Wheat seed germination and kernel weight affected by blast depend on the cultivar resistance and spikes age

Blast, caused by Pyricularia oryzae, on wheat can negatively impact yield. This study investigated the effect of blast on seed germination and kernel weight of seeds obtained from the infected spikes of plants from the wheat cultivars BR-18 (moderately resistant) and BRS-Guamirim (susceptible). Spikes of each plant were inoculated at anthesis (0) as well as at 7, 14, and 21 days after anthesis (daa) with a conidial suspension of P. oryzae. Non-inoculated spikes served as the control treatment. Seed germination and the weight of 1000 seeds were determined. Based on regression analyses, blast severity was great both at anthesis and 7 daa causing great reductions on seed germination and weight of 1000 seeds. Blast severity in the spikes of plants from cultivar BR-18 was reduced by 38, 35, 45, and 41% at anthesis and at 7, 14, and 21 daa, respectively, in comparison to spikes from plants of cultivar BRS-Guamirim. Blast severity was lower on spikes from 14 to 21 daa in comparison to anthesis and caused less impact on seed germination and weight of 1000 seeds. In conclusion, the negative effect of blast on seed germination and weight of 1000 seeds was dependent on the level of basal resistance of each cultivar and the time when the spikes were infected by P. oryzae.