Interpretation of variety × sowing date × sowing depth interaction for bean–Fusarium–Rhizoctonia pathosystem

Abstract

Through this study, the sowing date × sowing depth × variety interaction for Rhizoctonia root rot (RRR) development was investigated in field trials over two growing seasons. Four-way Wald tests indicated that there was a lower RRR incidence in var. Red compared to var. White in the majority of experimental plots. At a 5 cm seeding depth, RRR incidence for plantings on 22 May and 5 June was often lower than that for 5 May date. A hierarchical cluster analysis grouped experimental plots using averages of RRR incidence, Fusarium root rot (FRR) index and the number of seeds per plant. Sowing depth influenced FRR, RRR and productivity more than variety and date factors. Comparison of clusters recognised lower disease and greater production levels for sowing on 22 May and 5 June at 5 cm depth. Thus, shallow seeding of bean varieties in late spring should be incorporated into FRR–RRR-control programmes.

Keywords:

• Fusarium solani
• Rhizoctonia solani
• cluster analysis

Acknowledgements

Research support was provided by the grant from the Iranian Ministry of Agriculture, research project no. 4-47-16-88113. The author thanks Ms G. Haddadi, Mr M. Maleki and Mr S.H. Nazer Kakhaki for their technical assistance.