Potassium use efficiency of upland rice genotypes

Use of nutrient efficient cultivar in crop production is an important strat egy in reducing cost of crop production. A greenhouse experiment was conduc ted at the Embrapa-Centro Nacional de Pesquisa de Arroz e Feijao, Experimen tal Station of Capivara, Santo Antonio de Goias, Brazil, to study the effic iency of 15 genotypes of upland rice (Oryza saliva L.) at low (without K ap plication) and high (application of 200 mg kg(-1) of K) levels of K applied in the soil. Genotypes differed significantly in relation to grain yield a nd K use efficiency. Based on grain yield at low K level and agronomic effi ciency of K use, genotypes were classified as efficient and unefficient. Ge notypes Rio Paranaiba, L141 and Guarani were classified as efficient and re sponsives. Second most important group of the genotypes was efficient and n on-responsive. Genotypes CNA6187, CNA7911 and CNA7680 fall in this category .