Barnyard grass (Echinochloa crus-galli L.) was used as test target plant in both Sandwich and Relay seeding methods. The allelopathic effects of rice accessions were observed on seed germination, mean germination time, shoot length, root length and dry matter production of test plants. Average percent inhibition (API) due to allelopathic effects in the growth of barnyard grass was also determined. Both bioassays revealed that the selected rice accessions adversely affected the quantitative traits of barnyard grass seedlings. Rice accession MR73, caused > 40% API in the growth of barnyard grass. Some traditional and modern rice accessions also showed > 30% API. Reductions in traits like shoot length, root length and dry weight were positively and significantly correlated with API. Finally, rice accession MR 73 was selected for further improvement. It is expected that this accession would contribute not only in biological weed control but also reduce the use of synthetic herbicides and problems associated with the chemical weed control
Mazid et al. (Mon,) studied this question.