Studies On Diapause And MtDNACO Ⅰ Sequence Of The Hybrids Between Diffent Geographic Populayion Of Ostrinia Furnacalis (Guenée)

The Asian corn borer, Ostrinia furnacalis (Guenée)(Lepidoptera: Crambidae）is aserious pest of agriculture and widely distributed from south to north in China. Thiswidely-distributed species encounters a great diversity of environmental conditions indifferent localities, and exhibits considerable diversity in life history between separategeographical populations. Populations show clear differences in voltinism, criticalday-lengths, postdiapause emergence time and cold hardiness. In this study, differentgeographic populations were crossed, and the responses to photoperiod and geneticcharacteristic of mtDNACOⅠwere observed. The results are as follows:1、Geographic variation and inheritance of photoperiodic response controlling larvaldiapause in two distinct voltine ecotypes of Ostrinia furnacalisThe Asian corn borer Ostrinia furnacalis enters facultative diapause as fully-grownlarvae in response to short day lengths during autumn. As a result of geographicalvariations in photoperiodic response, the moths from Nanchang (28.8°N,115.9°E; NCstrain) judge both LD14:10h and LD15:9h photocycles as long days and developdirectly, whereas moths from Haerbin (44.9°N,127.2°E; HB strain) judge the samephotocycles as short days and enter diapause. Crosses between the two strains are used toevaluate the inheritance of diapause. The critical day lengths for diapause induction in theHB strain are significantly longer than those in the NC strain at22,25and28°C. Thecritical day length of F1progeny is intermediate between the two strains. However, thecritical day length in all crosses is significantly longer with HB strain fathers orgrandfathers than with NC strain fathers or grandfathers, indicating that the male parenthas significantly more influence on the critical day length of subsequent progeny than thefemale. The results from all crosses under LD14:10h or LD15:9h photocycles at25°Cshow that the inheritance of diapause in O. furnacalis does not fit a purely additivehypothesis and that the capacity for diapause is transmitted genetically in the manner ofincomplete dominance. The incidence of diapause for F1progeny under an LD14:10hphotocycle is significantly higher than that under an LD15:9h photocycle, suggestingthat the induction of diapause can be influenced by interactions between the F1genotypeand photoperiod.2、Studies on diapause of the hybrids between Sanya population and different geographicpopulation of Ostrinia furnacalisThe photoperiodic responses for diapause induction in crosses between Sanya anddifferent geographic populations are investigated at22,25and28°C. The photoperiodicresponse curves show a typical long day response in crosses. The critical daylength in F1progeny of SY×GZ、SY×NC、SY×TA、SY×LF、SY×HB increased with latitude of strain fathers, suggesting a positive relationship between the critical daylength and latitude. Thecritical daylengths in F1progeny with GZ、NC、TA、LF、HB strain father are significantlylonger than those in F1progeny with SY strain fathers, indicating that the male parent hassignificantly more influence on the critical daylength of subsequent progeny than thefemale.3、Variation of mtDNA COⅠsequences in different geographic populations of the Asiancorn borer, Ostrinia furnacalisThe mitochondrial DNA (mtDNA) cytochrome oxidase subunitⅠ(COⅠ) of6geographical populations of O. furnacalis are sequenced. The identity and variation of theresultant sequences and their phylogenic relationships are established by Mega5. Theresults show that there are some differences in COⅠ sequences among differentgeographical populations of O. furnacalis and that the average evolutionary divergencebetween populations is0.012. Molecular phylogeny shows that the Sanyan, Guangzhouand Nanchang populations form one branch, and the Taian, Haerbin and Langfangpopulations form separate branches. The results of evolutionary divergence and molecularphylogeny suggest that the separation of different geographical populations of O.furnacalis is, at least to some extent, relative to geographic distance.4、Genetic variation of mtDNA COⅠsequences between NC population, HB populationand therir hybrid strains of the Asian corn borer, Ostrinia furnacalismtDNA COⅠsequences between NC and HB populations and therir hybrid strains ofOstrinia furnacalis are sequenced. The identity and variation of the resultant sequencesand their phylogenic relationships are established by Mega5. The results show that thereare11Nucleotide mutation sites in COⅠ sequences among four strains of O. furnacalis.There are no significant genetic differentiation in the evolutionary divergence betweenstrains that the genetic distance changes in0.003-0.006. The results indicate that the twohybrids don’t follow the maternal inheritance in mitochondrial COⅠ genes.5、 Genetic variation of mtDNA COⅠsequences between SY population, differentgeographic population and therir hybrid strains of the Asian corn borer, Ostrinia furnacalismtDNA COⅠsequences between NC and HB populations and therir hybrid strains ofOstrinia furnacalis are sequenced. The identity and variation of the resultant sequencesand their phylogenic relationships are established by Mega5. The results show that thereare16Nucleotide mutation sites in COⅠ sequences among13strains of O. furnacalis.There are no significant genetic differentiation in the evolutionary divergence betweenstrains that the genetic distance changes in0.001-0.007. The results indicate that the twohybrids don’t follow the maternal inheritance in mitochondrial COⅠ genes.