Inhibitory activity of plant growth regulators on Phytophthora palmivora causing cassava tuber rot

Abstract

Auxins and cytokinins are implicated in a wide variety of developmental and physiological processes in plants. Phytophthora palmivora causes tuber rot in cassava growing regions of Tamil Nadu and Kerala, South India. The in vitro effect of cytokinin, benzyl amino purine (BAP) and auxins, naphthalene acetic acid (NAA) and indole acetic acid (IAA) on P. palmivora mycelium growth was investigated. The inhibitory activity varied among the growth regulators and complete inhibition of the pathogen was observed at 50, 2000 and 2500 ppm by the BAP, IAA and NAA, respectively. The effective growth regulator, BAP was also analysed on tubers before and after the invasion of the pathogen to observe its effect in tuber. Further, it was also checked against the bio-control agent Trichoderma harzianum. The study indicates that the use of BAP could be an important approach in controlling tuber rot pathogen, P. palmivora.

Keywords:

• tuber rot
• cassava
• P. palmivora
• IAA
• NAA
• BAP

Acknowledgements

The funding provided for conducting the research work by the Indian Council of Agricultural Research, New Delhi, under IISR Outreach Programme is gratefully acknowledged. The authors thank Director, Central Tuber Crops Research Institute, Thiruvananthapuram, for providing the infrastructure facilities.