Molecular Plant Breeding 2015, Vol.6, No.13, 1
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2
1995; Khan et al.,
2001; Haq et al., 2002) but the
resistance is subject to break down due to appearance
of new/more virulent races of the pathogen. The
present study reports on the screening/evaluation of
rice germplasm for sources of resistance against rice
blast disease.
2 Results and Discussion
The screening of all the parents and crosses against
rice blast disease revealed that, none of the variety
was immune, four crosses K-08-60 x IR-68888A,
K-08-61 x SKAU-11A, K-08-61 x IR-68888A, PS-5 x
SKAU-11Aand only one parent PS-5 were found to be
resistant against blast (Table 1). Seven crosses namely
SKAU-382 x SKAU-11A, SKAU-382 x IR-68888A,
SR-1 x SKAU-7A, SR-1 x SKAU-11A, SR-1 x
IR-68888A, K-08-61 x SKAU-7A, PS-5 x IR-68888A,
and four parentsSR-1, K0-8-60, K0-8-61 and IR-68888
were found to be moderately resistant. Three hybrids
SKAU-382 x SKAU-7A, K-08-60 x SKAU-11A, PS-5
x SKAU-7A and three parents SKAU-382, SKAU-7A
and SKAU-11Adisplayed susceptible response toward
the disease. All the remaining hybrids K-08-59 x
SKAU-7A, K-08-59 x SKAU-11A, K-08-59 x
IR-68888A, Jhelum x SKAU-7A, Jhelum x SKAU-11A,
Jhelum x IR-68888A, SK-389 x SKAU-7A, Ch-988 x
SKAU-7A, Ch-988 x SKAU-11A and parents K-08-59,
Jhelum, China-988, showed susceptible to highly
susceptible response. These sources of resistance
identified from rice germplasm, can be exploited in
breeding programs for the development of disease
resistant commercial cultivars after determining their
genetics, if these are found to possess other desirable
agronomic characters. Since I have also analyzed the
general and specific combining ability of all these
parents and crosses besides their pollen and spikelet
fertility in a separate experiment and I have found that
out of twelve resistant and moderately resistant cross
combinations six have shown full restoration and
hence good yield and other agronomic characters.
Further as the experiment was carried out at two
locations and the results indicated almost equal range
of disease infestation at both of these locations.
Very few reports are available on the screening of rice
germplasm against the blast disease
(Table 2). Saifullah,
(1995) screened 23 genotypes during 1990 and 1991
that 19 genotypes were highly resistance and 3 resistant
to leaf and neck blast caused by
Pyricularia oryzae.
Table 1 Disease intensity of different lines, testers and their
crosses at two locations. DMRT analysis is needed (treatment
means can be compaired by using C.D. and S.E. already given
in the table hence DMRT is not necessory)
Genotype
Disease
intensity (E1)
Disease
intensity (E2)
K-08-59 x SKAU-7A
11.778
13.562
K-08-59 x SKAU-11A
9.084
11.064
K-08-59 x IR-68888A
10.778
13.432
Jhelum x SKAU-7A
12.113
15.189
Jhelum x SKAU-11A
11.282
14.122
Jhelum x IR-68888A
11.091
16.765
SKAU-382 x SKAU-7A
3.172
4.760
SKAU-382 x SKAU-11A
2.705
2.123
SKAU-382 x IR-68888A
2.684
2.269
SK-389 x SKAU-7A
8.602
10.876
SK-389 x SKAU-11A
5.931
6.330
SK-389 x IR-68888A
5.491
6.760
Ch-988 x SKAU-7A
13.922
15.187
Ch-988 x SKAU-11A
11.943
16.342
Ch-988 x IR-68888A
5.318
6.975
SR-1 x SKAU-7A
1.535
1.863
SR-1 x SKAU-11A
1.624
1.231
SR-1 x IR-68888A
2.250
2.750
K-08-60 x SKAU-7A
5.350
5.120
K-08-60 x SKAU-11A
4.881
3.768
K-08-60 x IR-68888A
0.713
0.381
K-08-61 x SKAU-7A
1.724
1.532
K-08-61x SKAU-11A
0.238
0.901
K-08-61 x IR-68888A
0.163
0.768
PS-5x SKAU-7A
3.703
3.907
PS-5x SKAU-11A
0.329
0.726
PS-5x IR-68888A
1.564
1.667
K-08-59
15.811
15.811
Jhelum
16.908
16.908
SKAU-382
3.684
4.684
SKAU-389
5.376
7.675
China-988
10.104
13.104
SR-1
1.181
1.235
K-08-60
2.183
2.790
K-08-61
1.251
1.899
PS-5
0.704
0.974
SKAU-7A
3.461
3.764
SKAU-11A
4.653
4.383
IR-68888A
1.377
1.856
Check
14.251
16.908
CD
0.632
0.722
SE (d)
0.216
0.362
SE (m)
0.142
0.256
CV
3.221
3.821
