The resistance of various maize germplasms collected from several regions in Indonesia to downy mildew (Peronosclerospora philippinensis)

Abstract

Downy mildew is one of the limiting factors of corn production in Indonesia. Several efforts have been needed to control pathogens, one of them is the development of resistant varieties. New resistant varieties must be developed to prevent a decrease in genetic diversity in a region due to dependence on one variety. Germplasms collected from a variety of different environmental conditions is a potential source of genetic diversity. This study aims to determine the resistance of maize germplasm accession to downy mildew caused by P. philippinensis. In this study, the total number of 96 accessions of maize germplasm were tested. The experiment was arranged in a group design with 2 replications. The intensity of downy mildew infection was observed based on the incidence of the disease in 25, and 35 days after planting(DAP). The value of Area under Disease Progress Curve (AUDPC) is also calculated based on the intensity of downy mildew infection in a particular observation period. One accession which showed high resistance to downy mildew (Peronosclerospora philipinensis) was obtained, namely accession number 808 with 0 per cent infection and 0 AUDPC value, lower than the resistant varieties (Bima 3) used as a comparison, which had an average 5-10% infection and 103.5 AUDPC value. The accession obtained can be used as the source of the downy mildew resistance trait for the development of the new highly resistant variety.