The effects of Pyricularia oryzae, the causal agent of blast disease in rice, on plant growth, grain yield, and grain quality under Mediterranean conditions were studied in 2002 and 2003. | Research Article Turk J Agric For 33 (2009) 487-494 © TÜBİTAK doi: Blast disease influence on agronomic and quality traits of rice varieties under Mediterranean conditions Spyridon D. KOUTROUBAS1, Dimitrios KATSANTONIS2, Dimitrios A. NTANOS2,*, Elisabetta LUPOTTO3 1Democritus University of Thrace, School of Agricultural Development, 682 00 Orestiada, GREECE 2National Agricultural Research Foundation, Cereal Institute, 570 01 Thermi-Thessaloniki, GREECE Istituto Sperimentale per la Cerealicoltura, per Torino, 13100 Vercelli, ITALY Received: Abstract: The effects of Pyricularia oryzae, the causal agent of blast disease in rice, on plant growth, grain yield, and grain quality under Mediterranean conditions were studied in 2002 and 2003. Four rice varieties were grown under high and low disease pressure, achieved by early inoculation with the blast fungus and by natural infection, respectively. Results showed that inoculation affected the overall plant growth and yield and resulted in a reduction in plant height, number of productive tillers per plant, grain weight, and grain yield. The magnitude of the reduction was dependent on the varietals’ susceptibility to the disease. Both types of the disease (leaf blast and neck blast) were negatively correlated with grain yield. It was estimated that each unit increase in leaf blast rating and neck blast resulted in and g plant-1 yield reduction, respectively. Grain quality traits were less affected by the disease treatments compared to the agronomic traits. The most pronounced effect of the disease was on total milling yield, which in some cases was reduced by inoculation up to 11%. Key words: Grain quality, grain yield, leaf blast, neck blast, Pyricularia oryzae Introduction Blast disease [Pyricularia oryzae Cavara (synonym P. grisea Sacc (teleomorph Magnaporthe grisea (Hebert) Barr)], is one of the most destructive diseases of rice (Oryza sativa L.) worldwide .
