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ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #324687
Title: Development of a user friendly method to produce massive amounts of Rhizoctonia Solani for field evaluation of sheath blight resistance.

Author
item GIBBONS, ANDREW - University Of Arkansas
item Jia, Yulin
item Bianco, Tracy

Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/25/2016
Publication Date: 7/2/2017
Citation: Gibbons, A., Jia, Y., Bianco, T.A. 2017. Development of a user friendly method to produce massive amounts of Rhizoctonia Solani for field evaluation of sheath blight resistance. Proc. 36th Rice Technical Working Group Meeting, Galveston, TX. pg 98. March 1-4, 2016. CDROM..

Interpretive Summary:

Technical Abstract: The purpose of this study was to develop a relatively simple, economical, and user friendly method to produce large volumes of Rhizoctonia solani. Large volumes of R. solani are the key to testing various rice varieties for sheath blight resistance under field conditions. To produce the required amounts of sheath blight fungi, a slow growing sheath blight field isolate (RR0134) was chosen. The field isolate was grown on a potato dextrose agar (PDA) by introducing shredded mycelium-infiltrated filter paper to the culture plate. The plate was incubated at 30°C until the appearance of black-bodied sclerotia. This product was used as the initial inoculant. To grow large amounts of R. solani, corn chops, whole rye grain, and water in the proportion of 2.48 Kg: 1.27 Kg: 3.5 to 3.75 liters (L), respectively was mixed and allowed to soak for 30 minutes. The mixture was then autoclaved for 1 hour at 121°C/1.0 Kg/cm 2. After the media were allowed to cool overnight, it was mixed and double-bagged. The double-bagged media were loosely sealed and autoclaved an additional two cycles (1 hour/121°C/1.0 Kg/cm2). The sterilized media was then transferred into 42cm x 20 cm x 16cm (11.4L) plastic containers and allowed to cool prior to inoculation. The corn/rye media was inoculated by cutting the PDA media containing R. solani into 1 to 2 cm squares. The PDA squares were transferred into the sterilized mixture and the tubs were covered with a lid and placed in a growth environment of 25-30°C and 45% relative humidity. The fungi were grown in the sterilized mixture for 3-5 days until the presence of white-bodied sclerotia were noted. The sheath blight containing media was then air dried and ground. Ultimately, we produced a total of 87.3 Kg of inoculation media using this method. The ground media was ultimately used to inoculate trimmed leaves of susceptible rice varieties allowing us to verify pathogenicity before storage. We have successfully demonstrated that a large-scale inocula production using this method is suitable to evaluate rice sheath blight resistance in the field.