The dynamic of dry matter accumulation and distribution and its heterosis during the panicle heading to grain filling in two-line hybrid rice

The dynamic of dry matter accumulation and distribution of various plant parts, the correlation between them with the yield, and their heterosis by comparing the hybrids to their male-parent from the level of per stem during the panicle heading to grain filling in 25 two-line hybrid rices were studied. The results showed: The variability of the dry matter accumulation and distribution was different among each hybrid, match on the whole, dry matter accumulation of leaf and stem-sheath was the greatest at flowering stage, while that of panicle and stem-plant peaked at the end of filling stage. The proportion of dry matter of leaf and stem-sheath of most hybrids appeared downtrend from the day of panicle heading, while that of panicle ascended at all times. Stem-sheath was the main dry matter storage organ from the 1 to 7 days after heading, while panicle changed into the main dry matter storage organ at 14 days after heading. The correlation between per panicle yield with leaf dry matter after heading was positive, and the correlation coefficient was high from 1 to 7 days. The correlation between per panicle yield with stem-sheath dry matter at 1 day was positive too, while it changed into negative from 7 days after heading. The correlation between per panicle yield with panicle dry matter and the whole stem-plant parts after heading were positive. The correlation between per panicle with dry matter distribution of various plant parts after heading was basically consistent with that of dry matter accumulation. Dry matter accumulation of leaf, stem-sheath, stem-plant of most hybrid matches appeared negative male-parent heterosis, while that of panicle showed positive, and male-parent heterosis of per stem grain yield and seed-setting rate appeared different on the basis of different hybrids.