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Spatio-temporal characterization of changes in the resistance of widely grown soybean cultivars to Soybean mosaic virus across a century of breeding in China
Soybean mosaic virus (SMV) causes significant yield losses and seed-quality deterioration in the soybean-growing areas of China and breeding disease-resistant cultivars is the most common approach for controlling the spread of the disease and the destruction of soybean crop. In the present study, 97 widely grown soybean cultivars, representing nine decades (1923–2006) of breeding, from the four main soybean-producing sub-regions in China, i.e., Northern Heilongjiang (NH), Mid-Southern Heilongjiang (MSH), Jilin-Liaoning (JL), and the Yellow-Huai-Hai Rivers Valley (YHH), were inoculated with six prevalent SMV strains: SC3, SC7, SC8, SC11, SC15, and SC18. The average disease index (ADI) values of the six SMV strains ranged from 26.95 to 48.97, and the numbers (percentages) of resistant and susceptible cultivars to the six SMV strains ranged from 27 (27.8%) to 64 (66.0%) and 33 (34.0%) to 70 (72.2%), respectively. The ADIs of cultivars from NH, MSH, JL, and YHH were 50.82, 47.27, 43.10, and 33.05, respectively. Soybean cultivars released in the 1940s and 1960s had the highest (53.95) and lowest (32.03) ADI values, respectively. In the regions of NH and JL, all disease index (DI) values exhibited the descendant tendency, but no descendant tendency in DI values was observed in MSH. In YHH, DI values for SC3 and SC18 displayed apparent ascendant tendency, and an obvious descendant tendency in DI values was observed for SC15. Twenty-four soybean cultivars were identified to have broad-spectrum resistance with ADI values ranging from 0.80 to 35.52 for the six SMV strains, and a total of 13 soybean cultivars were identified to be highly resistant to at least one SMV strain. The findings of this study will positively contribute to monitoring the pattern of spatio-temporal variation in SMV resistance in different soybean-producing areas of China and facilitates conventional and molecular breeding programs to breed for SMV resistance in soybean.
CP17296 Accepted 11 January 2018
© CSIRO 2018