Sectorial resistance of plum to sharka (Plum Pox Virus)

Abstract

A special resistance to sharka (Plum Pox Virus, PPV) has been discovered and studied in plum trees. That resistance is characterized by the absence of sharka symptoms and PPV, too, in some of primary branches of plum trees otherwise diseased by sharka. Symptoms appearance was observed and PPV presence was checked serologically by DAS-ELISA test as well as by grafting transmission. That resistance mainly appears in a portion of the tree crown, i.e. on some primary branches of young plum trees and it is diminishing in following years. That distinct resistance to sharka (PPV) was found in trees of Čačanska rodna, Stanley and Crvena ranka cvs. In selected plum trees in the parts with such resistance no sharka symptoms appeared nor PPV was proved. The absence of sharka symptoms as well as PPV in a portion of a plum tree otherwise diseased by sharka is considered as a sign of resistance. For such resistance the name 'Sectorial Resistance' is proposed. More and detail research on sectorial resistance of plum to PPV are in progress.

Otkrivena je i istraživana jedna posebna otpornost šljive na virus šarke šljive (VŠŠ, Plum pox virus - PPV) za koju se predlaže naziv 'sektorijalna otpornost'. Ta otpornost se ispoljava u delu krune, odnosno na pojedinim skeletnim granama obolelih stabala. U tom delu krune, odnosno na skeletnim granama koje pokazuju sektorijalnu otpornost nema simptoma oboljenja, niti je prisutan VŠŠ. Odsustvo VŠŠ proveravano je serološki DAS-ELISA testom i kalemljenjem. Sektorijalna otpornost je nađena kod stabala Čačanska rodna, Stenley-a i Crvene ranke. Sektorijalna otpornost šljive na VŠŠ je u negativnoj korelaciji sa starošću stabala na kojima se javlja. Broj skeletnih grana sa sektorijalnom otpornošću kod obolelih stabala se smanjuje iz godine u godinu, a povećava broj skeletnih grana sa simptomima oboljenja. U toku su dalja i svestranija proučavanja te novootkrivene otpornosti šljive prema VŠŠ.