The objective of this study was to phenotypically evaluate the traditional rice cultivars Guarani and Caiapó, and the modern rice cultivars CIRAD L(-1)41, Maravilha, BR IRGA 409, and Metica 1 through association among various yield components to establish a genetic selection base in plant population. The study was conducted during the rainy season of 2003-2004, at the Embrapa Rice & Beans experimental station, in Santo Antônio de Goiás, Goiás, Brazil. With supplementary irrigation, the upland rice cultivars CIRAD L(-1)41, Guarani, Caiapó, and Maravilha presented higher grain harvest indexes and lower spikelet sterility than the lowland cultivars BR IRGA 409 and Metica 1. It was concluded that the highest biomass yield of the lowland rice cultivars did not have an effect upon the grain yield. The upland cultivar CIRAD L(-1)41, with high leaf area, panicles with high grain number and average performance of the agronomic components evaluated, such as harvest index, grain weight, tiller fertility, tillering, spikelet sterility and growth index, yielded 12.5% higher than Guarani, the second best cultivar. The increase in grain harvest index and weight of grain and the reduction in spikelet sterility, due to their high correlation with grain yield, are considered high priority in the upland rice breeding programs for higher yields.
Oryza sativa; harvest index; crop growth rate; foliar area index; tillering
