Growth and Yield Responses of Rice Genotypes Subjected to Water Deficit in Varied Soil Types

Abstract

Inconsistent results were obtained on the yield of rice genotypes established along the soil toposequence thus the need to validate these under controlled environment with rice genotypes. This investigation hypothesised there could be variation in the growth and yield of rice genotypes in different soil types under soil water deficit. A pot experiment was established in an open screen house, Ibadan. The treatment consisted of rice varieties (IR 64, IR 77298-14-1-2-B-10, NERICA 4 and WAB 56-104), soil ecologies [hydromorphic (H), lowland (L) and upland soils (U)] and soil moisture regime (Control and water deficit stress), in completely randomised design replicated three times. Growth in rice genotypes were significantly higher under optimum water supply than under water deficit. Conversely, rice genotypes under water deficit flowered later and had significantly higher spikelet sterility than under optimum water supply. Number of tillers plant-1 was in the order H > L > U. However, 1000 grain mass was in the order U > H > L. IR 64 had the highest grain yield. Similar pattern was observed on the shoot biomass, number of tillers and number of panicles. In different soil ecologies under water deficit, IR 64 and IR 77298-14-1-2-B-10 had significantly the highest number of panicles plant-1. These evidences suggested that high number of tillers observed in hydromorphic soil is associated with the duration of vegetative growth. Isohydric behaviour was not maintained by rice genotypes used as reflected in the variation in number of panicles under water deficit in the soil types.