Agronomic Characteristics of Aromatic Rice Cultivars Collected from Japan and Other Countries(Genetic Resources and Evaluation)

Abstract

Aromatic rice has been cultivated in many regions throughout Japan and in South and South-East Asian countries from ancient days. In an attempt to clarify the agronomic characteristics of aromatic rice collected from all over Japan, 71 randomly selected cultivars were cultivated along with 21 foreign aromatic cultivars from 7 countries and 18 Japanese non-aromatic leading cultivars. In addition, 44 Japanese aromatic cultivars and 6 old and 12 new non-aromatic cultivars were examined their leaf characters. (1) Local Japanese aromatic cultivars had larger height, fewer and larger panicles, greater straw weight, lower yield, less tolerance to lodging, and more awns than the new cultivars. (2) Morphologically, the local Japanese aromatic cultivars were divided into eastern and western groups. The former showed earlier heading, shorter culm, smaller panicle, lower yield, thinner stem, and less tolerance to lodging than the latter. (3) Foreign aromatic cultivars were similar to Japanese ones in terms of long-culm, heavy-panicle and low-yield, but they had poorer biomass and harvest index with later maturing-larger panicle. (4) Local Japanese aromatic cultivars had longer and wider flag leaf, larger flag-leaf angle, faster leaf senescence, and longer neck internode of panicle than new cultivars. The old, non-aromatic cultivars were medium of aromatic cultivars and new, non-aromatic cultivars. (5) Because aromatic cultivars possess the old agronomic characters and big variations, it is important to make ample examinations to select them for cultivation or breeding.