Nakhon Sawan 72 hybrid corn
Nakhon Sawan 72 is the first single-cross hybrid corn variety released by the Field Crops Research Institute, Department of Agriculture. It was developed from a cross between two inbred lines, Nei 9008 and Nei 9202, during 1989-1991 at Nakhon Sawan Field Crops Research Centre. This promising single-cross hybrid, coded NSX 9210 (Nakhon Sawan 72), has passed through many steps of evaluations (preliminary yield trial, standard yield trial, regional yield trial, on-farm trial and field test), conducted during 1992-1997 across the Corn Belt area of Thailand. This hybrid produced about 23% higher grain yield than an open-pollinated variety, Nakhon Sawan 1. Data on grain yield in each step of evaluation or yield trial are shown in Table 1.
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Table 1 Mean grain yield of Nakhon sawan 72 compared with an open-pollinated variety, Nakhon sawan 1 in various |
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levels of yield tri al or evaluations during 1992-1997. |
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Trial |
PYT |
SYT |
RYT |
FYT |
FT |
Mean |
Relative to |
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Variety |
1st year |
2nd year |
1st year |
2nd year |
check(%) |
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Nakhon Sawan 72 |
1182 |
1015 |
1160 |
972 |
1015 |
883 |
754 |
913 |
123 |
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Nakhon Sawan 1 |
955 |
837 |
1073 |
720 |
861 |
712 |
602 |
740 |
100 |
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Number of locations |
3 |
6 |
5 |
12 |
8 |
11 |
24 |
69 |
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Remarks: PYT = preliminary yield trial, SYT = standard yield trial, RYT = regional yield trial, FYT = on-farm trial, and |
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FT = farm test. |
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This hybrid also has resistance to downy mildew, which is the most serious disease for growing corn. |
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Data on downy mildew resistance are shown in Table 2. |
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Table 2 percent incidence of downy mildew of Nakhon Sawan 72 and its parents together with resistant and |
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susceptible check varieties under inoculation condition. |
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Line\variety |
%Downy mildew1 |
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Nei 9008 (female parent line) |
1.27a |
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Nei 9202 (male parent line) |
8.40ab |
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Nakhon Sawan 72 |
5.17a |
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Suwan 1 (resistant check) |
11.35b |
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Nakhon Sawan 1 (resistant check) |
8.72ab |
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Tuxpeno (susceptible check) |
96.25c |
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CV(%) |
19.5 |
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1 / Number in the same column which are followed by a common letter are not significantly different at 95% |
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confidence level tested by DMRT. |
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Agronomic traits |
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Trait |
Nakhon Sawan 72 |
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Average grain yield (kg/rai) |
913 |
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Number of days to silking |
54 |
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Number of days to tasseling |
53 |
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Number of days to harvest |
110-120 |
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Ear height (cm) |
107 |
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Plant height (cm) |
205 |
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Lodging (%) |
2.2 |
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Number of ear/plant |
1.02 |
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Number of husks |
12 |
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Shelling percentage |
78.63 |
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Downy mildew (%) |
5.17 |
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Rust (1 - 5) (1 = resistant, 5 = susceptible) |
1.9 |
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NS72