Resistance of rice cultivars to Pyricularia oryzae in Southern Spain

The susceptibility of 14 commercial rice cultivars to Pyricularia oryzae was tested under field conditions agronomically appropriate for natural infection to occur. The first symptoms of infection were detected on the leafs when the crops were at the medium tillering stage. Generally speaking, the incidence of infection for each particular cultivar was similar in the 2002 and 2003 seasons and at the two trial locations (the Sartenejales and Casudis estates in the Province of Seville). The pathogen infected 80-100% of "Maratelli", "Baixet", "Thainato" and "Galatxo" plants. Differences were seen among the cultivars with respect to the parts of the plant affected. "Baixet" and "Maratelli" were the most susceptible cultivars, followed by "Thainato". "Ullal" was the most tolerant, followed by "Marisma", "Puebla", "Maso", "L-202", "Susan", "Doongara", "Fonsa" and "Jacinto"; these last six cultivars showed medium disease severity according to the scale used in this work. Further studies on the interactions between different strains of P. oryzae and rice cultivars are underway.