The response to row spacing of two tropical rice varieties of contrasting plant type

Abstract

The growth of two rice varieties of contrasting plant type and of different origin was compared at two row spacings under wet season tropical conditions in northern Australia. The short, erect-leaved variety SML 81b responded to the closer spacing by producing fewer tillers and a smaller leaf area per plant during active vegetative growth. The tropical leafy variety Sircna did not exhibit any compensatory reduction of the growth of individual plants, and dense crop growth and high leaf area indices resulted at the closer spacing. The heavy vegetative growth of Sircna was not reflected in grain yield at harvest, while the higher tiller number per unit area of SML 81b resulted in a higher grain yield at the closer spacing. The agricultural implications of the results are discussed.