Comparing cotyledon, leaf and root resistance to downy mildew in radish (Raphanus sativus L.)

Abstract Radish downy mildew (DM) caused by the oomycete Hyaloperonospora brassicae f. sp. raphani is a serious problem in radish crop, an edible root vegetable of Brassicaceae family. The objective this research was to assess germplasm for DM resistance and evaluate response different organs disease under controlled conditions. Forty-four accessions were inoculated at cotyledons true-leaves with H. isolate R10, collected field plants. roots tested isolates R10 R6, last one radish. symptoms varied genotype plant organ analysed. Twenty-seven resistant partially identified all stages are promising sources DM, namely 16 commercial varieties, 10 breeding lines, landrace. A significant correlation observed between cotyledon leaf (1st 2nd leaves) resistance, but low no found or roots, respectively. Cotyledon evaluation cannot be used predict However, has its own value because non-infected will act as barrier slow progression roots. Interesting that can programs.