Studies on the Grain Productivity in Rice Tillers of Different Order and Position on the Main Stem

以抽穗期基本相同的不同生态型、不同株型品种的4.5株左右叶龄秧苗为材料，在大田条件下进行移栽试验。1/1000盆，每穴1株。并去除从基部到主茎第5节（T1）、第8节（T2）和第11节（T3）的一次分蘖，以阐明分蘖部位对主茎上不同顺序和位置的水稻分蘖产量的影响。结果表明：T1、T2和T3小区的始分蘖期分别对应于未处理（C）小区的始分蘖活跃期和终分蘖至最大分蘖期;主茎节位越低，各小区的穗重越高，主要是由于穗数的差异。总穗数和主茎同一部位的平均单穗重均表现为T3>T2>T1> C区。3.虽然最大分蘖数和有效穗数在T1<T2<T3<C-区的顺序上都是较低的，但平均穗重对去除低分蘖的反应相反。但穗重的增加量品种间差异较大，穗数型品种的增加量大于穗重型品种。因此，穗重，即产量，前者类型的品种没有改变，而是增加，但在后一种类型的品种的情况下，通过处理降低。这种增产效果与营养生长期（分蘖期至抽穗期）密切相关，因此，在正常季节栽培中，早播效果最好。

About 4.5 leaf-aged rice seedlings of different ecotype and plant type cultivars with almost same heading time were transplanted in ca. 1/1000a pot with one seedling per hill. And primary tillers developed from base to the 5th(T1), 8th(T2) or 11th(T3) node on the main stem were removed to clarify the effects of tillering position on the grain productivity in rice tillers of different order and position on the main stem. The results were summarized as follows:1.First tillering date of T1,T2 and T3-plot corresponded to the beginning active and final to maximum tillering stage of non-treated(C) plot, respectively.2.The lower the nodal position on the main stem was, the higher the panicle weight in all plots, mainly due to the difference of panicle number. Both of the total panicle and average a panicle weight at the same position on the main stem was higher in order of T3>T2>T1>C-plot. And also the average of a panicle weight was higher in tillering order and marked decrease of a panicle weight by ascending the nodal position was found in higher order tillers.3.Although the number of maximum tillers and panicles were lower in order of T1<T2<T3<C-plot, the average of a panicle weight showed reverse response to the removal of lower tillers. But great varietal difference was found in the increment of a panicle weight by the treatment, that is, increasing rate was higher in panicle number type than panicle weight type cultivars. Consequently, panicle weight per hill, namely yield, of the former type cultivars did not change or rather increase, but decrease in case of the latter type cultivars by the treatment. And this yield in-crease was closely related to the period of vegetative growth, that is, days from tiller appearance to heading, so the highest effect was obtained in the early planting in normal season culture.