Genetic Diversity Study of the Brachiaria Brizantha (A. Rich.) Stapf Collected From Ethiopia Using Inter Simple Sequence Repeat (Issr) Markers
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Date
2014-02-02
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Addis Ababa University
Abstract
Brachiaria brizantha is a C4 grass commonly used as forage in the tropics. Leaf samples
from seven populations originating from Welega, Jimma, Omo, Gondar, Gojam, Borena
and Ilu Ababora were collected from Zeway Regeneration and Conservation Site of ILRI,
Ethiopia. Genomic DNA was extracted from 79 accessions each from three individuals
using CTAB extraction method. A diluted genomic DNA was subjected to PCR
amplification. From the ISSR primers tested, only six amplified 80 scorable bands from
the 79 accessions used. 96.25% Percentage of polymorphic loci (PPL), gene diversity (h)
= 0.366 and Shannon information’s index (I) = 0.539 were detected at species level. The
number of bands identified by each primer ranged from 8 to 19, with an average of 13.3.
The highest genetic diversity was generated from accessions collected from Ilu Ababora
(PPL= 58.75 %, h=0.210 and I =0.315) while the least was from those collected from
Gondar region (PPL=28.75%, h=0.124 and I =0.183). Jaccard’s similarity coefficients
ranged from 0.302 to 0.431 and analysis of molecular variance indicated the presence of
higher proportion of variation within population (64.66%) than between populations
(35.34 %). Cluster analysis using the un-weighted paired group method with arithmetic
average (UPGMA) and Jaccard’s similarity coefficient (0.38) clustered the accessions
into three major (I, II and III) clusters in their respective regional collection. Principal
Component Analysis (PCO) showed accessions in populations formed their own cluster.
Thus ISSR markers detected a range of genetic diversity from Brachiaria brizantha
germplasm collections from Ethiopia.
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Keywords
Forage, Genetic Variability, Molecular Markers