Production and deployment of virus-free sweetpotato in China

Abstract

China is the biggest cultivator of sweetpotato in the world. The cultivated area of sweetpotato in China, about 6.6 million ha, accounted for 70% of total area under sweetpotato cultivation in the world. The output of sweetpotato in China, about 100 million metric tons, accounted for 84.4% of total world output. Sweetpotato in China is mainly cultivated in the Yellow River and the Yangtse River Basins. According to the climatic conditions and the cropping system, five regions of sweetpotato cultivation are distinguished: Northern spring sweetpotato region, Yellow River spring–summer sweetpotato region, Yangtse River summer sweetpotato region, Southern summer–fall sweetpotato region and Southern fall–winter sweetpotato region. By now, about 20 kinds of sweetpotato viruses have been reported in the world, but only three of them have been found in China: Sweetpotato Feathery Mottle Virus (SPFMV), Sweetpotato Latent Virus (SPLV) and Sweetpotato Caulimo-Like Virus (SPCLV). They have been found in almost all of sweetpotato production regions in China. On average, sweetpotato yield in China loses over 20% due to sweetpotato virus diseases. Because there are no chemotherapeutants to control sweetpotato virus diseases, shoot tip culture of sweet potato has become the most effective way to eliminate sweetpotato viruses. In China, an effective propagation and delivery system of virus-free sweetpotato plants has been established and carried out very well in some provinces, especially in Shandong and Jiangsu provinces. It included production of virus-free sweetpotato plantlets, detection of virus in sweetpotato, production of original stock plants, production and supply of original plants, propagation of productive “seed” sweetpotato and delivery to commercial production. The use of virus-free sweetpotato can restore a cultivar's original excellent yield and quality, improve the resistance against other pathogens, such as the fungal pathogen Monilochaetes infuscans and Ceratocystis fimbriata and the nematode Pratylenchus coffeae. In China, the area of virus-free sweetpotato production reached 70,000 ha in 1994, 90,000 ha in 1995 and 466,000 ha in 1998. The problems and prospects on virus-free sweetpotato cultivation in China are also discussed in this paper.