Gene bank: Where seeds can be stored for over 1,000 years

Did you know that you can properly store seeds for more than 1,000 years?

Researchers in Kenya say plant species are facing extinction due to climate change, population pressure, desertification, change in land use and many other threats.

This, they say, calls for the storage of plant species in seed banks to preserve genetic diversity for the future.

A researcher at the Kenya Agricultural and Livestock Research Organisation talked to the Star in an interview about a seed bank, where seeds can be stored for more than 1,000 years, if put under the right temperatures.

Joseph Ireri, a research scientist at Kalro Genetic Resources Research Institute at Muguga in Kiambu county, said it is possible to store seeds for many years when put under the right temperatures.

He said the institute has a seed bank where they conserve biodiversity of plants.

“We go round the country collecting seeds of different plant species then come with them to the gene bank. We then dry them to a moisture content of less than seven per cent, seal them in aluminium foil packets and store them at a temperature of -20 degrees Centigrade, where they can remain viable for even over a 1,000 years,” Ireri said.  

He said they are doing this to make the material available for use, as the genetic material is important for use in the crop improvement programme.

“We need it, for example, to produce feed for livestock, food for human beings and even restoration of degraded habitats,” he said.

Ireri said there is need to safeguard the material against loss.

“We know wherever our plants are growing in Kenya, they are faced by extinction because of climate change, population pressure, desertification, change in land use and many other threats. Our role is to ensure these materials are available and do not get extinct. So we collect and preserve them for posterity,” the researcher said.

When collecting the materials to save, researchers look for diversity that exists between and within species.

For instance, maize is different from forage grass but within maize you get different varieties.

Ireri said they are looking at that diversity because it is that gene that "we will use to mine genes which will be tolerant to stress factors like high temperature or salinity of the soil."

“Again that diversity will be able to tell you, for example, which plants we can use for food, production of timber, or other uses that we want,” he said.

The seed banks benefit farmers get access to high yielding varieties. Secondly, farmers can go to the gene bank directly and get seeds of the some of the varieties which they lost.

“For example, in sorghum, we work with farmers and grow different sorghum varieties that we are preserving in the gene bank. We invite farmers to do participatory evaluation so that they get what they feel is good for them,” the researcher said. 

He said farmers have been accessing seeds at the seed bank for free but going forward, the institute will be charging a small fee so that they can get funds to do regeneration.

Ireri said this is because conservation work is costly from the process of collecting seeds to seed testing so that they do not store dead seeds.

“Again, we have to do characterisation as a way of adding value to the materials we are conserving.  We do this so that we are able to know which attributes that seed sample is carrying.

"When you are storing, over time some of these materials loose viability so we have to regenerate in time so that we do not lose the genetic integrity that we want to preserve,” he said.  

The researcher added that going forward, they will be charging a small fee to generate some money to do the seed test and support in the collection and regeneration, as well as help cover all parts of the country.

Currently, he said, they are holding about 52,000 different accessions at their gene bank comprising about 2,000 different plant species, adding that they store different species grouped into cereals, pulses and medicinal plants, among others.

Kenya has between 7,000 and 7,500 different plant species and half of that can be conserved in a seed bank. The remaining half are those seeds which cannot be dried to a low moisture content.

Ireri said based on seed storage behaviour, there are three seed categories: One is the orthodox seed which can be dried to a moisture content of less than seven per cent and you can store them under frozen conditions without damaging the embryo.

These are the seeds the institute is keeping in their seed bank.

Then there is the intermediate category of seeds that you can dry to a moisture content of around 10 per cent but not under frozen conditions such as the seeds of sugar and coffee.

The other category is the recalcitrant seed, which can neither be dried nor stored under frozen condition without damaging the embryo, for example, avocado seed.

“For those seeds which can be dried to a low moisture content and can be able to withstand freezing, we store them in a seed bank. For those which cannot be stored in a seed bank, we use other techniques like the vitro bank at Muguga," Ireri said. 

"Here we store life tissues of cassava, yam and sweet potatoes. You can also use field bank where you grow them as life plants and manage them in the field.” 

(edited by Amol Awuor)