Genotype by environment analysis on multi-canopy cropping system towards vertical harvest space in rice

The multi-canopy cropping system is considered a novel idea for increasing rice yield, derived from the concept of vertical agriculture. This method utilizes short and tall genotypes planted in the same hill. The tall plants form a canopy, and therefore the vertical harvest space can be used. The objective of the study was to determine the potential of breeding programs to develop varieties for multi-canopy cropping system in rice (Oryza sativa L.). The experiments were conducted at the IPB University Experimental Station at Babakan, Bogor, West Java, Indonesia, in four environments: (1) monoculture in the dry season 2018, (2) multi-canopy in the dry season 2018, (3) monoculture in the wet season 2018/2019, (4) multi-canopy in the wet season 2018/2019. Twenty-two short rice genotypes and two check varieties were evaluated using a randomized complete block design in each environment. The genotype x canopy (G x C) interaction effect was significant (p < .05) for plant height, stem length, and number of tillers. Yield reductions of the short genotypes from the monoculture to the multi-canopy system were varied (30.55-49.67%), eventhough the G x C was not significant. The average total yield of multi-canopy (6.44 t ha(-1)) was higher (p < .05) than the monoculture (5.90 t ha(-1)), indicating that breeding for the development of suitable varieties for multi-canopy system is possible. Results of this novel study, we hope, would inspire and stimulate new breeding objectives to develop varieties for multi-canopy system and utilize vertical harvest space, as a new effort to increase rice production worldwide.