Resistance to Botryosphaeria dothidea in pistachio

Abstract

Procedures were developed to permit screening pistachio for resistance to infection by Botryosphaeria dothidia panicle and shoot blight. A method of growing B. dothidea in liquid culture was developed and two inoculation procedures, direct injection of inoculum into shoots at the base of leaf petioles and a leaf scratch assay, were used to test selected pistachio (Pistacia vera L.) clones for resistance to B. dothidea. Both the direct injection and the scratch test procedures provided easily scored symptoms. Both solid and liquid cultures produced visible infections. Sources of resistance were identified in an F1 interspecific P. vera cv. Sfax x P. integerrima hybrid cross and P. integerrima genotypes. P. integerrima may be a valuable source of resistance for cultivar improvement, but resistant P. vera genotypes were not found. No correlation between Alternaria alternata resistance and B. dothidea resistance was found in P. vera.