Heterosis in Grain Sink Activity in Pearl Millet

The constituent biochemical components (starch and protein) of grain size revealed sufficient heterosis in the hybrid on unit weight basis, which, however, was not the case with regard to assimilates sources, that is sugar content in stem, glumes and leaves. The glumes and the reserve sugar content of stem appeared to be the preferential sources for assimilates to the developing grain. The top two and the other leaves in this crop seemed to primarily augment the stem reserve. It is suggested, that long, thick and solid stem, along with short ear bearing internode and greater size of glumes may be conducive to better storage and quick mobilisation of photosynthates to developing grain. The source size per se might not condition an increase in potential grain sink.