Flag Leaf Number Determination of Secondary and Tertiary Tillers and Heading Characteristics of Rice Plants.

Abstract

When the number of leaves on the main culm is known, the number of leaves on secondary to quarternary tillers can be determined based on the following growth characteristics and procedures, even if the lower leaves are no longer on the stem. Growth characteristics : a) The leaves are located on stem alternately. b) Left tip outside and right tip outside sheath wrapping also appear alternately. c) The tillers which emerged from the node of left (right) tip outside of sheath wrapping have left (right) tip outside sheath wrapping at the first leaf. Procedures : 1) Mark the leaves of the main culm and record heading date of all tillers in a plant on the flag leaf. 2) Dig out the plant at maturity and separate it into its primary tiller groups. 3) Arrange odd-numbered primary tillers on the left side of the main culm and even-numbered tillers on the right side, in order of emergence, from outside to inside. 4) If the main culm has an odd-numbered flag leaf with right tip outside sheath wrapping, or an even-numbered flag leaf with left tip outside sheath wrapping, the first leaf of primary tillers appears on the front side of the primary tillers. 5) The first tertiary tiller points toward the main culm and in the same way, the first quarternary tiller points toward its parental primary tiller. Investigation findings : 1) Number of leaves on secondary and tertiary tillers of Moritawase and Norin 1 increased over the number of leaves of primary and secondary tillers, respectively. 2) Main culm of Moritawase heads first, whereas, in Norin 1, primary tillers head first. 3) Heading date of secondary tillers tend to be delayed when the number of leaves increased over that of the primary tillers.