Resumen
- A similar study as in section A was conducted with direct-seeded (pre-germinated) irrigated rice. Average rice yield reduction from E. colona competition was 42%, within a range of 25 and 62%. The most competitive varieties were CICA 8, Eloni and CICA 9. E. colona growth recorded 60 days after emergence correlated negatively with rice leaf area index and tiller number (R2= -0.83 and -0.76, respectively). All three varieties were among the best yielding ones in monoculture. These parameters were closely related to canopy light interception. Again, height was not closely related to competitiveness. Quick screening for rice competitiveness could be done by measuring the amount of light reaching the ground, preferably with rice growing under competition. Estimation of genetic parameters for the characteristics identified will be performed, preliminary results are reported here.