The aim of the present study was to quantify rust disease caused by Puccinia substriata var. penicillariae in pearl millet and its correlations with yield components. The rust quantification was done by visual evaluations using two scales based on visual description, in five plants per plot in three different kinds of samples: entire plant and fifth and second leaves. Using these values of the area under the disease progress curve (AUDPC) the residual correlation (r e) and genetic correlations (r g) were calculated between the values of AUDPC and production of grain, total dry matter and stover dry weight. The evaluation of rust severity on the second leaf, from the flowering stage of pearl millet, was the most efficient method to quantify the disease because of the higher correlation with biomass and grain production. A second assay was conducted in a greenhouse to quantify rust disease indirectly by measuring photosynthetic potential (Fv/Fm), by chlorophyll "a" fluorescence emission, in leaves of six genotypes: HKP, Guerguera, Souna III, BRS 1501 and ENA 1 and bulk ENA 2. In this assay, it was demonstrated that rust affected the photosynthetic potential of pearl millet leaves and that the measurement of chlorophyll "a" fluorescence, which is rapid and independent of evaluator, would be a physiological parameter for selection of rust-resistant genotypes.
Puccinia substriata var. penicillariae; Pennisetum glaucum; area under the disease progress curve; chlorophyll "a" fluorescence; genetic breeding; genetic resistance
