Identification,Resistance Mechanisms And Core Collection Of Resistant Rice Germplasms Against Whitebacked Planthopper

In this thesis, the main research work was focused on the following aspects:resistance of rice germplasms against whitebacked planthopper (WBPH) were screened;The hierachical cluster analysis was applied as the method to establish core collection ofrice varieties resistance to WBPH; The resistant mechanisms of rice varieties againstWBPH were studied; The principal component analysis and the step-wise multiplelinear regression analysis were applied as the methods to analyse main resistantsecondary compounds which associated with resistance of rice varieties to WBPH. Themain results were as follows:1. Resistance of rice resources introduced from INGER against WBPH wereevaluated. The results showed that of 520 rice varieties(lines), 2 of these belonged tohighly resistance, 33 of these belonged to resistant, and 83 of these belonged tomoderately resistant, the proportion of them was 0.38%, 6.35% and 15.96%respectively.2. "Core collection"conception and method was used firstly to establish corecollection of rice varieties resistant against WBPH. The results showed that corecollection was composed of 12 accessions. Representational tests showed that corecollection covered genetic diversity of the whole collection by comparison of valuesincluding characteristic value, mean coincidence rate, standard deviation coincidencerate and index of diversity of 10 main agronomic traits.3. The results showed that WBPH was tended towards oviposit and feed onsusceptible rice varieties. Compared with TN1, WBPH reared on resistant varieties hadlong nymphal development duration and adult preoviposition period, short longevity, high mortality and low fecundity. Therefore, the population growth of WBPH on theresistant rice varieties was suppressed significantly.4. All rice varieties included 13 resistant secondary compounds(X1-X13) whetherthe varieties were resistant to WBPH or not. The results of principal component analysisand step-wise multiple linear regression analysis demonstrated that X3,X5,X6,X8,X11 and X12 were main resistant secondary compounds of rice varieties resistantagainst WBPH. The resistant activity in rice varieties was not the action of onecompound but the action of several compound. The contribution of each compound toresistance was different.There were significantly negative relationships between thecontents of X3,X6,X8,X12 and resistant grades of rice varieties.This meantX3,X6,X8,X12 were main resistant secondary compounds.