Reproductive Mode And Molecular Detection Of RhPV Of Rhopalosiphum Padi(Hemiptera: Aphididae) Populations From Different Regions Of China

The bird cherry-oat aphid, Rhopalosiphum padi (L.)(Hemiptera: Aphididae), is one of themost economically important insect pests on wheat, Triticum aestivum L.(Poaceae). It cancause direct damage by sap sucking, and transmit a serious virus (barley yellow dwarf virus,BYDV) that damge wheat. Currently, R. padi has become the dominant insect pest in manywheat-growing regions of China.In this study, individuals of Rhopalosiphurn padi were collected from eight provincesthroughout China in2012and2013. Fifiteen individuals from each region were transferred towheat seedlings in the laboratory to establish clonal lines, and the clones were induced by lowtemperature (12℃) and short photoperiod (L:D=8h:16h) conditions to investigate thereproduction mode. We used a gene sequence to investigate the infection of R. padi virus(RhPV) in R. padi populations from different regions, the main results and conclusions are asfollows:The reproductive mode of R. padi from all regions was the same in the two years exceptthe clones from Taian. Among the six generations, only alate and apterous parthenogenticfemales were produced in the clones collected from Nanyang, Beibei, Wuhan and Xianyang in2012and2013, and in the clones from Taian and Chuzhou in2013, and the reproductionmode of these clones was obligate parthenogenesis. The reproductive mode of the clonescollected in Lanzhou was mixture of cyclical parthenogenesis and obligate parthenogenesis.The reproductive mode of the clones collected in Hami was cyclical parthenogenesis. Theclones were collected in Taian in2012were a mixture population of obligate parthenogenesisand obligate parthenogenesis with male production. There were different reproduction modesof R. padi sampled in China.Among the six continous generations, gynoparae produced firstly in the secondgeneration, the ratio reached peak in the third generation, and the proportion of gynoparaedeclined since the fourth generation. A few clones produced males firstly in the secondgeneration, but most males were produced in the third and the fourth generations for all theclones. Oviparae was firstly found in the third generation, then increased till it reached the peak in the fifth generation. Meanwhile, sex ratio variation among the clones and thegenerations differed significantly.In anholocyclic clones, the percentage of winged parthenogenetic female wassignificantly different in different region, whereas the percentage of winged parthenogeneticfemale was not significantly different in a same region. The percentage of wingedparthenogenetic female among different generations was significantly different. No significantdifference was found between clones from the two years.The RhPV was detected in all populations of R. padi. The infection rates are between66.7and100%. The RhPV gene sequences used were conservative in aphid indivuduls fromdifferent regions, with only two different sequences obtained (GenBank accession number:KJ135026and KJ135027). RhPV widespreadly distributes in R. padi populations analyzed.The infection rates ranged from66.7to100%in anholocyclic clones, and it was75%inholocyclic clones and100%in clones whose reproductive mode was the mixture of cyclicalparthenogenesis and obligate parthenogenesis, indicating no correlation between the RhPVinfection and the reproductive mode of R. padi.