Cryopreservation protocol for cowpea pollen storage.

Background: Long-term storage of cowpea pollen is important for the fertilization of spatially or temporally isolated female parents, especially during cowpea crop improvement and wide hybridization programs.

Objective: Experiments were conducted to determine pollen longevity at different storage temperatures and to develop a cryopreservation protocol for pollen of different cowpea accessions.

Materials And Methods: The investigation was carried out at the Research Farm of ICAR-NBPGR, New Delhi, India, during the kharif (rainy) season of 2022. Pollen viability was studied after storage for 1, 3, 6, 12 and 24 h, 1 and 2 weeks and 1, 3 and 5 months at three different temperatures (4, -20 and -196 degree C).

Results: Fresh pollen viability ranged from 78 to 91 %. The optimal pollen moisture content was 12-14 % and the optimal air desiccation period under the laminar air flow chamber (22 +/- 1 degree C) was 5 min for subsequent preservation at -196 degree C. Pollen viability was lost completely at 4 and -20 degree C after 1 and 2 weeks of storage, respectively. Pollen stored in liquid nitrogen (-196 degree C) retained vaiblity similar to that of fresh pollen for > 5 months storage. Pollination using cryostored pollen resulted in normal fertilization.

Conclusion: This finding opens a gateway for cowpea haploid germplasm conservation and wide hybridization programs. https://doi.org/10.54680/fr24610110312.