It is very important to protect these plant species. Rice, wheat, potatoes and sugar are commonly used in cooking all over the world. Sorghum is grown in the US and in Southern Africa and can be used to make oils, alcoholic drinks, syrups and can even be used as biofuel. Maize, which originated in Central America and soybean are used primarily for cattle feed, however humans also eat these two crops all over the world. 80% of the world's soybean is just grown within the US, Brazil and Argentina. Millet is widely consumed in Africa and Asia and is very similar to sorghum.
When we rely so heavily on plants, it is important to preserve them in order to protect a sample of the seeds of these plants in case they are suddenly lost. Many seeds are kept in the biggest seed bank in the world, the Svalbard Global Seed Vault.
There are many reasons why these seeds need to be stored away in an ice cave. They act as protection against climate change, natural disasters, and are a gene pool for protection and resistance from diseases and other potential man-made disasters. A seed collection acts as a sort of insurance policy.