Molecular Plant Breeding 2016, Vol.7, No.25, 1
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Table 1 Production and viability of
Alternaria solani
conidia on infected potato leaves kept on ground surface and at 20 cm depth in
the soil during the year 2009
Month
Fortnight
Number of conidia
(cm
-2
leaf area)*
Viability (%)
Ground surface
20 cm
Ground surface
20 cm
March
I
20
-
27.0
NA
II
63
-
29.4
NA
April
I
86
-
30.8
NA
II
123
-
32.3
NA
May
I
173
-
37.0
NA
II
203
-
40.6
NA
June
I
294
-
44.3
NA
II
263
-
38.4
NA
July
I
160
-
31.7
NA
II
-
-
-
NA
Note: *Mean of three replications each comprising of 30 leaf discs of 1 cm
2
surface area
-= Material perished
NA= Spores not available
Table 2 Production and viability of
Alternaria solani
conidia on infected potato leaves kept on ground surface and at 20 cm depth in
the soil during the year 2010.
Month
Fortnight
Number of conidia
(cm
-2
leaf area)*
Viability per cent
Ground surface
20 cm
Ground surface
20 cm
March
I
42
-
28.3
NA
II
83
-
31.6
NA
April
I
110
-
32.0
NA
II
138
-
34.4
NA
May
I
206
-
42.0
NA
II
240
-
45.6
NA
June
I
323
-
49.3
NA
II
308
-
40.5
NA
July
I
220
-
32.4
NA
II
-
-
-
NA
Note: * Mean of three replications each comprising of 30 leaf discs of 1 cm
2
surface area
- = Material perished
NA = Spores not available
1.2 Survival on diseased potatoes kept at ambient store
Perpetuation of pathogen
Alternaria solani
in diseased potatoes was studied by keeping them in ambient store and
the production and viability of spores at fortnightly intervals commencing from the first fortnight of March was
recorded. The data recorded is presented in Table 3, Table 4.
The perusal of data revealed that the diseased potatoes continuously produced spores during entire period of study
in both the years (2009 and 2010). The average number of spores increased upto first fortnight of June, both in
2009 and 2010, with a maximum number of 430 and 508 spores, respectively. The number then gradually declined
to 216 and 263 spores, respectively, till last observation recorded in the second fortnight of July.
Initial viability of spores from diseased potatoes in first week of March was 24.5 and 29.0 per cent during 2009
and 2010, respectively. The viability of spores gradually increased with time till first fortnight of June during the
year 2009 and 2010, respectively, which then showed a gradual decrease to 23.5 and 27.6 per cent till last
observation.
