Investigating Incidence and Distribution of Alfalfa-Infecting Viruses in China

Abstract

Alfalfa is a primary forage crop in China that occupies a wide planting area and exhibits a variety of beneficial traits such as being nutrient rich and producing high yields. As the planting area continues to expand, alfalfa pests and pathogens are becoming more prolific, especially viral pathogens which negatively impact alfalfa quality and yield significantly. From 2016 to 2019, 516 alfalfa samples exhibiting potential symptoms of viral infection were collected from several major production regions in China, including 13 provinces and 21 collection sites. RT-PCR using special conserved primers designed to detect several common alfalfa-infecting viruses was used to determine the incidence and distribution of these viruses throughout China. AMV, TMV, ToMV, CPMV, BYMV, CMV, YMV, and SMV were detected in alfalfa crops throughout China, with AMV being most prevalent with an incidence rate of 57.6%, while this is the first time that CMV and TMV have been found infecting alfalfa crops in China. This is also the first investigation of the distribution of various alfalfa viruses throughout China, providing theoretical and technical support for early warning and control of viral disease of alfalfa in China.