T.G. Beckman, W.R. Okie, A.P. Nyczepir, G.L. Reighard, E.I. Zehr, W.C. Newall
In some areas of the southeastern United States average peach tree life has dropped to less than 9 years. The primary cause of premature mortality is peach tree short life (PTSL), to which trees are predisposed by the ring nematode, Criconemella xenoplax. PTSL is responsible for more than $6 million in lifetime production losses annually in South Carolina alone. GuardianTM (BY520–9) peach rootstock was cooperatively released in 1993 by USDA-ARS and Clemson University researchers. Through 8 years on a severe PTSL site, Guardian has provided significantly better survival and productivity than Lovell, the currently recommended commercial rootstock for PTSL prone sites. Guardian also appears to have root-knot nematode resistance similar to Nemaguard. Guardian's pedigree traces back to a cross of Nemaguard and a seedling of S-37. This cross was part of a USDA program to develop root-knot nematode resistant rootstocks. Currently, Guardian (BY520–9) consists of bulked seed from a population of 69 siblings out of B594520–9. Testing is continuing on individual selections from this group. Guardian's unique combination of PTSL and root-knot nematode resistance makes it a candidate to replace both Lovell and Nemaguard rootstocks, currently the two most widely utilized rootstocks in the southeastern United States.
Beckman, T.G., Okie, W.R., Nyczepir, A.P., Reighard, G.L., Zehr, E.I. and Newall, W.C. (1997). HISTORY, CURRENT STATUS AND FUTURE POTENTIAL OF GUARDIANTM (BY520–9) PEACH ROOTSTOCK. Acta Hortic. 451, 251-258
DOI: 10.17660/ActaHortic.1997.451.27
Prunus persica, peach tree short life, PTSL, Criconemella xenoplax, Meloidogyne spp., Armillaria spp.

Acta Horticulturae