| Soybean Fusarium root rot is one of the main diseases of soybean [Glycine Max(L.)Merr.],and become increasingly serious in China.Using resistant varieties in agricultural production is one of the most economical and effective approach of controlling this disease.However,soybean Fusarium root rot is a complex disease affected by a variety of factors,it is not enough to exploit and utilize the resistant genetic resources of soybean.In this study,200 soybean inbred lines derived from Nandou12(high resistance)× Jiuyuehuang(midium sensitive)were used to evaluate the resistance by artificial inoculation of Fusarium oxysporum,and the traits of seedling were estimated between the uninoculation(CK)and the inoculated Fusarium oxysporum(FO),and the QTLs of all traits were analysis using the previous genetic map.The main results were as follows:1.Disease index(DI)and disease ratio index(DRI)showed very significant difference among 200 soybean inbred lines.The mean of DI was 49.18 and the coefficient of variation(CV)was 34.22% in the population.The DI of the 25 lines(0~29.9)showed high resistance,and 76 inbred lines(30~49.9)showed medium resistance.DI of 10 lines was less than that of Nandou 12(19.29),and 25 lines were more than their parents Jiuyuehuang(65.48).The mean value of disease ratio indexes(DRI)was 1.98 and the CV was 33.93% in 200 recombinated inbred lines population.A total of 86(43%)inbred lines were at the 1-2 level of DRI,and 79(39.5%)of the inbred lines are in the 2-3 level,and most of lines belong to the intermediate type.2.High significant difference between genotypes and between treatments was observed.The CVs of all traits under the inoculation condition was higher than those under the control condition,suggested ithat the inoculation of F.oxysporum affected strongly and significantly the performance of the traits.Effective value of inoculation(EVI)showed that F.oxysporum could make a 39.80% drop in root fresh weight,30.05% drop in shoot fresh weight,and 10.79% drop in root shoot ratio,and 21.29% drop in plant height,47.39% drop in total root length,40.34% drop in total root surface area,10.21% drop in root diameter,38.04% drop in total root volume and 41.84% drop in root tip number.The decrease of the negative influence of the pathogen on all traits was between 10%~ 50%,and the decrease of total root length,total root surface area and root tip number was the most obvious.3.Simple correlation analysis of 20 traits showed that 81 pairs of traits had remarkable significant correlation,and 12 pairs had significant correlation.In control condition,disease index(DI)was remarkable significantly positive correlation with root fresh weight,and significantly correlation with root shoot ratio.In inoculation condition of F.oxysporum,disease index(DI)were very significant negative correlation with root fresh weight,shoot fresh weight,the root shoot ratio,total root length,total root surface area,and total root volume,suggested that higher fresh root and root shoot ratio will lead to higher disease index.4.Using the high density genetic map,a total of 10 QTLs on nine chromosomes were identified.Under the control(CK)condition,were d five QTLs were detected,and could explained the phenotypic variation from 4.34% to 12.85%;After inoculating F.oxysporum,five QTLs were detected and could explained the phenotypic variation from 2.71% to 11.91%.Among them,qSFWC-Ch3-2,qRADC-Ch4 and qTRLF-Ch20 showed more than 10% of phenotype contribution,and were considered as the major QTLs.Bioinformation analysis further identified 88 and 8candidate genes in qSFWC-Ch3-2 and qRADC-Ch4 regions,and two genes in qRADC-Ch4 locus encoded the proteins with LOB domain,could related the development of organs. |
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