A multi-canopy cropping system—where short and tall rice (Oryza sativa L.) genotypes involve closer planting on the same hill—can considerably enhance the grain yield. Although the factors involved in this yield advantage have been the subject of intensive studies, the breeding of rice cultivars for such a cropping system remains at an early stage. The following study aimed to identify the effective breeding strategies for developing rice genotypes adapted to a multi-canopy system. Rice advanced lines totaling 35 from the F5 and F6 generations received evaluation under monoculture and multi-canopy systems. The field experiments, laid out in a randomized complete block design, had three replications in a multi-canopy and two in the monoculture. The multi-canopy system demonstrated more considerable sensitivity than monoculture in distinguishing genotypes’ performance and thus became identified as an ideal environment for selecting rice lines aimed for multi-canopy. For multi-canopy rice, the proposal for two primary selection strategies emerged, namely, sequential selection and simultaneous selection. For developing short genotypes, the key selection traits were plant height, the number of productive tillers, and filled grains per panicle. Under a multi-canopy system, the weighted index selection based on these traits proved to be effective in achieving the breeding objectives.
Rice (O. sativa L.), selection strategy, complementary interaction, cropping system, selection differential, selection method, growth and yield traits
The multi-canopy system emerged to be effective in differentiating the rice (O. sativa L.) genotypes’ performance targeted for this system, and the weighted index selection was considerably reliable for selecting suitable rice genotypes.