RED SMUDGE IN DURUM-WHEAT REDUCES SEEDLING VIGOR

The effect of red smudge, caused by Pyrenophora tritici-repentis (Died .) Drechs, on germination and early seedling development of four durum wheat (Triticum turgidum L. var. durum Desf.) cultivars was examined using artificially and naturally infected seeds. Rate of germination w as similar for red smudged and healthy seeds. Percent germination of n aturally infected, but not of artificially infected seeds, was lower f or the red smudge than for the control treatments. The number of semin al roots was also lower for the naturally infected than for the contro l seeds. Lengths of the longest seminal root and of the coleoptile at 12 d were greater in the control than in the disease treatments, regar dless of whether the seeds were naturally or artificially infected. It was concluded that red smudge of durum wheat seed reduced seedling vi gour. There was transmission of P. tritici-repentis to the coleoptile but not to the true leaves.