SYNTHESIS OF HETEROKARYONS IN RHIZOCTONIA SOLANI KÜHN

The single-spore progeny of an isolate of Rhizoctonia solani showed a wide range of cultural types. When these progeny were paired by plating on opposite sides of Petri plates or by mixing semiliquid cultures, certain combinations gave rise to heterokaryons. The heterokaryons originated from hyphal anastomoses and were culturally distinct from either of the contributing homokaryons. Observations suggested a bipolar coaipatibility mechanism among the homokaryons. Some homokaryotic strains fruited, yielding culturally indistinguishable progeny. These homothallic lines also formed heterokaryons with other homothallic lines. The progeny of these heterokaryons showed a wide range of cultural types, indicating that some homokaryons could fruit either homothallically or heterothallically.