Studies on transplanting injury in rice [Oryza sativa] plant, 10: Competition among seedlings with different earliness of seedling establishment for the growth and yield

Four six leaf-aged rice seedlings (cv. Koganenishiki) with different damaged part, that is, seedlings without pruning (CS) and with pruning all leaf blades (LS), top at 3 cm from its base (T3S) or all roots (RS) were transplanted in a pot (ca. 1/1000a) at 17*17 cm (MA plot) or 5*5 cm (MB plot) with one plant per hill to clear the effects of earliness of seedling establishment (days required to first tiller appearance after transplanting, DRFTA) due to the damaged part on the subsequent growth and characters related to yield in comparison with the case of transplanting each of the treated seedlings (S plot). 1) In MA and MB plots, as well as S plot, DRFTA was shorter in order of CS RS near eQual LS T3S, and seedlings with longer DRFTA had more main culm leaves and delayed flag leaf expansion or heading data. Vegetative growth of CS, RS and LS was promoted, but that of T3S was inhibited and resulted in advancing the heading date and decrease of leaf number on the main culm, as compared with those of S plot. 2) In MA and MB plots, yield of seedling with shorter DRFTA was higher than that of seedling with longer DRFTA, mainly due to the greater panicle number. Yield of CS, RS and LS in MA and MB plots were greater than that in S plot, and the increasing ratio was the highest in CS (76-112%). Although yields of T3S in MA and MB plots were lower than that in S plot, mainly due to the less panicle number, the decreasing ratio in MB plot (54%) was higher than that in MA (42%). 3) The growth and yield of each treated seedling in MA plot with dividing the soil surface and volume in the pot evenly were nearer to those in S plot than hose in MA plot without such soil treatment. These results suggested that the difference of growth and yield among seedlings with different earliness of seedling establishment due to the damaged part were caused by the competition of both top and underground parts