Effects of inoculation of barley inflorescences with <i>Drechslera teres</i> upon the location of seed‐borne inoculum and its transmission to seedlings as modified by temperature and soil moisture

Abstract

An investigation of the location of Drechslera teres on barley (cv. Thibaut) seeds showed that, when artificial contamination was carried out at the time of flowering, all parts of the caryopsis. including the embryo, were infected by the two forms (f. teres and f. maculata ) of the pathogen. An assessment was made of the possible role of abiotic factors, including the effects of temperature and soil moisture, on the expression of the primary symptoms caused by the two forms of the pathogen. The most severe damage was observed in dry soils (pF 3‐4) at temperatures off. 12°C. On young barley seedlings, the seed‐borne inoculum caused coleoptile symptoms in the case of the form maculata , whereas the form teres induced mostly foliar symptoms. Foliar necroses may result from systemic invasion by the pathogen located in the seed.