Genetic resistance to the root rot pathogen Phytophthora cinnamomi in Ananas
The Australian pineapple industry is expanding as market demand for new high quality fresh fruit products increases. The major fresh fruit cultivars, 'MD-2' and '73-50' are more suited to the fresh market than 'Smooth Cayenne', because of their superior eating quality however they also have greater production problems. Both cultivars are considered more susceptible than 'Smooth Cayenne' to the root pathogen Phytophthora cinnamomi. Root rot is the most serious disease of pineapple in Australia. While the disease can be controlled using chemicals, costs associated with this solution are high and control is incomplete where fields are ratooned. Partial control of the pathogen results in poor yields and disruption of harvest schedules through increased natural flower initiation. Considerable variation in genetic susceptibility to root rot is known to exist within the Ananas genus but a reliable screening system is not yet described. In this project a reliable screening method utilising an aeroponics system was developed to evaluate genetic resistance to root rot in a broad range of pineapple genotypes. Roots were inoculated with a motile zoospore suspension in the laboratory before placing the plants back into the aeroponics system for disease expression over seven days. The plant response ranged from highly resistant in most wild varieties to highly susceptible in the fresh market cultivar 'MD-2'.
Sanewski, G., Ko, L., DeFaveri, J. and Kilian, A. (2016). Genetic resistance to the root rot pathogen Phytophthora cinnamomi in Ananas. Acta Hortic. 1111, 281-286
pineapple, zoospores, aeroponics, Cayenne, disease, ananassoides, bracteatus