Cryopreservation protocol for cowpea pollen storage

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.

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

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).

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.

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