Maize Genomics and Genetics 2015, Vol.6, No.2, 1-5
4
and Xia et al. (2004), heterosis has been predicted on
the basis of genetic distance based on molecular
markers. Goff (2011) found that generally the greater
the genetic diversity of the parents, the higher the
level of heterosis achieved. This suggested that since
the genetic distance among lines was not wide, it
would have been impossible to get any good hybrid
combination. The current results differed from the
assumption used to establish the heterotic groups
based on molecular maker data as stated by Reif et al.
(2005). All these findings were different from the
results got from the present study. Also Sserumaga et
al. (2014) realized that high overall genetic diversity
(0.65) among the inbred line combinations indicates
an opportunity to exploit the inbred lines for the
development of varieties and start point of pedigree
breeding population used to produce promising inbred
lines (Sserumaga et al., 2014). For a crop like maize,
the strategy of developing good hybrids depends on
genetic diversity present in the available inbred lines.
In the present study, the molecular markers identified
genetic diversity. Analysis of genetic diversity and of
relationship among the elite breeding materials could
significantly aid in crop improvement. Moreover, the
lines find themselves close to clusters due to a
decrease in variation between them.
3 Conclusions
The variability among the inbred lines in this study
was not very high. Also, the genetic distance between
the studied lines was low. The prediction of the
heterosis effect of the crosses between them would
have been in the negative way. Cluster I contained all
the introduced inbred lines and most of the locally
adapted lines. It was subdivided into 16 sub-clusters.
All the four inbred lines used as heterotic testers in the
next chapter were found to be in different sub-clusters
based on molecular characterization but were all in the
same main cluster I.
4 Materials and methods
4.1 Plant material and data collection
Thirty inbred lines were collected from CIMMYT,
IITA and IRAD. They were planted in the breeding
nursery during the 2013. Fourteen of these lines were
from CIMMYT, three from IITA and thirteen from the
Institute of Agricultural Research for Development
(IRAD). The origin of these lines and their respective
characteristics are presented in Table 3. Fresh leaf
samples of the 30 maize genotypes were collected,
packed and sent in double wells per genotype to
Laboratory of the Government Chemist (LGC) Genomics
for genotyping. Young leaves were harvested from 14
day old seedlings from two plants per inbred line.
Four samples of six millimeter leaf discs were taken
from each inbred line and placed in a 96 well plate.
The 96 well plates containing the leaf samples were
sealed with a perforated heat seal and sent to LGC
Genomic for genotyping. The sampling was carried
Table 3 Maize inbred lines used in the study
Lines
Code Origin
Characteristics
4001
1
IITA
Tolerant to low N
88069
2
IRAD
Good root volume
9450 (1)
3
IITA
Temperate adapted
ATP 32
4
IRAD
Acid soil tolerant
ATP 50
5
IRAD
Acid soil tolerant
ATP S5 31Y – 2 6
IRAD
Acid soil tolerant
ATP S6 20Y – 1 7
IRAD
Acid soil tolerant
ATP S6 31Y-2
8
IRAD
Acid soil tolerant
ATP S6 31Y-BB 9
IRAD
Acid soil tolerant
ATP S8 26Y – 2 10
IRAD
Acid soil tolerant
ATP S8 30Y – 2 11
IRAD
Acid soil tolerant
ATP S9 30Y – 1 12
IRAD
Acid soil tolerant
ATP S9 36Y – 1 13
IRAD
Acid soil tolerant
CI gp1 17
14
IRAD
Tolerant and P
efficient
CI gp1 17 (F)
15
IRAD
/
CLA 135
16
CIMMYT Susceptible
CLA 183
17
CIMMYT Acid soil tolerant
CML 304
18
CIMMYT Susceptible
CML 332
19
CIMMYT Susceptible
CML 434
20
CIMMYT Acid soil tolerant
CML 435
21
CIMMYT Acid soil tolerant
CML 437
22
CIMMYT Acid soil tolerant
CML 439
23
CIMMYT Acid soil tolerant
CML 479
24
CIMMYT Acid soil tolerant
CML 486
25
CIMMYT Acid soil tolerant
CML 533
26
CIMMYT Acid soil tolerant
CML 534
27
CIMMYT Acid soil tolerant
CML 535
28
CIMMYT Acid soil tolerant
D300-17
29
CIMMYT Acid soil tolerant
KU 1414
30
IITA
Tolerant to low N
