ICRISAT Archival Report 2006 - The seedlings of success in the ...

Fig 1. Relationships among 3008 sorghum landrace accessions in the Generation Challenge Program
composite germplasm collection for sorghum, based on allelic variation at 39 SSR loci distributed across
all 10 sorghum linage groups. In this figure landraces representing the five major sorghum races are
colored: race bicolor accessions are orange, race kafir are red, race durra (D) are blue, race caudatum
(C) are green, and race guinea (G) are purple (including the margaritiferum group, Gm). Geographic
regions from which the different groups of accessions originated are: W Africa = Western Africa; S
Africa = Southern Africa; E Africa = Eastern Africa; C Africa = Central Africa; IND = Indian
subcontinent; and, E Asia = Eastern Asia (Figure courtesy of Claire Billot).
ICRISAT - CT Hash, HD Upadhyaya, Punna Ramu and DA Hoisington;
CIRAD – C Billot, J-F Rami, L Gardes, R Rivalian and M Deu;
CAAS – Y Li, T Wang and P Lu.
Milestone C.3.1.7: Genetic diversity and population structure of chickpea and sorghum assessed
(HDU/CTH/RKV/PR/CLLG/SC/DH/PMG/MB/SMU/CB/JB/SC, 2007)
Chickpea:
The composite collection was genotyped using high throughput assay (ICRISAT: ABI3700 and ICARDA:
ABI3100) and 50 SSR markers. ICRISAT generated data on 35 SSR loci and ICARDA on 15 SSR loci on 3000
accessions. Except for TA21, TA22, TA28, and TA58, all markers produced an allele size expected on the basis
of SSR repeat motif). Preliminary data analysis detected 1829 alleles, ranging from 15 to 68 alleles with an
average of 36.6 alleles per SSR locus. Mean PIC (Polymorphism Information Content) value of 0.858 (ranging
from 0.471 to 0.974) and gene diversity 0.873 (ranging 0.536 – 0.975) were observed in the entire composite
collection (Table 6). Kabuli types were more genetically diverse than the other three types. Gene diversity
ranged from 0.253 to 0.965 in kabuli types, 0.419 to 0.974 in desi, 0.479 to 0.955 in pea-shaped, and 0.560 to
0.928 in wild types. Accessions from the West Asia region revealed high gene diversity (0.871) while those
from Oceania revealed lowest gene diversity (0.504) (Table 5). Detected 1539 rare and 290 common alleles at
5% and 1137 rare and 692 common alleles at 1% in the entire composite collection. There were 252 alleles that
were detected in all the four biological groups (desi, kabuli, pea-shaped, and wild relatives). Accessions from
the Mediterranean region had the largest number of region-specific alleles (137) and 69 alleles were common
across all the seven geographical regions. Principal coordinate analysis delineated the accessions in two clusters
(Fig 2). The desi and kabuli chickpeas each formed two distinct clusters; however, a number of desi chickpeas
also grouped into kabuli cluster indicating progressive evolution of kabuli traits from the desi chickpeas.
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