Agriculture Reference
In-Depth Information
TABLE 1.10
Panicle Number and Panicle Length of 19 Upland Rice Genotypes as
Influenced by Two N Rates
Panicle Number per Pot
Panicle Length (cm)
Genotype
0 mg N kg
−
1
400 mg N kg
−
1
0 mg N kg
−
1
400 mg N kg
−
1
CRO 97505
8.0ab
17.7fg
17.9bcd
23.8abcd
CNAs 8993
8.3ab
22.0a-f
16.7de
19.5efgh
CNAs 8812
10.3a
28.0ab
16.2def
19.1fgh
CNAs 8938
7.7abc
20.3c-g
17.5cde
20.6defgh
CNAs 8960
6.0bc
15.0fg
20.8a
26.6a
CNAs 8989
8.0ab
21.7a-g
16.3def
18.9fgh
CNAs 8824
9.3ab
26.3abcd
17.6cde
19.2efgh
CNAs 8957
6.7abc
17.0fg
19.6abc
25.4abc
CRO 97422
7.3abc
18.7efg
16.8de
23.9abcd
CNAs 8817
8.0ab
19.3defg
20.5ab
25.3abc
CNAs 8934
8.7ab
21.3b-g
17.6cde
21.6c-h
CNAs 9852
3.7c
14.3 g
18.6abcd
22.6b-g
CNAs 8950
6.7abc
19.7c-g
17.3cde
23.1a-e
CNA 8540
8.7ab
25.3a-e
13.9f
18.4 h
CNA 8711
8.7ab
21.0b-g
17.4cde
22.8a-f
CNA 8170
10.0ab
29.0a
18.8abcd
21.2d-h
BRS Primavera
7.7abc
17.0fg
19.7abc
25.7ab
BRS Canastra
8.0ab
25.3a-e
17.6cde
20.9d-h
BRS Carisma
8.3ab
27.0abc
15.3ef
18.7gh
Average
7.9
21.4
17.7
22.0
F-test
N level (N)
**
**
Genotype (G)
**
**
N × G
**
**
CV (%)
11
5
Source:
Adapted from Fageria, N. K., O. P. Morais, and A. B. Santos. 2010.
J. Plant Nutr
. 33:1696-1711.
With permission.
Note:
Means followed by the same letter in the same column are not significantly different at the 5%
probability level by Tukey's test.
**Significant at the 1% probability level.
1.2.1.5 Spikelet Sterility
The spikelet sterility of lowland rice genotypes was significantly influenced by N and genotype
treatments (Table 1.12). The N × genotype interaction was also significant for this trait. This
means that spikelet sterility varied among genotypes with the variation in N levels. The varia-
tion in spikelet sterility was from 3.95% to 30.37% at the lower N level and from 4.93% to
24.53% at the higher N level. Overall, the spikelet sterility was 22.33% at the low N level and
19.08% at the higher N level. Similar results were obtained by Fageria and Baligar (2001) in
lowland rice.
Spikelet sterility is an important yield component in rice (Figure 1.12), and reducing spikelet is
one way to improve the yield. Overall, the filled spikelet percentage is about 85% in rice, even under
favorable conditions (Yoshida, 1981). Hence, there exists a possibility of increasing rice yield by
15% if breeding eliminates spikelet sterility. The increase in photoassimilates during the spikelet
