if (piplus[ipiplus]->GetMcTruth()){
 RhoCandidate* motherId = piplus[ipiplus]->GetMcTruth()->TheMother();
 if(motherId && motherId->PdgCode()==88888) { ... }
}

#0  0x00007fa22815844e in waitpid () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007fa2280de29e in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#2  0x00007fa229031407 in TUnixSystem::StackTrace() () from /home/panda/fairsoft/sep12build/lib/root/libCore.so.5.34
#3  0x00007fa229033ce3 in TUnixSystem::DispatchSignals(ESignals) () from /home/panda/fairsoft/sep12build/lib/root/libCore.so.5.34
#4  <signal handler called>
#5  0x00007fa215bb0a60 in RhoCandidate::TheMother (this=0x8011) at /home/panda/pandaroot/trunk/rho/RhoBase/RhoCandidate.h:267
#6  0x00007fa215b5c808 in G__G__RhoDict_321_0_68 (result7=0x176e9a0, funcname=0x281 <Address 0x281 out of bounds>, libp=0x7fff6c89f730, hash=-85) at /home/panda/pandaroot/trunkbuild/rho/G__RhoDict.cxx:7519
#7  0x00007fa22730d9ab in Cint::G__ExceptionWrapper(int (*)(G__value*, char const*, G__param*, int), G__value*, char*, G__param*, int) () from /home/panda/fairsoft/sep12build/lib/root/libCint.so.5.34
#8  0x00007fa2273202de in G__exec_asm () from /home/panda/fairsoft/sep12build/lib/root/libCint.so.5.34
#9  0x00007fa2273ec4ff in G__exec_loop(char const*, char*, std::list<G__FastAllocString, std::allocator<G__FastAllocString> > const&) [clone .constprop.69] () from /home/panda/fairsoft/sep12build/lib/root/libCint.so.5.34
#10
....