Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 7, 2002
Publication Date: November 1, 2002
Citation: BECKMAN, T.G., OKIE, W.R., NYCZEPIR, A.P. INFLUENCE OF SCION AND ROOTSTOCK ON INCIDENCE OF PEACH TREE SHORT LIFE. ACTA HORTICULTURAE. 2002. v.592(2). p.645-648. Interpretive Summary: Peach tree short life (PTSL) is the primary cause of premature tree mortality in the SE U.S. A number of management practices are known to mitigate incidence of PTSL; chief among these is rootstock selection. Preliminary work suggests that the scion variety itself may be comparable to rootstock in its influence on incidence of PTSL. If scion influence is consistent across a range of rootstocks, this would offer a new tool to growers for managing PTSL, i.e., growers could minimize losses on PTSL prone sites by using those scion/rootstock combinations most resistant to PTSL. In this trial 5 different scion varieties and 4 different peach seedling rootstocks were budded in all combinations (20 total) in order to determine the relative scion and rootstock influence on incidence of PTSL. After 7 years, 31% of the test trees had succumbed to PTSL and 18% to other causes. Although there were profound scion and rootstock effects on incidence of PTSL, there was a significant scion x rootstock interaction caused by anomalous performance of several scion/rootstock combinations. If this interaction is verified, then it may not be possible to reliably predict the relative influence of a given scion variety by testing it on a single rootstock. Instead researchers may have to perform these tests on the rootstock(s) most likely to be used on a PTSL site, i.e., Lovell or Guardian (BY520-9). These results indicate that researchers should use considerable caution in extrapolating the results of a typical rootstock trial to their expected performance beneath a range of untested scion varieties.
Technical Abstract: Previous work has suggested that peach scion cultivar exerts a significant influence on incidence of peach tree short life (PTSL) in trees budded onto Nemaguard and Flordaguard seedling peach rootstocks. If this influence is consistent across a range of rootstocks, then the influence of scion cultivar might offer a new tool for the management of PTSL. Growers could minimize losses on those sites most prone to PTSL by using the least susceptible scion/rootstock combinations. In this trial trees of 'Agua 6-4', 'Springcrest', 'Redglobe', 'Redhaven' and 'Cresthaven' budded onto Guardian (BY520-9), Lovell, Nemaguard and Siberian C peach seedling rootstocks were planted on a site with a known history of PTSL. After 7 years, 31% of test trees had succumbed to PTSL and 18% to other causes. Both scion and rootstock exerted a profound influence on incidence of PTSL (P<0.0001). Main effects of scion cultivar ranged from 10 to 49% PTSL mortality. Main effects of rootstock treatment ranged from 10 to 85% PTSL mortality. However, a significant scion x rootstock interaction was also present (P<0.05). This appeared to be largely the result of anomalously low or high PTSL incidence observed in 2 scion/rootstock combinations. These results suggest that some caution should be used in extrapolating the rootstock treatment effects determined in a typical PTSL trial budded with a single scion cultivar to their influence beneath other untested scion cultivars.