Agriculture Reference
In-Depth Information
2.0
a(t)
a(t)
a(t)
1.6
ab(t)
1.2
abc(t)
abc(mt)
abc(mt)
0.8
bc(mt)
c(s)
0.4
c(s)
0
Upland rice genotypes
FIGURE 8.28
Classification of upland rice genotypes to acidity tolerance. Same letters on the bar at the
same pH level do not differ significantly at the 5% probability level. Letters in parentheses indicate: t = toler-
ant, mt = moderately tolerant, and s = susceptible.
(Zhang et al., 2010). The increase of activities of asparaginate synthetase and glutamine synthetase
of oilseed rape through gene transformation can raise the N use efficiency (Seifert et al., 2004).
Zhang et al. (2010) also reported a variation in N use efficiency among rape cultivars. These authors
also reported that under low N supply, high N use efficiency cultivars had longer roots, more lateral
roots, higher amounts of reuse of nitrate from the stem and leaves, and higher nitrate reductase
activities in leaves.
Several reasons have been cited why some genotypes are more efficient in N utilization com-
pared to others (Thomason et al., 2002). Nutrient absorbing efficiency is one of the important causes
of variation of nutrient efficiency in crop plants (Dhugga and Waines, 1989; Zhang et al., 2010).
B062008
B072041
B072001
Without lime
With lime
Without lime
With lime
Without lime
With lime
FIGURE 8.29
Root growth of upland rice with and without lime.
