Molecular Plant Breeding 2016, Vol.7, No.11, 1
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selected. Majority of the AVRDC genotypes inferred
in this cluster primarily; into a separate sub-cluster.
Similarly, the individuals from Afabet clustered in a
separate sub-cluster similar to genotypes from HAC
and NARI which clustered also in smaller groups
indicating of variability within the cluster (Figure 2).
Baral and Bosland (2002), found that clustering of
pepper accessions collected from diverse geographical
and ecological features in Nepal did not cluster
according to geographical region. In studying
C.
annuum
accessions from 89 countries Nicolaï et al.
(2013) also found that geographic origin was not
clearly visible in clustering genotypes. Gonz
á
lez-P
é
rez et al. (2014) also found partial influence of
geographic origin in clustering Spanish pepper. A
similar condition was observed in the current study,
geographic and agro-climatic factors seem to have
some influence but were not preponderant in
clustering the landraces collected from farmers.
Sub-region Gindae is one of the oldest pepper
growing areas. Genotypes of the Gindae population
have been collected from three distinct areas, viz a
midland area (Gindae town and Dongolo), a lowland
area (Damas) and two new production areas near to
the coast. Majority of the genotypes from Damas
clustered in cluster 1 with genotypes from Elabered
(Midland) and Dbarwa, (highland) which are located
in the Anseba and Debub administrative regions
respectively. The three areas are distantly located from
each other therefore, acquiring seed from common
ancestry or movement of seed among the three areas
could be the main reason of this close relationship. On
the other hand the remaining genotypes from the
midland and coastal areas of Gindae clustered with
genotypes from Mendefera and Dekemhare in cluster
2. Both Mendefera and Dekemhare are highland areas
located adjacent to each other, but relatively far away
from Gindae. However, seed exchange among farmers
in the three areas is common practice. Thus clustering
of germplasm of the three areas together could be
partially due to influence of geographic factors but
mainly due to seed exchange or common ancestry.
The Nm values (Table 6) and ancestry levels of farmer
varieties from these areas (Supplementary Table 4)
supports the influence of seed exchange and common
ancestry factors for clustering of these materials.
One genotype (NRSG28) from the coastal area of
Gindae inferred to cluster 3 at 98.9% ancestry level,
this is a breeding line from the Red-long of NARI that
inferred to the same cluster at ancestry level of 99%.
Gahteilay, another breeding line of Red-long was also
inferred to the same cluster at similar ancestry level.
This indicates that the 28 SSR markers used in this
study were specific enough to group closely related
genotypes together at high ancestry level.
The genomes of tomato and pepper are similar, but a
typical number of common types of chromosomal
rearrangements differentiate the genomes of tomato
and pepper (Livingstone et al. 1999). Dias et al., (2013)
reported that a dendrogram generated using data from
26 ISSR primers used for evaluating four pepper
species and tomato as outgroup separated tomato from
the pepper species. However, although
C. annuum
,
C.
fruitiscens
and
C. chinense
belong to the same
complex and
C. baccatum
to a different complex, the
same dendrogram clustered
C. chinense
away from its
complex, while
C. baccatum
clustered with the
annuum complex. In the current study, although mean
genetic distance between tomato and the other pepper
populations was much greater (0.829) compared to
0.29 among the pepper populations, the eight tomato
genotypes did not cluster separately from pepper,
instead inferred with the pepper genotypes to cluster 2
but appeared distinct within sub-cluster IV (Figure 2).
The reason could be due to weak number of genotypes
representing the tomato so it is maintained as distinct
group within the closest cluster (Nicolaï et al. 2013) or
the set of 28 SSR markers were not specific enough to
distinguish tomato as a separate species.
Afabet is an isolated area which is difficult to access.
Commercial pepper production in Afabet started
recently, not more than 15-17 years ago (Saleh et al.,
2013). Kubkub and Naro-Ans are the two villages
active in pepper production. Only few kilometres
separate them, but all genotypes of Kubkub except
one inferred to cluster 3 (Figure 2). NRSAF19 B is the
only one from Kubkub that inferred with some of
Naro-Ans genotypes to cluster 1, but was separate in
sub-cluster II (Figure 2). The Naro-Ans genotypes
divided into two equal groups each with 13 genotypes
and were grouped in clusters 1 and 2. Only two
genotypes (NRSAF11 A and NRSAF11 C) of
Naro-Ans were closer to Kubkub genotypes and
