Agriculture Reference
In-Depth Information
Table 35
Yield of RCPL I-IC in upper Shillong. India, 1985-90.
Cultivar
Grain yield (t/ha)
1985
1986
1987
1988
1989 1990
RCPL I-IC
2.3
1.6
3.6
4.2
2.8
3.1
Khonorullo 1.9
1.3
2.9
3.3
2.1
2.5
Increase
Over check (%) 22
25
24
28
25
16
Furthermore, geological environment and vertical decline rate
of temperature vary from region to region. Therefore, rice has
different maximum altitude in different regions. Planting rice
in the mountain region with a large altitude difference, one
can get a high productivity within the region. Research has
indicated that the seed setting rate decreases with the increase
in altitude (Yuan et al. 2005a). The reason is that the lower
temperature restrains the transportation of content from the
assimilate to grain which cannot be fully made use of (Liaud
Lin 1990). As the infl uence of the altitude on the amount of
grain and the effective panicles, an experiment in Mianyang,
Sichuan province the altitude of which ranges from 400 m to
1400 m, has shown that the productivity with the increase of
altitude, yield, the effective panicles and the quantity of grain
fi rst increased and then decreased with altitudes (Luo et al.
1999).
Planting rice in the mountain region with a large altitude
difference, the rice can still get a high productivity within
the safe stage if illumination, temperature and water are
guaranteed, for, e.g., the average productivity of 'Shanyou
63' in Heenan province is merely 7t/ha. However, if it is
transplanted to Taoyuan county (with an altitude of 1107
m) in Yunnan province, the productivity can reach to more
