The National Small Grain Germplasm Collection plays a vital role in the conservation of small grain genetic resources for future use. In order to meet the challenges of increased demand for food from the worlds burgeoning population it is essential to preserve the diverse gene pool found within old landraces, obsolete cultivars, older and modern breeding lines as well as wild relatives of crops in the Tritceae tribe. This gene pool potentially contains diversity that can be utilised to increase and maintain yield potential, improve grain quality, ensure adaptation to changing climatic conditions in addition to providing resistance to biotic (pests and diseases) and abiotic (drought, heat, acidic soil, etc.) stresses.
Annually, through collaboration with various international partners such as CIMMYT (Mexico and Turkey) and ICARDA, nurseries containing promising lines are imported and evaluated for their characterics under South African conditions. In addition, a part of the collection is rejuvenated each year to ensure viability of the seed and approximately 1000 accessions are evaluated by pre-breeders, entomologists and pathologists to build the body of knowledge regarding the traits of each entry in the collection. The collection contains in excess of 17 000 accessions most of which are wheat. The oldest South African wheat cultivar in the collection is "Du Toits" which was released in 1876. The collection also contains a unique rye accession, Secale africanum, which is indigenous to South Africa.
Rejuvenation nurseries are planted annually to ensure fresh seed of accessions that are losing viability. Rows of oats are planted between wheat accessions to ensure that each wheat line remains pure.
Following harvest the seed of each accession is placed in a drying room to reduce the moisture content of the seed to about 4-5 %.
Accessions are then stored in sealed foil bags in freezers at -18°C. When dried and stored like this, seed can retain its viability for up to ten years.
In past centuries, crop improvement increased yields through the replacement of landraces and old, farmer selected varieties with modern high-yielding cultivars. This process has however also resulted in the erosion of the genetic diversity of these crops. Collections like this one are utilised by local and internationally plant breeders who make use of unique genes identified in the stored accessions to reintroduce needed characteristics to the newest generation of improved cultivars.
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