The document discusses the development and use of mini core collections of plant genetic resources by ICRISAT. It notes that ICRISAT has developed mini core collections for several crops including chickpea, groundnut, pigeonpea, sorghum, and pearl millet containing 1-2% of the total germplasm collection. The mini core collections have been extensively evaluated for traits like resistance to biotic and abiotic stresses. Several accessions with resistance to drought, salinity, and high temperatures were identified. The mini core collections are being provided to researchers to facilitate crop improvement while ensuring conservation of genetic diversity.

1. Mini Core collection - an International Public Good
Nov 2009
Introduction
Plant genetic resources are the basic materials for progress in crop improvement and an insurance against unforeseen threats to
agricultural production. Greater use of germplasm in crop improvement is needed for sustainable conservation of genetic resources, to
protect the natural ecosystems and simultaneously enhance agricultural production for food security.
ICRISAT genebank distributed 0.70 million seed samples to researchers in 144 countries and 0.65 million samples to researchers at
ICRISAT
77 countries
A very small proportion (<1%) of the available germplasm has been used
in crop improvement
Core collections (10% of entire collection) developed in chickpea,
large
ICRISAT scientists postulated the mini core (10% of core collection or
Mini core collections of chickpea, groundnut, pigeonpea, sorghum, pearl
Extensive multi-disciplinary screening/evaluation of core/mini core collections at
Resistance to biotic stresses
Sterility mosaic-8 accessions
Resistance to abiotic stresses
Drought-18 accessions; salinity-12; high temperature-5
Salinity-16 accessions
Salinity-7 accessions
Drought-10 accessions; salinity-10
Drought-10 accessions; salinity-10
Early maturing accessions in chickpea (28), groundnut (21) and pigeonpea (19)
early maturity.
Chickpea: Protein-5; anthocyanin-5
Provided on request 84 sets of mini core and 19 sets of core collections to NARS
partners in 20 countries (Canada, China, France, Germany, India, Japan, Kenya,
Groundnut
India (10 each in four locations)
Lectin content – India (11)
Confectionary type – India (15)
in various crops.
Number of accessions
Crop Entire
collection development
Core
collection
Mini core
collection
Sorghum 2,247 242
Pearl millet 21,594 20,766 2,094
Chickpea 20,140 16,991 1,956 211
Pigeonpea 1,290 146
Groundnut 15,419 1,704 184
Finger millet 5,949 5,940 622 80
Foxtail millet 1,474 155
Flow diagram to establish core and mini core collections
in a crop species.
Ascochyta blight-6
Early maturity-8
Variation for drought tolerance (root length density) in chickpea
mini core.
Variation for low temperature tolerance (at germination) (left) and
salinity tolerance in groundnut (right).
Genotypic variation for root mass (left) and salinity tolerance (right) in
chickpea.
Early maturity-4
Green fodder-19
Grain yield-9
Finger millet – Seed yield and
early maturity (15 accessions
in 4 locations)
Foxtail millet - Seed yield and
early maturity (15 accessions
in 4 locations)
Conclusions
Our strategic research on core and mini core collections and
has enhanced usefulness of germplasm to breeders in enhancing
improvement programs
Characterize and evaluate EC for complete data set
Entire Collection (EC) in Genebank
Step 1
Step 2
Group 1 Group 2…………………………..Group n-1 Group n
Form groups (using taxonomic, morphological and geographic data; accessions
from smaller and adjacent countries with similar agroclimatic conditions could
be grouped together)
Step 3
Step 4
Step 5
Step 6
Clusters
Analyse the standardized data sets within each group separately. Use standard
clustering procedure to group accessions in clusters in each group.
Select 10% of accessions from each cluster, minimum 1 accession if <10
accessions in a cluster to constitute core collection (CC).
Compare CC with EC to determine the representativeness in terms of mean,
variance, diversity, frequency distributions, etc. CC is representative of EC if
these parameters did not differ significantly between the two sets (CC & EC).
Evaluate the representative CC in replicated multilocation trial for
morphological, agronomical and quality traits to identify parents for use. Use
unreplicated data for making subgroups and developing mini core collection
(MCC) if the size of CC is too large.
ClustersClustersClustersClusters
Repeat step 3 and 4 to select MCC that represent CC. Follow step 5 to confirm
representativeness of MCC with CC. Mini core is ready for use.
Step 7