Agriculture Reference
In-Depth Information
In China, it has shown that there was real linear relationship
between light-temperature factors and grain yield. The size
order of standard regression coeffi cient was: Crop illumination
intensity > duration of day > average temperature > average
illumination intensity > maximum temperature > effective
accumulated temperature > minimum temperature. There was
extremely signifi cant negative correlation between average
temperature and spike length while there was signifi cant
positive correlation between average illumination intensity
and spike length. The particle correlation coeffi cient between
average temperature and number of effective spikes per
plant was bigger (r=0.4576). Except for duration of day, the
correlation between other light-temperature factors and
numbers of effective spikes per plant was signifi cant. The
partial correlation coeffi cient between duration of day and
grains per panicle, seed setting rate were bigger which was
0.3746, -0.5599 respectively. The partial correlation coeffi cient
between minimum temperature and 1000 grain weight was
bigger (r=-0.1897) but the correlation between all the light-
temperature factors and 1000 grain weight was not signifi cant
(Wen-Jiang and Wen-Yu 2010).
In Lao PDR, two varieties of rice grown during dry season
of 2001-2002 at 5 different altitudinal heights showed some
variations in grain yield (Sipasenth et al. 2007) (Table 42).
In one investigation in Bangladesh, genotypes having
yield level more than 400 gm
-2
were selected primarily
as low temperature tolerant. There were short and long
duration genotypes in those groups. The combination of yield
components was quite better in groups. The genotypes having
the highest spikelet number with better yield was found
in group III and IV but they had lower 1000 grain weight.
The maximum and minimum temperature around panicle
