Resistance of 10 Genotypes of Grapevines to Downy Mildew Disease (Plasmopara viticola Berk. et Curt.) on Batu High Land

Abstract

Downy mildew (Plasmopara viticola Berk. et Curt.) is a major disease of grapevines (Vitis spp.) in Indonesia, especially during the rainy season. The use of downy mildew-resistant grape varieties is an effective solution to increase yields, but it is not always easy because grapes are plants that come from subtropical regions that are adaptive to growing in the lowlands of Indonesia. This study was aimed to test the resistance of 10 grape genotypes and species to downy mildew. Field trials in the Batu highlands of East Java used the natural inoculation method against 10 genotypes of productive grapevines with 1 resistant and 1 susceptible control genotypes using a randomized block design with 3 replications. The results showed that the P. viticola fungus found at the study site had the best performance on all resistance characters such as latency, number of spore spots, number of non-spore spots, resistance score, and intensity of disease attack on jestro AG5, Jestro AG45, Jestro AG86. Jestro AG5 is the most resistant genotype based on disease severity index. Vitis labrusca was the most disease resistant species, Vitis vinifera was the most sensitive, and Vitis interspecific crosses had moderate resistance. The resistant genotypes Jestro AG 45 (V. interspecific cross) and Jestro AG 86 (V.vinifera) need to be investigated further for their resistance mechanisms and their potential as parents in breeding programs.