Agriculture Reference
In-Depth Information
Table 19
Protein and apparent amylose contents of rice cultivars with low and
high fertilizers (LF & HF).
(IRRI)
Cultivar
Protein LF
Protein HF
Amylose LF
Amylose HF
Basmati 370
7.2
+
0.0
12.2
+
0.3
23.5
+
0.2
21.8
+
0.2
IR60
6.5
+
0.2
12.9
+
0.5
29.0
+
0.4
26.2
+
0.4
IR71137-243
7.4
+
0.1
12.3
+
0.5
26.6
+
0.3
24.1
+
0.3
IR72
5.4
+
0.3
11.0
+
0.0
29.2
+
0.4
26.9
+
0.3
IR8
5.9
+
0.3
9.7
+
0.5
28.7
+
0.2
27.1
+
0.2
IR841-85
6.2
+
0.1
11.1
+
0.0
20.3
+
0.6
19.7
+
0.5
Mean
6.4
+
0.7
11.6
+
1.0
26.2
+
3.4
24.3
+
2.8
(after Champagne et al.)
Fertilizer level (Nitrogen) affects both protein and apparent
amylose contents of rice grains. Interestingly the protein
content of the low nitrogen treatment was within normal
ranges of 6-7.5% (Shih 2004) for almost all cultivars. For
each cultivar protein contents were signifi cantly (P <0.0001)
higher at the higher fertilizer level, whereas apparent amylose
contents were signifi cantly (P <0.0001) lower. This suggests
that protein synthesis is stronger than starch synthesis, which
is consistent with data indicating that mechanisms within the
endosperm exist to partition the supplied substrates towards
the maintenance of protein synthesis at the expense of starch
production (Emes et al. 2003).
Two factors affecting protein accumulation during the fi rst 2
weeks of grain development—the level of free amino acids and
the capacity of the intact grain to incorporate amino acids—are
correlated with the varietal differences in protein content of the
mature rice grain. High protein grains have higher levels of all
the nitrogenous fractions including RNA.
