Published online by Cambridge University Press: 27 March 2009
Different geranium (Pelargonium graveolens L. Herit) clones differed in susceptibility to root rot and wilt caused by Rhizoctonia solani Kuhn. Reactions were consistent when assessed either by standardized laboratory tests or by pot experiments using 60-day-old well-rooted plants. Plants of an Algerian-type clone (Kd) had a lower survival rate and higher root rot index values than those of a Reunion type (Lo) and an Egyptian type (Eg). Field studies conducted in naturally-infected plots in southern India from 1987 to 1990 showed that summer planting resulted in higher plant losses of all clones than winter planting. As in the laboratory and pot experiments, the Lo and Eg clones sustained less plant loss and produced higher herbage and oil yields than the Kd clones in both field experiments.