Agriculture Reference
In-Depth Information
leaves are green (8 days after fertilization). During the dough
grain stage, the milky portion of the grain fi rst turns into a soft
dough and later into a hard dough. The grain in the panicle
begins to change from green to yellow. Senescence of tillers
and leaves is noticeable. The fi eld starts to look yellowish.
As the panicle turns yellow, the last two remaining leaves of
each tiller began to dry at the tips (14 days after fertilization).
In the mature grain stage, the individual grain is mature,
fully developed, hard and has turned yellow. The upper
leaves are now drying rapidly although. The leaves of some
varieties remain green. A considerable amount of dead leaves
accumulate at the base of the plant.
Blanking or spikelet sterility caused by poor anther
dehiscence and low pollen production and hence low numbers
of germinating pollen grains on the stigma is induced at this
stage (Jagadish et al. 2007). Series of investigations have shown
that spikelet sterility or blanking is induced by low temperature
during the reproductive growth phase, especially during
booting stage in areas with cool climate. Furthermore, Farrell
et al. (2006) reported that low temperature during reproductive
stage disrupts proper pollen development, leading to a shortage
of sound pollen at the fl owering stage.
It is noted, that spikelet fertility and specifi c spikelet fertility
were mainly affected by the interaction effect between genotype
and environment, with little maternal effect (Table 15).
Interaction heritability in broad sense between genotype and
environment for SF and SSF are 63.5% and 56.5% respectively,
the highest compared with other effect values for heritability.
Correlations between phenotype, genotype, additive and
dominant effects of SF and SSF reached signifi cant level with the
correlation coeffi cients ranged from 0.717 to 1.000. Correlations
between phenotype, genotype, additive and dominant effects of
