The Effect of Major Viruses and Virus-free Planting Materials on Sweetpotato Root Yield in China

摘要

Viruses were detected by the ELISA method in leaf samples from 1,580 accessions of sweetpotato from three provinces of China, Shandong, Jiangsu and Aanhui. The results show that SPFMV and SPLV were the two most common viruses in the Huanghuai sweetpotato production region, where their infection rate ranged from 20.8-100% and from 2.1-90%, respectively. SPMMV, SPCFV, C-6 and SPMSV, were also found in some regions, while SPCSV was detected for the first time in China with an 8.9% infection rate. Fieldtrials conducted in the three above-mentioned provinces using five popular cultivars over three years showed that virus-free planting materials significantly increased the storage root yield and marketable ratio. On the average, fresh root yields increased by 37.9%, ranging from 10.3-101.9%, and the marketable ratio increased by 22.2%. However, virus-free planting materials had no significant effect on dry matter content of roots. Surveys over 30 locations in Shandong indicated that the yield incrementof virus-free planting materials decreased with subsequent planting. The annual rates of decrease in spring and summer sweetpotato were 4.4% and 8.0%, respectively, from the first year to the third year after virus-elimination.