Molecular Plant Breeding 2016, Vol.7, No.33, 1
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These markers were distributed across the 12 chromosomes of rice with an average distance of 0.44 Mb between
markers. In case of Osmancik-97 and DP, 676 (14.68%) SNPs were found to be polymorphic providing an average
genomic coverage of 0.43 Mb interval. A total of four ABLs of Osmancik-97 were SNP genotyped. These lines
had an average recurrent parent genome recovery of 88.75% and ranges from 87.7 to 90.07% (Figure 1c). A total
of seven ABLs were genotyped from the cross between Halilbey and DP. These ABLs registered an average
background genome recovery of 66.88%, which ranges from 63.98 to 70.78% (Supplementary Figure 2). SNP
markers designed in certain regions of chromosomes 1, 3, 4, and 12 were not polymorphic between Osmancik-97
and DP which left these regions partly characterized or uncharacterized at all. Further analysis of these regions
will be carried out using simple sequence repeat markers.
Figure 1 (c) Graphical genotype of an Osamncik-97 ABL showing 90.07% recurrent parent genome recovery. Blue lines represent
alleles for the recurrent parent while red lines represent alleles from the donor parent. Encircled is the region where the gene
Pi40
is
located.
1.2 Evaluation for blast resistance
Selected ABLs of Halilbey and Osmancik-97 were evaluated for blast resistance in uniform blast nursery (UBN)
during 2014WS and 2015DS. Halilbey and Osmancik-97 showed susceptibility to blast during the 2014WS
evaluation. Both cultivars recorded scores of 6 and 5 for Halilbey and Osmancik-97 respectively. The DP and
resistant (R) check were resistant with a score of 1. Scores of the seven ABLs of Halilbey consistently showed
resistance with a mean of 0.43 score. Likewise, Osmancik-97-derived ABLs also showed resistance to blast under
natural field conditions registering mean score of 1.0. Percent disease leaf area (DLA) of the selected lines were also
recorded and were observed to be of congruence to the results using standard evaluation system (SES) of scoring.
Halilbey-derived ABLs recorded an average DLA of 0.21% and ranges from 0% to 0.5%. The same observation was
also recorded in ABLs of Osmancik-97 which showed resistance with DLA of 0.38%. The same experiment was
carried out during 2015DS. Results obtained from this experiment produced results that were similar to the 2014WS
evaluation (Figure 2a, Figure 2b).
Twenty one different virulent strains of Philippines were used to evaluate parents and ABLs for blast reaction by
spray inoculation method in glasshouse. Seven ABLs derived from Halilbey were tested. Of these ABLs, one
(ABL9) showed resistance to all of the strains tested. On the average, Halilbey-derived ABLs showed resistance to
18 out of 21 (85.7%) isolates tested while Halilbey showed resistance to only four (19%) strains (Figure 2c). All
ABLs derived from Halilbey showed resistance to strains M36-1-3-10-10, JMB840610, Ca23-49, V86010,
