Improving the identification, handling and storage of “difficult” seeds ...

The farmer varieties, Kasela, Misale and Bulule exhibited higher levels of stem lodging than the
control varieties Sima and Kuyuma and genebank sorghum materials.
Most of the households grow more than one crop in a particular season, possibly as a guard against
total crop failure. It will necessary that the host farmer’s choice of any other crop(s) should be taken
into account when deciding the number of entries. It was observed that focusing on one crop may
not be quite attractive to the farmers and as such it may be necessary to include one or two more
crops that have local importance such as maize and cowpea for Rufunsa if the farmer desired it.
Germplasm storage facilities (question 5.3)
The main method of conservation used at the National Genebank is ex-situ and involves the storage
of seed samples for orthodox seeded germplasm and to limited extent maintenance of living
collections in field genebanks for such crops like Manihot esculentum and Ipomoea batatas.
Although the NPGRC is supposed to maintain an active collection the storage conditions employed
are good enough to allow for long-term storage used for base collection. The seed is conserved in
deep freezers which are maintained at a temperature of -20ºC. There are 19 deep freezers in good
working condition.
Drying facilities/methods
The drying of seed is being done by SPGRC. The NPGRC has no drying facilities. The seed after
cleaning is taken to SPGRC for drying. The process used is a slow drying process where the seed is
put into the dryer until the moisture content reaches the required amount, and this usually takes
about 3 to 4 weeks. The temperature in the seed dryer is set at 15 to 20ºC with RH at 18 to 20%.
The packaging of seed in aluminium packets is done by NPGRC personnel at SPGRC, after the
seed has dried to the required moisture. Cereals are dried to 6% to 7% while legumes are dried to
7% to 8%.
Measuring seed moisture status
Steps involved in moisture content analysis:
▪ Firstly the drying procedure requirements are: when you harvest a crop from the field, carry out
an initial MC analysis of the harvested accessions to be dried which are usually 12 to 15%.
▪ Recommended conditions for the Drier are 15 to 20 0 C (temperature) and 18 to 20% (relative
humidity).
▪ Dry accessions up to 6-7% for cereals and 7-8% for legumes.
▪ Use the Domestic Grinder to grind 2.5g per sample to be tested for moisture content analysis.
Storage containers
The seed is packed in aluminium foil packets. Once sealed in the aluminium foil packet the seed is
supposed not to gain or lose moisture. The moisture content is from 5% to 8%. Five small
distribution packets are used for each small accession. Big packets are used for extra seed.
Viability monitoring (question 5.5)
The viability of seed samples maintained in the genebank is monitored through germination tests.
The general standards for acceptable minimum viability levels recommended by IPGRI are
followed. For most field and horticultural crops, accessions with germination percentage of 85% or
below, will be recommended for regeneration (Ellis et al, 1985). In the interim, the monitoring
interval has been put at 5 years.
Most of wild Oryza sp. collections show low level of viability. Actually most of it has failed to
germinate at all. The seed lot was kept under room conditions after collections for a long time