Relative competitive ability of rice with strawhull and blackhull red rice biotypes

Resumo

The weed interference varies on several factors, especially the composition of the weed community and the ability to compete with the culture. Thus, this study aimed at evaluating the competitive ability of rice and different populations of red rice (strawhull or blackhull). The experiments were conducted in greenhouse from January to August 2013, at United States Department of Agriculture, Dale Bumpers National Rice Research Center (USDA/DBNRRC) in the city of Stuttgart, Arkansas. The experimental design was completely randomized with four replications. Treatments consisted of rice or red rice plant ratios (100:0, 75:25, 50:50, 25:75 and 0:100%). Variables evaluated included: shoot dry weight, leaf area and plant height. Results show that strawhull or blackhull red rice biotypes have superior competitive ability than rice, CL 142 AR. Overall, the blackhull red rice biotype has superior competitive ability compared to strawhull one. For rice, the interspecific competition dominates, while for red rice biotypes the intraspecific competition was more harmful.

Additional keywords: interference; Oryza sativa; replacement series.