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ARS Home » Southeast Area » Miami, Florida » Subtropical Horticulture Research » Research » Publications at this Location » Publication #383930

Research Project: Development and Application of Genomic-assisted Breeding Strategies to Produce Disease-resistant Cacao Genetic Resources

Location: Subtropical Horticulture Research

Title: Seed Transmission of a Cacao Virus From the Americas and the Implication on Crop Cultivation and Movement of Germplasm

item Puig, Alina

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/28/2021
Publication Date: 8/2/2021
Citation: Puig A.S. 2021. Seed transmission of a cacao virus from the Americas and the implication on crop cultivation and movement of germplasm. Plant Health Conference, Online, Aug 2-6, 2021

Interpretive Summary:

Technical Abstract: Cacao mild mosaic virus (CaMMV) was recently reported in Puerto Rico and Brazil and may be widespread in the Americas. The virus causes mosaic and mottling on leaves and pods of Theobroma cacao and is associated with dieback symptoms in the field. The importance of screening budwood for viruses is well understood, but trees whose seeds are grown for rootstock are not routinely screened for viruses. To determine if CaMMV is seed-transmissible, a grow-out test was conducted in laboratory growth chambers. After six and twelve weeks, 58 and 64% of seedlings, respectively, tested positive for CaMMV using a nested PCR test. Results were confirmed with Sanger sequencing, and most seedlings developed symptoms such as leaf mosaic and vein banding. Two leaves per plant were tested to account for uneven virus distribution, however, only in four of the 28 infected plants (14%) could the virus be detected in both leaves. Due to evidence of seed transmission of CaMMV, care must be taken when transporting pods. Also, in areas where the virus is present, seeds grown for rootstock should be taken from trees that have been previously screened.