Abstract
Using two types of nodal position of tiller development (counted acropetally from base and basipetally from panicle), relationships between the nodal position of tiller development and the final number of leaves emerged on the tiller (LN) were investigated. To compare the tendency of LN between different tiller positions, we used two indicators, the relative leaf position (RLP) of the flag leaf (RLP-FL) and the relative tiller position (RTP). RLP is the leaf position expressed with the acropetal position of the "synchronously emerging leaf" of the main stem according to the Katayama's theory (Katayama, 1951) and RTP is the acropetal tiller position arranged in theoretical order of tiller emergence. According to the Katayama's theory, there should be no differences in RLP-FL among individual tillers. But in actual measurement, RLP-FL increased with tiller order in each RTP and with emergence order after panicle initiation. The developmental position of tiller was rearranged in basipetal order (bT-position : bT 1 designated the tiller from the axil of the flag leaf), the relationship between bT-position and LN of each tillers was analyzed. At bT 6 position and lower, LN decreased 1.0 by 1.0 for every upward node order, while at bT 5 position and upper, LN was reduced 0.5 by 0.5 for every upward node order. We concluded that the cause of the difference of these decreasing patterns depends on that the time of the tiller bud development is situated before or after panicle initiation of its mother stem.
