Abstract
Pinot noir grapevines grafted to five rootstocks (Vitis vinifera) and a self-rooted control known to vary in resistance to ring nematode (Mesocriconema xenoplax) were studied over four years to 1) evaluate durability of resistance to ring nematode, and 2) better understand how ring nematode parasitism affects below and above ground vine growth and physiology. Ring nematode populations in infested microplots of all three susceptible vines (self-rooted, 3309C, 1103P) increased rapidly during the second year and remained high throughout the study, while nematodes increased in two of the previously resistant rootstocks (110R, 101–14) during the third year. Only 420A remained resistant through the entire four year period. The impact of ring nematode parasitism on vines was most apparent in the susceptible rootstocks and self-rooted vines with reductions in fine root growth and colonization by arbuscular mycorrhizal fungi (AMF) occurring as early as the second year. Reductions in both fine root production and AMF colonization due to ring nematode were greater in subsequent years in the susceptible vines. The frequency of fine roots containing vesicles of AMF was reduced in all five rootstocks that supported a population increase of ring nematode (only 420A was unaffected). Ring nematode did not alter above ground vine performance until the third or fourth growing season, when shoot lengths and pruning weights were reduced in the three susceptible vines. Ring nematode did not alter shoot growth in any of the three resistant rootstocks, nor did it affect leaf gas exchange or leaf water potential in any vines in any year. However, by year four ring nematode reduced fruit yield as a main effect across all rootstock treatments.
Sign in for ASEV members
ASEV Members, please sign in at ASEV to access the journal online.
Sign in for Institutional and Non-member Subscribers
Log in using your username and password
Pay Per Article - You may access this article (from the computer you are currently using) for 2 day for US$10.00
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.