The Role of Root System of Rice Plant in Relation to the Physiological and Morphological Characteristics of Aerial Parts : III. Relationships of the root system with the leaf-shoot units and the number of spikelets per panicle

The object of this study was to know how the diameter of the first elongated internode and diameter of loots formed at each leaf-shoot unit are related to the number of spikelets per panicle of main culm and tillers in individual or group of varieties. The results of study were as follows : (1) A close positive correlation was found to exist between the number of spikelets per panicle, and the diameter of roots formed at the 3rd, 4th, 5th and 6th leaf-shoot units. (2) The positive correlation was recognized between the number of spikelets per panicle and the number and diameter of vascular-bundles in roots formed at the 3rd leaf-shot units. (3) It was detected that the number of spikelets per panicle was those positively and significantly correlated with the diameter of roots, especially formed at the 3rd leaf-shoot units, the diameter of the first elongated inter-node at the base of the culm and the diameter of neck-node. The same tendency was observed even among varieties or within tillers of one same hill.