Resistance of different cassava varieties to Tetranychus Cinnabarinus

ObjectiveResistance of different cassava varieties to Tetranychus cinnabarinus was studied to provide reference for promoting cassava varieties with fine comprehensive traits,high yield and strong mite resistance.MethodSix cassava varieties(XX048,SC205,SC8,GR4,D346 and F50)were taken as the materials.The damage degrees of different cassava varieties at the first T.cinnabarinus hazard peak were investigated and their mite resistances were also de-tected.Nutrient components in leaves of different cassava varieties and their leaf morphological characters were determi-nated,and the relations between each index and mite damage degree were analyzed to investigate resistance mechanism of cassava to T.cinnabarinus.During the harvest stage,yields and related traits of six cassava varieties to select the ones with fine comprehensive traits,high yield and strong mite resistance.ResultResults of the trial indicated that XX048, D346 and F50 were moderate resistant(MR)varieties with mite resistance index being 56.11%-61.41%,SC8,SC205 and GR4 were susceptible(S)varieties with mite resistance index being 74.26%-84.07%.Mite damage indexes had significant positive correlation(P<0.05)with soluble sugar content,protein content,proline content,soluble,water content and leaf thickness.Besides,the indexes had extremely significant positive correlation with free amino acids content(P<0.01).But the relations between mites damage indexes and SPAD,wax content,length of the biggest lobed leaf and width of the big-gest lobed leaf were not significant(P>0.05,the same below).Mite damage indexes had negative correlation with yield and related traits,but the correlation was not significant.ConclusionAmong the six varieties,XX048 has the strongest mite resistance,its yield related traits are fine,and the yield is the highest among them all.Therefore,it can be promoted in planting areas where T.cinnabarinus hazards occur frequently.Soluble sugar,soluble protein,proline,water content,free amino acids and leaf thickness can be used as important identification index for the resistance of cassava to T.cinnabarinus.