Selection of upland rice lines to grain yield and diseases tolerance

Bacterial and fungal diseases directly affect rice yield and quality, and the simplest and, often, the most cost effective management for diseases is planting resistant varieties. The aim of this study was to evaluate thirteen elite lines from the Brazilian Upland Rice Breeding Program for grain yield and tolerance to leaf blast, neck blast, grain discoloration, and leaf scald diseases, in order to select superior genotypes with potential to turn into new cultivars adapted to the upland crop system. The experiments were carried out in two environments considering the randomized block design with two replicates. The means for each trait were grouped according to the Scott-Knott approach, and it was obtained the Pearson correlation of diseases grades with grain yield. Lines showed significant differences for all traits, except for leaf scald resistance. All diseases showed negative correlation with grain yield, meaning that the occurrence of these diseases resulted in losses in lines productivity. Despite the incidence of diseases, nine of the thirteen lines showed grain yield above the national mean in 2015. However, lines CMG1509 and CMG1896 showed a bad performance for grain discoloration, what can be a limitation to its acceptance in the market. The lines with best performance for both grain yield and tolerance to the diseases considered were CMG1511, CMG2085, CMG2089, CMG1977, and CMG2170, indicating potential to be new upland rice cultivars.