A laboratory bioassay using water extracts was conducted to determine the alleopathic potential of different parts of rice crop on seed germination and growth of barnyardgrass, and to select high allelopathic potential rice varieties using genetic characters and phenotypes.
The alleopathic potential was evaluated from extracts of leaf, straw and hull of 114 rice varieties, i.e. the first group was of leaf extracts and its inhibition rate was the highest in CUBA 65-v-58, the second group of straw extracts was observed with inhibition rate highest in Dangneunbangju and third group of rice hull extracts was observed with inhibition rate highest in Baekambyeo.
Another part of the study examined comparison of allelopathic rice varieties: using genetic characters and phenological types; from different origins; with different maturity times; with the existence or non-existense of hull color; with the existence or non-existense of an awn or awn color. Scientists have observed about 114 rice varieties with different parts of plant i.e. allelopathic effects of extracts from leaves, straw and hull on barnyardgrass. The study is published in the July-August 2003 issue of Agronomy Journal
Ill-Min Chung, project leader, stated, "These results suggest that rice body parts may be a source of natural herbicides and that it is necessary to develop acceptable selection standard, there may also be genetic variation in rice varieties for their allelopathic potential on barnyardgrass. In the future it might be possible to develop rice varieties with high allelopathic potential."