ARS | Publication request: Cold temperature tolerance of apple rootstock trunk and root tissues

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 26, 2011
Publication Date: August 25, 2011
Citation: Moran, R., Zhang, D., Geng, F., Sun, Y., Fazio, G. 2011. Cold temperature tolerance of apple rootstock trunk and root tissues. HortScience. 46:1460-1464.

Interpretive Summary: Cold hardy apple rootstocks are an essential component for survival and productivity of trees in orchards planted in regions that can be subject to severe cold stress. The series of experiments described in this manuscript test the cold hardiness properties of several recently released rootstocks and compare it to well established controls. Apple rootstock G.935 appears to be the most cold hardy of the group tested, performing much better than the cold hardy control M.26. Apple rootstock G.41 seems to be just as cold hardy as M.26 depending on experiments and quality of the material.

Technical Abstract: G.11, G.30, G.41, P.2 and B.9 apple (Malus xdomestica) rootstocks have root tissue hardiness similar to M.26, but G.935 has greater hardiness than M.26 when based on shoot regrowth in ungrafted trees. The LT50 of M.26 and P.2 roots ranged from -12 to -14 degrees C. The LT50 of B.9 was -13 degrees C, -13.4 to -14.6 degrees C for G.30 and was -12 degrees C for G.11. The LT50 of G.41 was one of the highest in one experiment, -8 degrees C and one of the lowest in another, below -15.0 degrees C. The LT50 of G.935 roots was the lowest and ranged from -16 to -19 degrees C. Compared to M.26, trunk cold hardiness in December was greater in B.9 and P.2, slightly greater in G.11 and similar in G.30. In October, M.26 and G.935 trunks had little injury after exposure to -24 degrees C.