Genetic variations in embryo and endosperm weights, seedling growth parameters and alpha-amylase activity of the germinated grains in rice (Oryza sativa L.).

Relative Contribution of Hetero-and Auto-trophic Growth to Genotypic Variation of Seedling Vigor in Rice (Oryza sativa L.)

“…One possible explanation is that the larger embryo cultivar tended to have a larger DW h.Max with r=0.43 (P<0.01). Thus, the occasionally observed correlation between embryo size and DW t (Sasahara et al, 1986, for javanica cvs.) may be in part attributed to the larger DW h.Max .…”

“…Close correlations have been reported between seed size and seedling growth (Chen et al, 1986;Lafond and Baker, 1986;Sasahara et al, 1986), indicating that seedling vigor of the plant is strongly affected by the seed reserve utilization, i.e., heterotrophic growth. However, the extent to which heterotrophic growth contributes to genotypic variation of seedling growth has not been quantifi ed and hence the signifi cance of autotrophic process for the variation is not clear.…”

“…On the other hand, the effect of DW em was smaller than the other two parameters resulting in the C.V. of only 4%. Although the embryo size may have some importance in the initial growth (Sasahara et al, 1986;Lopez-Castaneda et al 1996), this result suggested that the contribution of embryo weight may be limited compared to those of DW h.Max and RGR. One possible explanation is that the larger embryo cultivar tended to have a larger DW h.Max with r=0.43 (P<0.01).…”

“…Genotypic variability and heritability of seedling vigor in rice have been recognized in a number of studies (Chen et al, 1986;Lee et al, 1986;Sasahara et al, 1986;Redona and Mackill, 1996a;Mackill and Lei, 1997) and identifi cation of genetic factors for this trait has recently been attempted by QTL approaches (Redona and Mackill, 1996b;Cui et al, 2002;Zhang et al, 2005). However, the presumed genomic regions for seedling vigor varied depending on genetic background of the studied populations and a number of epistatic effects (Zhang et al, 2005).…”

α-Amylase Activity and Soluble Sugar Supply from Endosperm in Relation to Varietal Differences in Seedling Establishment under Low-Temperature Conditions in Rice (Oryza sativa L.)

“…A difference in growth stages might have caused these discrepancies, since α-amylase activity and its mRNA level in the endosperm vary with seedling age (Williams and Peterson, 1973;Itoh et al, 1995), and their time course vary with the ecotype and variety (Sasahara et al, 1986;Sasahara and Ikarashi, 1989).…”