Evaluation efficiency of severity of angular leaf spot in common bean based on diseased and healthy leaf area

Abstract

This study compared severity of angular leaf spot in common bean lines, based on the healthy and diseased leaf area, and the graded scale. We used 12 common bean lines in the dry and rainy seasons. Two contiguous experiments were conducted in each season, with and without chemical control of the pathogen. We evaluated the percentage of the healthy and diseased leaf area; severity based on a graded scale and the area under the disease progress curve; and yield. The diseased or healthy leaf area is efficient to evaluate the severity of angular leaf spot with a sample of 20 to 30 leaflets per plot. For all traits, the results of central and border areas did not differ, indicating that the evaluation of border rows is unnecessary and, finally, the severity assessment of the upper plant half can discriminate the lines more efficiently.

Estimation of optimal size of plots for experiments with radiometer in beans

“…For experiments with beans, the size of the portions differ according to the purpose of the study. To check the efficiency of the severity assessment of angular leaf spot in common bean based in healthy and diseased areas of the leaf, Parrella et al (2013) adopted portions 8 m² (4 m long and 2 m wide). Doblinski et al (2010) adopted a 2 m² area in the study of diffuse pollution of swine wastewater on the beans.…”