Agronomic performance of four upland rice genotypes under rainfed condition
Upland rice fields cover up to 1.8 million hectares of the 4.7 million hectares of global rice fields, while farmers’ average yield of upland rice is far below the yield potential of existing traditional genotypes, particularly in West Africa. Grain yields of rice in Liberia are generally low, ranging from 0.5-1.5 tons per hectare (t/ha). A field study was conducted to evaluate yield and agronomic performances of four genotypes of rice (Nerica 8, Nerica 4, Arica 5 and LAC 23) on a typical fine sandy loam soil in the upper highland tropical forest agro-ecological Zone (UHTF AZ) of Liberia. The Randomized Complete Block Design (RCBD) was used with four replicates in four blocks. Data were taken on key agronomic characters including plant height; days to 50 % flowering; number of tillers; number of panicles; grain weight; panicle length; number of grains per plant; seed length and stem diameter at the base. Results from the Analysis of Variance (ANOVA) indicated that there were significant differences between the control (Lac 23) and the improved genotypes (Nerica 8, Arica 5 and Nerica 4) for all characters measured except for panicle length, seed length and stem diameter. Correlation analysis was also performed to establish extent of association between major yield components and grain yield. Days to 50 % flowering correlated significantly with plant height, number of tillers and number of panicles per plant. Nerica 8, Arica 5 and Nerica 4 recorded the highest yield and may, therefore, be recommended to smallholder farmers in the upper highland forest zone. Lac 23, Arica 5 and Nerica 8 may be recommended for local farmers, who prefer high yielding, and relatively medium heighted improved rice cultivars or their interspecific hybrids. This is because extremely tall rice genotypes are susceptible to lodging, particularly in stormy conditions that are prevalent in the upper highland tropical forest agro-ecological zone of Liberia. Other approaches may be required to test these cultivars under harsh environments (such as water deficit condition) and different agroecologies across the country. We also recommend organoleptic assessments of Nerica 4, Nerica 8 and Arica 5 to boost their acceptability among consumers in the country.
Keywords: Upland rice, agronomic performance, improved genotypes, Nerica, correlation, Liberia