Agriculture Reference
In-Depth Information
20
15
10
Y = 5.4548 + 1.1335X - 0.0230X
2
R
2
= 0.7228**
5
0
20
30
40
50
60
Shoot dry weight (g plant
-1
)
FIGURE 1.8
Relationship between shoot dry weight and grain yield of irrigated or lowland rice. (Adapted
from Fageria, N. K., A. B. Santos, and A. M. Coelho. 2011b.
J. Plant Nutr
. 34:371-386. With permission.)
of 12 lowland rice genotypes. The increase in shoot dry weight was linear or quadratic with the
application of N in the range of 0-200 kg ha
−1
. The variation in shoot dry weight with the applica-
tion of N was varied from 58% to 78%, depending on the genotypes (Table 1.8). N fertilization
influences the shoot dry weight of lowland as well as upland rice genotypes (Fageria et al., 2003;
Fageria and Baligar, 2005).
Grain yield in cereals is related to biological yield and GHI (Donald and Hamblin, 1976). The
biological yield of a cereal crop is the total yield of plant tops and is an indication of the yield of the
photosynthetic capability of a crop (Yoshida, 1981). The biological yield is a function of crop growth
duration and CGR at successive growth stages (Tanaka and Osaki, 1983). GHI is the ratio of grain to
the aboveground biological yield. The GHI is controlled by the partition of photosynthates between
harvesting and nonharvesting organs during the crop growth cycle. Hence, the economic yield is
closely related with the crop growth process. Grain yield or economic yield can be increased either
by increasing total dry matter production or by increasing GHI. Some authors have speculated that a
TABLE 1.8
Relationship between N Rate (X) and Shoot Dry Weight (Y)
of 12 Lowland Rice Genotypes
Genotype
Regression Equation
R
2
BRS Jaçanã
Y = 2442.44 + 29.21X − 0.0595X
2
0.5812**
CNAi 8860
Y = 2978.50 + 31.49X − 0.0759X
2
0.5401**
BRS Fronteira
Y = 3467.83 + 20.25X
0.7832**
CNAi 8879
Y = 2860.37 + 31.59X − 0.0759X
2
0.7365**
CNAi 8880
Y = 3047.00 + 34.45X − 0.1054X
2
0.6641**
CNAi 8886
Y = 2876.00 + 34.49X − 0.1013X
2
0.6548**
CNAi 8885
Y = 2513.42 + 41.25X − 0.1044X
2
0.7380**
CNAi 8569
Y = 3726.67 + 28.76X
0.7464**
BRSGO Guará
Y = 2550.09 + 43.56X − 0.1267X
2
0.7213**
BRS Alvorada
Y = 2886.66 + 23.62X
0.7191**
BRS Jaburu
Y = 2577.11 + 25.69X − 0.0566X
2
0.7837**
BRS Biguá
0.6496**
Y = 2174.00 + 18.67X
Source:
Adapted from Fageria, N. K., A. B. Santos, and V. A. Cutrim. 2008.
J. Plant
Nutr
. 31:788-795. With permission.
Note:
Values are averages of 2 years.
**Significant at the 1% probability level.
