Distribution Of SMV Strains And Resistance Resources Mining And Genetic Analysis Of Resistance In Soybean

Soybean mosaic virus (SMV) disease is a worldwide soybean disease in soybeanproduction region. It causes yield loss and seed quality deficiency seriously. Atpresent, there has been no effective chemical control method, screening and breedingresistant cultivars is the most efficient method to control the damage. Virus variationis the important reason of emerging new virus, change of host range and pathogenicityvariation. Keeping abreast of the new virus information, determining the pathogenicof viruses plays important roles in the prevention and control of pandemic virus. Onthe base of determining popular SMV strains in the region, screening for identifyingsoybean resistance source to prevalence strains is the basis for the resistance breeding,using the excellent resistance materials to conduct genetics analysis and allelismresearch will helpful to molecular marker assisted selection in breeding. In this study,we collected virus samples from the central and south of Hebei province andsystematic studied composition and distribution of the SMV strains in Hebei province.Following, four prevalence SMV strains and mixed strain were used to evaluate thesoybean cultivars (accession) SMV resistances. Evaluation of166soybean cultivars(accession), which were widely cultivated and recent bred in the north ofHuang-Huai-Hai area, was conducted. And other39wild type soybeans and150introducing soybean accessions were also evaluated using two prevalent strains SC3and SC7for broadening the genetic basis of resistance. Crosses were made betweenresistance and susceptible (resistance) materials to determine the genetic mechanismsand alleles of the resistance genes lay a foundation for molecular assisted breeding.The main results were as following:(1)Total180virus samples were collected from south and central of Hebeiprovince. Finally,35virus isolates were obtained from biological purification andidentified to be SMV isolates. Base on the differential host responses to these isolates,these SMV isolates were classified into8strains, SC1, SC3, SC6, SC7, SC7, SC8,SC11and a undetermined groups, respectively. The SC7is the prevalent strains, SC6,SC8and SC18strains are advantage strain.In addition, the strains SC1, SC3and SC18which are undetected before, were also detected in this study.(2)The resistances to soybean mosaic virus (SMV) of166soybean cultivars mostof which were bred from northern Huang-Huai-Hai. Four prevalence SMV strains andmixed strain were used to evaluate the soybean cultivars (accession) SMV resistances.Our results showed that82cultivars (49.4%) were resistant（MR, HR and SY）to thefour strains. In these82soybean cultivars (accession), thirty-two (19.3%) showed HRor SY to three strains and23(13.9%) showed SY to all four strains. After inoculatedwith mixed stain, one hundred and eight (65.1%) cultivars (accession) showed MR,HR and SY. In these108soybean cultivars, forty-five (27.1%) and29(17.5%)showed SY and HR, respectively. In the166soybean cultivars (accession), sixty-two(37.3%) cultivars (accession) showed resistant (MR, HR and SY) to the four strainsand the mixed strain and14(8.4%) cultivars (accession) showed HR and SY. Jidou9and Shidou6were immune to all strains and can be used as resistance resources inbreeding programs.(3)The resistances to soybean mosaic virus (SMV) of39wild soybeanaccessions which were collected from Hebei province. Two prevalence SMV strainsSC3and SC7were used to evaluate the soybean cultivars SMV resistances. One(2.6%) cultivars showed MR to SC3, seventeen (43.6%) cultivars showed MS, eleven(28.2%) cultivars showed S, ten (25.6%) cultivars showed HS. One (2.6%) cultivarsshowed HR to SC7, two (5.1%) cultivars showed MR; fourteen (35.9%) cultivarsshowed MS, eleven (28.2%) cultivars showed S, eleven (28.2%) cultivars showed HS.The average disease index was57.3and58.2after infection, respectively. The HR andMR cultivars can be used resistance resources in breeding programs.(4) The resistances to soybean mosaic virus (SMV) of150introduction soybeanaccession. Two prevalence SMV strains SC3and SC7were used to evaluate thesoybean cultivars SMV resistances. Eight cultivars showed SY to SC3, eighteencultivars showed SY to SC7. PI555396, PI591506, PI633970, R07-2001showed SYto the two strains. Sixteen (10.7%) cultivars showed HR to SC3, seventeen (11.7%)showed HR to SC7. The SY and HR cultivars can be used as good parent materialsapplied in the breeding programs.(5) Resistant (R) cultivars were crossed respectively with susceptible (S) andresistant (R) cultivars to determine resistance to SC7, Jidou12、Jidou17and Newtonall showed resistant, Franklin and10Y105all showed susceptible. The cross Jidou12×Franklin and Jidou17×10Y105the F2population exhibited a segregation patternof3R:1S. The test of the allelism of the resistance genes to SC7showed that Jidou12×Newton F2population exhibited resistant, Jidou17×Newton F2populationexhibited a segregation pattern of15R:1S. The result suggested that Jidou12andJidou17carried a dominant resistant gene for SMV strains SC7, respectively. The results suggested that the resistance genes between Jidou12and Newton were at thesame locus. Jidou17and Newton were not at the same locus.