it was higher than in triploid 'Hiroshim a Green'. Pollen viability declined to 0% after storage for three months at 25 degrees C. Optimum storage temperature, at which pollen viability could be maintained after 12 months storage, was either -20 or -40 degrees C.