Evaluation of new sugarcane cultivars against brown rust, with the use of qualitative and quantitative scales

Abstract

The experiment was carried out in the Territorial Research Station of Sugarcane Center Oriental Camagüey with 16 cultivars selection from 2009 to 2010, evaluated by two scales, one quantitative and one qualitative. Nine known reaction patterns were used and analyzed, for the quantitative scale, the amount of pustules, length of the most frequent pustule and length of the largest pustule allowed to calculate the percentage of pustules per square centimeter. For qualitative case the percentage of involvement was visually observed. The influence of the environment on the manifestation of the disease was taken into account. The results showed that the qualitative scale masks the true behavior of the disease, mainly in those of the intermediate behavior, while the quantitative one provides a more reliable reaction and the individuals are grouped correctly in their respective degrees. The climatic variables provided a favorable environment for the development of brown sugarcane rust.

Keywords

• puccinia melanocephala
• scales
• resistance