Pollen cryopreservation to support maintenance of a wild species collection of the genus Allium.

摘要

Pollen cryopreservation was initiated to support preservation of the complex outbreeding Allium species collection at IPK Gatersleben. Pollen germination was counted and results compared with staining by fluorescein diacetate in order to test viability. Germination tests gave more reliable results than staining. A screening of 176 accessions belonging to most of the subtaxa of genus Allium was performed in three subsequent summer seasons. In 159 direct comparisons within 78 Allium species, the mean germination rate of cryopreserved pollen was 78% of the value obtained with fresh pollen. A feasibility study was performed comparing pollen germination and fertilization of female test plants between fresh and cryopreserved pollen. Two species were used, Allium cepa and A. obliquum. In A. obliquum, seed set with cryopreserved pollen was 60% of that obtained with fresh pollen (calculated on a maximum of six seeds per flower), whereas in A. cepa, the results were only 25% of the result obtained with fresh pollen. The individual rates revealed high variability, but no dependence on species, accession, nor on the season. Although the general usability of pollen cryopreservation was clearly shown for genus Allium, further studies are needed to gain more insight into harvest and storage conditions to further improve the germination rates. CT II International Symposium on Plant Cryopreservation, Fort Collins, Colorado, USA.