Difference in Grain Productivity of Tillers among Main Stem Nodes in Rice Plant : I. Effects of the number and position of tillering nodes on grain productivity

[摘要] Tillering of the 2nd to 11th main stem nodes in potted, direct-seeded rice plants was artificially controlled by the removal of tillers on specific nodes. Treatments consisted of limiting tillering on one main stem node only, on 2, 3, or 5 consecutive main stem nodes, or on 2 or 5 non-consecutive main stem nodes. Grain productivity of the tillers at different nodal positions and the influence of the number and position of other tillers on grain productivity of the specific nodal tiller or group of tillers were investigated. 1. Main stem flag leaf number and panicle weight increased as the number of tillering nodes decreased and tillers shifted higher on the main stem. 2. Tillering date and survival rate of primary tillers positioned from 2nd to 6th main stem nodes were not influenced by the other primary tillers. In contrast, the presence of lower nodal tillers delayed tillering and decreased survival rate of tillers above the 6th node. Panicle weight was not influenced by nodal position, but the number of days from tillering to heading or flag leaf number of primary tillers were higher at lower nodes. 3. Generally, lower node had higher panicle weight or grain productivity mainly due to higher panicle number. However, grain productivity of specific nodal tiller or group of tillers was greater when other tillers were fewer or positioned at more distant higher nodes. 4. As compared to the control, plants with only one or two tillering nodes at or above the middle of the main stem had lower panicle number and straw weight per plant, but panicle weight was more than 80% of the control due to the greater mean panicle weight in spite of the greater percentage of high order tillers. Consequently, panicle/straw weight ratio was also higher in these treated plants.

[学科分类] 农业科学（综合）

[关键词] Nodal position on main stem;1次分げつ;Panicle weight;子実生産力;Panicle/straw weight ratio;主稈節位;Primary tiller;水稲;Rice plant;分げつの出現;Tiller grain productivity;穂重/わら重比;Tillering