ICARDA annual report 2004

accessions (Fig. 20) were sent to
ICRISAT for DNA extraction and
molecular analysis as per agreement
in the Challenge Program.
Fig. 20. Types of accessions from ICARDA’s chickpea collection
chosen for inclusion in a global composite
germplasm set that will be used to find valuable genes
for crop breeding.
ICARDA’s collection of nearly
26,000 barley accessions is the second
largest in the world. It includes
15,500 accessions of locally-adapted
landraces, a quarter of the global
total, and 8700 accessions from
CWANA, the largest collection of
landraces from that region. The
Center’s 1800 accessions of H. vulgare
ssp. spontaneum represent its
full geographical range.
Using GIS, researchers generated
detailed agroclimatological
information, based on 67 variables,
for accessions with collection-site
Fig. 21. Types of accessions chosen by ICARDA from its
barley collection for inclusion in a global composite
germplasm set that will be used to find valuable genes
for crop breeding.
coordinates: 72% of the landrace
accessions and 52% of the wild progenitor
accessions. Landrace and
wild barley accessions were selected
for the composite
set by analyzing this
information using a
two-step cluster
analysis. This produced
260 clusters,
from which
researchers selected
accessions from different
geographical
areas. Improved
germplasm was
selected for the barley
composite set using
passport information,
including pedigrees,
to ensure that the
most common parental varieties
and lines were represented.
ICARDA barley breeders also chose
improved drought-tolerant
germplasm for inclusion.
The final barley composite set
(Fig. 21) consisted of 445 accessions
of H. vulgare ssp. spontaneum (15%
of the total), 1935 landrace accessions
(65%), and improved
germplasm (20%). The improved
germplasm category includes cultivars,
unfinished breeders’ materials,
and genetic stocks, representing
13%, 6%, and 1% of the composite
barley set, respectively.
Of the barley wild
progenitor accessions,
65% are original
accessions collected
during GRU missions.
Hyper-arid, arid and
semi-arid collection
sites represent 1%,
20%, and 63% of the
total, respectively.
These accessions originate
from 20 coun-
tries and their collection
sites belong to 58
ecological clusters.
Of the landraces,
Theme 3
20% are original materials collected
by ICARDA. Hyper-arid, arid and
semi-arid collection sites represent
3%, 33%, and 43% of the total,
respectively. The landrace set originates
from 85 countries, and 78%
are from CWANA. Collection sites
belong to 255 ecological clusters.
Exploring variation in
barley’s photothermal
response to meet the
challenges of climate
change
Global warming is expected to
reduce grain yields in rainfed farming
systems in CWANA’s arid and
semi-arid regions. To develop crop
varieties able to cope with climate
change, breeders are working to
optimize the timing of the crop’s
growing season in relation to temperatures
and the amount of rainfall
expected. This requires the use
of traits associated with a crop’s
photothermal response. To identify
these traits, researchers from
ICARDA and Germany’s Institute
of Genetics and Plant Breeding are
evaluating ICARDA’s germplasm
collection as part of a project funded
by the German Federal Ministry
for Economic Cooperation and
Development (BMZ) and GTZ.
The speed with which cereals
reach the heading stage is controlled
by three separate genetic
mechanisms which determine (i)
response to temperature over a
period of time (earliness per se); (ii)
response to day length (photoperiod
sensitivity); and (iii) response to
low temperatures at the initial
stages of plant development (vernalization
sensitivity). Researchers
studied these responses in 77
improved barley lines and cultivars
from ICARDA breeders’ collections,
and in 115 landraces and 35
wild barley (Hordeum vulgare ssp.
ICARDA Annual Report 2004
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