Graft incompatibility in Solanaceae: Callus co-culture as a technique for early recognition

Abstract

Incompatibility has long been a barrier in grafting procedures, often not being expressed until considerable time and effort have been expended on the grafted plants. The development of an early identification strategy for graft compatibility was the objective of the current experiment.

Evaluation methods of graft survival, tensile strength determination and particulate iron oxide uptake assessment were undertaken to detect plant material expressing graft compatibility and incompatibility in the Solanaceae family. Lycopersicon esculentum 'Beefsteak' and Physalis ixocarpa were selected as rootstocks, and Solaman melongena 'Violetta de Firenze' as a mutual scion, expressing high grafting success and low grafting success on respective rootstocks. Callus co-culture experiments were carried out as an attempted method of recognition of graft incompatibility.

In the high success graft combination, no growth difference was observed in Solanum or Lycopersicoll callus tissue in heterocultures compared with each species cultured alone. In the low success combination, similar results were observed.

Solanum material gave no significant difference in weight increase in the presence of Physalis compared to Solanum controls. While the callus co-culture failed to express inhibitory metabolite based graft incompatibility through differences in weight increase, definition of the method's precision may assist in detecting graft incompatibilities more accurately and may accommodate incompatibilities of a smaller degree.