Agriculture Reference
In-Depth Information
panicle exsertion did not allow for the distinction between
cold to tolerant from cold sensitive genotypes and when the
spikelet fertility was considered, a minimum seven days was
required to differentiate the genotypes for cold tolerance.
Genotypes were more sensitive to cold at anthesis than at the
microsporogenesis and as these stages were highly correlated,
cold screening could be performed at anthesis only, since it is
easier to determine. Cold tolerance of rice at the reproductive
stage may be characterized by the reduction in spikelet fertility
due to cold temperature (17ºC) applied for seven days at
anthesis (Cruz et al. 2010).
Further, it indicates the developmental regulation of the
yield related genes pertaining to the genetic reprogramming
involved at the corresponding developmental stage. The gene
expression data can be utilized to specifi cally select particular
genes which can potentially function synergistically for
enhancing the yield while maintaining the source-sink balance.
Furthermore, to gain some insight into the molecular basis of
yield penalty during various abiotic stresses, the expression of
selected yield-related genes has also been analyzed by QRT-FCR
under such stress conditions. Analysis clearly showed a tight
transcriptional regulation of a few of these yield-related genes
by abiotic stresses. The stress responsive expression patterns of
the genes could explain some of most important stress related
physiological manifestations such as reduced tillering, smaller
panicle and early completion of the life cycle causing reduced
duration of vegetative and reproductive phases.
Development of high yielding rice varieties which maintain
their yield even under stress conditions may be achieved by
simultaneous genetic manipulation of certain combination of
genes such as LRK1 and LOG, based on their function and
expression profi le obtained. In the future we will get to know
