Evaluation of Cultivar Interplainting Ratio on the Productivity of Rice/rice System

A field study was conducted in Calabar, Southeastern forest belt of Nigeria during the cropping seasons of 2006 and 2007, to evaluate the effect of various cultivar ratios on the growth and yield of interplanted lowland rice cultivars. Two lowland rice cultivars viz Muduga (a traditional, late-maturing and lodging susceptible cultivar), and FARO 15(an improved, semi- dwarf, mid-maturing variety) were used for the study. The experimental design was randomized complete block with three replications. Treatments were sole Muduga, sole FARO15, Muduga+ FARO15 in 1:4 ratio, Muduga + FARO15 in 2:3 ratio, Muduga + FARO15 in 3:2 ratio and Muduga + FARO15 in 4:1 ratio. Results indicated that increasing the proportion of one genotype over the other had the general effect of making it dominant in terms of plant height, tillering ability and grain yield. The mixtureʹs ability to suppress weeds was directly related to the proportion of Muduga, whereas the higher the proportion of FARO15 in the mixture, the greater the reduction in lodging. Yield advantages from cultivar mixtures were attributable to the synergy of a meaningful reduction in weed incidence and significant reduction in plant lodging. On the basis of combined grain yield, the best crop combination were at the ratios of 1:4, 2:3, 3:2 and 4:1 Muduga to FARO15, in that order.