Relationship between plant type and root growth in rice

Abstract

The relationship between plant type and root growth was examined using the root box technique. Correlation studies on 1,081 varieties or lines indicated that the deep root system is correlated with taU plant stature and low tiller number; it is not closely correlated with Iong growth duration. Subsequent studies on two isogenic lines of early Peta with different plant heights, however, indicated that plant height is not related to rooting depth. The same conclusion was reached from a comparison of three sorghum varieties with different plant heights. The shortest of the three varieties had the deepest root system. Examination of tillering habit and root growth of individual shoots (tiller or main culm) c1early showed that earIy tillers have more and longer roots than do Iate tillers regardless of the tiller order and the position of the node from which they emerge. Thus, a high tiUering plant tends to have a short root system. The advantages and disadvantages of low- or high-tillering varieties in different water regimes are discussed.