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Influence of retained node number on S auvignon B lanc grapevine phenology in a cool climate
Author(s) -
Greven M.M.,
Neal S.M.,
Hall A.J.,
Bennett J.S.
Publication year - 2015
Publication title -
australian journal of grape and wine research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.65
H-Index - 77
eISSN - 1755-0238
pISSN - 1322-7130
DOI - 10.1111/ajgw.12122
Subject(s) - veraison , ripening , ripeness , phenology , vine , horticulture , berry , crop , agronomy , biology
Background and Aims In M arlborough's cool climate, slow ripening grapes often do not reach ripeness. This study determined the effect of crop load, achieved via different levels of retained node number, on S auvignon B lanc phenology and ripening. Methods and Results Two to six canes, each single cane unit having 12 nodes, were laid down and from these vines phenological development was recorded and growth curves were calculated for budburst, flowering, veraison and ripening over 4 years, from 2007 to 2010. The different crop loads, obtained through these pruning treatments, had little influence on vine phenology until after veraison when the retained node number had a significant influence on the rate of accumulation of total soluble solids during the ripening period. Target ripeness was delayed by up to 41 days when 72 nodes were retained, compared with 24 nodes. Simple modelling with generalised logistic functions accurately described phenological changes in the plant and improved the reliability of statistical comparison of time courses between the different treatments. Conclusion For all 4 years of the study, differences in retained nodes per vine had little influence on the phenology of the vine up to veraison, but had a strong effect on the rate of ripening because of subsequent differences in crop load. After the first year of the trial, the influence of the retained nodes on yield gradually diminished and as a consequence so did the influence on the rate of ripening. Significance of the Study A clear demonstration of the strong influence of crop load on the rate of ripening of M arlborough S auvignon B lanc, together with the capacity of the vines to adjust their source/sink balance over time, with the direction of the adjustment determined by the node number.