Controlled Atmosphere Preservation

Controlled atmosphere preservation (CAP) is a post-harvest technique used to extend seed and plant material viability by modifying oxygen, carbon dioxide, and nitrogen levels in sealed storage environments. By slowing metabolic processes and reducing oxidative stress, CAP can maintain genetic material stability over extended periods. This method is particularly relevant in cannabis breeding programs where preserving rare or backcrossed lineages is critical. Temperature and humidity are typically maintained at precise levels alongside gas ratios. CAP differs from standard cold or vacuum storage by actively managing the chemical composition of the air surrounding stored material, potentially offering finer control over degradation rates.

Breeders maintaining seed banks and clone libraries often employ CAP systems to preserve F1 hybrids, rare parent lines, and finished cultivars across multiple growing seasons without loss of phenotypic stability. This technique is especially valuable for long-term genetic archiving and international seed exchange programs.